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Chlorine Inactivation of Highly Pathogenic Avian Influenza Virus (H5N1)
Abstract
To determine resistance of highly pathogenic avian infl uenza (H5N1) virus to chlorination, we exposed allantoic fl uid containing 2 virus strains to chlorinated buffer at pH 7 and 8, at 5°C. Free chlorine concentrations typically used in drinking water treatment are sufficient to inactivate the virus by>3 orders of magnitude. Growing concerns about the public health threat posed by highly pathogenic avian influenza (HPAI) subtype H5N1 has prompted interest in evaluating environmental control measures for this virus. The World Health Organization has noted that more information is needed on the effectiveness of inactivation of subtype H5N1 in water (1). Since 2002, HPAI (H5N1) has been reportedly isolated from>50 different wild avian species, mainly aquatic birds in the order Anseriformes (2). Experimentally infected waterfowl
... The inactivation/disinfection practices currently used are effective against non-enveloped viruses will also be effective for enveloped viruses also [99]. Enveloped viruses are more susceptible to oxidants than non-enveloped viruses [12,158,227]. Chemical-based disinfectants damage viral capsid, where UV irradiation affects nucleic acid [159]. Direct oxidation of reactive radicals damages the viral envelope manifesting the functional loss of the receptors [154]. ...
... Phi6 peptides contain a relatively large number of solvent-accessible Met and Cys residues which are responsible for rapid inactivation with FC [158]. UV 254 photolysis kinetics of four model viral genomes (ssRNA, dsRNA, ssDNA, and dsDNA) showed high resistance of dsRNA [227]. UV and free chlorine applications cause protein backbone cleavage in MS2 in part inactivate the virus by inhibiting the genome injection function [142]. ...
The unprecedented global spread of the severe acute respiratory syndrome caused by SARS-CoV-2 is depicting the distressing pandemic consequence on human health, the economy as well as ecosystem services. So far novel coronavirus (CoV) outbreaks were associated with SARS-CoV-2 (2019), middle east respiratory syndrome coronavirus (MERS-CoV, 2012), and SARS-CoV-1 (2003) events. CoV relates to the enveloped family of Betacoronavirus (βCoV) with positive-sense single-stranded RNA (+ssRNA). Knowing well the persistence, transmission, and spread of SARS-CoV-2 through proximity, the fecal-oral route is now emerging as a major environmental concern to community transmission. The replication and persistence of CoV in the gastrointestinal (GI) tract and shedding through stools is indicating a potential transmission route to the environment settings. In spite of the evidence, based on fewer reports on SARS-CoV-2 occurrence and persistence in wastewater/sewage/water, the transmission of the infective virus to the community is yet to be established. In this realm, this communication attempted to review the possible influx route of the enteric enveloped viral transmission in the environmental settings with reference to its occurrence, persistence, detection, and inactivation based on the published literature so far. The possibilities of airborne transmission through enteric virus-laden aerosols, environmental factors that may influence the viral transmission, and disinfection methods (convention and emerging) as well as the inactivation mechanism with reference to the enveloped virus were reviewed. The need for wastewater epidemiology studies for surveillance as well as for early warning signal was elaborated. This communication will provide a basis to understand the SARS-CoV-2 as well as other viruses in the context of the environmental engineering perspective to design effective strategies to counter the enteric virus transmission and also serves as a working paper for researchers, policymakers and regulators.
... A common approach in many scientific fields is the use of vaporous hydrogen peroxide, which has been shown to be effective in surface inactivation of biological agents, such as Bacillus anthracis spores as well as the vegetative bacteria Brucella suis, Burkholderia pseudomallei, Francisella tularensis, and Yersinia pestis (Canter, 2005;Rogers et al., 2005;Rogers et al., 2009;Rogers et al., 2010). The inactivation of H5N1 has been demonstrated by using heat and aqueous chemical treatments (Rice et al., 2007;Thomas & Swayne, 2007;Wanaratana et al., 2010); however, such inactivation has not been demonstrated for surfaces contaminated with H5N1. Therefore, the purpose of this study was to evaluate the effect of drying and exposure to vaporous hydrogen peroxide on H5N1 viability. ...
... avian influenza viruses can persist in water, soil, feces, and non-porous surfaces for days, but can be inactivated by heat and chemical treatment (Rice et al., 2007;Thomas & Swayne, 2007;Wanaratana et al., 2010;Wood et al., 2010). To our knowledge, this is the first study demonstrating that the A/Vietnam/1203/2004 H5N1 strain inoculated onto three non-porous material surfaces exhibits reduced viability as a function of drying and is further inactivated when exposed to vaporous hydrogen peroxide within a large-scale chamber. ...
This study demonstrated the combined effect of drying and vaporous hydrogen peroxide exposure on inactivating highly pathogenic avian influenza (H5N1) on the non-porous materials glass, Hypalon® rubber glove, and stainless steel. Approximately 7.7 log10 TCID50 (median 50% tissue culture infectious dose)/mL of A/Vietnam/1203/2004 H5N1 in allantoic fluid was dried on coupons of each type of test surface and exposed to vaporous hydrogen peroxide fumigation within a ∼15 m3 chamber. A significant reduction in the total log10 TCID50 of H5N1 on all test materials was observed between the controls evaluated after a 1-hour drying time and unexposed controls evaluated after decontamination. The H5N1 exhibited a 2–3 log decrease in viability, and vaporous hydrogen peroxide further inactivated the virus to below detectable levels. In parallel Geobacillus stearothermophilus biological indicators exposed to vaporous hydrogen peroxide exhibited no growth after 1 and 7 days' incubation. This study provides information on the persistence in viability of H5N1 on non-porous surfaces that can be mitigated by vaporous hydrogen peroxide fumigation of a large chamber.
... Furthermore, they partition to wastewater solids just like non-enveloped viruses (Ye et al., 2016), and wastewater temperature is positively linked to their inactivation rates (Ye et al., 2016). In wastewater treatment processes, these viruses generally become susceptible to oxidant disinfectants (Rice et al., 2007;Ye et al., 2018) while the presence of an envelope appears to protect them from UVC light (Ye et al., 2016). ...
Despite recent global outbreaks of viral diseases caused by enveloped viruses including Coronaviruses, studies have mostly focused on non-enveloped viruses such as norovirus and enteroviruses, with scant knowledge on the presence of infective enveloped viruses in wastewater environments hampering response capabilities for managing outbreaks. However, recent evidence indicates a shift towards focusing on enveloped virus and how wastewater environments impact their fate and transport. The behaviour of SARS-CoV-2 in wastewater is reviewed, highlighting the potential risks of coronaviruses in wastewater, and their environmental fate and transport, providing insight into SARS-CoV-2 and the environment, particularly its behaviour in wastewater and associated potential risks. Research on environmental persistence and routes of transmission of novel pathogens is complicated by safety concerns of working with highly infectious viruses. This chapter provides insight into SARS-CoV-2 and the environment, particularly the persistence of its fragments and behaviour in water and wastewater, providing information on the potential risks.
... All the studies used buffered water or partially treated water with 1.9 mg/L TOC and 0.17 NTU [71]. The majority of chlorination experiments selected are performed under around 5 C [64,66,[70][71][72][75][76][77][78]. All viruses included are hypersensitive or high-sensitive to chlorination and can be inactivated within a CT value of 10 mg⋅min/L. ...
The COVID-19 pandemic draws much attention to virus inactivation since the SARS-CoV-2 was detected in miscellaneous environments and the wastewater can be a potential transmitting pathway. UV irradiation, ozonation and chlorination are widely used disinfection processes in water treatment. In this review, the mechanisms and applications of three disinfection processes are introduced, and their inactivation effects on virus as well as other microorganisms are compared and discussed. The resistance of viruses to UV irradiation is generally stronger than that of bacteria. 4-log inactivation of bacteria can be easily obtained within a UV dose of 10 mJ/cm². However, the doses to reach the same virus removal rate vary greatly from 10 to 140 mJ/cm². The coronaviruses have even stronger UV resistance. Comparatively, ozonation and chlorination are effective methods to inactivate viruses, and the CT values of 4-log removal for most viruses concerned are lower than 1 mg·min/L and 10 mg·min/L, respectively. Protozoa, fungal spores and bacterial spores are more resistant to disinfection. Temperature, pH, organic matters, turbidity and other parameters all have influences on the disinfection. With a 10 °C decrease in temperature, the CT value required for certain removal rates doubles. Generally low pH promotes disinfection and high pH is against it. In drinking water and wastewater treatment process, the resistance properties of microorganisms and other influence parameters should be taken into consideration when choosing disinfection technologies.
... Sanekata et al. (2010) suggested that the enveloped viruses (influenza virus, measles virus, human herpesvirus, canine distemper virus) experienced higher levels of inactivation than the nonenveloped viruses (human adenovirus, canine adenovirus, canine parvovirus, feline calicivirus) when being exposed to 1.0 mg L −1 ClO 2 . Other researchers also suggested that enveloped viruses were much easier to be inactivated by free chlorine than nonenveloped ones (Gallandat and Lantagne 2017; Rice et al. 2007;Ye et al. 2018). The explanation could be that the ClO 2 can react with proteins on the enveloped membrane, such as the spike glycoprotein, the damage of which results in the failure of attachment to the host cell and thus the unsuccessful cell invasion and infection (Casais et al. 2003;Li et al. 2003;Yang et al. 2004). ...
