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Jing Lv,
Baozhi Wei,
Yan Yang, Meiling Yao,
Yumei Cai,
Yuwei Gao,
Xianzhu Xia,
Xiaonan Zhao,
Zhihao Liu,
Xinxian Li,
Hao Wang,
Huili Yang,
Uwe Roesler,
Zengmin Miao,
Tongjie Chai
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ABSTRACT: This study aimed to determine the transmission characteristics of H9N2 avian influenza viruses (AIVs) derived from the air. Eight H9N2 AIVs were isolated from chicken houses between 2009 and 2010. We analyzed the phylogenic and pathogenic traits of these isolates. What is more, transmission characteristics in guinea pigs of two airborne isolates were determined in experimental conditions. Phylogenetic analyses indicated that the homologies of HA and NA genes of eight isolates were 95.4-99.7% and 86.6-99.8% respectively. They were able to duplicate in lung tissues of guinea pigs without prior adaptation. Two airborne isolates could both transmit among guinea pigs by direct contact. No infection was detected in aerosol contact animals while H9N2 AIV aerosols were detected in the air of isolators. Aerosol infection dose experiment showed that aerosol median infective dose (ID(50)) of H9N2 AIV to guinea pigs was 3.58×10(6)copies, demonstrating that the aerosols could infect guinea pigs at certain concentrations in experimental condition. In conclusion, H9N2 AIV aerosols were infectious to mammals, suggesting that urgent attention will need to be paid to its transmission.
Virus Research 09/2012; · 2.94 Impact Factor
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ABSTRACT: Sampling was conducted from June 2007 to May 2008 in an enclosed rabbit house to investigate composition and variability of
airborne fungi. Samples were collected using an Andersen-6 sampler, with Sabouraud culture medium as sampling medium. The
results showed that monthly mean concentration was 2.79–5.46×103 colony forming unit/m3 air (CFU/m3 air), with the maximum level in October, and the minimum level in January. Within a day, the maximum level occurred at 09:00,
followed by 17:00 and then 13:00. A total of 6,523 fungal colonies, belonging to 17 genera and 36 species, were obtained.
The predominant genera included Cladosporium, Penicillium, Aspergillus and Altemaria, comprising 71.45% of the colony count. The obtained fungi of the year were mainly centralized in the stage D of the sampler
(2.0–3.0μm), accounting for 37.8% of the colonies. The minimum value occurred at stage F (<0.65μm), accounting for 1.10%
of the colonies.
KeywordsEnclosed rabbit house-Airborne fungi-Monthly mean concentration-Predominant genera
Aerobiologia 04/2012; 26(2):135-140. · 1.51 Impact Factor
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ABSTRACT: Avian influenza virus (AIV) has caused serious epidemics all over the world. Notably, the low-pathogenic AIV H9N2 has been spreading widely, leading to enormous economic losses to the poultry industry. To rapidly monitor airborne H9 AIVs in chicken houses, a real-time RT-PCR method was established and used to detect virus in air samples, and it was also compared with the traditional RT-PCR. The results showed that the real-time RT-PCR possessed high specificity and sensitivity for H9 AIVs, and the sensitivity reached 100 copies/reaction, much higher than the traditional RT-PCR; airborne H9 AIVs were found in the six chicken houses by real-time RT-PCR, and their mean concentrations ranged from 1.25×10(4) to 6.92×10(4) copies/m(3) air. Overall, the real-time PCR is a valuable tool for detecting airborne H9 AIVs.
