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Effects of Chlorine, Iodine, and Quaternary Ammonium Compound Disinfectants on Several Exotic Disease Viruses

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The effects of three representative disinfectants, chlorine (sodium hypochlorite), iodine (potassium tetraglicine triiodide), and quaternary ammonium compound (didecyldimethylammonium chloride), on several exotic disease viruses were examined. The viruses used were four enveloped viruses (vesicular stomatitis virus, African swine fever virus, equine viral arteritis virus, and porcine reproductive and respiratory syndrome virus) and two non-enveloped viruses (swine vesicular disease virus (SVDV) and African horse sickness virus (AHSV)). Chlorine was effective against all viruses except SVDV at concentrations of 0.03% to 0.0075%, and a dose response was observed. Iodine was very effective against all viruses at concentrations of 0.015% to 0.0075%, but a dose response was not observed. Quaternary ammonium compound was very effective in low concentration of 0.003% against four enveloped viruses and AHSV, but it was only effective against SVDV with 0.05% NaOH. Electron microscopic observation revealed the probable mechanism of each disinfectant. Chlorine caused complete degeneration of the viral particles and also destroyed the nucleic acid of the viruses. Iodine destroyed mainly the inner components including nucleic acid of the viruses. Quaternary ammonium compound induced detachment of the envelope of the enveloped viruses and formation of micelle in non-enveloped viruses. According to these results, chlorine and iodine disinfectants were quite effective against most of the viruses used at adequately high concentration. The effective concentration of quaternary ammonium compound was the lowest among the disinfectants examined.
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Effects of Chlorine, Iodine, and Quaternary Ammonium Compound Disinfectants on
Several Exotic Disease Viruses
Junsuke SHIRAI, Toru KANNO, Yoshinori TSUCHIYA, Satoru MITSUBAYASHI1) and Reiji SEKI1)
Department of Exotic Diseases, National Institute of Animal Health, 6–20–1, Josuihoncho, Kodaira, Tokyo 187–0022 and 1)Tamura
Pharmaceutical Co., Ltd., 1–4 Kanda Jinbocho, Chiyoda-ku, Tokyo 101–0051, Japan
(Received 23 July 1999/Accepted 27 September 1999)
ABSTRACT. The effects of three representative disinfectants, chlorine (sodium hypochlorite), iodine (potassium tetraglicine triiodide), and
quaternary ammonium compound (didecyldimethylammonium chloride), on several exotic disease viruses were examined. The viruses
used were four enveloped viruses (vesicular stomatitis virus, African swine fever virus, equine viral arteritis virus, and porcine reproductive
and respiratory syndrome virus) and two non-enveloped viruses (swine vesicular disease virus (SVDV) and African horse sickness virus
(AHSV)). Chlorine was effective against all viruses except SVDV at concentrations of 0.03% to 0.0075%, and a dose response was
observed. Iodine was very effective against all viruses at concentrations of 0.015% to 0.0075%, but a dose response was not observed.
Quaternary ammonium compound was very effective in low concentration of 0.003% against four enveloped viruses and AHSV, but it was
only effective against SVDV with 0.05% NaOH. Electron microscopic observation revealed the probable mechanism of each disinfectant.
Chlorine caused complete degeneration of the viral particles and also destroyed the nucleic acid of the viruses. Iodine destroyed mainly
the inner components including nucleic acid of the viruses. Quaternary ammonium compound induced detachment of the envelope of the
enveloped viruses and formation of micelle in non-enveloped viruses. According to these results, chlorine and iodine disinfectants were
quite effective against most of the viruses used at adequately high concentration. The effective concentration of quaternary ammonium
compound was the lowest among the disinfectants examined.—KEY WORDS: disinfection, electron microscopy, exotic disease virus.
J. Vet. Med. Sci. 62(1): 85–92, 2000
disease for horse racing in Japan [15]. PRRSV is not an
exotic disease virus in Japan now [17], but it is a new disease
virus; therefore, a disinfection against this virus has not
been tested well.
MATERIALS AND METHODS
Viruses and cell culture: The J1 strain of SVDV [23], the
New Jersey strain of VSV [4], the Lisbon strain of ASFV
[20], the type 4 vaccine strain of AHSV [16], the modified
Bucyrus strain of EVAV [15], and the EDRD strain of
PRRSV [17] were used in this study. SVDV and VSV were
propagated in IBRS-2 cells [11]. ASFV and AHSV were
propagated in Vero cells [16]. EVAV and PRRSV were
prepared in Marc-145 cells [17]. The viral samples of
SVDV, VSV, AHSV were prepared in cells cultured with
the serum free medium, but those of ASFV, EVAV, and
PRRSV were prepared in cells cultured with the medium
containing 2% bovine serum.
