Detection of highly pathogenic avian influenza (H5N1) in apparently healthy ducks (Anas sparsa sparsa) in live bird markets, Nigeria

Abstract

Nigeria reported the first outbreak of Highly Pathogenic Avian Influenza (HPAI) in Africa, February 2006. Since then effort by relevant authorities to control the spread and persistence of the disease has been effective, with only sporadic resurgence in backyard and live bird markets. Surveillance for HPAI was carried out in live bird markets (LBM) between May and June 2008 in ducks among other species. A total of 4,707samples including sera and swabs of trachea and cloaca from live birds, and parenchymatous organs from dead or moribund birds were collected from 11 states of the country where HPAI has not been previously reported. Tissues were processed for virus isolation in embryonating chicken eggs, sera analyzed by Agar Gel Immuno Diffusion test (AGID) and Haemaglutination Inhibition (HI) tests with standard monoclonal antisera to H5 and the swabs by RT-PCR using gene specific matrix and H5 primers. Two isolates of HPAI were recovered from the tracheal swab samples from apparently healthy ducks.