Archives of Virology 07/2011; 156(10):1795-801. · 2.11 Impact Factor
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Huiyong Duan,
Tongjie Chai,
Jianzhu Liu,
Xingxiao Zhang,
Chunhua Qi,
Jing Gao,
Yaling Wang,
Yumei Cai,
Zengmin Miao, Meiling Yao,
Gerd Schlenker
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ABSTRACT: Evidence is mounting that microorganisms originating from livestock impact the air quality of the animal houses themselves and the public in the surrounding neighborhoods. The aim of this study was to develop efficient bacterial source tracking capabilities to identify sources of Escherichia coli aerosol pollution caused by pigs. Airborne E. coli were isolated from indoor air, upwind air (10 and 50 m away) and downwind air samples (10, 50, 100, 200 and 400 m away) for five swine houses using six-stage Andersen microbial samplers and Reuter-Centrifugal samplers (RCS). E. coli strains from pig fecal samples were also collected simultaneously. The enterobacterial repetitive intergenic consensus polymerize chain reaction (ERIC-PCR) and the repetitive extragenic palindromic (REP-PCR) approaches were used to study the genetic variability and to determine the strain relationships among E. coli isolated from different sites in each swine house. Results showed that 35.1% (20/57) of the bacterial DNA fingerprints from the fecal isolates matched with the corresponding strains isolated from indoor and downwind air samples (similarity > or = 90%). E. coli strains from the indoor and downwind air samples were closely related to the E. coli strains isolated from feces, while those isolated from upwind air samples (swine house C) had low similarity (61-69%). Our results suggest that some strains isolated from downwind and indoor air originated in the swine feces. Effective hygienic measures should be taken in animal farms to prevent or minimize the downwind spread of microorganism aerosol.
Environmental Research 05/2009; 109(5):511-7. · 3.40 Impact Factor
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ABSTRACT: In order to better understand airborne transmission of Newcastle disease, a model system was established and two trials were conducted. Twenty-five principal specific pathogen free (SPF) chickens were inoculated with NDV and were housed in one isolator. 6 days after the chickens were challenged, 15 chickens were placed into another isolator which received its air supply from the first isolator. The NDV aerosol originating from inoculated chickens was collected with All Glass Impinger-30 (AGI-30) to study the occurrence and concentration of NDV aerosol. The antibody response to infection was assessed by the hemagglutination inhibition (HI) test and viral shedding was detected by RT-PCR and Dot-ELISA. NDV aerosol was initially detectable by RT-PCR and cell culture at day 2 or 3 post-inoculation (dpi). The aerosol concentration peaked at 1.69x10(4)PFU/m(3) air at 13dpi in trial 1, 9.14x10(3)PFU/m(3) air at 11dpi in trial 2 and was consistently detectable up to 40dpi. NDV shedding was detectable from 2 to 40dpi of inoculated chickens and from 6 days post-aerosol exposed infection (dpi) to 33dpi of aerosol exposed chickens. The viral strain induced high antibody level, both in inoculated and in aerosol exposed chickens. Airborne transmission did occur, as shown by NDV shedding and seroconversion to NDV in aerosol exposed chickens. The results indicated that viruses shed from infected chickens readily aerosolized and airborne transmission of NDV was possible.
Veterinary Microbiology 12/2008; 136(3-4):226-32. · 3.33 Impact Factor
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ABSTRACT: The co-infection of duck circovirus (DuCV) with Riemerella anatipestifer (RA) or/and Escherichia coli (E. coli) or/and duck hepatitis virus I (DHV-I) in Cherry Valley ducks in China's Shandong Province was investigated by using polymerase-chain-reaction (PCR)-based methods. For this study, 742 ducks sampled at random from 70 duck farms during 2006-2007 were examined using PCR and dot-blot hybridisation (DBH) tests. Overall the DuCV infection rate was 33.29%. Compared with those at 2 weeks of age, the ducks at 3-4 weeks of age were more susceptible to DuCV infection. Compared with the DuCV-negative ones, the DuCV-positive ducks had a higher rate of infection by DHV-I (25.5% vs. 7.475%), RA (23.48% vs. 8.28%) and E. coli (16.19% vs. 4.85%). This investigation shows that DuCV infection is common in Cherry Valley ducks on some farms in Shandong Province.