Virus titration: The virus titers before and after treatment
with disinfectants were titrated in each of culture cells. The
titration of SVDV and VSV was carried out by plaque
formation method as previously described [11] and the titers
were expressed as plaque-forming unit (PFU) per 0.1 ml.
The titers were expressed as 50% tissue culture infectious
dose (TCID50) per 0.1 ml in ASFV, AHSV, EVAV and
PRRSV.
Disinfectants: A commercial chlorine disinfectants
containing 6% sodium hypochlorite (SHC) (Purelox, 6%
(w/v) Ohyalax Co., Ltd.) was used for chlorine disinfectant.
Preventing the entry and spread of infectious disease
agents is a critical step in controlling infectious diseases,
and the effective use of disinfectants is a vital and necessary
measure for the control of infectious routes. Historically,
there are many instances when disinfectants have been used
successfully in the control and prevention of both human
and animal infectious diseases [2, 8]. The notifiable animal
infectious diseases, named in the Office International des
Epizooties (OIE) list A diseases, were mostly viral diseases
[19]. However, effects of disinfection against these exotic
viral agents have been not investigated in Japan. There is
little information for the routine disinfection for the
protection against these pathogens. Therefore we studied
the effects of representative disinfectants on exotic disease
viruses.
The viruses used in this study and its selected reasons
were as follows. Swine vesicular disease virus (SVDV)
belongs to a family picornaviruses similar to foot-and-mouth
disease virus (FMDV) and causes a disease similar to FMD.
But SVDV has stronger resistance to chemicals and
disinfectants than FMDV [1, 9]. African horse sickness
virus (AHSV) belongs to the orbiviruses and it causes severe
or even fatal disease in horses. Vesicular stomatitis virus
(VSV) belongs to rhabdoviruses and it causes a disease
similar to FMD [4]. African swine fever virus (ASFV) is a
pox-like virus and it causes a disease similar to classical
swine fever [20]. Equine viral arteritis virus (EVAV) and
porcine reproductive and respiratory syndrome virus
(PRRSV) belong to the arteriviruses. EVAV causes
reproductive failure in horses and it is a most threatening
FULL PAPER Virology
86 J. SHIRAI ET AL.
A commercial iodine compound disinfectant containing 3%
potassium tetraglicine triiodide (PTT) (Poliup-3, 3% (w/w)
Kyowa Hakko Kogyo Co., Ltd.) was used for iodine
disinfectant. Commercial quaternary ammonium compound
containing 10% didecyldimethylammonium chloride
(DDAC) (Cleakil-100, 10% (w/v) Tamura pharmaceutical
Co., Ltd.) was used for the quaternary ammonium
compound.
Assay procedures for virucidal activity: The chlorine
disinfectant (6% SHC) diluted in 1/100, 1/200, 1/400, 1/
800, 1/1,600, and 1/3,200 was used. The iodine disinfectant
(3% PTT) diluted in 1/100, 1/200, 1/400, 1/800, 1/1,600,
and 1/3,200 was used. The quaternary ammonium
compound (10% DDAC) diluted in 1/400, 1/800, 1/1,600,
1/3,200, 1/6,400, and 1/12,800 was used. Each virus sample
was directly used and mixed with equal volume of each
diluted disinfectant and the mixtures were incubated at room
temperature for 30 min. Following incubation, the
specimens were immediately diluted in tissue culture
medium containing 5% calf serum and titrated.
Each virus sample except for ASFV was mixed with an
equal volume of each adequately diluted disinfectant and
incubated at room temperature for 1, 5, 10, 30, and 60 min.
Then the specimens were immediately diluted in tissue
culture medium containing 5% calf serum and titrated.
Specimens diluted in distilled water and incubated for 60
min were used as a control.
Electron microscopy: SVDV, VSV, AHSV, and PRRSV
were propagated in roller bottle and purified for examination
by electron microscopy. The purified viruses were mixed
with an equal volume of distilled water, 0.06% of SHC in
chlorine disinfectant (0.12% of SHC for SVDV), 0.03% of
PTT in iodine disinfectant, or 0.025% of DDAC in
quaternary ammonium compound and allowed to stand for
30 min at room temperature. One drop of each sample was
mounted on a 400-mesh carbon-coated grid, and negatively
stained with 2% phosphotungstic acid, pH 7.05, for 1 min.
