Headlines - Update on the avian influenza A(H7N9) virus as of February 4, 2014

The new avian influenza A(H7N9), identified in eastern China in March 2013, caused an outbreak between late March and early May 2013 that affected 132 people, 32 of whom died (24%). The outbreak then subsided following the closure of live bird markets and the end of the winter season. As expected, this outbreak resumed in China in mid-October with the return of cold weather and has been accelerating since the beginning of 2014. The WHO has reported 134 cases since January 1, including 23 deaths (17%). According to the WHO and the ECDC, this increase in human cases of A(H7N9) could be linked to various epidemiological factors: an expansion of the animal reservoir, an increase in the number of people exposed, greater transmissibility of the virus, seasonal transmission patterns, or a combination of these factors. The concurrent circulation of seasonal influenza viruses A(H3N2), (H1N1)pdm09, and B has prompted enhanced surveillance with active case finding in many provinces in eastern China. The genetic characteristics of the A(H7N9) virus, its lethality and severity, as well as the possibility of recombination with other influenza viruses, may pose a significant risk on an international scale. Furthermore, the persistence of this low-pathogenic virus in poultry represents a significant threat of establishing an enzootic circulation with a virus that has pandemic potential. This virus is transmitted from animals to humans, and no sustained human-to-human transmission has been identified to date. The risk of importing cases of influenza A(H7N9) into France is low, but it is important to consider this possibility when faced with a suggestive clinical presentation (see case definition on the InVS website). In France, the InVS, through its network of CIREs and the Regional Health Agencies (ARS), is responsible for monitoring these viruses and validating the classification of possible cases of infection with emerging infectious agents.In the event of any suspected case, healthcare professionals must contact the SAMU-centre 15, which will coordinate the patient’s care in collaboration with the ARS and the InVS-Cire.