Interventions in live poultry markets for the control of avian influenza: a systematic review

Modelling the transmission dynamics of H9N2 avian influenza viruses in a live bird market

H9N2 avian influenza viruses (AIVs) are a major concern for the poultry sector and human health in countries where this subtype is endemic. By fitting a model simulating H9N2 AIV transmission to data from a field experiment, we characterise the epidemiology of the virus in a live bird market in Bangladesh. Many supplied birds arrive already exposed to H9N2 AIVs, resulting in many broiler chickens entering the market as infected, and many indigenous backyard chickens entering with pre-existing immunity. Most susceptible chickens become infected within one day spent at the market, owing to high levels of viral transmission within market and short latent periods, as brief as 5.3 hours. Although H9N2 AIV transmission can be substantially reduced under moderate levels of cleaning and disinfection, effective risk mitigation also requires a range of additional interventions targeting markets and other nodes along the poultry production and distribution network.

Live poultry markets beyond health risks: Understanding consumer preferences for live poultry in South China

Live poultry markets (LPMs) are veterinary and public health risks because of potential for zoonotic spillover of pathogens from diseased animals to humans. To control these health risks, veterinary and public health authorities in Asia, including China, have closed or restricted LPMs. In south China, however, LPM closure has been opposed or rendered infeasible by consumers who prefer to purchase live poultry. Previous scholarship has suggested this preference is due to cultural values of freshness. In this study, we present results from detailed interviews with shoppers in south China, including those who prefer live poultry and those who prefer pre-slaughtered poultry. We argue that broader concerns about food safety and quality, rather than freshness alone, drive the demand for LPMs. Live poultry provide sensory information that enable shoppers to evaluate safety and quality in ways that are not possible with pre-slaughtered, refrigerated meat. Based on these findings, we suggest that hygienic interventions into LPMs should recognize that not only freshness, but also trust, must be constructed and maintained in any intervention.

Zoonotic Animal Influenza Virus and Potential Mixing Vessel Hosts

Influenza viruses belong to the family Orthomyxoviridae with a negative-sense, single-stranded segmented RNA genome. They infect a wide range of animals, including humans. From 1918 to 2009, there were four influenza pandemics, which caused millions of casualties. Frequent spillover of animal influenza viruses to humans with or without intermediate hosts poses a serious zoonotic and pandemic threat. The current SARS-CoV-2 pandemic overshadowed the high risk raised by animal influenza viruses, but highlighted the role of wildlife as a reservoir for pandemic viruses. In this review, we summarize the occurrence of animal influenza virus in humans and describe potential mixing vessel or intermediate hosts for zoonotic influenza viruses. While several animal influenza viruses possess a high zoonotic risk (e.g., avian and swine influenza viruses), others are of low to negligible zoonotic potential (e.g., equine, canine, bat and bovine influenza viruses). Transmission can occur directly from animals, particularly poultry and swine, to humans or through reassortant viruses in "mixing vessel" hosts. To date, there are less than 3000 confirmed human infections with avian-origin viruses and less than 7000 subclinical infections documented. Likewise, only a few hundreds of confirmed human cases caused by swine influenza viruses have been reported. Pigs are the historic mixing vessel host for the generation of zoonotic influenza viruses due to the expression of both avian-type and human-type receptors. Nevertheless, there are a number of hosts which carry both types of receptors and can act as a potential mixing vessel host. High vigilance is warranted to prevent the next pandemic caused by animal influenza viruses.

Phasing out live poultry market trading policy in China: characteristics of chicken consumption, decision-making behavior, and consumer cluster analysis

With the emergence of avian influenza viruses, many Chinese cities periodically close the live poultry markets to restrict the trade of live chicken. This study investigated customers' decision-making clusters and consumption preferences. Data from 1108 participants were collected in May 2021 in the Jiangsu province using a mixed sampling method. Eight decision-making behaviors were identified using the Exploratory Factor Analysis. Five consumer clusters were identified using K-Means Cluster Analysis. Chi-square tests and pairwise comparisons of multiple sample rates were used to identify the differences in consumption preferences between the consumer clusters. The results show that only the concern of risking an avian influenza virus infection might not effectively change consumer preferences towards live chicken and patronage of wet markets and farms. Product quality, consumer habits and loyalty, limited knowledge and technology, and leisure elements in visiting farms are hindering changes in consumer preferences. Effective policies are needed to help customers to overcome the barriers of buying chilled and frozen chicken.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00003-022-01411-y.

Epidemiology and molecular characterization of avian influenza virus in backyard poultry of Chattogram, Bangladesh

Ducks, the natural reservoir of avian influenza virus (AIV), act as reassortment vessels for HPAI and low pathogenic avian influenza (LPAI) virus for domestic and wild bird species. In Bangladesh, earlier research was mainly focused on AIV in commercial poultry and live bird markets, where there is scanty literature reported on AIV in apparently healthy backyard poultry at the household level. The present cross-sectional study was carried out to reveal the genomic epidemiology of AIV of backyard poultry in coastal (Anowara) and plain land (Rangunia) areas of Bangladesh. We randomly selected a total of 292 households' poultry (having both chicken and duck) for sampling. We administered structured pre-tested questionnaires to farmers through direct interviews. We tested cloacal samples from birds for the matrix gene (M gene) followed by H5 and H9 subtypes using real-time reverse transcriptase-polymerase chain reaction (rRT-PCR). All AIV-positive samples were subjected to four-gene segment sequencing (M, PB1, HA, and NA gene). We found that the prevalence of AIV RNA at the household level was 6.2% (n = 18; N = 292), whereas duck and chicken prevalence was 3.6% and 3.2%, respectively. Prevalence varied with season, ranging from 3.1% in the summer to 8.2% in the winter. The prevalence of subtypes H5 and H9 in backyard poultry was 2.7% and 3.3%, respectively. The phylogenetic analysis of M, HA, NA, and PB1 genes revealed intra-genomic similarity, and they are closely related to previously reported AIV strains in Bangladesh and Southeast Asia. The findings indicate that H5 and H9 subtypes of AIV are circulating in the backyard poultry with or without clinical symptoms. Moreover, we revealed the circulation of 2.3.2.1a (new) clade among the chicken and duck population without occurring outbreak which might be due to vaccination. In addition to routine surveillance, molecular epidemiology of AIV will assist to gain a clear understanding of the genomic evolution of the AIV virus in the backyard poultry rearing system, thereby facilitating the implementation of effective preventive measures to control infection and prevent the potential spillover to humans.