The samples were examined in a JEM-1200 EX electron
microscope (JEOL Ltd., Tokyo, Japan).
RESULTS
Virucidal activity of disinfectant: The effects of the
concentration of each disinfectant are summarized in Figs.
1, 2, and 3. The effects of the chlorine disinfectant were
observed at the final concentrations from 1/200 to 1/800.
The effective concentration of this disinfectant were 0.03%
to 0.0075% for SHC, calculated from the original
concentration of SHC in the starting material. But a slight
effect of chlorine against SVDV was observed at high
concentration. The effects of chlorine varied depending on
the viral species. A dose response was observed for the
chlorine disinfectant, so a small amount of virus was
inactivated by a lower concentration of disinfectant (Fig. 1).
The effects of the iodine disinfectant also were observed at
the final concentrations from 1/200 to 1/400. The effective
concentrations of the iodine disinfectant were 0.015% to
0.0075% for PTT, calculated from the original concentration
of PTT in the starting material. Iodine was effective against
SVDV at a concentration of 1/200. The effects of iodine
were variable depending on the viral species. However, a
dose response was not observed for the iodine disinfectant
(Fig. 2). The effects of quaternary ammonium compound
were observed at the concentration of 1/3,200 against all
enveloped viruses. The effects of quaternary ammonium
compound against AHSV was observed at the concentration
of 1/800. But no effect was observed against SVDV. The
effective concentration of this disinfectant was 0.003% of
DDAC calculated from the original concentration of DDAC
in the starting material. The effective concentration of
DDAC against AHSV was 0.0125%. A dose response was
observed for quaternary ammonium compound and small
amounts of the viruses were killed by a concentration of 1/
12,800 (Fig. 3). No cytotoxicity was observed when the
disinfectants were diluted more than 1:200.
The effects of time of exposure to each disinfectant
against all of the viruses except for SVDV were within 10
min in the adequate concentration. However, the effect of
time for disinfection showed clearly the sensitivity of each
virus to each disinfectant; for example, EVAV and PRRSV
are more resistant to chlorine disinfectant and VSV is more
resistant to each disinfectant than other viruses. The effect
of iodine disinfectant against SVDV was within 5 min, but
those of other disinfectants were 60 min. This showed that
SVDV was the most resistant virus to disinfection (Table
1).Electron microscopy: Electron micrographs of virus
particles affected by the compounds are shown in Figs. 4
and 5. Figure 4 shows the effects of each disinfectant
against AHSV. Round viral particles 50 nm in diameter
were observed in control material (Fig. 4-a). Non-structural
substances shaped like micelles produced by the effects of
quaternary ammonium compound were observed (Fig. 4-b).
Definitive particles that lost nucleoprotein by exposure to
chlorine disinfectant were observed (Fig. 4-c). Definitive
viral particle aggregation was observed in the iodine
disinfectant material (Fig. 4-d). Figure 5 shows the effects
of each disinfectant against VSV. Bullet shape particles
about 120 nm in diameter were observed (Fig. 5-a). The
virus envelopes were completely removed by quaternary
ammonium compound, and the inner structure
(nucleoprotein) was clearly observed (Fig. 5-b). The virus
particles were completely degenerated by chlorine and the
shape of the viral particle changed to round (Fig. 5-c).
Definitive particles whose inner structure was destroyed by
iodine disinfectant were observed, but their outer structure
remained (Fig. 5-d). The effects of each disinfectant on
SVDV and PRRSV were also observed in the electron
microscope. In SVDV specimens, the virus particles were
gathered by quaternary ammonium compound, but each viral
particle retained its intact form. Completely destroyed
particles or definitive viral particles were observed in the
chlorine and iodine disinfectant material. In PRRSV
specimens, the viral particles were completely destroyed by
87
EFFECTS OF DISINFECTANTS ON EXOTIC DISEASE VIRUSES
quaternary ammonium compound; however the outer
structure remained. The viral particles were destroyed but a
few intact particles were observed in the chlorine
disinfectant material. The definitive particles were observed
in the iodine disinfectant material.
DISCUSSION
The outbreak of FMD in Taiwan [6] is a big threat for
Japanese animal industries because of its enormous damage.
The first eradication strategy against the outbreak of FMD
started from effective disinfection, because FMD spread
very rapidly. Almost all the important animal diseases
called exotic diseases of Japan are caused by viruses [19].