Chlorine dioxide (ClO2), an alternative disinfectant to chlorine, has been widely applied in water and wastewater disinfection. This paper aims at presenting an overview of the inactivation kinetics and mechanisms of ClO2 with viruses. The inactivation efficiencies vary greatly among different virus species. The inactivation rates for different serotypes within a family of viruses can differ by over 284%. Generally, to achieve a 4-log removal, the exposure doses, also being referred to as Ct values (mutiplying the concentration of ClO2 and contact time) vary in the range of 0.06–10 mg L−1 min. Inactivation kinetics of viruses show two phases: an initial rapid inactivation phase followed by a tailing phase. Inactivation rates of viruses increase as pH or temperature increases, but show different trends with increasing concentrations of dissolved organic matter (DOM). Both damages in viral proteins and in the 5′ noncoding region within the genome contribute to virus inactivation upon ClO2 disinfection.
... The frequency or intensity of cleaning may need to change based on the patient's level of hygiene and the degree of environmental contamination and for certain for infectious agents whose reservoir is the intestinal tract [71,30,72,73]. A summary of the substances used for disinfecting and cleaning is presented in Table 3 [74][75][76][77][78][79][80][81][82][83][84][85][86][87]. ...
Background:
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes serious acute respiratory diseases including pneumonia and bronchitis with approximately 2.3% fatality occurrence.
Main body:
This study argues the main concepts that need to be considered for the gradual reopening of dental offices include treatment planning approaches, fundamental elements needed to prevent transmission of SARS-CoV-2 virus in dental healthcare settings, personal protection equipment (PPE) for dental health care providers, environmental measures, adjunctive measures, and rapid point of care tests in dental offices.
Conclusion:
This article seeks to provide an overview of existing scientific evidence to suggest a guideline for reopening dental offices.
... 15,18 In water purification processes, they are generally more susceptible to oxidant disinfectants than nonenveloped viruses. 19,20 The presence of an envelope does not appear to impact virus susceptibility to ultraviolet C (UVC) light, 15 likely because UVC targets virus genomes and lipid membranes do not shield the genomes from UVC radiation. ...
... The abiotic and biotic components of water have their individual effect on survivability and persistence of the virus in the water, and the lake water in the natural environment has its own mechanism of purification of water like exposure to sunlight and oxidation which is not possible if the lake water is filled in the tank (Srivastava, Gupta, & Chandra, 2008). Some workers have reported the deleterious effect of chlorinated tap water on virus survivability (Rice et al., 2007). We, therefore, used non-chlorinated demineralized water for our study. ...
Low pathogenic avian influenza virus (LPAIV) exhibits an ecological climax with the aquatic ecosystem. The most widely prevalent subtype of LPAIV is H9N2. Wild aquatic birds being the natural reservoirs and ducks, the “Trojan horses” for Avian Influenza Virus (AIV), can contaminate the natural water bodies inhabited by them. The virus can persist in the contaminated water from days to years depending upon the environmental conditions. Various aquatic species other than ducks can promote the persistence and transmission of AIV; however, studies on the role of aquatic fauna in persistence and transmission of avian influenza virus are scarce. This experiment was designed to evaluate the survivability of H9N2 LPAIV in water with and without Atyopsis moluccensis (bamboo shrimp) for a period of 12 days. The infectivity and amount of virus in water were calculated and were found to be significantly higher in water with A. moluccensis than in water without A. moluccensis. The study also showed that A. moluccensis can accumulate the virus mechanically which can infect chicken eggs up to 11 days. The virus transmission potential of A. moluccensis requires further studies.
... Disinfectants evaluated in this study including Fnvirolyte , Virkon®-S 1%, Aldekol 0.5%, and bioscentry 0. Muhammad et al. [13] reported the efficacy of Virkon-S against H7N3 subtype and found that 0.5% dilution was able to inactivate AIV fully after 90 min while 1% and 2% concentration achieved virucidal activity in just 30 min. because of the nature of the envelope [25]. The use of chlorine inactivated HPAIV at a level of more than three orders of magnitude, but did not inactivate the virus completely. ...
In this study we have presented some aspects of the highly pathogenic avian influenza virus (HPIIV) in Egypt and the effect of some physical and chemical agents on its activity. The effect of temperature and UV light on the infectivity of isolated avian influenza virus H5N1 virus in litter could be inactivated by increasing temperature above 50 º C for at least 24 hr. UV light could not destroy the infectivity of the virus completely even after exposure for 48 hr. Disinfectants evaluated in this study including Fnvirolyte , Virkon®-S 1%, Aldekol 0.5%, and bioscentry 0.5%. The results revealed that Envirolyte was very e f f e c t i v e in r e d u c i n g the titre of H5N1 virus after 1 0 , 30 min and 12 hr of exposure at 25°C from (2 8) to (2 3) but it completely destroying the virus after 24 hr of exposure at 25°C with complete reduction in HA activity. The results a l s o , revealed that Virkon-S ® and Aldekol were effective in r e d u c i n g the titre of virus after 30 min of exposure at 25°C to (2 3) without any additional reduction afterwards for Virkon-S ®. While, Aldekol succeeded in r e d u c i n g the titre of H5N1 virus after 12 hr of exposure at 25°C to (2 2) but without any inactivation o f HA.
... A(H5N1) was susceptible to hypochlorite solutions with 15 seconds. 123,124 Currently, circulating influenza A strains are susceptible to the neuraminidase inhibitors, including A(H5N1). 125 However, because circulating strains of A(H1N1) in 2008 exhibited resistance, one must be concerned that in the future, circulating influenza strains may develop resistance to neuraminidase inhibitors. ...
Over the past several decades, we have witnessed the emergence of many new infectious agents, some of which are major public threats. New and emerging infectious diseases which are both transmissible from patient-to-patient and virulent with a high mortality include novel coronaviruses (SARS-CoV, MERS-CV), hemorrhagic fever viruses (Lassa, Ebola), and highly pathogenic avian influenza A viruses, A(H5N1) and A(H7N9). All healthcare facilities need to have policies and plans in place for early identification of patients with a highly communicable diseases which are highly virulent, ability to immediately isolate such patients, and provide proper management (e.g., training and availability of personal protective equipment) to prevent transmission to healthcare personnel, other patients and visitors to the healthcare facility.
... Washing with soap and hot water is also effective at removing organic matter and inactivating influenza virus [236]. Many chemical disinfectants are able to inactivate avian influenza virus, including iodophors, hydrogen peroxide, ethanol (70%), bleach (2-3% sodium hypochlorite for a 10-to 30-minute contact time at a temperature not higher than 15°C), phenols, cresols, glutaraldehyde (best at temperatures >10°C), formaldehyde and formalin, acids (hydrochloric and citric), and sodium hydroxide (caustic soda) [236,237]. Phenols, cresols, iodophors, and glutaraldehyde are effective in the presence of organic matter. Quaternary ammonium compounds, sodium hypochlorite, and ethanol are not as effective in the presence of organic matter [236]. ...
This chapter discusses etiology, transmission and epidemiology, clinical signs, pathology, diagnosis, treatment and prevention of viral diseases of ferrets. The viruses discussed in the chapter are: canine distemper virus (CDV), ferret coronaviruses, Aleutian disease virus (ADV), influenza viruses, ferret rotaviruses, rabies virus, pseudorabies virus (PRV), bovine herpesvirus 1 (BoHV-1), feline panleukopenia virus (FPV), ferret papillomavirus, severe acute respiratory syndrome (SARS), henipaviruses, respiratory syncytial virus (RSV), vesicular stomatitis virus, retrovirus and transmissible spongiform encephalopathies (TSE). Canine distemper (CD) is one of the most important viral diseases in ferrets and, as also happens with ferret systemic coronavirus disease, the mortality rate approaches 100%. The availability of highly effective, safe vaccines and better awareness of ferret owners toward the disease have significantly decreased the prevalence of CD in the ferret population.
... H1N1, H9N2) posing a real and potential horrendous threat to human (EPA, 2006). Emergence of HPAIV H5N1 in Hong Kong during 1996(Swayne and Halvorson, 2003) has posed major concerns to public health and has gained immense attentions in evaluat- ing environmental control measures ( Rice et al. 2007). ...
... Hypochlorous acid solution is one of the chlorine compounds with good disinfection ability [5,7,27]. In the present study, the aqueous phase of the original solution containing a free available chlorine concentration of 50 ppm could reduce the titer of an ordinary AIV (H7N1) from 10 7.7 TCID 50 / ml to lower than the detectable limit within 5 sec (Table 1), which is faster than in previous reports [18,27], and its harvested solution after spraying from a distance of 1 cm had the same ability, but it lost its efficacy after spraying from a distance of 30 cm. Zhao et al. also showed similar data; they reported free chlorine loss during spraying depending on the distance [32]. ...
Hypochlorous acid (HOCl) solutions were evaluated for their virucidal ability against a low pathogenic avian influenza virus (AIV), H7N1. HOCl solutions containing 50, 100 and 200 ppm chlorine (pH 6) or their sprayed solutions (harvested in dishes placed at 1 or 30 cm distance between the spray nozzle and dish) were mixed with the virus with or without organic materials (5% fetal bovine serum: FBS). Under plain diluent conditions (without FBS), harvested solutions of HOCl after spraying could decrease the AIV titer by more than 1,000 times, to an undetectable level (< 2.5 log10TCID50/ml) within 5 sec, with the exception of the 50 ppm solution harvested after spraying at the distance of 30 cm. Under the dirty conditions (in the presence of 5% FBS), they lost their virucidal activity. When HOCl solutions were sprayed directly on the virus on rayon sheets for 10 sec, the solutions of 100 and 200 ppm could inactivate AIV immediately after spraying,
while 50 ppm solution required at least 3 min of contact time. In the indirect spray form, after 10 sec of spraying, the lids of the dishes were opened to expose the virus on rayon sheets to HOCl. In this form, the 200 ppm solution inactivated AIV within 10 min of contact, while 50 and 100 ppm could not inactivate it. These data suggest that HOCl can be used in spray form to inactivate AIV at the farm level.