Patterns and risk factors of avian influenza A(H5) and A(H9) virus infection in pigeons and quail at live bird markets in Bangladesh, 2017-2021

The avian influenza virus (AIV) impacts poultry production, food security, livelihoods, and the risk of transmission to humans. Poultry, like pigeons and quail farming, is a growing sector in Bangladesh. However, the role of pigeons and quails in AIV transmission is not fully understood. Hence, we conducted this study to investigate the prevalence and risk factors of AIV subtypes in pigeons and quails at live bird markets (LBMs) in Bangladesh. We collected oropharyngeal and cloacal swab samples from 626 birds in 8 districts of Bangladesh from 2017 to 2021. We tested the swab samples for the matrix gene (M gene) followed by H5, H7, and H9 subtypes using real-time reverse transcriptase-polymerase chain reaction (rRT-PCR). We then used exploratory analysis to investigate the seasonal and temporal patterns of AIV and a mixed effect logistic model to identify the variable that influences the presence of AIV in pigeons and quails. The overall prevalence of AIV was 25.56%. We found that the prevalence of AIV in pigeons is 17.36%, and in quail is 38.75%. The prevalence of A/H5, A/H9, and A/H5/H9 in quail is 4.17, 17.92, and 1.67%, respectively. Furthermore, the prevalence of A/H5, A/H9, and A/H5/H9 in pigeons is 2.85, 2.59, and 0.26%. We also found that the prevalence of AIV was higher in the dry season than in the wet season in both pigeons and quail. In pigeons, the prevalence of A/untyped (40%) increased considerably in 2020. In quail, however, the prevalence of A/H9 (56%) significantly increased in 2020. The mixed-effect logistic regression model showed that the vendors having waterfowl (AOR: 2.13; 95% CI: 1.04-4.33), purchasing birds from the wholesale market (AOR: 2.96; 95% CI: 1.48-5.92) instead of farms, mixing sick birds with the healthy ones (AOR: 1.60; 95% CI: 1.04-2.45) and mingling unsold birds with new birds (AOR: 3.07; 95% CI: 2.01-4.70) were significantly more likely to be positive for AIV compared with vendors that did not have these characteristics. We also found that the odds of AIV were more than twice as high in quail (AOR: 2.57; 95% CI: 1.61-4.11) as in pigeons. Furthermore, the likelihood of AIV detection was 4.19 times higher in sick and dead birds (95% CI: 2.38-7.35) than in healthy birds. Our study revealed that proper hygienic practices at the vendors in LBM are not maintained. We recommend improving biosecurity practices at the vendor level in LBM to limit the risk of AIV infection in pigeons and quail in Bangladesh.

THE IMPLEMENTATION GAP IN EMERGING DISEASE RISK MANAGEMENT IN THE WILDLIFE TRADE

The wildlife trade has been characterized as one of the biggest risk factors in the emergence of new infectious diseases. In the shadow of COVID-19, there is growing political and scientific urgency to manage this risk. Existing studies and experiences make it clear that something must be done but are less clear on how to get it done. It is a quite different task to accumulate evidence on the presence of pathogens, their locations in the supply chain, and their spillover to new hosts than to identify effective ways to prevent and mitigate emerging disease under real-world conditions. This study sought peer-reviewed evidence on the effectiveness, acceptability, feasibility, and sustainability of risk reduction interventions for zoonotic and nonzoonotic disease emergence in the wildlife trade. An environmental scan triangulated information from a scoping review following a Preferred Reporting Items for Systematic Reviews and Meta-analysis extension for scoping review protocol, two narrative literature reviews, and key informant interviews of 26 international wildlife health experts. Existing literature has been inattentive to program implementation or evaluation studies. There was insufficient evidence to identify effective and sustainable risk management actions. Studies on the effects of social, epidemiologic, and ecologic context on intervention success was lacking, as was research using a complex systems perspective. The lack of systematic program evaluations or implementation studies leaves decision makers with insufficient evidence to select interventions likely to be acceptable, effective, and sustainable within and across the disparate context of the wildlife trade. This necessitates adaptive risk management and innovations in program implementation and evaluation to ensure evidence-based risk management.

Surveillance of the spread of avian influenza virus type A in live bird markets in Tripoli, Libya, and determination of the associated risk factors

Background and Aim: Studies on avian influenza virus (AIV) in Libya are few and limited. This study aimed to determine the presence of AIV in live bird markets (LBMs) in Tripoli and determine the risk factors associated with AIV spread. Materials and Methods: In total, 269 cloacal swabs were randomly collected from different bird species in 9 LBMs located in Tripoli and its surrounding regions. The target species were ducks, geese, local chickens, Australian chickens, Brahma chickens, turkeys, pigeons, quails, peacock broiler chicks, and pet birds. Total RNA was extracted from the swab samples and used for real-time polymerase chain reaction to detect AIV type A. Results: Of the 269 samples, 28 (10.41% of total samples) were positive for AIV type A. The LBMs with positive samples were Souq Aljumaa, Souq Alkhamees, Souq Althulatha, and Souq Tajoura. The highest percentage (35.71%) of AIV was recorded in Souq Aljumaa. Positive results for AIV type A were obtained primarily in three species of birds: Ducks (14/65; highest percentage: 21.5%), local chickens (12/98; 12.24%), and geese (2/28; 7.14%). Furthermore, the following three risk factors associated with the spread of AIV type A were identified: Time spent by breeders/vendors at the market (odds ratio [OR] = 11.181; 95% confidence interval [CI] = 3.827–32.669), methods used for disposing dead birds (OR = 2.356; 95% CI = 1.005–5.521), and last visited LBM (OR = 0.740; 95% CI = 0.580–0.944). Restricting the movement of poultry vendors from one market to another may protect against AIV spread. Conclusion: The findings of this study indicate the high risk of AIV spread in LBMs and highlight the need for continuous surveillance of LBMs across the country.

First detection of avian influenza subtype H4N6 in Israel in a wild mallard (Anas platyrhynchos)

Avian influenza viruses (AIV) are a worldwide threat to animal and human health. As wild waterfowl circulate and spread these viruses around the world, investigations of AIV prevalence in wild populations are critical for understanding pathogen transmission, as well as predicting disease outbreaks in domestic animals and humans. Surveillance efforts in this study have isolated H4N6 for the first time in Israel from a faecal sample of a wild mallard (Anas platyrhynchos). Phylogenetic analyses of the HA and NA genes revealed that this strain is closely related to isolates from Europe and Asia. This Eurasian origin, together with Israel serving as an important migratory bottleneck of the mid Palearctic-African flyway, suggests a potential introduction of this strain by migratory birds. Additional phylogenetic analysis of the isolate's internal genes (PB1, PB2, PA, NP, M and NS) revealed high levels of phylogenetic relatedness with other AIV subtypes, indicating previous reassortment events. High reassortment rates are characteristic for H4N6 viruses, which, together with this subtype's ability to infect pigs and adaptability to the human receptor binding domain, raises the concern that it would potentially become zoonotic in the future. These results emphasize the importance of continuous AIV monitoring in migratory birds.

