The application of epidemiology in aquatic animal health -opportunities and challenges

Over recent years the growth in aquaculture, accompanied by the emergence of new and transboundary diseases, has stimulated epidemiological studies of aquatic animal diseases. Great potential exists for both observational and theoretical approaches to investigate the processes driving emergence but, to date, compared to terrestrial systems, relatively few studies exist in aquatic animals. Research using risk methods has assessed routes of introduction of aquatic animal pathogens to facilitate safe trade (e.g. import risk analyses) and support biosecurity. Epidemiological studies of risk factors for disease in aquaculture (most notably Atlantic salmon farming) have effectively supported control measures. Methods developed for terrestrial livestock diseases (e.g. risk-based surveillance) could improve the capacity of aquatic animal surveillance systems to detect disease incursions and emergence. The study of disease in wild populations presents many challenges and the judicious use of theoretical models offers some solutions. Models, parameterised from observational studies of host pathogen interactions, have been used to extrapolate estimates of impacts on the individual to the population level. These have proved effective in estimating the likely impact of parasite infections on wild salmonid populations in Switzerland and Canada (where the importance of farmed salmon as a reservoir of infection was investigated). A lack of data is often the key constraint in the application of new approaches to surveillance and modelling. The need for epidemiological approaches to protect aquatic animal health will inevitably increase in the face of the combined challenges of climate change, increasing anthropogenic pressures, limited water sources and the growth in aquaculture

Molecular ecology of Beak and Feather Disease Virus in the Endangered Mauritius parakeet (Psittacula eques)

The occurrence of Psittacine Beak and Feather Disease (PBFD) has been reported in both wild and captive parrot populations since the mid-1970s. PBFD has been found to be widely infectious and often fatal, affecting both Old and New World psittacine species. Consequently, determining routes of transmission and developing pathological and serological tests for screening for presence of the Beak and Feather Disease Virus (BFDV) have emerged as important priorities for biodiversity managers. Here, we consolidate information collected from 82 PBFD- and BFDV-based publications on the primary screening methods being used and identify important knowledge gaps regarding potential global disease hotspots. We present trends in research intensity in this field, and critically discuss advances in screening techniques and their applications to both aviculture and to the management of threatened wild populations. Finally we provide an overview regarding estimates of BFDV prevalence in captive and wild flocks alongside a complete list of all psittaciform species known to be susceptible. Advances in BFDV screening and diagnostic tools currently available allow for a broader application of results to conservation management strategies. Our evaluation highlights the need for standardised diagnostic tests and more emphasis on studies of wild populations, particularly when considering the intrinsic connection between global trade in companion birds and the spread of novel BFDV strains into wild populations. Increased emphasis should be placed on the screening of captive and wild parrot populations within their countries of origin across the Americas, Africa and Asia

Étude épidémiologique du virus de l’influenza aviaire et du virus de la maladie de Newcastle chez l’avifaune sauvage aux Émirats Arabes Unis.

L'infection des élevages avicoles par le virus de l‟Influenza aviaire et par le virus de la maladie de Newcastle a un impact sanitaire et économique majeur. Le rôle de l‟avifaune sauvage dans la transmission de tels virus est souvent étudié même si on manque encore d'informations dans certains pays comme c‟est le cas aux Emirats Arabes Unis. Après avoir exposé une synthèse des données scientifiques sur les deux virus étudiés et sur le contexte épidémiologique au Moyen Orient, nous présenterons les résultats de notre étude. Celle-ci vise à connaitre le statut épidémiologique de six espèces d‟oiseaux sauvages proches d‟élevages conservatoires d‟outardes houbara (Chlamydotis macqueenii) afin d‟évaluer le risque potentiel de transmission aux outardes. Notre étude a montré des prévalences faibles pour le virus de l‟Influenza aviaire par ELISA et RT-PCR. Les séroprévalences sont plus élevées pour le virus de la maladie de Newcastle mais la prévalence par RT-PCR reste faible. A partir de produits de PCR, nous avons pu séquencer les souches virales du virus de la maladie de Newcastle