... If complete elimination of the virus is desired, then environmental decontamination may be required. Because of the outer lipid envelope associated with influenza viruses, chlorination has been proposed as a potentially effective method for decontamination [52,53]. Given the impossibility of large-scale field trials, simulation exercises using models such as we report here may be crucial for determining whether such methods are indeed practically feasible. ...
Avian influenza viruses (AIVs) have been pivotal to the origination of human pandemic strains. Despite their scientific and public health significance, however, there remains much to be understood about the ecology and evolution of AIVs in wild birds, where major pools of genetic diversity are generated and maintained. Here, we present comparative phylodynamic analyses of human and AIVs in North America, demonstrating (i) significantly higher standing genetic diversity and (ii) phylogenetic trees with a weaker signature of immune escape in AIVs than in human viruses. To explain these differences, we performed statistical analyses to quantify the relative contribution of several potential explanations. We found that HA genetic diversity in avian viruses is determined by a combination of factors, predominantly subtype-specific differences in host immune selective pressure and the ecology of transmission (in particular, the durability of subtypes in aquatic environments). Extending this analysis using a computational model demonstrated that virus durability may lead to long-term, indirect chains of transmission that, when coupled with a short host lifespan, can generate and maintain the observed high levels of genetic diversity. Further evidence in support of this novel finding was found by demonstrating an association between subtype-specific environmental durability and predicted phylogenetic signatures: genetic diversity, variation in phylogenetic tree branch lengths, and tree height. The conclusion that environmental transmission plays an important role in the evolutionary biology of avian influenza viruses—a manifestation of the “storage effect”—highlights the potentially unpredictable impact of wildlife reservoirs for future human pandemics and the need for improved understanding of the natural ecology of these viruses.
... It has been demonstrated that the H5N1 virus survives from 4 to 23 days in wet chicken manure [5], many months in cool water [6] , [7] , and 72 hours on plastic, steel and rubber materials [8] . Disinfectants induced inactivation of AIV has been reported by various researchers all over the world [9] , [10] [12]. " Reference [13] shows the effect of several chemical compounds and compound mixtures (acetic acid, citric acid, calcium hypochlorite, sodium hypochlorite, laundry detergent with peroxygen, commercial iodine/acid disinfectant) to disinfect LPAIV a " . ...
The present investigation was undertaken to evaluate the virucidal activity of five disinfectants; a peroxygen compound (Virkon-S), Glutraldehyde (Aldekol), an organic acid (Longlife 250 S), an innovative Disinfectant-lyte (It contains various mixed oxidants predominantly hypochlorous acid and sodium hypochlorite) and TH4 (a combination of four quaternary ammonium compounds and gluteraldhydes against avian influenza virus (AIV) under laboratory conditions. Disinfectant-Lyte 1/250 (Envirolyte-Egypt) was the most effective disinfectant in killing AIV, showed complete reduction in hemagglutinating (HA) activity) and damage of the nucleic acid (RNA) and viral protein We report that; disinfectants are inactivating AIV by different methods. The study, however, points out that, we have to know how much damage must be done to the virus before virus infection is prevented.
... Time: 10minutes; ⃰ : second application of the disinfectant after 4days from the first one (samples were taken 10 m post-exposure) (Suarez et al., 2003; Lamichhane, 2006; OIE, 2004; Reed &Munench, 1938) It was also noticed that Long life (0.5%) in houses failed to control AIV even after the second application at 4 th day. Aldekol 0.5%, TH 4 0.5% and Envirolyte-Egypt (1/500) after the second application in houses gave complete sanitation of the houses from AIV. Disinfectants induced inactivation of AIV has been reported by various researchers all over the world [27] – [29]. " Reference [30] mixtures (acetic acid, citric acid, calcium hypochlorite, sodium hypochlorite, laundry detergent with peroxygen, commercial iodine/acid disinfectant) to disinfect LPAIV " . ...
This study was carried out in 6 layer houses at Giza province, during2010-2011 outbreaks of high pathogenic avian influenza (HPAI) diagnosed in Egypt. The present investigation was undertaken to evaluate the virucidal activity of different disinfectants against avian influenza virus (AIV) under laboratory and field conditions. Anigen Rapid AIV Ag Test Kit was used for detection of AIV from environment and embroynated chicken's eggs (ECE). Five disinfectants were evaluated for their effectiveness against AIV contaminated premises (in vitro and vivo). They were an organic acid (Longlife 250 S), a peroxygen compound (Virkon-S)-, Glutraldehyde (Aldekol) and (TH4)-(a combination of four quaternary ammonium compounds and gluteraldhydes) and innovative Envirolyte-Egypt (It contains various mixed oxidants predominantly hypochlorous acid and sodium hypochlorite. Envirolyte-Egypt (1/250) and Virkon S 1% were the most effective disinfectants in killing AIV. Despite the good results obtained with Aldekol 0.5%, Longlife 250 S 0.5% and TH4 0.5% in laboratory test after 10 min, but the effect of both disinfectants on AIV infected premises was failed.
... Risk and protective factors identifi ed in this study, together with fi ndings from other studies, can assist in developing environmental or behavioral interventions to reduce AIV transmission in LBMs. Previous studies have shown that regular cleaning with detergents, including free chlorine concentrations typically used in drinking water treatment, can rapidly decontaminate surfaces from AIVs (8,24). Previous studies also have shown that periodic market rest days coupled with thorough cleaning can minimize the reservoir of AIV in LBMs (4,12,25). ...
To identify environmental sites commonly contaminated by avian influenza virus A (H5N1) in live-bird markets in Indonesia, we investigated 83 markets in 3 provinces in Indonesia. At each market, samples were collected from up to 27 poultry-related sites to assess the extent of contamination. Samples were tested by using real-time reverse transcription–PCR and virus isolation. A questionnaire was used to ascertain types of birds in the market, general infrastructure, and work practices. Thirty-nine (47%) markets showed contamination with avian influenza virus in >1 of the sites sampled. Risk factors were slaughtering birds in the market and being located in West Java province. Protective factors included daily removal of waste and zoning that segregated poultry-related work flow areas. These results can aid in the design of evidence-based programs concerning environmental sanitation, food safety, and surveillance to reduce the risk for avian influenza virus A (H5N1) transmission in live-bird markets.
... These results suggest that the minimum concentration of FAC for a virucidal effect of NEW is approximately 40 ppm, which is similar to the value given in previous reports [10,11]. On the other hand, Lénès et al. [15] and Rice et al. [16] reported that low concentrations of free chlorine (0.5-2 ppm), which is typically used in drinking water treatment, were sufficient to inactivate influenza viruses, including H5N1 HPAI virus, in 1-5 min. Additional studies are required to understand the differences between the results of this study and those of previous studies. ...
The virucidal effects of two types of electrolyzed water, acidic electrolyzed water (AEW) and neutral electrolyzed water (NEW), on avian influenza viruses were studied. Virus titers of the highly pathogenic H5N1 virus and the low-pathogenic H9N2 virus irreversibly decreased by >5-log at 1 min after the viruses were mixed with NEW containing ≥43 ppm free available chlorine (FAC), but not with NEW containing <17 ppm FAC. The minimum concentration of FAC for a virucidal effect of NEW was estimated at around 40 ppm. In contrast, the virus titers decreased by >5 log at 1 min after the viruses were mixed with AEW, in which the concentration of the FAC ranged from 72 to 0 ppm. Thus, the virucidal effect of AEW did not depend on the presence of FAC. Reverse transcription polymerase chain reaction amplified fragments of the M and NP genes, but not the complete M gene, from RNA extracted from the AEW-inactivated virus. Moderate morphological changes were found under the electron microscope, although no changes were observed in the electrophoresed proteins of the AEW-inactivated virus. No viral genes were amplified from the RNA extracted from the NEW-inactivated virus, regardless of the length of the targeted genes. No viral particles were detected under the electron microscope and no viral proteins were detected by electrophoresis for the NEW-inactivated virus. Thus, this study demonstrated potent virucidal effects of AEW and NEW and differences in the virucidal mechanism of the two types of electrolyzed water.
... − Transfer of viable influenza A virus from paper tissue to hands was only possible for 15 minutes, but transfer from stainless steel to hands for 24 hours (Bean et al., 1982). − It is probably inactivated in water with free residual chlorine (0.52-1.08 mg/L) (experiments performed used avian influenza virus) (Rice et al., 2007). ...
Approximately 320 million passengers ferry trips were recorded through European ports in 2007 and 66 cruise lines with 192 cruise ships were domiciled or participated in the European cruise ship market the same year. The European cruise market has grown by 41% from 2006 to 2009 and more than doubled over the last 10 years. A considerable proportion of the European population travels in modern ships, which are becoming more complex and which are designed to carry many more passengers and crew. Ships move continuously from one country to another where different standards of sanitation are required. These differences can cause administrative difficulties for competent authorities of countries, as well as ship operators, when trying to deal with the prevention and control of communicable diseases aboard ships. Therefore, standards are needed to regulate health related issues, which can be adopted and accepted by all European Union Member States (EUMS). The SHIPSAN project (No A/790577) study revealed a diversity of approaches and practices in the conduct of inspections, differences in the competencies of inspectors and the legislation applied during inspections, and a lack of communication and training among many EUMS. Common inspection tools at a European level for hygiene inspection practices and port to port communication were recommended. This document is Deliverable No 9 produced under Work Package 5 of the SHIPSAN TRAINET project. Ten working groups were established for the development of this document with participants/experts from 17 European countries. The European Centre for Disease Prevention and Control (ECDC), the World Health Organization (WHO), the International Maritime Organization (IMO) and the US Vessel Sanitation Program (VSP) also provided input. The European Cruise Council (ECC), the Cruise Lines International Association (CLIA) and individual cruise and ferry companies have also contributed to the development of this document. The content of the manual was based on expert opinion consensus reached during working group meetings and on the EU legislation and International Health Regulations 2005 (IHR) requirements. Moreover, the SHIPSAN project (No A/790577) assessment results, the literature review and the analysis of collected data on policies, guidelines and practices implemented by the EUMS were used to develop this manual.