Therefore, good disinfection against viruses is important for
disease control. There are eight main kinds of disinfectants
now in use, chlorine, peracetic acid, and iodine compounds
are effective disinfectants against viruses [10]. But peracetic
acid is too expensive to be used in routine disinfection.
Therefore, chlorine and iodine compounds were used for
Fig. 1. The effects of chlorine disinfectant against several exotic disease viruses. Lines show the titers of the
inactivated virus. Bars show the remaining virus titers. SVDV and AHSV are non-enveloped viruses. VSV,
ASFV, EVAV, and PRRSV are enveloped viruses. SHC is the initial letters of sodium hypochlorite.
88 J. SHIRAI ET AL.
this study. Quaternary ammonium compound is used widely
as a disinfectant against pathogens including viruses, but
the effects of quaternary ammonium compound against
viruses are believed to be none or little [5, 12, 14].
However, inactivation of infectious bursal disease virus and
SVDV by quaternary ammonium compound with 0.05%
NaOH was reported recently [21, 22]. Therefore, in this
study, we confirmed the inactivation of several exotic animal
diseases viruses by chlorine, iodine and quaternary
ammonium compound. And the probable mechanisms of
Fig. 2. The effects of iodine disinfectant against several exotic disease viruses. Lines show the titers of the
inactivated virus. Bars show the remaining virus titers. The names of viruses were referred to Fig. 1. PTT is the
initial letters of potassium tetraglicine triiodide.
each disinfectant are revealed morphologically by electron
microscopy.
The chlorine disinfectant has a volatile character and it is
better to use a high concentration. Therefore, this
disinfectant is considered to be not very economically useful
as a routine disinfectant. However, this disinfectant gives a
dose response, so a low concentration is not always
ineffective against the viruses. The iodine disinfectant is
susceptible to sunshine and it has no dose response;
therefore, it is better to use this disinfectant at higher
89
EFFECTS OF DISINFECTANTS ON EXOTIC DISEASE VIRUSES
concentration than chlorine. Non-enveloped viruses such as
SVDV and AHSV were considered to be resistant to
quaternary ammonium compound [12, 14]. However, our
results showed that AHSV was inactivated at a final
concentration of 0.0125% DDAC.
The mechanism of the effect of chlorine was considered
to be degeneration of the virus particles, because the
morphological study by electron microscopy revealed a
dramatic morphological change and loss of the inner
structure of the virus particles. These results were consistent
with a previous observation on the efficacy of the action of
SHC on bacteriophages [13]. The mechanism of the effect
of the iodine was considered to be degeneration of the inner
component (nucleoprotein) of the virus particles. The
electron micrographs revealed degeneration of inner
structure of the virus particles after exposure to iodine
disinfectant. This kind of conformational change to the
protein by iodine was observed in the case of bacteriophages
[3]. The mechanism of the effect of quaternary ammonium
compound was considered to be removal of the envelope of
Fig. 3. The effects of quaternary ammonium compound against several exotic disease viruses. Lines show the
titers of the inactivated virus. Bars show the remaining virus titers. The names of viruses were referred to
Fig.1. DDAC is the initial letters of didecyldimethylammonium chloride.
90 J. SHIRAI ET AL.
the virus and/or micelle formation of virus particles, since it
clearly removed the envelope and partially destroyed the
virus particles of enveloped viruses. For non-enveloped
viruses, quaternary ammonium compound formed
nonstructural substances, so called micelle, with or without
0.05%NaOH.
From these results we conclude that the effects of each
disinfectant against several exotic disease viruses are as
follows. In order of effectiveness against viruses, it could
be considered that the first was the iodine disinfectant, and
the second was the chlorine disinfectant. Although the
effective concentrations and persistence of both disinfectants
are very important, and the effective term of both
disinfectants diluted is considered to be short. Therefore,
when we use the chlorine and iodine disinfectants, we have
to use very fresh and adequately diluted ones. Quaternary
ammonium compound did not have the same effect against
non-enveloped viruses as the others, but it had much
stronger effect against enveloped viruses than the others.
Considering the enhancement of the disinfecting effect
against non-enveloped viruses when quaternary ammonium
compound was used with 0.05% NaOH [21, 22], it is a very
useful disinfectant to use routinely against viral diseases.
Other effects for disinfection, for example, temperature
and pH etc. were not examined in this study. These factors
also very important for virucidal effect of disinfection.
