Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused great harm to global public health, resulting in a large number of infections among the population. However, the epidemiology of coronavirus has not been fully understood, especially the mechanism of aerosol transmission. Many respiratory viruses can spread via contact and droplet transmission, but increasing epidemiological data have shown that viral aerosol is an essential transmission route of coronavirus and influenza virus due to its ability to spread rapidly and high infectiousness. Aerosols have the characteristics of small particle size, long-time suspension and long-distance transmission, and easy access to the deep respiratory tract, leading to a high infection risk and posing a great threat to public health. In this review, the characteristics of viral aerosol generation, transmission, and infection as well as the current advances in the aerosol transmission of zoonotic coronavirus and influenza virus are summarized. The aim of the review is to strengthen the understanding of viral aerosol transmission and provide a scientific basis for the prevention and control of these diseases.

The objective of this study was to obtain insight into the adverse health effects of airborne particulate matter (PM) collected from live bird markets and to determine whether biological material in PM accounts for immune-related inflammatory response. Mice were exposed to a single or repeated dose of PM, after which the expression of toll-like receptors (TLRs), cytokines, and chemokines in the lungs of infected mice were examined by enzyme-linked immunosorbent assay and histopathological analysis. Results after single and repeated PM stimulation with [Formula: see text] indicated that TLR2 and TLR4 played a dominant role in the inflammatory responses of the lung. Further analysis demonstrated that the expression levels of IL-1β, TNF-α, IFN-γ, IL-8, IP-10, and MCP-1 increased significantly, which could eventually contribute to lung injury. Moreover, biological components in PM were critical in mediating immune-related inflammatory responses and should therefore not be overlooked.

Background: Low pathogenic H9N2 avian influenza virus (AIV) has been spreading worldwide, leading to huge economic losses to poultry husbandry, but few studies were concerned about its aerosol infection. Methods: This study compared the infective doses of H9N2 AIV to chickens by three different routes, aerosol infection, intranasal and gastrointestinal infection, and determination of the results was conducted by detecting virus shedding and seroconversion of chickens. Results: The results indicated that chickens were susceptible to H9N2 AIV with a different infection rate which depended on the route of inoculation. H9N2 AIV media aerosol-infective dose (aID50) to chickens was about 491 TCID50, intranasal infection was 398 TCID50, and gastrointestinal infection was 19,952 TCID50. Conclusion: The infection ability of H9N2 AIV to chickens was related to its way of invading. The respiratory infection ability was about 40 times more effective than gastrointestinal infection, which suggested that urgent attention should be paid to environmental disinfection to block airborne transmission of influenza virus.

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 (ID50) of H9N2 AIV to guinea pigs was 3.58 x 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. (c) 2012 Elsevier B.V. All rights reserved.

At present, there are three main research directions in querying and searching XML data: structure index method, node-based encoding method and sequence method. However, a common problem of querying and searching XML data is that the execution time as well as the input size of algorithms grows rapidly as the size of XML document increases. To overcome this problem, we propose a new three-phase XML twig pattern matching algorithm called Twig3Version. The new algorithm firstly executes holistic XML twig pattern matching algorithm on the structure index named Version Tree that compresses all repetitive structures in XML document, and returns subtrees of Version Tree that matching query twig in structure. Then the algorithm implements a simple and efficient version filter module on the concise intermediate results to find matching versions. Finally, it merges elements in the original document corresponding to these matching versions to generate final results. Because the new algorithm executes structural matching on the concise structure index and implements a simple and efficient version filter module on the concise intermediate results, the new algorithm outperforms other existing XML twig pattern matching algorithms. Both theoretical analysis and experimental results indicate the superiority of the new algorithm.

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. © 2011 Schlütersche.

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 unidi-rectionally 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 (Ti: 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.

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.

In view of the problem that XML twig matching algorithms,such as TwigStack,TJFast,TwigVersion fail to take redundant result into account,a comparison was conducted of the time spent with these representative algorithms for obtaining non-redundancy target elements.An improved XML twig matching algorithm named AdvancedTwigVersion is thus proposed.The experiment results show that the proposed algorithm has good performance.

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 (2.0–3.0 μm), accounting for 37.8% of the colonies. The minimum value occurred at stage F (<0.65 μm), accounting for 1.10% of the colonies.

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 ⩾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.

Abstract Staphylococcus aureus was used as an indicator to study the origin and spread of microbial aerosol in and around chicken houses. Air samples indoor, upwind (10 and 50 m), and downwind (10, 50, 100, 200, and 400 m) of four chicken houses were collected using Andersen‐6 stages sampler. The concentrations of S. aureus were determined for every sample site. Isolation of S. aureus from chicken feces was performed according to the standard method. The genetic relationship among the isolates was determined by profiles of PCR‐amplified repetitive extragenic palindromic (REP‐PCR) elements. The results showed that the concentrations of S. aureus indoor of four chicken houses were higher than those upwind and downwind sites (P < 0.05 or P < 0.01), but there were no significant concentration differences among downwind sites (P > 0.05). The fingerprints and the phylogenetic tree indicated that a part of the S. aureus (55.6%, 10/18) isolates from indoor air had the same REP‐PCR fingerprints as feces isolates. Consequently, most isolates (57.1%, 20/35) from downwind 10, 50, 100, 200, even 400 m had the same REP‐PCR fingerprints as those from indoor or feces. These data indicated that some isolates from downwind and indoor originated from the chicken feces. However, those isolates from upwind had low similarity (similarity index 0.6–0.87) to those from indoor or feces. Therefore, the isolates upwind were not from the chicken feces or indoor. These results suggest that microbes in chicken feces can be aerosolized and spread indoor and outdoor, especially to downwind of the chicken houses. It should have an important epidemiological and public health significance. Practical Implications Thus, the use of S. aureus as an indicator to study the origin and spread of airborne pathogens from chicken houses is potentially useful for enhancing public health and understanding the airborne epidemiology of this pathogen. Meanwhile it can provide evidence for studying the spreading model of airborne pathogens.