... Two or three cardboard boxes were provided as nest boxes for the rats. The pool was filled daily (but not emptied within the first week of the trial) with 5 gallons of water that had been sitting at room temperature and aerated with an aquarium pump for 24 hours to dechlorinate and thus prevent inactivation of any influenza virus [35]. This was also done to better mimic the natural state of water such as lakes and streams and farm water, which are typically not chlorinated. ...
Waterfowl and shorebirds harbor and shed all hemagglutinin and neuraminidase subtypes of influenza A viruses and interact in nature with a broad range of other avian and mammalian species to which they might transmit such viruses. Estimating the efficiency and importance of such cross-species transmission using epidemiological approaches is difficult. We therefore addressed this question by studying transmission of low pathogenic H5 and H7 viruses from infected ducks to other common animals in a quasi-natural laboratory environment designed to mimic a common barnyard. Mallards (Anas platyrhynchos) recently infected with H5N2 or H7N3 viruses were introduced into a room housing other mallards plus chickens, blackbirds, rats and pigeons, and transmission was assessed by monitoring virus shedding (ducks) or seroconversion (other species) over the following 4 weeks. Additional animals of each species were directly inoculated with virus to characterize the effect of a known exposure. In both barnyard experiments, virus accumulated to high titers in the shared water pool. The H5N2 virus was transmitted from infected ducks to other ducks and chickens in the room either directly or through environmental contamination, but not to rats or blackbirds. Ducks infected with the H7N2 virus transmitted directly or indirectly to all other species present. Chickens and blackbirds directly inoculated with these viruses shed significant amounts of virus and seroconverted; rats and pigeons developed antiviral antibodies, but, except for one pigeon, failed to shed virus.
... Risk and protective factors identifi ed in this study, together with fi ndings from other studies, can assist in developing environmental or behavioral interventions to reduce AIV transmission in LBMs. Previous studies have shown that regular cleaning with detergents, including free chlorine concentrations typically used in drinking water treatment, can rapidly decontaminate surfaces from AIVs (8,24). Previous studies also have shown that periodic market rest days coupled with thorough cleaning can minimize the reservoir of AIV in LBMs (4,12,25). ...
To identify environmental sites commonly contaminated by avian influenza virus A (H5N1) in live-bird markets in Indonesia, we investigated 83 markets in 3 provinces in Indonesia. At each market, samples were collected from up to 27 poultry-related sites to assess the extent of contamination. Samples were tested by using real-time reverse transcription-PCR and virus isolation. A questionnaire was used to ascertain types of birds in the market, general infrastructure, and work practices. Thirty-nine (47%) markets showed contamination with avian influenza virus in ≥ 1 of the sites sampled. Risk factors were slaughtering birds in the market and being located in West Java province. Protective factors included daily removal of waste and zoning that segregated poultry-related work flow areas. These results can aid in the design of evidence-based programs concerning environmental sanitation, food safety, and surveillance to reduce the risk for avian influenza virus A (H5N1) transmission in live-bird markets.
... Maintaining free chlorine residues higher than this level, 0.52-1.08 mg/L, in treated tap water, was reported to inactivate the highly pathogenic avian influenza (H5N1) virus (Rice et al. 2007). ...
Samples of artesian well, shallow well, surface water, tap water, and bottled water were collected from different areas in Khartoum; these were chemically analyzed and used as diluents to vaccinate chicks against Newcastle disease. Immune response in vaccinated chicks, as measured by the hemagglutination inhibition test, was significantly better in birds which received the vaccine diluted in bottled water followed by those vaccinated using tap water. It appears that water with low turbidity and total dissolved solids were the best water for vaccine dilution. The order of preference of water source, according to this study was bottled water, tap water, shallow well water, artesian well water, and finally surface water.
... There have been several reports on the inactivation of avian influenza viruses by physical and chemical treatments to implement effective measures of controlling the outbreak of the highly pathogenic virus in chicken farms. 30,31,[36][37][38][39] Previous reports have shown that avian influenza viruses are readily inactivated by heat treatment, acetic acid (1% and 3%), sodium hydroxide (2%), calcium hydroxide (1%), sodium hypochlorite (750 ppm), calcium hypochlorite (750 ppm), chlorine (0.52-1.08 mg/L), or commercially available disinfectants. However, little has been learned about the inactivation of H1N1 by such treatments. ...
Because any patient, health care worker, or visitor is capable of transmitting influenza to susceptible persons within hospitals, hospital-acquired influenza has been a clinical concern. Disinfection and cleaning of medical equipment, surgical instruments, and hospital environment are important measures to prevent transmission of influenza virus from hospitals to individuals. This study was conducted to evaluate the efficacy of disinfection processes, which can be easily operated at hospitals, in inactivating influenza A virus H1N1 (H1N1).
The effects of 0.1 mol/L NaOH, 70% ethanol, 70% 1-propanol, solvent/detergent (S/D) using 0.3% tri (n-butyl)-phosphate and 1.0% Triton X-100, heat, and ethylene oxide (EO) treatments in inactivating H1N1 were determined. Inactivation of H1N1 was kinetically determined by the treatment of disinfectants to virus solution. Also, a surface test method, which involved drying an amount of virus on a surface and then applying the inactivation methods for 1 minute of contact time, was used to determine the virucidal activity.
H1N1 was completely inactivated to undetectable levels in 1 minute of 70% ethanol, 70% 1-propanol, and solvent/detergent treatments in the surface tests as well as in the suspension tests. H1N1 was completely inactivated in 1 minute of 0.1 mol/L NaOH treatment in the suspension tests and also effectively inactivated in the surface tests with the log reduction factor of 3.7. H1N1 was inactivated to undetectable levels within 5 minutes, 2.5 minutes, and 1 minute of heat treatment at 70, 80, and 90 degrees C, respectively in the suspension tests. Also, H1N1 was completely inactivated by EO treatment in the surface tests.
Common disinfectants, heat, and EO tested in this study were effective at inactivating H1N1. These results would be helpful in implementing effective disinfecting measures to prevent hospital-acquired infections.
EPA approved disinfectants for coronavirus lists many products for use on hard, non-porous materials. There are significantly less products registered for use on porous materials. Further, many common, high-touch surfaces fall in between non-porous materials such as glass and porous materials such as soft fabrics. The objective of this study was to assess the efficacy of selected commercially available disinfectant products against coronaviruses on common, high-touch surfaces. Four disinfectants (Clorox Total 360, Bleach solution, Vital Oxide, and Peroxide Multi-Surface Cleaner) were evaluated against Murine Hepatitis Virus A59 (MHV) as a surrogate coronavirus for SARS-CoV-2. MHV in cell culture medium was inoculated onto four materials: stainless steel, latex-painted drywall tape, Styrene Butadiene rubber (rubber), and bus seat fabric. Immediately (T0) or 2-hours (T2) post-inoculation, disinfectants were applied by trigger-pull or electrostatic sprayer and either held for recommended contact times (Spray Only) or immediately wiped (Spray and Wipe). Recovered infectious MHV was quantified by median tissue culture infectious dose assay. Bleach solution, Clorox Total 360, and Vital Oxide were all effective (>3-log10 reduction or complete kill of infectious virus) with both the Spray Only and Spray and Wipe methods on stainless steel, rubber, and painted drywall tape when used at recommended contact times at both T0 and T2 hr. Multi-Surface Cleaner unexpectedly showed limited efficacy against MHV on stainless steel within the recommended contact time; however, it showed increased (2.3 times greater efficacy) when used in the Spray and Wipe method compared to Spray Only. The only products to achieve a 3-log10 reduction on fabric were Vital Oxide and Clorox Total 360; however, efficacy of Vital Oxide against MHV on fabric was reduced to below 3-log10 when applied by electrostatic sprayer compared to trigger-pull sprayer. This study highlights the importance of considering material, product, and application method when developing a disinfection strategy for coronaviruses on high-touch surfaces.
Infectious severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has the potential to be collected in wastewater from mucus, sputum, and feces of infected individuals, raising questions about the appropriate handling and treatment of resulting wastewater. Current evidence indicates the likelihood of waterborne SARS-CoV-2 transmission is low; nonetheless, confirming the efficacy of disinfection against SARS-CoV-2 is prudent to ensure multiple barriers of protection for infectious SARS-CoV-2 that may result in the municipal and hospital wastewater stream. Sodium hypochlorite (free chlorine) is widely used for pathogen control in water disinfection applications. In the current study, we investigated the inactivation of SARS-CoV-2 in DI water and primary influent municipal wastewater by sodium hypochlorite (free chlorine) addition. Our results showed rapid disinfection of SARS-CoV-2, with less than 1 mg-min/L required for >3 log10 TCID50 reduction in DI water. More than 5 mg-min/L was required for 3 log10 TCID50 reduction in wastewater, suggesting potential shielding of the virus by solids. These results are consistent with expected virus inactivation by free chlorine and indicates the adequacy of free chlorine disinfection for inactivation of SARS-CoV-2 in water matrices.