Survey of low pathogenic avian influenza viruses in live poultry markets in Guangxi Province, Southern China, 2016-2019

Low pathogenic avian influenza viruses (LPAIVs) have been widespread in poultry and wild birds throughout the world for many decades. LPAIV infections are usually asymptomatic or cause subclinical symptoms. However, the genetic reassortment of LPAIVs may generate novel viruses with increased virulence and cross-species transmission, posing potential risks to public health. To evaluate the epidemic potential and infection landscape of LPAIVs in Guangxi Province, China, we collected and analyzed throat and cloacal swab samples from chickens, ducks and geese from the live poultry markets on a regular basis from 2016 to 2019. Among the 7,567 samples, 974 (12.87%) were LPAIVs-positive, with 890 single and 84 mixed infections. Higher yearly isolation rates were observed in 2017 and 2018. Additionally, geese had the highest isolation rate, followed by ducks and chickens. Seasonally, spring had the highest isolation rate. Subtype H3, H4, H6 and H9 viruses were detected over prolonged periods, while H1 and H11 viruses were detected transiently. The predominant subtypes in chickens, ducks and geese were H9, H3, and H6, respectively. The 84 mixed infection samples contained 22 combinations. Most mixed infections involved two subtypes, with H3 + H4 as the most common combination. Our study provides important epidemiological data regarding the isolation rates, distributions of prevalent subtypes and mixed infections of LPAIVs. These results will improve our knowledge and ability to control epidemics, guide disease management strategies and provide early awareness of newly emerged AIV reassortants with pandemic potential.

Wild bird trade at live poultry markets potentiates risks of avian influenza virus introductions in Iran

Wild aquatic birds are the main natural host reservoir of avian influenza viruses (AIV). Migratory aquatic birds can translocate AI viruses over wide geographic distances. AIV may be transmitted reciprocally at the wild bird–poultry interface, increasing viral variability and potentially driving the zoonotic potential of these viruses. A cross-sectional study on AIV and several further avian viral pathogens conducted in 396 trapped migratory aquatic birds traded at live bird markets (LBM) in northern Iran identified 11 AIV-positive cases. The 10 identified H9N2 viral sequences fell into wild bird H9 lineage Y439; in addition, an H10N3 virus of Eurasian lineage was detected. Ten samples contained low viral loads of avian coronavirus but could not be further characterized. Although traditional trading of live-trapped wild birds provides income for hunters, particularly during fall migration periods, it increases the risk of introducing new AIV strains from the natural reservoir to poultry kept at LBMs and, potentially, to traders and customers. Banning these birds from poultry trading lines would lower such risks considerably.

Assessing different interventions against Avian Influenza A (H7N9) infection by an epidemiological model

This paper aims at evaluating the effectiveness of different intervention measures against the infection of avian influenza A (H7N9) by using an epidemiological model. The model formulates the intrinsic interactions of domestic poultry (DP), H7N9 virus and humans by ordinary differential equations and couples the essential roles of various interventions (including culling, vaccinating, screening, disinfecting, and reducing contact rate, etc). Qualitative analysis indicates that when the recruiting poultry is virus-free, there is a transmission threshold denoted by basic reproduction number which can determine the invasion of H7N9; and there is always a stable H7N9 endemic in case of persistent import of virus-carrying poultry, under which only complete vaccination or cutting off poultry-to-poultry/human contacts can stop H7N9 transmission. By performing numerical analysis of the model with biological background parameters, the intervention outcomes against H7N9 infection are further quantified. It is found that (1) reducing poultry-human/poultry interaction and per-contact infection probability, as well as culling DP, are highly effective in diminishing the infections of humans and DP; (2) the disease is prevented when larger than (1 − 0.1λ_p) proportion of DP is vaccinated, where λ_p is the DP-to-DP transmission rate; (3) cleaning and disinfecting environment play limited role in reducing the risk of infection; and (4) screening imported poultry is quite important for stopping disease diffusion, but it works little when local epidemic is prevailing. Combing these measures with real situations would be necessary for controlling H7N9 epidemics and reaching one health purpose.

Different intervention strategies toward live poultry markets against avian influenza A (H7N9) virus: Model-based assessment

BACKGROUND

Different interventions targeting live poultry markets (LPMs) are applied in China for controlling avian influenza A (H7N9), including LPM closure and "1110" policy (i.e., daily cleaning, weekly disinfection, monthly rest day, zero poultry stock overnight). However, the interventions' effectiveness has not been comprehensively assessed.

METHODS

Based on the available data (including reported cases, domestic poultry volume, and climate) collected in Guangdong Province between October 2013 and June 2017, we developed a new compartmental model that enabled us to infer H7N9 transmission dynamics. The model incorporated the intrinsic interplay among humans and poultry as well as the impacts of absolute humidity and LPM intervention, in which intervention strategies were parameterized and estimated by Markov chain Monte Carlo method.

RESULTS

There were 258 confirmed human H7N9 cases in Guangdong during the study period. If without interventions, the number would reach 646 (95%CI, 575-718) cases. Temporal, seasonal and permanent closures of LPMs can substantially reduce transmission risk, which might respectively reduce human infections by 67.2% (95%CI, 64.3%-70.1%), 75.6% (95%CI, 73.8%-77.5%), 86.6% (95%CI, 85.7-87.6%) in total four epidemic seasons, and 81.9% (95%CI, 78.7%-85.2%), 91.5% (95%CI, 89.9%-93.1%), 99.0% (95%CI, 98.7%-99.3%) in the last two epidemic seasons. Moreover, implementing the "1110" policy from 2014 to 2017 would reduce the cases by 34.1% (95%CI, 20.1%-48.0%), suggesting its limited role in preventing H7N9 transmission.

CONCLUSIONS

Our study quantified the effects of different interventions and execution time toward LPMs for controlling H7N9 transmission. The results highlighted the importance of closing LPMs during epidemic period, and supported permanent closure as a long-term plan.