The study was to evaluate inactivation of indicative bacteria or bacterial flora:Fecal Coliforms,C.perfringens(Clostridium perfringens),the total number of anaerobic and aerobic bacteria,by bioaugmenting anaerobic digestion of cow dung slurry with a commercial product containing selected strains of bacteria from genera Lactobacillus,Pseudomonas,Microzymes and Actinomycetes,along with ancillary organic compounds containing various micronutrients.Specifically,the effects of the bioaugment on the concentration of volatile fatty acids,NH4+-N,the value of pH,the number of Fecal Coliforms and C.perfringens during anaerobic digestion of dairy cattle dung slurry were studied.The results indicated that the bioaugmenting anaerobic digestion could reduce the number of Fecal Coliforms significantly(P0.05),as well as could be of advantage to form a better and more stable digestive system,however,no obvious effect on reduction of the number of C.perfringens,the total number of anaerobic and aerobic bacteria were observed.The bioaugmenting anaerobic digestion could not significantly affect the output of volatile fatty acids(VFA),NH4+-N and the value of pH(P0.05).In brief,the bioaugmenting anaerobic digestion could improve anaerobic digestive microecology and could be used for treatment of dairy cattle dung slurry before their land application.

为了研究鸡舍环境中大肠杆菌气溶胶向舍外环境的传播,本实验采用Andersen-6级空气微生物样品收集器和RCS(reuter centrifugal sampler)-离心式采样器分别在5个鸡场舍内空气、舍外上风向10,50m和下风向10,50,100,200,400m不同距离收集气载大肠杆菌,计算每一个采样点的大肠杆菌的浓度(CFU-m3空气);并采集鸡的粪便,分离大肠杆菌.利用肠杆菌基因间重复一致序列的聚合酶链式反应(enterobacterial repetitive intergenic consensus-polymerase chain reaction,ERIC-PCR)鉴定技术,扩增不同测量点收集的大肠杆菌的DNA条带,形成聚类图谱.通过每一个采样点分离的大肠杆菌遗传相似性分析以及大肠杆菌浓度变化,确认动物舍微生物气溶胶向舍外环境的传播模式.结果显示,5个鸡场舍内空气中大肠杆菌的浓度(中间值)为9～63 CFU·m3,远远高于舍外上风和舍外下风处的大肠杆菌浓度(P<0.05),但是舍外下风不同距离间的大肠杆菌浓度差异并不显著(P>0.05).ERIC-PCR结果表明,从鸡的粪便中分离到的大肠杆菌与从舍内空气中分离到的部分大肠杆菌(34.1%)相似性可达100%,从鸡场舍外下风方向(10,50,100,200 m)分离到的多数大肠杆菌(54.5%)与舍内空气或粪便中分离的大肠杆菌相似性可达100%.而从鸡舍上风分离到的大肠杆菌与舍内空气或粪便中分离的大肠杆菌相似性仅在73%～92%之间.结果表明:从上风分离到的多数大肠杆菌并非来源于鸡的粪便或者舍内空气,而很多从舍内空气和舍外下风方向分离到的大肠杆菌来源于鸡的粪便,说明源于鸡舍的微生物气溶胶能够通过舍内外气体交换传播到舍外,依气象条件传播到舍外不同的距离,造成周边环境的生物污染以及病原微生物的扩散.对动物舍环境微生物气溶胶的发生与传播规律的研究,具有公共卫生及流行病学意义.

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 1.69×104PFU/m3 air at 13dpi in trial 1, 9.14×103PFU/m3 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.

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 AFG2, AFB1, and ZEA were 0.189±0.024 (n=9), 0.080±0.003 (n=11) and 2.363±0.030 (n=5)ng/m3 air, while the concentration for OTA was 8.530 (n=1)ng/m3. No positive sample was found for either AFG1 or AFB2. A chicken may inhale 0.019–0.057ng AFG2, 0.013–0.019ng AFB1, 0.436–0.513ng ZEA, and 1.706ng OTA, respectively, in a day. A poultry worker may inhale 0.504–1.512ng AFB1, 0.752–2.28ng AFG2, 68.240ng OTA, and 17.432–20.512ng 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.

文章对现阶段集约化畜禽生产的福利内容与要求,人们对福利的偏差认识,缺乏动物福利保障及管理的教训等,进行了深入探讨,为未来逐步关注、提高我国集约化畜禽生产福利水平提供了有益帮助。

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.