It is imperative to understand the behavior of enveloped viruses during water treatment to better protect public health, especially in the light of evidence of detection of coronaviruses in wastewater. We report bench-scale experiments evaluating the extent and mechanisms of removal and/or inactivation of a coronavirus surrogate (ϕ6 bacteriophage) in water by conventional FeCl3 coagulation and Fe(0) electrocoagulation. Both coagulation methods achieved ∼5-log removal/inactivation of ϕ6 in 20 min. Enhanced removal was attributed to the high hydrophobicity of ϕ6 imparted by its characteristic phospholipid envelope. ϕ6 adhesion to freshly precipitated iron (hydr)oxide also led to envelope damage causing inactivation in both coagulation techniques. Fourier transform infrared spectroscopy revealed oxidative damages to ϕ6 lipids only for electrocoagulation consistent with electro-Fenton reactions. Monitoring ϕ6 dsRNA by a novel reverse transcription quantitative polymerase chain reaction (RT-qPCR) method quantified significantly lower viral removal/inactivation in water compared with the plaque assay demonstrating that relying solely on RT-qPCR assays may overstate human health risks arising from viruses. Transmission electron microscopy and computationally generated electron density maps of ϕ6 showed severe morphological damages to virus' envelope and loss of capsid volume accompanying coagulation. Both conventional and electro- coagulation appear to be highly effective in controlling enveloped viruses during surface water treatment.
Los virus de influenza causan infecciones
respiratorias agudas y afectan a todos los
grupos de edad con altos índices de morbilidad y
mortalidad. La transmisión es por expulsión de gotitas
de saliva, que se pueden depositar en manos
y objetos. Para desinfectar áreas y materiales
de trabajo se emplean soluciones
desinfectantes como detergentes y cloro
y, más recientemente, la solución electrolizada
superoxidada (SES). Esta última se
prepara con agua purificada, solución
saturada de cloruro de sodio, y es electrolizada
a pH neutro.
A huge number of investigations on the ecological sources, fate, and transport of viruses have been dedicated to non-enveloped viruses such as norovirus and enteroviruses. However, more recent global outbreaks of viral diseases have been provoked by enveloped viruses comprising viruses from the Coronavirus family (SARS, MERS, COVID-19). Enveloped viruses have a lipid membrane encircling their protein capsid and genome. SARS-CoV-2 will surely not be the ultimate fresh virus to jut and badly terrorize worldwide public health and life. Scientists and funding agencies have a trend to concentrate largely on a particular virus throughout its eruption; however, then advance on to different themes when the eruption calms. Considering the historical contributions from environmental engineering, and the huge dares that emerge, environmental science and engineering specialists have to adopt a larger, long-term, and more quantitative strategy to comprehending viruses that are diffusing through nature. Identical to the manner by which chemical contaminants are handled in the environment, the particular properties that control transport and demobilization of enveloped viruses in solutions, on surfaces, and in the air must be understood. Besides, the fashion by which ecological parameters form likely virus transmission mechanisms should be comprehended. Thereby, despite the identity of the enveloped virus that provokes the following main eruption, more sophisticated detailing of its endurance and guidance on how to reduce its diffusion may be given.
Abstract Cloacal and tracheal swab-samples were collected from commercial farms, backyards
and live market birds (LBM) to identify the potential existence and genetic drifts of avian influenza
subtypes (AI) H5 and H9 that are circulating among bird species in Egypt. The results
revealed that, one sample out of 50 samples of chicken commercial farms was positive for
the isolation of subtype H9N2 [KC699549, Influenza A virus: A/chicken/Egypt/VRLCU-R33/
2012(H9N2)]; from Sharkeia province. Two samples out of 20 samples of Backyard ducks were
positive for the isolation of 2 subtypes H5N1; [KC699547, Influenza A virus: A/duck/Egypt/
VRLCU-R11/2012(H5N1), ‘‘backyard duck’’] from El-Fayoum province and the other from
Giza province [A/duck/Egypt/VRLCU-R28/2012(H5N1), ‘‘backyard duck’’]. Analysis of haemagglutinin
(HA) and the phylogenetic tree of the isolated viruses (H5N1) were fallen within
the clade 2.2.1.1. Antigenic cartography for the isolated Egyptian H9N2 AI virus can intuitively
be of group-B. The number of mutations in the amino acid sites (33, 47, 65, 90, 92, 143, and
150) and the Long Branch observed in the phylogenetic tree may suggest a rather long evolution
period. The sequenced H9N2 Egyptian virus in the study was closely related to the previous
Egyptian isolates.
Evaluation of some disinfectants against locally isolated Avian Influenza Viruses in Egypt
This study was carried out to evaluate the virucidal ability of some chemical disinfectants commercially available in the Egyptian markets and commonly used in cleaning and disinfecting poultry farms, against Highly Pathogenic Avian Influenza (HPAI) circulating in Egypt and infecting poultry farms since 2006. In this study standard identification and molecular characterization of two isolates of AIV subtype H5N1 isolated from commercial poultry flocks in Egypt during 2011(layer flocks) and 2013(broiler flocks), from different localities in Egypt (isma1lya and bani-sweief respectively) was carried out. Phylogenatic analysis of both strains reveled that the two isolates were of two different clades, the first virus isolated in 2011 belonged to clade 2.2.1.1 a variant virus (A/chicken/Egypt/VRLCU67/ 2011(H5N1)), while the other virus belonged to clade 2.2.1/c a classical virus (A/chicken/Egypt/13VIR37294/2013(H5N1)). The tested disinfectants included synthetic phenol compound (PROPHYL 75®), aldhyde and surfactant (ALDEKOL® ), surfactant with different generations of Quats (BIOSENTERY 904®), iodophores (BIOSENTERY IODINE®), Non chlorine oxidizing agent (PERACLEAN 5%®), chlorine releasing agents ( VIRKON S®, Calcium and sodium hypochlorite), beside two clutching and detergent organic Acids (Citric Acid and Formic Acid). Most of the tested disinfectants effectively inactivated HPAI on cement surface (coupons) which was designed specifically to resemble poultry farm floors used in Egypt according to the guidelines of EPA after 5 min contact time, the exception was (Calcium hypochlorite after 10 min, sodium hypochlorite, PERACLEAN 5% ® and Formic acid after 30 min). When the same
disinfectants were tested against the two identified HPAI strains no difference in inactivation ability were found.
We have examined a variety of sampling strategies for detecting pathogens in turkey flocks undergoing infections with low pathogenicity avian influenza virus (LPAIV). We found that viral RNA was widely distributed in the barn environment of turkey flocks undergoing an active LPAIV infection and was in both water and drinker biofilm samples. Viral RNA was concentrated in drinker biofilm and sediment and was detectable using real-time reverse-transcription polymerase chain reaction (RRT-PCR) and by virus isolation. Drinker biofilm sample results correlated with concurrently collected oropharyngeal (OP) sample results from flocks on a farm with LPAI in which the two sampling strategies were directly compared. To evaluate the utility of biofilm sampling for the detection of highly pathogenic avian influenza virus (HPAIV), biofilm and OP swabs from mortality pools were collected daily from negative turkey flocks on an HPAI-positive premise. The biofilm swabs were positive 1-2 days prior to positives appearing in the OP sample pools. The drinker biofilm sampling strategy overcame the difficulty of finding a subclinical infectious bird in a population by collecting material from a large number of individuals and testing a sample in which a positive signal persists for several days to weeks. The sampling method is convenient for use in turkey barns and has been reliably used in both active and passive surveillance programs for LPAIV and HPAIV using RRT-PCR.
An evaluation of poultry farm water supplies was conducted to determine the impact of broiler farm daily water system sanitation
practices on microbial levels. The water systems of 4 commercial poultry barns were sanitized daily with 0.5 to one ppm of
free chlorine (Cl) residual, which resulted in an Oxidation Reduction Potential (ORP) value of ≥ 600 mV at the beginning of
the waterlines. Prior to the trial, waterlines were cleaned between flocks with a concentrated chlorine based disinfectant
with greater than 1,000 ppm of free Cl. Waterline drip samples were collected from the nipple drinkers throughout the bird
grow-out period in order to determine the microbial levels including the aerobic plate counts (APC), yeast, and mold in the
water from all 4 barns for 3 consecutive flocks. This evaluation showed that water systems are vulnerable to microbial contamination
regardless of consistent water sanitation. Microbial growths (> 4 log10 cfu/mL APC) were detected in water samples at different periods throughout the flock grow-out period. However, daily water
sanitation practices helped to control the persistence of occasional microbial growth in water and kept the drinking water
at a microbiologically safe level (<1,000 cfu/ml of APC).
Wild waterfowl are considered as the natural reservoir of all influenza A virus subtypes, including H5N1. Influenza A viruses replicate preferentially in the gastrointestinal tract of waterfowl, high concentrations are excreted in feces, and the viruses can be transmitted via the fecal-oral route among the waterfowl. Infected waterfowl can contaminate open water bodies, including drinking water sources and recreational areas, and the oral ingestion or aspiration of water containing influenza A virus could be a possible mode of transmission to humans. Quantitative microbial risk assessment (QMRA) framework is a powerful tool to understand how to control pandemics mediated by environmental reservoirs or human-to-human transmission (e.g. calculating risk of infection due to a low dose). Essential steps in the QMRA process are, exposure assessment and dose-response analysis. Recently, H5N1 influenza risk assessment models (1) to estimate the probability of human infection from H5N1 through water and (2) to describe mortality of experimental animals exposed to H5N1 (time-dependent dose-response model) were developed. These models will be useful to evaluate the risks of infection under various transmission scenarios and contribute to prevention of a future human influenza pandemic caused by this lethal virus.