Association of Biosecurity and Hygiene Practices with Environmental Contamination with Influenza A Viruses in Live Bird Markets, Bangladesh

In Bangladesh, live bird market environments are frequently contaminated with avian influenza viruses. Shop-level biosecurity practices might increase risk for environmental contamination. We sought to determine which shop-level biosecurity practices were associated with environmental contamination. We surveyed 800 poultry shops to describe biosecurity practices and collect environmental samples. Samples from 205 (26%) shops were positive for influenza A viral RNA, 108 (14%) for H9, and 60 (8%) for H5. Shops that slaughtered poultry, kept poultry overnight, remained open without rest days, had uneven muddy floors, held poultry on the floor, and housed sick and healthy poultry together were more frequently positive for influenza A viruses. Reported monthly cleaning seemed protective, but disinfection practices were not otherwise associated with influenza A virus detection. Slaughtering, keeping poultry overnight, weekly rest days, infrastructure, and disinfection practices could be targets for interventions to reduce environmental contamination.

Bird flu outbreak amidst COVID-19 pandemic in South Africa: Efforts and challenges at hand

Over the months of April and May 2021, South Africa has witnessed several outbreaks of highly infective avian influenza (H5N1) in different poultry farms. This came as a shock to a country that was already battling with the deadly COVID‐19 pandemic. The emergence of the virus has spurred import bans and massive culls in the poultry business. Local experts have also called for a restriction on the movement of people and cars in and out of their chicken farms. Employees have also been encouraged to shower in the mornings when they arrive at the farms and wear fresh clothes, as the flu spreads very quickly. In a country that is already facing the economic implications of the COVID‐19, this has the potential to cause a significant dent in the economy, as well as severely impact people's day‐to‐day life. Bird flu—also called avian influenza—is a viral infection that can infect not only birds but also humans and other animals. The threat of a new influenza pandemic has prompted countries to draft national strategic preparedness plans to prevent, contain and mitigate the next human influenza pandemic. This paper describes the South African burden, current efforts, and preparedness against the avian influenza virus.

Value chain analysis of yellow broiler industry in Guangxi, China to inform H7N9 influenza control strategies

Yellow broilers are the primary source of poultry consumption in China and the predominant trade of live poultry. However, knowledge of the value chain is limited, which is vital evidence for the effective control of H7N9 and other zoonotic avian influenzas. The aim of the study was to map the yellow broiler value chain in Guangxi Zhuang Autonomous Region, China and investigate its governance structure and practices relevant to the risk of H7N9 transmission. A value chain analysis was conducted in five areas of Guangxi from May to August 2018. To map the value chain, three focus group discussions (FGDs) were conducted and stakeholders, products and premises involved and their interactions were identified. Then, 55 key informant interviews (KIIs) collected qualitative data on stakeholders' profile, practices and interactions with other stakeholders and rules/norms that exist along the value chain. On-site observations were also carried out at different types of premises along the value chain to complement and validate findings of KIIs and FGDs. Participants were also asked to provide proportional estimates of each component in the value chain where possible. The qualitative data from FGDs, KIIs and on-site observations were analysed to create stakeholder profiles and a diagram of product flows and stakeholders' interactions. Thematic analysis was used to identify the governance structure of the value chains and practices relevant to the risk of H7N9 transmission. The stakeholders and premises involved in Guangxi yellow broiler production, wholesale and retail were described, as well as their interactions. Contract farming is extensively adopted in Guangxi; consequently yellow broiler grower companies are the dominant stakeholders. The trading platform was identified as a key premise linking farms and live bird markets. The thematic analysis highlighted poor biosecurity practices in different premises along the value chain, which was supported by on-site observations. The operation of trading platforms reported in this study presents a disease risk but is not considered in the current H7N9 control programs. The study suggested that biosecurity management gaps need to be addressed through government-industry partnerships that require engagement with private stakeholders in the planning and implementation of H7N9 control strategies incentivising participation of grower companies, wholesalers and retailers.

Hemagglutinin-neuraminidase Sequence and Phylogenetic Analysis of Two Newcastle Disease Virus Isolated from Chickens in Iran

Newcastle disease is a highly contagious viral infection affecting many species of birds that can spread fast between poultry houses and cause a heavy economic burden on the poultry industry all around the world. Fusion and hemagglutinin-neuraminidase (HN) protein are important in the pathogenesis of the Newcastle disease virus (NDV). The HN protein is a critical viral protein with multiple functions and plays a key role in the formation of the virulence of NDV. Head of HN protein is responsible for receptor binding, neuraminidase activity. This study aimed to investigate the sequence homology of hemagglutinin-neuraminidase of two NDV isolates sampled from infected farms in Iran. The samples were collected from flocks that had been vaccinated by both types of live and killed vaccines for NDV. After isolation of NDV, the viruses were subjected to the polymerase chain reaction (PCR) amplification using two pairs of specific primers designed for the HN gene to amplify the complete HN gene (1730bp). Afterward, the PCR products were sequenced and analyzed by phylogenetic tree construction software. Based on the analysis, substantial sequence homology among Iranian isolates is within the range of 97.1-100%. Moreover, the sequence homology searching revealed a level of similarity between HN sequences of Iranian isolates and the HN sequences from other countries, particularly Asian ones. For instance, a high homology ratio (95.34%) was found between Iranian isolates and the sequences registered on online molecular databases from China. Based on phylogenetic analysis, the NDV isolates belong to the VIId genotype. Finally, it can be concluded that monitoring the circulation of NDVs among poultry and other birds can help to obtain an insight into the evolution of NDVs and control of panzootic viruses in the future.

The potential of diagnostic point-of-care tests (POCTs) for infectious and zoonotic animal diseases in developing countries: Technical, regulatory and sociocultural considerations

Remote and rural communities in low‐ and middle‐income countries (LMICs) are disproportionately affected by infectious animal diseases due to their close contact with livestock and limited access to animal health personnel). However, animal disease surveillance and diagnosis in LMICs is often challenging, and turnaround times between sample submission and diagnosis can take days to weeks. This diagnostic gap and subsequent disease under‐reporting can allow emerging and transboundary animal pathogens to spread, with potentially serious and far‐reaching consequences. Point‐of‐care tests (POCTs), which allow for rapid diagnosis of infectious diseases in non‐laboratory settings, have the potential to significantly disrupt traditional animal health surveillance paradigms in LMICs. This literature review sought to identify POCTs currently available for diagnosing infectious animal diseases and to determine facilitators and barriers to their use and uptake in LMICs. Results indicated that some veterinary POCTs have been used for field‐based animal disease diagnosis in LMICs with good results. However, many POCTs target a small number of key agricultural and zoonotic animal diseases, while few exist for other important animal diseases. POCT evaluation is rarely taken beyond the laboratory and into the field where they are predicted to have the greatest impact, and where conditions can greatly affect test performance. A lack of mandated test validation regulations for veterinary POCTs has allowed tests of varying quality to enter the market, presenting challenges for potential customers. The use of substandard, improperly validated or unsuitable POCTs in LMICs can greatly undermine their true potential and can have far‐reaching negative impacts on disease control. To successfully implement novel rapid diagnostic pathways for animal disease in LMICs, technical, regulatory, socio‐political and economic challenges must be overcome, and further research is urgently needed before the potential of animal disease POCTs can be fully realized.