Table 1. The effects of time for disinfection
Percentage of virus inactivated after each exposure time
Exposure time (minutes) 1 5 10 30 60
Viruses and disinfectans*
Swine vesicular disease virus
Chlorine (0.06%) 42 50 66 100 100
Iodine (0.015) 82 100 100 100 100
Quaternary ammonium 59 62 70 79 100
compound (0.0125%)
with 0.05%NaOH
Vesicular stomatitis virus
Chlorine (0.03%) 71 79 100 100 100
Iodine (0.0075%) 77 100 100 100 100
Quaternary ammonium 64 67 100 100 100
compound (0.003%)
African horse sickness virus
Chlorine (0.0075%) 100 100 100 100 100
Iodine (0.0075%) 100 100 100 100 100
Quaternary ammonium 81 100 100 100 100
compound (0.0125%)
Equine viral arteritis virus
Chlorine (0.015%) 64 100 100 100 100
Iodine (0.015%) 100 100 100 100 100
Quaternary ammonium 100 100 100 100 100
compound (0.003%)
Porcine reproductive and respiratory syndrome virus
Chlorine (0.03%) 47 84 100 100 100
Iodine (0.0075%) 100 100 100 100 100
Quaternary ammonium 100 100 100 100 100
compound (0.0063%)
* The percentage in the parenthesis indicated in the final concentration of each disinfec-
tant.
Therefore, the further studies are required to reveal the good
disinfecting method.
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... In terms of disinfection, using iodine (0.0075 percent) or quaternary ammonium compounds (0.0063 percent), the virus was totally inactivated in 1 minute (Shirai et al., 2000). Chlorine can also completely inactivate PRRSV, though a higher disinfectant concentration (0.03 percent) and a longer exposure time (10 minutes) are required (Shirai et al., 2000). Similarly, 10 minutes of exposure to UV light completely inactivated the virus on farm surfaces and equipments (Dee et al., 2011). ...
... Firstly, GS-2 displayed activity against C. auris, an emerging pathogen that is considered extremely difficult to eradicate with current disinfectant products [55]. In this study, GS-2 and GS-2 with thymol also demonstrated efficacy against C. difficile, P. aeruginosa, and poliovirus, all of which are considered problematic for quats [55][56][57]. It is also worth noting that the concentrations of GS-2 (capric acid; 15-30 mg/mL) and thymol (5-7.5 mg/mL) used in this study are comparable to the concentrations of BAC used in commercial disinfectants (1-30 mg/mL) [56], suggesting that GS-2 with thymol would be an acceptable alternative to quats. ...
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The environmental control of microbial pathogens currently relies on compounds that do not exert long-lasting activity on surfaces, are impaired by soil, and contribute to the growing problem of antimicrobial resistance. This study presents the scientific development and characterization of GS-2, a novel, water-soluble ammonium carboxylate salt of capric acid and L-arginine that demonstrates activity against a range of bacteria (particularly Gram-negative bacteria), fungi, and viruses. In real-world surface testing, GS-2 was more effective than a benzalkonium chloride disinfectant at reducing the bacterial load on common touch-point surfaces in a high-traffic building (average 1.6 vs. 32.6 CFUs recovered from surfaces 90 min after application, respectively). Toxicology testing in rats confirmed GS-2 ingredients were rapidly cleared and posed no toxicities to humans or animals. To enhance the time-kill against Gram-positive bacteria, GS-2 was compounded at a specific ratio with a naturally occurring monoterpenoid, thymol, to produce a water-based antimicrobial solution. This GS-2 with thymol formulation could generate a bactericidal effect after five minutes of exposure and a viricidal effect after 10 min of exposure. Further testing of the GS-2 and thymol combination on glass slides demonstrated that the compound retained bactericidal activity for up to 60 days. Based on these results, GS-2 and GS-2 with thymol represent a novel antimicrobial solution that may have significant utility in the long-term reduction of environmental microbial pathogens in a variety of settings.
... The consumed free iodine is then replaced by PVP bound iodine. The determining factor of the microbicidal action of PVP-I is the concentration of free iodine [37][38][39] . A study by Schreier H et al., investigating the virucidal activity of different disinfectants, electron micrographs revealed how exposure to iodine led to degeneration of the nucleoproteins of viral particles, which was the main mechanism ofaction 40 . ...