The highly pathogenic H5N1 avian influenza virus (A/H5N1) devastated the poultry industry and posed serious health threat. Cleaning and disinfection are essential parts of preventative and postoutbreak management of A/H5N1 infections in poultry. In this preliminary study, we evaluated the impact of concentration, time of exposure, surface porosity and organic matter on effectiveness of four commercial chemicals disinfectant to inactivate two A/H5N1 viruses of clade 2.2.1 isolated in 2006 and 2010 from broiler flocks in Egypt using suspension and carrier tests. Viruses were incubated with 0.5, 1 and 2% of Formalin, Glutheraldhyde, TH4® and Virkon® S for 15, 30, 60 and 120 minutes at room temperature (22 ± 2 C). Using suspension test, in the absence of organic matter all disinfectants at each concentration but Virkon S 0.5% had effectively inactivated virus suspensions after 15 min exposure time. In the presence of organic matter, the use of low concentrations of Formalin (0.5%), Glutheraldhyde (0.5%) or Virkon S (0.5% and 1%) was not sufficient to inactivate the viruses after 15 min. Using gauze carrier test, only Formalin at any concentration for 15 min was sufficient to inactivate the viruses, whereas different concentrations or exposure time to Glutheraldhyde (0.5% for 60 min), TH4 (0.5% for 30 min) and Virkon S (0.5% for 60 minutes or 1% for 30 min) were required. Using wood carrier test, total inactivation of the virus was obtained at concentration of 0.5% for 30 min (Formalin and TH4) or 60 min (Glutheraldhyde and Virkon S). This study emphasizes the need to use high concentration of and/or extended time of exposure to disinfectants for efficient inactivation of A/H5N1 particularly in the presence of organic matter or different surfaces which is common in poultry operations. In addition, it seemed that the virus isolated in 2010 was more resistant to disinfectants than the isolate from 2006 when wood was used as a carrier.-
This report summarizes the current state of knowledge on the persistence of radiological agents on drinking water infrastructure (such as pipes) along with information on decontamination should persistence occur. Decontamination options for drinking water infrastructure have been explored for some important radiological agents (cesium, strontium and cobalt), but important data gaps remain. Although some targeted experiments have been published on cesium, strontium and cobalt persistence on drinking water infrastructure, most of the data comes from nuclear clean-up sites. Furthermore, the studies focused on drinking water systems use non-radioactive surrogates. Non-radioactive cobalt was shown to be persistent on iron due to oxidation with free chlorine in drinking water and precipitation on the iron surface. Decontamination with acidification was an effective removal method. Strontium persistence on iron was transient in tap water, but adherence to cement-mortar has been demonstrated and should be further explored. Cesium persistence on iron water infrastructure was observed when flow was stagnant, but not with water flow present. Future research suggestions focus on expanding the available cesium, strontium and cobalt persistence data to other common infrastructure materials, specifically cement-mortar. Further exploration chelating agents and low pH treatment is recommended for future decontamination studies.
URL: http://www.ifpri.org/publication/quantitative-risk-assessment-onward-transmission-highly-pathogenic-avian-influenza-h5n1
Evaluación de un nuevo proceso de desinfección para virus aviares. El compuesto químico metam-sodio se probó bajo tres concentraciones para determinar su capacidad de inactivar la infecciosidad del virus de influenza aviar de baja patogenicidad y del virus de la enfermedad infecciosa de la bolsa, utilizando cama contaminada como substrato. Independientemente de la concentración utilizada, el virus de la influenza aviar de baja patogenicidad fue inactivado dentro de la primera hora posterior a la adición del metam-sodio. El virus de la enfermedad infecciosa de la bolsa no se inactivó con la cantidad mas baja de metam-sodio, pero a concentraciones mayores el virus se inactivó dentro de la primera hora posterior a la aplicación. Estos resultados muestran que este compuesto es capaz de penetrar la cama e inactivar virus envueltos y no envueltos debido a su capacidad para formar el compuesto activo metil isotiocianato que actúa como un fumigante. Abbreviations: AIV = avian influenza virus; DMEM = Dulbecco's minimal essential medium; EID50 = egg infectious dose 50%; HA = hemagglutinin; HPAIV = highly pathogenic avian influenza virus; IBDV = infectious bursal disease virus; LPAIV = low pathogenicity avian influenza virus; MITC = methyl isothiocyanate; NA = neuraminidase; NAI = notifiable avian influenza; PBS = phosphate-buffered solution; RBC = chicken red blood cells; rpm = revolutions per minute; SPF = specific-pathogen free; TCID50 = tissue culture infectious dose 50%
The aims of this study were to assess the infectivity of highly pathogenic (HP) and low pathogenicity (LP) H7 AI viruses at different temperatures and pH values and to investigate the persistance of HP H7 virus in chicken, turkey and duck meat. The H7 viruses tested remained infectious at +4°C and +20°C for 200 and >50 days, respectively. At pH 5, H7 viruses retained their infectivity for a shorter period of time compared to pH 7. The infectivity of HP H7 was detected >2 months in meat maintained at +4°C and was higher in chicken meat compared to turkey and duck meat. Results of this study show that higher temperatures and lower pH values both reduce virus infectivity and demonstrate that HP H7 virus can remain infectious in meat for extended periods of time.
To control the spread of avian flu (influenza) and other viruses of concern among commercial flocks, it is essential that
proper disinfection procedures be developed along with methods for assessing their performance. Such methods must be rapid
and inexpensive. Coliphages were used as indicators to demonstrate the efficacy of quaternary ammonium compounds and chlorine
bleach for the inactivation of viruses in chicken cages. The concentration of indigenous coliphages in chicken litter was
found to be 104–107 per gram and from 0 to 8,500 per 100cm2 of floor surface. To assess the effectiveness of the disinfectants, floor samples were collected pre and post disinfection.
These results indicated that chlorine bleach was more effective than quaternary ammonium compounds in reducing the amount
of indigenous coliphages. To obtain better quantitative data, MS-2 coliphage was sprayed onto cage floors, left overnight
to dry, and then the surfaces disinfected. Similar results were obtained with both indigenous coliphages and MS-2. There appears
to be no significant difference in coliphage reduction by increasing the contact time from 10 to 30min. To ensure at least
a 99.9% reduction of virus at least 236ml of household bleach per 3.78l should be used.
The high risk associated with biological threat agents dictates that any suspicious sample be handled under strict surety
and safety controls and processed under high-level containment in specialized laboratories. This study attempted to find a
rapid, reliable, and simple method for the complete inactivation of a wide range of pathogens, including spores, vegetative
bacteria, and viruses, while preserving microbial nucleic acid fragments suitable for PCRs and proteinaceous epitopes for
detection by immunoassays. Formaldehyde, hydrogen peroxide, and guanidium thiocyanate did not completely inactivate high titers
of bacterial spores or viruses after 30 min at 21°C. Glutaraldehyde and sodium hypochlorite showed high microbicidal activity
but obliterated the PCR or enzyme-linked immunosorbent assay (ELISA) detection of bacterial spores or viruses. High-level
inactivation (more than 6 log10) of bacterial spores (Bacillus atrophaeus), vegetative bacteria (Pseudomonas aeruginosa), an RNA virus (the alphavirus Pixuna virus), or a DNA virus (the orthopoxvirus vaccinia virus) was attained within 30 min
at 21°C by treatment with either peracetic acid or cupric ascorbate with minimal hindrance of subsequent PCR tests and immunoassays.
The data described here should provide the basis for quickly rendering field samples noninfectious for further analysis under
lower-level containment and considerably lower cost.
Understanding factors that influence persistence of influenza virus in an environment without host animals is critical to appropriate decision-making for issues such as quarantine downtimes, setback distances, and eradication programs in livestock production systems. This systematic review identifies literature describing persistence of influenza virus in environmental samples, i.e., air, water, soil, feces, and fomites. An electronic search of PubMed, CAB, AGRICOLA, Biosis, and Compendex was performed, and citation relevance was determined according to the aim of the review. Quality assessment of relevant studies was performed using criteria from experts in virology, disease ecology, and environmental science. A total of 9,760 abstracts were evaluated, and 40 appeared to report the persistence of influenza virus in environmental samples. Evaluation of full texts revealed that 19 of the 40 studies were suitable for review, as they described virus concentration measured at multiple sampling times, with viruses detectable at least twice. Seven studies reported persistence in air (six published before 1970), seven in water (five published after 1990), two in feces, and three on surfaces. All three fomite and five air studies addressed human influenza virus, and all water and feces studies pertained to avian influenza virus. Outcome measurements were transformed to half-lives, and resultant multivariate mixed linear regression models identified influenza virus surviving longer in water than in air. Temperature was a significant predictor of persistence over all matrices. Salinity and pH were significant predictors of persistence in water conditions. An assessment of the methodological quality review of the included studies revealed significant gaps in reporting critical aspects of study design.
From January through July 2008, rabies reemerged in the Chhukha district of southwestern Bhutan. To clarify the distribution and direction of spread of this outbreak, we mapped reported cases and conducted directional tests (mean center and standard deviational ellipse). The outbreak resulted in the death of 97 animals (42 cattle, 52 dogs, and 3 horses). Antirabies vaccine was given free of charge to ≈674 persons suspected to have been exposed. The outbreak spread south to north and appeared to follow road networks, towns, and areas of high human density associated with a large, free-roaming, dog population. The outbreak was controlled by culling free-roaming dogs. To prevent spread into the interior of Bhutan, a well-coordinated national rabies control program should be implemented in disease-endemic areas.