Veterinary Microbiology 08/2008; 133(3):252-6. · 3.33 Impact Factor
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ABSTRACT: An AOZ method, based on high-performance liquid chromatography (HPLC), was optimized on HPLC condition such as mobile phase and wavelength to simultaneously quantify six kinds of mycotoxins [four aflatoxins (AFs), ochratoxin A (OTA) and zearalenone (ZEA)]. Conditions for immunoaffinity clean-up, HPLC and photo-derivatization were optimized in this study and successfully applied in assessment of airborne mycotoxins from a poultry house in Dalian, China. Fifty-two air samples were collected with AGI-30 air samplers using pure water as collection media. Twenty air samples (20/52, 38.46%) were positive for four toxins. Among the positive samples, airborne mycotoxin concentrations (mean+/-S.D.) for AFG(2), AFB(1), and ZEA were 0.189+/-0.024 (n=9), 0.080+/-0.003 (n=11) and 2.363+/-0.030 (n=5)ng/m(3) air, while the concentration for OTA was 8.530 (n=1)ng/m(3). No positive sample was found for either AFG(1) or AFB(2). A chicken may inhale 0.019-0.057 ng AFG(2), 0.013-0.019 ng AFB(1), 0.436-0.513 ng ZEA, and 1.706 ng OTA, respectively, in a day. A poultry worker may inhale 0.504-1.512 ng AFB(1), 0.752-2.28 ng AFG(2), 68.240 ng OTA, and 17.432-20.512 ng ZEA in a working day. This is the first report on airborne mycotoxins in poultry house. These data may have importance in animal and public health implications.
Environmental Research 07/2008; 107(2):139-44. · 3.40 Impact Factor
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ABSTRACT: In order to study E. coli aerosol spreading from chicken houses to their surrounding air, air samples, including indoor and outdoor air (upwind 10 and 50 m as well as downwind 10, 50, 100, 200 and 400 m away) of 5 chicken houses were collected using six-stage Andersen microbial samplers and Reuter-Centrifugal samplers (RCS). E. coli concentrations (CFU/m(3) air) collected from different sampling sites were calculated. E. coli strains from chicken feces samples were also isolated. Furthermore, the enterobacterial repetitive intergenic consensus (ERIC)-PCR method was applied to amplify the isolated E. coli strain DNA samples. Through the genetic similarity analyses of the E. coli obtained from different sampling sites, the spreading of bioaerosol from animal houses to the ambient air was characterized. The results showed that the isolated E. coli concentrations in indoor air (9-63 CFU/m(3)) in 5 chicken houses were higher than those in upwind and downwind air, but there were no significant differences between the indoor and downwind sites 10 m away from all the 5 houses (P>0.05). The phylogenetic tree indicated that a part of the E. coli (34.1%) isolated from indoor air had 100% similarity with those isolated from feces, and that most of E. coli isolated (54.5%) from downwind at 10, 50, 100 or even 200 m had 100% similarity with those isolated from indoor air or feces too. But those isolated from upwind air had a lower similarity (73%-92%) with corresponding strains isolated from indoor air or feces. Our results suggested that some strains isolated from downwind air and indoor air originated in the chicken feces, but most of isolates obtained from upwind air samples did not come from the chicken feces or indoor air. Effective hygienic measures should be taken in animal farms to prevent or minimize downwind spreading of microorganism aerosol.
Science in China Series C Life Sciences 03/2008; 51(2):164-73. · 1.61 Impact Factor
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Meiling Yao,
Xingxiao Zhang,
Jing Gao,
Tongjie Chai,
Zengmin Miao,
Weiming Ma,
Mei Qin,
Qinglei Li,
Xiaoxia Li,
Jingbo Liu,
Hongshuang Zhang
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ABSTRACT: To better understand the transmission route of H9N2 avian influenza virus (AIV), two duplicate trials were conducted to observe the process of aerosol infection and direct contact in specific pathogen free chickens. Fifteen chickens (G1) were inoculated with H9N2 AIV and housed together with another 15 chickens (G2) in the same positive-negative-pressure isolator (A). Fifteen chickens (G3) were bred in another isolator (B) which was connected with A so that air could flow unidirectionally from A to B. Air, oropharyngeal and cloacal swabs, and blood samples were collected for the detection of aerosolized virus, virus shedding, and seroconversion. AIV aerosols were initially detected at day 2-3 post inoculation (dpi), reaching peak concentrations at 7 dpi. Virus shedding was detected in all chickens of G2, but only in a part in G3 (T1: 87%, T2: 80%). Antibodies were initially detected at 4-5 dpi, peaking at 14-21 dpi. The results showed that H9N2 AIV could be transmitted by both aerosol exposure and direct contact.
Berliner und Münchener tierärztliche Wochenschrift 124(3-4):136-41. · 0.82 Impact Factor