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Various microbes like viruses, bacteria, fungi and protozoa can give rise to many common oral and oropharyngeal conditions such as dental caries, periodontal disease, gingivitis, also cause upper respiratory tract infections like sore throat, common cold and influenza. Respiratory syncytial viruses can be spread by large droplets propelled through the air and inoculated into the eyes, nose and mouth at close range. Considering these modes of transmission, oral hygiene by gargling, together with hand washing and mask use, may be beneficial to help minimise the risk of both community- and hospital acquired respiratory infections. Various in vitro studies demonstrated rapid bactericidal and virucidal activity of PVP-I gargle/mouthwash against respiratory pathogens. In the current scenario of Covid -19 pandemic, recommending PVP- I mouth rinsing as a practice along with regular handwashing with soap can be considered.
... The following list of disinfectants are recommended (see Haas et al., 1995;Heckert et al., 1997;Shirai et al., 1997Shirai et al., , 2000: chlorine (sodium hypochlorite); iodine (potassium tetraglicine triiodide); quaternary ammonium compound (dodecyl dimethyl ammonium chloride); vapo-phase hydrogen peroxide; aldehydes (formaldehyde); organic acids; oxidizing acids (peracetic acid); alkalis (calcium hydroxide and sodium hydroxide); ether and chloroform. Registered commercial disinfectants ...
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African swine fever (ASF) is a devastating haemorrhagic viral disease affecting domestic and wild pigs of all ages and sexes. This disease causes massive economic losses, threatens food security and trade, and presents a serious challenge for the pig production sector in affected countries. ASF also threatens the biodiversity conservation of several Asiatic wild Suidae. Since ASF was first introduced in Georgia in 2007, the disease has spread to many countries in Europe, Asia and the Pacific, and in 2021, it was detected in the Caribbean states of the Dominican Republic and Haiti, both in the Americas. In much of its Euro-Asiatic range, the African swine fever virus (ASFV) infects wild boar, which sometimes act as the main – if not the only – epidemiological reservoir of the infection, keeping it in the environment regardless of the presence of infected domestic pigs. The presence of the virus in wild boar populations is a continuous health threat for the sympatric domestic pig population, posing a challenge for veterinary and wildlife services that have had little success in attempting to eradicate infections among wildlife, especially in the absence of an effective vaccine. Finally, areas in which ASFV is detected in wild boar remain infected for at least one year after the last recorded case. This is a much longer period than that of domestic animals and puts a strain on the services involved, requiring a considerable amount of work and human and financial resources. The second edition of the handbook provides insights on surveillance and disease management in wild boar based on experiences with ASFV eradication in Belgium and Czechia, as well as other recent experiences in the prevention and control of the disease in wild boar in Europe.
... 19 The strength of povidone-iodine is dependent on the concentration of unbound iodine in the complex. 20,21 The assay results for povidone-iodine products revealed that 52.9% of samples representing six brands failed to comply with assay specifications within the 24-84% label claim range. Due to low iodine content, these non-compliant samples may be ineffective as gargles and mouth rinses. ...
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Background: The oral cavity harbors many microbes that may cause diseases, including dental caries and periodontal diseases. Progressive inflammation from periodontal diseases may lead to gum detachment from the teeth. Povidone-iodine and chlorhexidine mouth rinses and gargles are broad-spectrum antimicrobial products that effectively manage dental caries and periodontal diseases and eliminate plaques. This study was conducted in Nairobi County, Kenya to establish the quality of povidone-iodine and chlorhexidine oral care products by determining the content of the active pharmaceutical ingredient and compliance with labeling requirements. Methods: A total of 34 samples (from 15 brands) of povidone-iodine and 15 samples (from nine brands) of chlorhexidine were collected from retail pharmacies using convenience sampling. All samples were subjected to labeling analysis, identity, and assay tests. Potentiometric titration was used to assay povidone-iodine in the samples, while chlorhexidine was assayed using high-performance liquid chromatography (HPLC) according to British Pharmacopeia 2017 specifications. Results: All samples complied with identification tests. Moreover, 47.1% of povidone-iodine and 66.7% of chlorhexidine products complied with pharmacopoeial assay specifications. Five povidone-iodine (14.7%) and four chlorhexidine (26.7%) samples had missing label information on the storage conditions and the address of the manufacturer. Conclusions: Strict adherence to current Good Manufacturing Practices (cGMP) by manufacturers of povidone-iodine and chlorhexidine mouthwashes/gargles is necessary to guarantee quality assured products in the market. Regular post-market surveillance and regulatory enforcement of standards are instrumental in minimizing the circulation of poor-quality products.