We investigated carriage of avian influenza viruses by wild birds in Australia, 2005-2008, to assess the risks to poultry industries and human health. We collected 21,858 (7,357 cloacal, 14,501 fecal) samples and detected 300 viruses, representing a detection rate of ≈1.4%. Rates were highest in autumn (March-May) and differed substantially between bird types, areas, and years. We typed 107 avian influenza viruses and identified 19 H5, 8 H7, and 16 H9 (40% of typed viruses). All were of low pathogenicity. These viruses formed clearly different phylogenetic clades to lineages from Eurasia or North America, suggesting the potential existence of Australian lineages. H7 viruses were similar to highly pathogenic H7 strains that caused outbreaks in poultry in Australia. Several periods of increased detection rates (numbers or subtypes of viruses) were identified. This study demonstrates the need for ongoing surveillance to detect emerging pathogenic strains and facilitate prevention of outbreaks.
1997 年、アジア系統H5N1 亜型ウイルスによる高病原性鳥インフルエン ザ（HPAI）が香港の家禽に発生した。その後、本ウイルスは、アジアから ヨーロッパやアフリカへ伝播し、多くの国々に深刻な経済的損失をもたらし た。このH5N1 HPAI ウイルスの主要な伝播経路として、野鳥や家禽の移動、 汚染鶏肉の流通、生鳥市場等の関連が指摘されている。特に、東南アジアに おける流行には、鶏群におけるHPAI の発生と水生家禽との疫学的関連が報 告されている。さらに、斃死した野生水禽からのH5N1 HPAI ウイルス分離 が多数報告されている。以上の知見から、著者は、水禽の体内でのウイルス 増殖に関する解析が、水禽を介するH5N1 HPAI ウイルスの伝播経路の解明 に寄与すると考え研究を行った。 本研究において、著者はH5N1 HPAI ウイルスが水禽の羽組織で増殖する ことを見出し、羽が感染水禽からのウイルス排泄経路に重要であることを提 示した。次に、ウイルスに汚染された羽が、健康な鳥や哺乳動物への感染源 となりうること示し、公衆衛生の観点から重要であることを指摘した。また、 感染水禽の羽が、ウイルス検出のための有用な組織サンプルとして利用でき る可能性を示した。最後に、ウイルスに汚染された感染水禽の羽が、環境中 において、ウイルス媒介物としての役割を果たす可能性を指摘した。本研究 は、H5N1 HPAI ウイルス伝播に水禽の羽組織が関わるという新しい見解を 提示した。上記の研究成果が、今後のHPAI の制圧に貢献することを期待す る。本論文の各章の概要を以下に記載する。 第Ⅰ章では、H5N1 HPAI ウイルス山口株を接種したアイガモにおける病 理発生について解析した。ウイルスを接種されたアイガモは斃死や神経症状 を示した。脳炎、膵臓壊死、角膜混濁、羽を構成する上皮組織の壊死等の病 理所見が認められた。幼アイガモでは高致死率が観察され、水禽の日齢が体 内でのウイルス増殖に影響することが示唆された。アイガモの羽でウイルス が増殖することを明らかにし、羽が感染水禽からのウイルス排泄経路となる 可能性を提示した。 第Ⅱ章では、前章で観察された山口株によるアイガモの羽における増殖に 関して、H5N1 HPAI ウイルス清武株やガチョウでの本現象の再現性につい て検索した。H5N1 HPAI ウイルスを実験感染させたアイガモやガチョウの羽を免疫組織化学、電子顕微鏡検索、およびウイルス分離に供し、山口株お よび清武株が、アイガモおよびガチョウの羽上皮細胞で増殖したことを確認 した。この結果、羽におけるH5N1 HPAI ウイルスの増殖が、感染水禽に共 通する現象である可能性が示された。 さらに、H5N1 HPAI ウイルスに自然感染した白鳥の羽組織を、病理組織 学的、ウイルス学的に検索した。羽軸根からウイルスが分離され、免疫組織 化学の結果、羽上皮細胞および羽包上皮細胞にウイルス抗原が検出された。 さらに羽のパラフィン包埋標本からH5N1 HPAI ウイルスの遺伝子が検出さ れた。この結果、ウイルスに自然感染した水禽の羽にウイルスが存在しうる ことが明らかとなった。 感染アイガモの綿羽を健康なアイガモに経口投与したウイルス伝播試験 の結果、投与アイガモの感染を確認した。この結果、山口株に感染したアイ ガモの羽が、鳥に対する感染性を有する事が示された。以上の成績に基づき、 感染水禽の羽が、動物や人への感染源となりうる可能性について指摘した。 第Ⅲ章では、ウイルス検出における、感染アイガモの羽の臨床診断におけ る有用性を評価した。H5N1 HPAI ウイルス清武株および秋田株をアイガモ に経鼻接種し、簡易抗原検出キット、ウイルス分離、免疫組織化学、および 逆転写PCR を用いて、羽の羽軸根、咽喉頭スワブおよびクロアカスワブか らのウイルス検出を経時的に行った。ウイルス分離の結果、スワブと比較し て、羽から大量のウイルスが長期間検出された。感染アイガモの羽が、スワ ブと同様に、ウイルス検出のための有用な試料となりうる可能性を提示した。 最後に、感染水禽の羽を介した環境中へのウイルス汚染を評価した。清武 株および秋田株を実験感染させたアイガモの羽、飲用水、糞便を採材し、異 なる2 つの温度条件下で、試料中のウイルスの感染性の存続期間を解析した。 飲用水や糞便と比較して、羽は大量の感染性ウイルスを長期間保持していた。 羽組織中からの感染性ウイルスの分離期間は、摂氏4 度で保存された場合 160 日間、摂氏20 度の場合15 日間であった。以上の成績から、感染水禽の 羽が、野外環境において高力価のH5N1 HPAI ウイルスを含有する感染媒介 物として成立する可能性が示唆された。 Asian lineage H5N1 highly pathogenic avian influenza (HPAI) virus has spread from Asia to Europe, the Middle East, and Africa, causing profound economic losses in the poultry industry. Several reports of virus detection in wild and domestic waterfowl indicate that waterfowl can serve as carriers and amplifying hosts of this virus. Therefore, the author hypothesized that the detailed analysis on the pathogenesis and viral replication in waterfowl would provide information to reduce the risk of viral transmission from infected waterfowl. In particular, the author focused on the viral replication in feathers, and discussed the possible role of waterfowl feathers in viral transmission from infected birds In chapter Ⅰ, the author examined the pathogenesis in domestic ducks inoculated with Japanese H5N1 HPAI virus. The virus caused mortality, neurologic symptoms, and pathologic changes such as the encephalitis, pancreatic necrosis, corneal opacity and epidermal necrosis of the feathers. High mortality in ducklings indicates that the age of birds is a factor influencing on the viral replication. The feather lesions caused by virus replication raise the potential of feathers as new route of virus shedding from waterfowl infected with H5N1 HPAI virus. In chapter Ⅱ, the experimental infection was performed to examine whether the feather lesion observed in the previous chapter is common to other H5N1 HPAI virus strains or other waterfowl species. Two different clades of the virus replicated in the feather epidermis of domestic ducks and geese in experimental infection. Electron microscopic examination provided the direct evidence of viral replication in feather epidermal cells. Viral replication in the feather tissue was also found in whooper swans naturally infected with the virus. In addition, the viral transmission was confirmed in domestic ducks by oral inoculation of down feathers plucked from a duck infected with the virus. In chapter Ⅲ, it was reported that feathers of infected domestic ducks can be useful samples for virus detection as well as their swabs. In the experimental infection using 2 H5N1 HPAI viruses and domestic ducks, larger amounts of viruses were isolated for longer period from feathers than from the swabs, indicating that feathers are considered to be useful clinical samples for surveillance or diagnostic examination of H5N1 HPAI virus in domestic ducks. The author also investigated the viral persistence in feathers detached from bodies of domestic ducks infected with H5N1 HPAI viruses to evaluate the possible environmental contamination by infective feathers. Feathers plucked from experimentally infected domestic ducks were examined by virus isolation. Infectious viruses persisted for the longest period in feather calami compared with drinking water and feces. Viral infectivity persisted in the feathers for 160 days at 4oC and for 15 days at 20oC. These results indicate that feathers detached from domestic ducks infected with H5N1 HPAI virus can function as fomites containing high viral loads in the environment. In conclusion, the author presented a new viewpoint on an epidemiological role of waterfowl feathers in Asian lineage H5N1 HPAI virus transmission. Hokkaido University(北海道大学） 博士 獣医学
Asian lineage highly pathogenic avian influenza virus (H5N1) continues to cause mortality in poultry and wild bird populations
at a panzootic scale. However, little is known about its persistence in contaminated tissues derived from infected birds.
We investigated avian influenza virus (H5N1) persistence in feathers detached from bodies of infected ducks to evaluate their
potential risk for environmental contamination. Four-week-old domestic ducks were inoculated with different clades of avian
influenza virus (H5N1). Feathers, drinking water, and feces were collected on day 3 postinoculation and stored at 4°C or 20°C.
Viral persistence in samples was investigated for 360 days by virus isolation and reverse transcription-PCR. Infectious viruses
persisted for the longest period in feathers, compared with drinking water and feces, at both 4°C and 20°C. Viral infectivity
persisted in the feathers for 160 days at 4°C and for 15 days at 20°C. Viral titers of 104.3 50% egg infectious doses/ml or greater were detected for 120 days in feathers stored at 4°C. Viral RNA in feathers was more
stable than the infectivity. These results indicate that feathers detached from domestic ducks infected with highly pathogenic
avian influenza virus (H5N1) can be a source of environmental contamination and may function as fomites with high viral loads
in the environment.