Avian Influenza Viruses Detected in Birds in Sub-Saharan Africa: A Systematic Review

In the recent past, sub-Saharan Africa has not escaped the devastating effects of avian influenza virus (AIV) in poultry and wild birds. This systematic review describes the prevalence, spatiotemporal distribution, and virus subtypes detected in domestic and wild birds for the past two decades (2000–2019). We collected data from three electronic databases, PubMed, SpringerLink electronic journals and African Journals Online, using the Preferred Reporting Items for Systematic reviews and Meta-Analyses protocol. A total of 1656 articles were reviewed, from which 68 were selected. An overall prevalence of 3.0% AIV in birds was observed. The prevalence varied between regions and ranged from 1.1% to 7.1%. The Kruskal–Wallis and Wilcoxon signed-rank sum test showed no significant difference in the prevalence of AIV across regions, χ²(3) = 5.237, p = 0.1553 and seasons, T = 820, z = −1.244, p = 0.2136. Nineteen hemagglutinin/neuraminidase subtype combinations were detected during the reviewed period, with southern Africa recording more diverse AIV subtypes than other regions. The most detected subtype was H5N1, followed by H9N2, H5N2, H5N8 and H6N2. Whilst these predominant subtypes were mostly detected in domestic poultry, H1N6, H3N6, H4N6, H4N8, H9N1 and H11N9 were exclusively detected in wild birds. Meanwhile, H5N1, H5N2 and H5N8 were detected in both wild and domestic birds suggesting circulation of these subtypes among wild and domestic birds. Our findings provide critical information on the eco-epidemiology of AIVs that can be used to improve surveillance strategies for the prevention and control of avian influenza in sub-Saharan Africa.

Perception of health risks in Lao market vendors

Wet markets are a critical part of South‐East Asian culture and economy. However, their role in circulation and transmission of both endemic and emerging disease is a source of concern in a region considered a hotspot of disease emergence. In the Lao People's Democratic Republic (Lao PDR, Laos), live and dead wild animals are frequently found in wet markets, despite legislation against the bushmeat trade. This is generally considered to increase the risk of disease transmission and emergence, although whether or not wildlife vendors themselves have indeed increased incidence of zoonotic disease has rarely been assessed. In preparation for a future longitudinal study of market vendors investigating vendors’ exposure to zoonotic pathogens, we conducted a pilot survey of Lao market vendors of wildlife meat, livestock meat and vegetables, to identify demographic characteristics and potential control groups within markets. We also investigated baseline risk perception for infectious diseases among market vendors and assessed the association between risk perception and risk mitigation behaviours. The surveys conducted with 177 vendors revealed similar age, sex, ethnic background and geographical origin between vendor types, but differences in professional background and work history for livestock meat vendors. The perception of disease risk was very low across all vendors, as was the reported use of personal protective equipment, and the two appeared unrelated. Personal risk discounting and assumptions about transmission routes may explain this lack of association. This information will help inform the development of future research, risk communication and risk mitigation policy, especially in the light of the COVID‐19 pandemic.

Geographical variation in the risk of H7N9 human infections in China: implications for risk-based surveillance

The influenza A (H7N9) subtype remains a public health problem in China affecting individuals in contact with live poultry, particularly at live bird markets. Despite enhanced surveillance and biosecurity at LBMs H7N9 viruses are now more widespread in China. This study aims to quantify the temporal relationship between poultry surveillance results and the onset of human H7N9 infections during 2013-2017 and to estimate risk factors associated with geographical risk of H7N9 human infections in counties in Southeast China. Our results suggest that poultry surveillance data can potentially be used as early warning indicators for human H7N9 notifications. Furthermore, we found that human H7N9 incidence at county-level was significantly associated with the presence of wholesale LBMs, the density of retail LBMs, the presence of poultry virological positives, poultry movements from high-risk areas, as well as chicken population density and human population density. The results of this study can influence the current AI H7N9 control program by supporting the integration of poultry surveillance data with human H7N9 notifications as an early warning of the timing and areas at risk for human infection. The findings also highlight areas in China where monitoring of poultry movement and poultry infections could be prioritized.

Effectiveness of Live Poultry Market Interventions on Human Infection with Avian Influenza A(H7N9) Virus, China

Various interventions for live poultry markets (LPMs) have emerged to control outbreaks of avian influenza A(H7N9) virus in mainland China since March 2013. We assessed the effectiveness of various LPM interventions in reducing transmission of H7N9 virus across 5 annual waves during 2013-2018, especially in the final wave. With the exception of waves 1 and 4, various LPM interventions reduced daily incidence rates significantly across waves. Four LPM interventions led to a mean reduction of 34%-98% in the daily number of infections in wave 5. Of these, permanent closure provided the most effective reduction in human infection with H7N9 virus, followed by long-period, short-period, and recursive closures in wave 5. The effectiveness of various LPM interventions changed with the type of intervention across epidemics. Permanent LPM closure should be considered to maintain sufficient effectiveness of interventions and prevent the recurrence of H7N9 epidemics.

Prevalence and Characteristics of Extended-Spectrum-β-Lactamase-Producing and Carbapenemase-Producing Enterobacteriaceae from Freshwater Fish and Pork in Wet Markets of Hong Kong

Extended-spectrum-β-lactamase-producing Enterobacteriaceae (ESBL-E) and carbapenemase-producing Enterobacteriaceae (CPE) are of global health importance, yet there is a paucity of surveillance studies on food animals in Hong Kong. Here, we report a high prevalence of ESBL-E (ranging from 0.5% to 52.4%) and CPE (0% to 9.9%) from various food animal samples procured from wet markets across Hong Kong. All CPE strains were characterized by whole-genome sequencing and possessed NDM-1 and -5 genes and other resistance determinants. Given the increased resistance profile of these strains, this study highlights the emerging threat of ESBL-E and CPE disseminated in farmed animals. Furthermore, our data enriched our understanding of antibiotic resistance reservoirs from a One Health perspective that can widely spread across various niches, beyond health care settings.