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Antifouling and antibacterial surfaces that can prevent nonspecific biological adhesion are important to support a myriad of biomedical applications. In this study, we have used an innovative photopolymerization technology to develop sulfur-containing polymer-grafted antifouling and antibacterial surfaces. The relationship between the hydrophilic property and the capability to resist protein and macrophage adsorption of the surface copolymer brushes was investigated. The sulfide monomer incorporated into the surface copolymer brushes can be further ionized to carry positive charges and impart antibacterial activity, leading to surfaces with dual antifouling and antibacterial functions. We believe that the reported sulfur-containing polymer brushes can be considered an emerging and important polymer for antifouling and antibacterial applications.
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Accounting for multiple modes of livestock disease dissemination in epidemiological models remains a challenge. We developed and calibrated a mathematical model for transmission of porcine reproductive and respiratory syndrome virus (PRRSV), tailored to fit nine modes of between‐farm transmission pathways including: farm‐to‐farm proximity (local transmission), contact network of batches of pigs transferred between farms (pig movements), re‐break probabilities for farms with previous PRRSV outbreaks, with the addition of four different contact networks of transportation vehicles (vehicles to transport pigs to farms, pigs to markets, feed and crew) and the amount of animal by‐products within feed ingredients (e.g. animal fat or meat and bone meal). The model was calibrated on weekly PRRSV outbreaks data. We assessed the role of each transmission pathway considering the dynamics of specific types of production (i.e., sow, nursery). Although our results estimated that the networks formed by transportation vehicles were more densely connected than the network of pigs transported between‐farms, pig movements and farm proximity were the main PRRSV transmission routes regardless of farm types. Among the four vehicle networks, vehicles transporting pigs to farms explained a large proportion of infections, sow = 20.9%; nursery = 15%; and finisher = 20.6%. The animal by‐products showed a limited association with PRRSV outbreaks through descriptive analysis, and our model results showed that the contribution of animal fat contributed only 2.5% and meat and bone meal only 0.03% of the infected sow farms. Our work demonstrated the contribution of multiple routes of PRRSV dissemination, which has not been deeply explored before. It also provides strong evidence to support the need for cautious, measured PRRSV control strategies for transportation vehicles and further research for feed by‐products modeling. Finally, this study provides valuable information and opportunities for the swine industry to focus effort on the most relevant modes of PRRSV between‐farm transmission. This article is protected by copyright. All rights reserved
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Objective To evaluate the reduction of the salivary viral load using oral antiseptic mouthwashes in patients testing positive for COVID-19. Methods 63 individuals were recruited after testing positive for COVID-19 by real-time RT-PCR assay and divided into 5 groups. Group 1 received sterile water, group 2 received 1.5% hydrogen peroxide solution (HP), group 3 received 0.12% chlorhexidine (CHX), group 4 received 0.1% sodium hypochlorite solution (NaClO), and group 5 received sequential rinses using CHX and HP. After collecting the initial saliva sample, individuals were asked to use the designated mouthwash for 1 minute. Additional saliva samples were collected immediately after rinsing, 15 and 30 minutes after rinsing. Real-time RT-PCR assays for RNA detection of SARS-CoV-2 were performed on the saliva samples. Results There were no significant differences among the experimental groups and the control group in any period. Compared to the baseline values, there was a significant reduction in the number of copies of SARS-Cov-2 after 30 minutes in Group 2, and immediately after the initial mouthwash in Group 4. Conclusion No experimental group demonstrated a significant reduction of the viral load compared to the control group.
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The complete sequence of RNA segment 5 of the African horsesickness virus serotype 4 (AHSV-4) vaccine strain was determined from cDNA clones inserted into pBR322. The RNA is 1751 bp long (M(r) 1.12 x 10(6)) and contains an open reading frame encoding a protein of 548 amino acids (M(r) 63,122) with a net charge of +0.5 at neutral pH. A comparison of the sequence of AHSV-4 segment 5 with that of segment 6 of bluetongue virus (BTV) serotypes 10 and 17 revealed 49.2% and 48.9% nucleotide similarity, respectively, and 31.4% amino acid similarity. However, AHSV-4 segment 5 has no significant similarity to BTV segment 5. In addition, Northern blot hybridization showed that full-length AHSV-4 segment 5 cDNA cross-hybridized with the corresponding genes of all serotypes of attenuated AHSV.
