22.03.2020

Nigeria notified WHO of the detection of human cases of infection with avian influenza A(H5) viruses associated with outbreaks of avian influenza A(H5N1) in poultry. According to the IHR notification, on 29 January and 3 February 2021, the Nigeria Centre for Disease Control (NCDC) received reports of confirmed avian influenza outbreaks among poultry in Kano and Plateau States, respectively. A joint team from NCDC and the Department of Veterinary Services and Pest Control were deployed to both states. As of 17 March, 64 nasopharyngeal/oropharyngeal swabs were collected from bird handlers, who had been exposed to avian influenza A(H5N1) positive birds. Seven of the 64 samples tested positive for influenza A virus (four in Kano State, three in Plateau State), three of which were positive for influenza A(H5) at the NCDC National Reference Laboratory (NRL). All of the seven influenza A positive cases were asymptomatic. Samples from the seven influenza A-positive human cases were shipped to the WHO Collaborating Centre at the United States Centers for Disease Control and Prevention (US CDC) for further characterization. Only fragments from three samples were able to be sequenced and the results indicated the influenza (H5) virus in the samples was from the H5 2.3.4.4b clade, and the HA gene sequences were similar to those from influenza A(H5N8) viruses recently reported in wild birds and poultry outbreaks in Africa, Asia, Europe, and the Middle East. NA gene sequences could not be generated; thus, the NA subtype could not be confirmed. The confirmation of infection with influenza A(H5) versus transient contamination of the nasopharynx/oropharynx after exposure to infected birds or contaminated environment, in these persons remains inconclusive. Outbreaks of avian influenza A(H5N1) in poultry in Nigeria were first reported in February 2006. One human case of infection with an influenza A(H5N1) virus was reported from Nigeria in 2007. Influenza A(H5N8) virus infections in poultry were reported in 2016 in several states including Plateau, Bauchi, and Kano. In 2019, Nigeria reported the first occurrence of influenza A(H5N6) virus outbreaks in birds at a live poultry market in Sokoto state.