EFSA: The role of mammals in Avian Influenza
Recently, there has been an increase in reported infections of avian influenza in mammals, spanning from asymptomatic cases to mass mortality events, and some human cases have also been recorded. Epidemiologically, there is great concern as evidence of mammalian adaptations to the virus has been found, yet the transmission routes and pathogenesis in mammals remain to be fully defined.
A new report by EFSA aims to assess the role of mammals in avian influenza epidemiology, virology, and pathology, including avian influenza maintenance, reservoir role, immunity, and the potential role of mammals in a pandemic scenario.
According to the report, the most represented taxa were found within the order Carnivora. The primary identified risk of infection was through predation (or feeding) upon infected birds or through contact with avian species. Evidence of mammal-to-mammal transmission in the wild is currently only circumstantial and yet to be confirmed.
The report concludes that there is no hard evidence for sustained mammal-to-mammal transmission in the wild.
We pose the question: what else does a clinician need to understand about mammal-to-mammal transmission when there is intense and widespread infection among thousands of marine mammals, from which avian influenza viruses that have adapted to mammals have been isolated?