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MS2 coliphage Viruses suspended in buffered distilled water were rapidly inactivated by < 5 mg/L iodine doses, losing 6 logs (99.9999%) of infectivity within less than 3 min contact time. The effect of pH on MS2 inactivation within the range of 6 to 8 was not statistically significant. However, in the presence of dissolved organic substances, such as detergents and proteins, the inactivation of MS2 viruses decreased significantly to less than 4 logs (99.99%). Of special interest was that in the presence of beef extract proteins, an apparent reversal of MS2 inactivation, dubbed rebound, was observed. It was observed that after an initial 5 to 6 log reduction in infectivity, a consistent and-statistically significant increase in the number of plaque forming units (PFU), as much as 2 logs, was measured. MS2 rebound occurred only when the oxidized iodine residual had been quickly consumed by beef extract proteins in solution. Neither virus particle aggregation nor water salinity were found to account for the increase in PFU values. Based on other investigators' suggestions that iodine disinfection caused changes to viral protein-coats, it was hypothesized that conformational changes in MS2's protein coat caused by iodine would result in a change in the isoelectric focusing point of whole MS2 virions. A shift in isoelectric focusing point from an acidic pH Value of 3.9 to more basic values, and a dispersion of the virus band after exposure to high levels of iodine was observed, supporting the hypothesis that iodine caused changes in the charge distribution characteristics of the protein coat.
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J.-Y. MAILLARD, A.C. HANN, V. BAUBET AND R. PERRIN. 1998. The Pseudomonas aeruginosa PAO1 phage F116 was used to investigate the viricidal activity and the mechanism of action of sodium hypochlorite. The bacteriophage was inactivated with a low concentration (0·0005% available chlorine) of the biocide prepared in tap water but it was less sensitive to a sodium hypochlorite solution prepared in ultra-pure water (0·0075% available chlorine). For all the effective concentrations of sodium hypochlorite (i.e. producing at least 4 log reduction in phage titre), F116 was readily inactivated within 30s. Electron microscopical investigations of the phage particles challenged with sodium hypochlorite showed a wide variety of deleterious effects, some of which have not been previously observed with other biocides. The wide range of structural alterations observed suggested that sodium hypochlorite has multiple target sites against F116 bacteriophage. A 30s exposure to sodium hypochlorite (0·001% available chlorine) produced severe damage, the number and severity of which increased with a higher concentration (0·0075% available chlorine) and with a longer contact time. These observations suggested that sodium hypochlorite inactivated F116 bacteriophage by causing structural alterations to the phage head, tail and overall structure, hence possibly releasing the viral genome from damaged capsids in the surrounding media.
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The effects of diverse chemical formulations and disinfectants at known concentrations were observed for their virucidal activity against the Hong Kong strain of swine vesicular disease virus. During an exposure period of up to 30 min at 25 °C, only 5 of the 13 compounds tested completely inactivated the virus. Of these five, only sodium hydroxide, sodium hypochlorite and formaldehyde inactivated the virus in less than 2 min under the test conditions.
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Acids, alkalis, oxidising agents, detergents and other chemicals and disinfectants were tested for their activity against swine vesicular disease virus. Virus diluted in hard water was inactivated by nitric, sulphuric, acetic and formic acids, by sodium hydroxide, sodium metasilicate, sodium hypochlorite, peracetic acid, potassium permanganate, benzene sulphonic acid, formalin and ethyl alcohol, and by iodophar disinfectants and disinfectants containing formic or acetic and benzene sulphonic acids, or sodium hydroxide and sodium hypochlorite. These chemicals and disinfectants were also active in the presence of pig faeces except sulphuric acid, potassium permanganate and sodium hypochlorite. Combinations of chemicals such as acids with detergents and oxidising agents with acids or alkalis were more effective than the individual constituents. The action of iodophors was shown to depend on the presence of both iodine and acid. At 5° C. at a pH of 7.54 the virus survived without loss of titre for 164 days, but at pH values of 2.88 and 10.14 more than 6 log units of virus were lost by 164 days. Virus suspended in milk was inactivated in two minutes at 60° C. and virus suspended in pig slurry in two minutes at 64° C. In the presence of 1% sodium hydroxide the titre of virus suspended in pig slurry fell 5.4 log units within one hour at 5° C and over 6.1 log units in 10 seconds at 40° C. The results are compared with those obtained with other enteroviruses and with foot and mouth disease virus and the conditions are discussed under which the heat, chemical and disinfectant treatment could be applied.
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Active ingredients used in microbiocidal products in the European Union constitute some 250 chemical entities. Approximately 100 of these chemicals are commonly used in disinfectant products. The majority of these substances may be classified into distinct chemical groupings. A brief review of the chemical, physical and microbiological properties of each group is given, together with some indications of additives which may be used to enhance their properties, and factors which may detract from them. Some indications of usage areas are given.