This study identified and characterized extended-spectrum-β-lactamase-producing Enterobacteriaceae (ESBL-E) and carbapenemase-producing Enterobacteriaceae (CPE) from farmed freshwater fish and pig offal procured from the wet markets across Hong Kong. During March 2018 to January 2019, 730 food animal samples, namely, 213 snakehead fish, 198 black carp, and 339 pig organs, were examined. ESBL-E and CPE were isolated from the homogenized samples plated on selective media and identified by matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF-MS). All ESBL-E and CPE strains were tested for antimicrobial susceptibilities. ESBL-E and CPE gene groups were detected by multiplex PCR and bla_{CTX-M-1/-2/-9} group strains were Sanger sequenced for CTX-M types. All CPE isolates were whole-genome sequenced. Isolation of ESBL-E from pig small (52.4%) and large (50%) intestines and tongues (25.1%) was significantly (P < 0.05) more frequent than from snakehead (0.94%) and black carp (0.5%) fish. ESBL-E isolates (n = 171) revealed resistance rates of 16.3%, 29.8%, 35.6%, 53.2%, 55.0%, and 100% to piperacillin-tazobactam, amoxicillin-clavulanate, cefepime, gentamicin, ciprofloxacin, and ampicillin, respectively, whereas CPE (n = 28) were resistant to almost all the antibiotics tested except gentamicin, ciprofloxacin, and fosfomycin. The predominant ESBL gene groups in fishes and pig offals were bla_CTX, where bla_CTX-M-55 was the major subtype in the bla_CTX-M-1 group (64.4% of isolates in the group). bla_CTX-M-14/-17 was the major genotype in the bla_CTX-M-9 group (32.2%). All CPE strains possessed bla_NDM genes. High rates of ESBL-E and CPE were identified in food animals from wet markets of Hong Kong, which may serve as a potential reservoir of antimicrobial-resistant genes and increase the challenges in tackling antimicrobial resistance beyond health care settings.

IMPORTANCE Extended-spectrum-β-lactamase-producing Enterobacteriaceae (ESBL-E) and carbapenemase-producing Enterobacteriaceae (CPE) are of global health importance, yet there is a paucity of surveillance studies on food animals in Hong Kong. Here, we report a high prevalence of ESBL-E (ranging from 0.5% to 52.4%) and CPE (0% to 9.9%) from various food animal samples procured from wet markets across Hong Kong. All CPE strains were characterized by whole-genome sequencing and possessed NDM-1 and -5 genes and other resistance determinants. Given the increased resistance profile of these strains, this study highlights the emerging threat of ESBL-E and CPE disseminated in farmed animals. Furthermore, our data enriched our understanding of antibiotic resistance reservoirs from a One Health perspective that can widely spread across various niches, beyond health care settings.

Interventions in Live Poultry Markets for the Control of Avian Influenza: A Systematic Review and Meta-analysis

BACKGROUND

This review aimed to provide constructive suggestions for the control and management of avian influenza through quantitative and qualitative evaluation of the impact of different live poultry market (LPM) interventions.

METHODS

Both English and Chinese language databases were searched for articles that were published on or before 9 November 2018. After extraction and assessment of the included literature, Stata14.0 was applied to perform a meta-analysis to explore the impacts of LPM interventions.

RESULTS

A total of 19 studies were identified. In total, 224 human, 3550 poultry, and 13 773 environment samples were collected before the intervention; 181 people, 4519 poultry, and 9562 environments were sampled after LPM interventions. Avian influenza virus (AIV) detection rates in the LPM environment (odds ratio [OR], 0.393; 95% confidence interval [CI], 0.262-0.589) and the incidence of AIV infection (OR, 0.045; 95% CI, 0.025-0.079) were significantly lower after LPM interventions, while interventions were not significantly effective in reducing AIV detection in poultry samples (OR, 0.803; 95% CI, 0.403-1.597).

CONCLUSIONS

LPM interventions can reduce AIV human infections and the detection rate of AIV in market environments.

Avian influenza viruses in humans: lessons from past outbreaks

BACKGROUND

Human infections with avian influenza viruses (AIV) represent a persistent public health threat. The principal risk factor governing human infection with AIV is from direct contact with infected poultry and is primarily observed in Asia and Egypt where live-bird markets are common.

AREAS OF AGREEMENT

Changing patterns of virus transmission and a lack of obvious disease manifestations in avian species hampers early detection and efficient control of potentially zoonotic AIV.

AREAS OF CONTROVERSY

Despite extensive studies on biological and environmental risk factors, the exact conditions required for cross-species transmission from avian species to humans remain largely unknown.

GROWING POINTS

The development of a universal ('across-subtype') influenza vaccine and effective antiviral therapeutics are a priority.

AREAS TIMELY FOR DEVELOPING RESEARCH

Sustained virus surveillance and collection of ecological and physiological parameters from birds in different environments is required to better understand influenza virus ecology and identify risk factors for human infection.

Immunopathological immunohistochemical study of low pathogenic avian influenza virus H5N1 infection in lovebirds (Agapornis spp.) in Indonesia

Background and Aim:

To date, persistent infection with low pathogenic avian influenza virus (AIV) subtype H5N1 (LPAI H5N1) in chickens is widespread in Indonesia. Commercially available ornamental birds on markets play an important role in triggering the occurrence of AIV outbreaks. Thus, the presence of AIV in ornamental birds such as lovebirds needs to be closely monitored. Here, the presence of LPAI H5N1 was investigated in lovebirds with no clinical signs that, although apparently healthy, can be a continuous source of AIV transmission to other sensitive birds such as chickens and even humans.

Materials and Methods:

In the present study, 30 lovebirds were necropsied. The immunopathology of the lungs, which had hemorrhages, was immunohistochemically studied using the streptavidin-biotin (SB) method to stain for LPAI H5N1. Polyclonal antibodies against the nucleoprotein or monoclonal antibodies against the hemagglutinin of the AIV subtype H5N1 were used to identify these antigens in lung tissue samples.

Results:

LPAI H5N1 was detected in the lungs of all lovebirds according to the brownish colored deposits in the histological samples. The highest intensity of the SB staining was found in the lumina of vascular capillaries and the cell membranes of air capillaries. The discovery of LPAI H5N1 in lovebirds increases the environmental health risk and raises the possibility of exposure to AIV. Thus, it is very important to improve the mechanisms that control the traffic of ornamental birds between regions and islands, as well as the AIV vaccination strategies related to the prevention, control, and eradication of AIV in Indonesia, and these procedures should be reevaluated.

