[Actualities on the avian influenza]

ABSTRACT

Influenza viruses cause yearly seasonal outbreaks and are periodically involved in the emergence of new subtypes causing pandemics. Wild birds are considered as the natural host of these viruses. At the present time, we are facing the progressive expansion of an H5N1 virus appeared in South-East Asia and affecting an increasing number of countries, the last one beeing Turkey. This highly pathogenic strain in birds passed from poultry to humans, resulting in a mortality of approximately 50%. Person-to-person transmission seems to be very scarce, most of patients were contamined by affected poultry. Compared to normal influenza, human infection by H5N1 virus is frequently associated with digestive symptoms and respiratory failure resulting from viral pneumonia. Diagnosis relies mainly on viral isolation and genomic tests performed in a biosafety level 3 laboratory. The most effective control measure is to eliminate animal source, which remains beyond reach. Antiviral therapy is available [neuraminidase inhibitors] and immunization trials with experimental vaccine are pending. Nevertheless, the massive needs for these products are hampered by limited production capacities and costs. According to WHO recommendations, Tunisia elaborated a preparedness plan and reinforced virological surveillance of both human and animal influenza. Efforts are needed to enhance the production of antiviral drugs and vaccines in order to be able to contain the future H5N1 pandemic influenza