The chemical compound metam-sodium was tested at three concentrations for the ability to inactivate the infectivity of low-pathogenic avian influenza virus (LPAIV) and infectious bursal disease virus (IBDV), with virus-contaminated chicken litter used as the substrate. LPAIV was inactivated within 1 hr after the addition of metam-sodium independent of the concentration used. IBDV was not inactivated with the lowest amount of metam-sodium, but at higher concentrations the virus was inactivated within 1 hr after application. The results show that metam-sodium is able to penetrate chicken litter and inactivate enveloped as well as nonenveloped viruses because of its ability to form the active compound methyl isothiocyanate, which acts as a fumigant.
Two bacteriophages, phi6 and phi8, were investigated as potential surrogates for H5N1 highly pathogenic avian influenza virus in persistence and chlorine inactivation studies in water. In the persistence studies, phi6 and phi8 remained infectious at least as long as the H5N1 viruses at both 17 and 28 degrees C in fresh water, but results varied in salinated water. The bacteriophage phi6 also exhibited a slightly higher chlorine resistance than that of the H5N1 viruses. Based upon these findings, the bacteriophages may have potential for use as surrogates in persistence and inactivation studies in fresh water.
An outbreak of highly pathogenic avian influenza A
(H5N1) has recently spread to poultry in 9 Asian countries.
H5N1 infections have caused >52 human deaths in
Vietnam, Thailand, and Cambodia from January 2004 to
April 2005. Genomic analyses of H5N1 isolates from birds
and humans showed 2 distinct clades with a nonoverlapping
geographic distribution. All the viral genes were of avian
influenza origin, which indicates absence of reassortment
with human influenza viruses. All human H5N1 isolates tested
belonged to a single clade and were resistant to the
adamantane drugs but sensitive to neuraminidase
inhibitors. Most H5N1 isolates from humans were antigenically
homogeneous and distinct from avian viruses circulating
before the end of 2003. Some 2005 isolates showed
evidence of antigenic drift. An updated nonpathogenic H5N1
reference virus, lacking the polybasic cleavage site in the
hemagglutinin gene, was produced by reverse genetics in
anticipation of the possible need to vaccinate humans.
We analyzed isolates of Escherichia coli O157:H7 (which has recently caused waterborne outbreaks) and wild-type E. coli to determine their sensitivity to chlorination. Both pathogenic and nonpathogenic strains were significantly reduced within 1 minute of exposure to free chlorine. Results indicate that chlorine levels typically maintained in water systems are sufficient to inactivate these organisms.
Waterfowl are the natural reservoir of all influenza A viruses, which are usually nonpathogenic in wild aquatic birds. However, in late 2002, outbreaks of highly pathogenic H5N1 influenza virus caused deaths among wild migratory birds and resident waterfowl, including ducks, in two Hong Kong parks. In February 2003, an avian H5N1 virus closely related to one of these viruses was isolated from two humans with acute respiratory distress, one of whom died. Antigenic analysis of the new avian isolates showed a reactivity pattern different from that of H5N1 viruses isolated in 1997 and 2001. This finding suggests that significant antigenic variation has recently occurred among H5N1 viruses. We inoculated mallards with antigenically different H5N1 influenza viruses isolated between 1997 and 2003. The new 2002 avian isolates caused systemic infection in the ducks, with high virus titers and pathology in multiple organs, particularly the brain. Ducks developed acute disease, including severe neurological dysfunction and death. Virus was also isolated at high titers from the birds' drinking water and from contact birds, demonstrating efficient transmission. In contrast, H5N1 isolates from 1997 and 2001 were not consistently transmitted efficiently among ducks and did not cause significant disease. Despite a high level of genomic homology, the human isolate showed striking biological differences from its avian homologue in a duck model. This is the first reported case of lethal influenza virus infection in wild aquatic birds since 1961.
The development of highly pathogenic avian H5N1 influenza viruses in poultry in Eurasia accompanied with the increase in human infection in 2006 suggests that the virus has not been effectively contained and that the pandemic threat persists. Updated virological and epidemiological findings from our market surveillance in southern China demonstrate that H5N1 influenza viruses continued to be panzootic in different types of poultry. Genetic and antigenic analyses revealed the emergence and predominance of a previously uncharacterized H5N1 virus sublineage (Fujian-like) in poultry since late 2005. Viruses from this sublineage gradually replaced those multiple regional distinct sublineages and caused recent human infection in China. These viruses have already transmitted to Hong Kong, Laos, Malaysia, and Thailand, resulting in a new transmission and outbreak wave in Southeast Asia. Serological studies suggest that H5N1 seroconversion in market poultry is low and that vaccination may have facilitated the selection of the Fujian-like sublineage. The predominance of this virus over a large geographical region within a short period directly challenges current disease control measures.
• influenza A
• molecular epidemiology
• virus evolution
Since 2002, H5N1 highly pathogenic avian influenza (HPA1) viruses have been associated with deaths in numerous wild avian species throughout Eurasia. We assessed the clinical response and extent and duration of viral shedding in 5 species of North American ducks and laughing gulls (Larus atricilla) after intranasal challenge with 2 Asian H5N1 HPAI viruses. Birds were challenged at approximately equal to 10 to 16 weeks of age, consistent with temporal peaks in virus prevalence and fall migration. All species were infected, but only wood ducks (Aix sponsa) and laughing gulls exhibited illness or died. Viral titers were higher in oropharyngeal swabs than in cloacal swabs. Duration of viral shedding (1-10 days) increased with severity of clinical disease. Both the hemagglutination-inhibition (HI) and agar gel precipitin (AGP) tests were able to detect postinoculation antibodies in surviving wood ducks and laughing gulls; the HI test was more sensitive than the AGP in the remaining 4 species.
This is the first report of the isolation of H13N2 avian influenza virus (AIV) subtype from domestic turkeys. This subtype was also isolated from nearby surface water. The observation of large numbers of gulls in close association with turkeys on range before the virus isolations suggests that this virus subtype was transmitted from gulls to range turkeys. Turkey flocks infected by this virus subtype did not show any clinical signs of the disease, although seroconversion did occur. The H13N2 isolates were found to be non-pathogenic in chickens.
Persistence of five avian influenza viruses (AIVs) derived from four waterfowl species in Louisiana and representing five hemagglutinin and neuraminidase subtypes was determined in distilled water at 17 C and 28 C. Infectivity was determined over 60 days by microtiter endpoint titration. One AIV was tested over 91 days at 4 C. Linear regression models for these viruses predicted that an initial concentration of 1 x 10(6) TCID50/ml water could remain infective for up to 207 days at 17 C and up to 102 days at 28 C. Significant differences in slopes for AIV persistence models were detected between treatment temperatures and among viruses. Results suggest that these viruses are adapted to transmission on waterfowl wintering habitats. Results also suggest a potential risk associated with waterfowl and domestic poultry sharing a common water source.
The pathogenicity potential of two H13N2 influenza viruses, one isolated from turkeys and the other isolated from surface water, was evaluated in turkeys, chickens, and mallard ducks (Anas platyrhynchos) after intracranial and oculonasal inoculation. Both isolates replicated in turkey poults, causing depressed weight gain, morbidity and mortality; both also caused histopathological lesions, such as mild to severe pancreatitis, hepatitis, and nephritis in turkeys. These isolates replicated in mallard ducklings but not in chickens. There was depressed weight gain in ducklings given the H13N2 isolate from water. Neither isolate caused morbidity or mortality in ducklings or chicks after inoculation.
Although fecal-oral transmission of avian influenza viruses (AIV) via contaminated water represents a recognized mechanism for transmission within wild waterfowl populations, little is known about viral persistence in this medium. In order to provide initial data on persistence of H5 and H7 AIVs in water, we evaluated eight wild-type low-pathogenicity H5 and H7 AIVs isolated from species representing the two major influenza reservoirs (Anseriformes and Charadriiformes). In addition, the persistence of two highly pathogenic avian influenza (HPAI) H5N1 viruses from Asia was examined to provide some insight into the potential for these viruses to be transmitted and maintained in the environments of wild bird populations. Viruses were tested at two temperatures (17 C and 28 C) and three salinity levels (0, 15, and 30 parts per thousand sea salt). The wild-type H5 and H7 AIV persistence data to date indicate the following: 1) that H5 and H7 AIVs can persist for extended periods of time in water, with a duration of infectivity comparable to AIVs of other subtypes; 2) that the persistence of H5 and H7 AIVs is inversely proportional to temperature and salinity of water; and 3) that a significant interaction exists between the effects of temperature and salinity on the persistence of AIV, with the effect of salinity more prominent at lower temperatures. Results from the two HPAI H5N1 viruses from Asia indicate that these viruses did not persist as long as the wild-type AIVs.
World Health Organization Global Infl uenza Program Surveillance Network. Evolution of H5N1 avian infl uenza viruses in Asia
World Health Organization Global Infl uenza Program Surveillance
Network. Evolution of H5N1 avian infl uenza viruses in Asia. Emerg
Infect Dis. 2005;11:1515-21.
List of species affected by H5N1 (avian infl uenza)
- National Wildlife
- Health Center
National Wildlife Health Center. List of species affected by H5N1
(avian infl uenza). Nov 2006. [cited 2007 Jul 25.] Available from
http://www.nwhc.usgs.gov/disease_information/avian_influenza/
affected_species_chart.jsp