Conclusion:

The present study proves that lovebirds are infected with LPAI subtype H5N1. Even if ornamental birds such as lovebirds do not show any clinical signs, they are likely to be a persistently infected with LPAI H5N1. Therefore, ornamental birds might be a continuous source of LPAI H5N1 infections in other sensitive birds, including poultry, and may also be responsible for virus transmission to humans.

Effectiveness of Market-Level Biosecurity at Reducing Exposure of Poultry and Humans to Avian Influenza: A Systematic Review and Meta-Analysis

Background

In this study, we aimed to identify the effect of market-level risk factors on avian influenza (AI) infection in poultry and humans and generate evidence that will inform AI prevention and control programs at live bird markets (LBMs).

Methods

We performed a systematic literature review in both English and Chinese search engines. We estimated the pooled odds ratios of biosecurity indicators relating to AI infections at market level using a quality effects (QE) meta-analysis model.

Results

Biosecurity measures effective at reducing AI market contamination and poultry infection at LBMs include smaller market size, selling single poultry species and separating different species, performing cleaning and disinfection and market closures, ban on overnight storage, and sourcing poultry from local areas. Our meta-analysis indicates that higher risk of exposure to AI infection occurs in workers at retail LBMs, female workers, and those who contact ducks, conduct cleaning, slaughtering, defeathering, or evisceration.

Conclusions

The most effective strategies to reduce AI market contamination identified in this study should target larger LBMs that are located at noncentral city areas and sell and slaughter multispecies of live poultry. Live bird market workers directly involved in cleaning and poultry processing tasks should participate in occupational health and safety programs.

Highly Pathogenic Avian Influenza A(H5N1) Outbreaks in West Java Indonesia 2015-2016: Clinical Manifestation and Associated Risk Factors

Knowledge of outbreaks and associated risk factors is helpful to improve control of the Highly Pathogenic Avian Influenza A(H5N1) virus (HPAI) in Indonesia. This study was conducted to detect outbreaks of HPAI H5N1 in endemically infected regions by enhanced passive surveillance, to describe the clinical manifestation of these outbreaks and identify associated risk factors. From November 2015 to November 2016, HPAI outbreak investigations were conducted in seven districts of West Java. In total 64 outbreaks were confirmed out of 75 reported suspicions and outbreak characteristics were recorded. The highest mortality was reported in backyard chickens (average 59%, CI95%: 49-69%). Dermal apoptosis and lesions (64%, CI95%: 52-76%) and respiratory signs (39%, CI95%: 27-51%) were the clinical signs observed overall most frequently, while neurological signs were most frequently observed in ducks (68%, CI95%: 47-90%). In comparison with 60 non-infected control farms, the rate of visitor contacts onto a farm was associated with the odds of HPAI infection. Moreover, duck farms had higher odds of being infected than backyard farms, and larger farms had lower odds than small farms. Results indicate that better external biosecurity is needed to reduce transmission of HPAI A(H5N1) in Indonesia.

Reassortments among Avian Influenza A(H5N1) Viruses Circulating in Indonesia, 2015-2016

Highly pathogenic avian influenza (HPAI) A(H5N1) viruses have been circulating since 2003 in Indonesia, with major impacts on poultry health, severe economic losses, and 168 fatal laboratory-confirmed human cases. We performed phylogenetic analysis on 39 full-genome H5N1 virus samples collected during outbreaks among poultry in 2015-2016 in West Java and compared them with recently published sequences from Indonesia. Phylogenetic analysis revealed that the hemagglutinin gene of all samples belonged to 2 genetic groups in clade 2.3.2.1c. We also observed these groups for the neuraminidase, nucleoprotein, polymerase, and polymerase basic 1 genes. Matrix, nonstructural protein, and polymerase basic 2 genes of some HPAI were most closely related to clade 2.1.3 instead of clade 2.3.2.1c, and a polymerase basic 2 gene was most closely related to Eurasian low pathogenicity avian influenza. Our results detected a total of 13 reassortment types among HPAI in Indonesia, mostly in backyard chickens in Indramayu.

A Global Perspective on H9N2 Avian Influenza Virus

H9N2 avian influenza viruses have become globally widespread in poultry over the last two decades and represent a genuine threat both to the global poultry industry but also humans through their high rates of zoonotic infection and pandemic potential. H9N2 viruses are generally hyperendemic in affected countries and have been found in poultry in many new regions in recent years. In this review, we examine the current global spread of H9N2 avian influenza viruses as well as their host range, tropism, transmission routes and the risk posed by these viruses to human health.

Spatiotemporal Variation and Hotspot Detection of the Avian Influenza A(H7N9) Virus in China, 2013⁻2017

This study aims to describe the spatial and temporal characteristics of human infections with H7N9 virus in China using data from 19 February 2013 to 30 September 2017 extracted from Centre for Health Protection of the Department of Health (CHP) and electronic databases managed by China's Center for Disease Control (CDC) and provincial CDCs synthetically using the Geographic Information System (GIS) software ArcMap™ 10.2 and SaTScan. Based on the multiple analyses of the A(H7N9) epidemics, there was a strong seasonal pattern in A(H7N9) virus infection, with high activity in the first quarter of the year, especially in January, February, and April, and a gradual dying out in the third quarter. Spatial distribution analysis indicated that Eastern China contained the most severely affected areas, such as Zhejiang Province, and the distribution shifted from coastline areas to more inland areas over time. In addition, the cases exhibited local spatial aggregation, with high-risk areas most found in the southeast coastal regions of China. Shanghai, Jiangsu, Zhejiang, and Guangdong were the high-risk epidemic areas, which should arouse the attention of local governments. A strong cluster from 9 April 2017 to 24 June 2017 was also identified in Northern China, and there were many secondary clusters in Eastern and Southern China, especially in Zhejiang, Fujian, Jiangsu, and Guangdong Provinces. Our results suggested that the spatial-temporal clustering of H7N9 in China is fundamentally different, and is expected to contribute to accumulating knowledge on the changing temporal patterns and spatial dissemination during the fifth epidemic and provide data to enable adequate preparation against the next epidemic.

