Newcastle disease virus transmission dynamics in wild peridomestic birds in the United Arab Emirates

International audienceTo understand the dynamics of a pathogen in an animal population, one must assess how the infection status of individuals changes over time. With wild animals, this can be very challenging because individuals can be difficult to trap and sample, even more so since they are tested with imperfect diagnostic techniques. Multi-event capture-recapture models allow analysing longitudinal capture data of individuals whose infection status is assessed using imperfect tests. In this study, we used a two-year dataset from a longitudinal field study of peridomestic wild bird populations in the United Arab Emirates during which thousands of birds from various species were captured, sampled and tested for Newcastle disease virus exposure using a serological test. We developed a multi-event capture-recapture model to estimate important demographic and epidemiological parameters of the disease. The modelling outputs provided important insights into the understanding of Newcastle disease dynamics in peridomestics birds, which varies according to ecological and epidemiological parameters, and useful information in terms of surveillance strategies. To our knowledge, this study is the first attempt to model the dynamics of Newcastle disease in wild bird populations by combining longitudinal capture data and serological test results. Overall, it showcased that multi-event capture-recapture models represent a suitable method to analyse imperfect capture data and make reliable inferences on infectious disease dynamics in wild populations

Exposure assessment for avian influenza and Newcastle disease viruses from peridomestic wild birds in a conservation breeding site in the United Arab Emirates

International audienceWorldwide, wild birds are frequently suspected to be involved in the occurrence of outbreaks of different diseases in captive-bred birds although proofs are lacking and most of the dedicated studies are insufficiently conclusive to confirm or characterize the roles of wild birds in such outbreaks. The aim of this study was to assess and compare, for the most abundant peridomestic wild birds, the different exposure routes for avian influenza and Newcastle disease viruses in conservation breeding sites of Houbara bustards in the United Arab Emirates. To do so, we considered all of the potential pathways by which captive bustards could be exposed to avian influenza and Newcastle disease viruses by wild birds, and ran a comparative study of the likelihood of exposure via each of the pathways considered. We merged data from an ecological study dedicated to local wild bird communities with an analysis of the contacts between wild birds and captive bustards and with a prevalence survey of avian influenza and Newcastle disease viruses in wild bird populations. We also extracted data from an extensive review of the scientific literature and by the elicitation of expert opinion. Overall, this analysis highlighted those captive bustards had a high risk of being exposed to pathogens by wild birds. This risk was higher for Newcastle disease virus than avian influenza virus, and House sparrows represented the riskiest species for the transmission of both viruses through direct exposure from direct contact with an infectious bird that got inside the aviary and indirect exposure from consumption of water contaminated from the faeces of an infected bird that got inside the aviary for Newcastle disease virus and avian influenza virus, respectively. These results also reaffirm the need to implement biosecurity measures to limit contacts between wild and captive birds and highlight priority targets for a thoughtful and efficient sanitary management strategy