The impact of surveillance and control on highly pathogenic avian influenza outbreaks in poultry in Dhaka division, Bangladesh

In Bangladesh, the poultry industry is an economically and socially important sector, but it is persistently threatened by the effects of H5N1 highly pathogenic avian influenza. Thus, identifying the optimal control policy in response to an emerging disease outbreak is a key challenge for policy-makers. To inform this aim, a common approach is to carry out simulation studies comparing plausible strategies, while accounting for known capacity restrictions. In this study we perform simulations of a previously developed H5N1 influenza transmission model framework, fitted to two separate historical outbreaks, to assess specific control objectives related to the burden or duration of H5N1 outbreaks among poultry farms in the Dhaka division of Bangladesh. In particular, we explore the optimal implementation of ring culling, ring vaccination and active surveillance measures when presuming disease transmission predominately occurs from premises-to-premises, versus a setting requiring the inclusion of external factors. Additionally, we determine the sensitivity of the management actions under consideration to differing levels of capacity constraints and outbreaks with disparate transmission dynamics. While we find that reactive culling and vaccination policies should pay close attention to these factors to ensure intervention targeting is optimised, across multiple settings the top performing control action amongst those under consideration were targeted proactive surveillance schemes. Our findings may advise the type of control measure, plus its intensity, that could potentially be applied in the event of a developing outbreak of H5N1 amongst originally H5N1 virus-free commercially-reared poultry in the Dhaka division of Bangladesh.

Ongoing circulation of avian influenza H5N1 viruses in poultry pose a global public health risk and cause extensive damage to the livestock industry. One of several countries in South Asia gravely affected is Bangladesh, where the poultry industry is an economically and socially important sector. Identifying the optimal control response in anticipation of further outbreaks is therefore a key challenge for policy-makers. This study tested a series of culling, vaccination and active surveillance intervention actions, assessing specific control objectives related to the burden or duration of H5N1 outbreaks among commercial poultry farms in the Dhaka division. This assessment was achieved through performing computational simulations of a previously developed H5N1 influenza transmission mathematical model. The findings of this assessment indicate that the impact of reactive culling and vaccination control policies are dependent upon transmission characteristics, control objectives and availability of resources to enact the control action, whereas proactive surveillance schemes significantly outperform reactive surveillance procedures irrespective of these conditions.

Live bird markets in Bangladesh as a potentially important source for Avian Influenza Virus transmission

Live bird markets (LBM) are important for trading poultry in many developing countries where they are being considered hotspots of Avian Influenza Virus (AIV) prevalence and contamination. An active surveillance for Avian Influenza Virus (AIV) was conducted on four species of LBM birds (chickens, ducks, quails and pigeons) from 10 of the largest LBM in Chittagong, Bangladesh, and two species of peri-domestic wild birds (house crow and Asian pied starling) in their direct vicinity from November 2012 until September 2016. Our aim was to identify the scale and annual pattern of AIV circulation in both the LBM birds and the two per-domestic wild bird species living in close proximity of the LBM. In the latter two species, the annual pattern in AIV antibody prevalence was additionally investigated. A total of 4770 LBM birds and 1119 peri-domestic wild birds were sampled. We used rt-PCR for detection of the AIV M-gene and AIV subtypes H5, H7 and H9 from swab samples. We used c-ELISA for AIV antibody detection from serum samples of peri-domestic wild birds. Average AIV prevalence among the four LBM species varied between 16 and 28%, whereas no AIV was detected in peri-domestic wild birds by rt-PCR. In all LBM species we found significantly higher AIV prevalence in winter compared to summer. A similar pattern was found in AIV antibody prevalence in peri-domestic wild birds feeding in the direct vicinity of LBM. For the subtypes of AIV investigated, we found a significantly higher proportion of AIV H5 in LBM chickens and H9 in LBM ducks. No H7 was detected in any of the investigated samples. We conclude that AIV and notably AIV H5 and H9 were circulating in the investigated LBM of Bangladesh with clear seasonality that matched the prevalence of AIV antibodies of peri-domestic wild birds. These patterns show great resemblance to the annual outbreak patterns in Bangladeshi poultry industry. Our data suggest considerable exchange of AIV within and among the four LBM bird species and peri-domestic wild birds, which likely contributes to the maintenance of the AIV problems in Bangladesh. Increasing biosecurity and notably reducing the direct and indirect mixing of various domestic bird species and peri-domestic wild birds and developing all-in-all-out selling systems with regular use of disinfectant are likely to reduce the risk of transmission and spread of AIV, including HPAI.

A Systematic Review and Meta-Analysis of Practices Exposing Humans to Avian Influenza Viruses, Their Prevalence, and Rationale

Almost all human infections by avian influenza viruses (AIVs) are transmitted from poultry. A systematic review was conducted to identify practices associated with human infections, their prevalence, and rationale. Observational studies were identified through database searches. Meta-analysis produced combined odds ratio estimates. The prevalence of practices and rationales for their adoptions were reported. Of the 48,217 records initially identified, 65 articles were included. Direct and indirect exposures to poultry were associated with infection for all investigated viral subtypes and settings. For the most frequently reported practices, association with infection seemed stronger in markets than households, for sick and dead than healthy poultry, and for H7N9 than H5N1. Practices were often described in general terms and their frequency and intensity of contact were not provided. The prevalence of practices was highly variable across studies, and no studies comprehensively explored reasons behind the adoption of practices. Combining epidemiological and targeted anthropological studies would increase the spectrum and detail of practices that could be investigated and should aim to provide insights into the rationale(s) for their existence. A better understanding of these rationales may help to design more realistic and acceptable preventive public health measures and messages.

Insight into live bird markets of Bangladesh: an overview of the dynamics of transmission of H5N1 and H9N2 avian influenza viruses

Highly pathogenic avian influenza (HPAI) H5N1 and low pathogenic avian influenza (LPAI) H9N2 viruses have been recognized as threats to public health in Bangladesh since 2007. Although live bird markets (LBMs) have been implicated in the transmission, dissemination, and circulation of these viruses, an in-depth analysis of the dynamics of avian transmission of H5N1 and H9N2 viruses at the human-animal interface has been lacking. Here we present and evaluate epidemiological findings from active surveillance conducted among poultry in various production sectors in Bangladesh from 2008 to 2016. Overall, the prevalence of avian influenza viruses (AIVs) in collected samples was 24%. Our data show that AIVs are more prevalent in domestic birds within LBMs (30.4%) than in farms (9.6%). Quail, chickens and ducks showed a high prevalence of AIVs (>20%). The vast majority of AIVs detected (99.7%) have come from apparently healthy birds and poultry drinking water served as a reservoir of AIVs with a prevalence of 32.5% in collected samples. HPAI H5N1 was more frequently detected in ducks while H9N2 was more common in chickens and quail. LBMs, particularly wholesale markets, have become a potential reservoir for various types of AIVs, including HPAI H5N1 and LPAI H9N2. The persistence of AIVs in LBMs is of great concern to public health, and this study highlights the importance of regularly reviewing and implementing infection control procedures as a means of reducing the exposure of the general public to AIVs.Emerging Microbes & Infections (2017) 6, e12; doi:10.1038/emi.2016.142; published online 8 March 2017.