An Outbreak Of Highly Pathogenic Avian Influenza (Hpai) In A Mixed Farm By The Introduction Of A Water Fowl

Abstract

Avian influenza (AI) is caused by a range of Influenza type A viruses of high and low pathogenicity (Fauci, 2005). H5N1 Highly Pathogenic Avian Influenza (HPAI) viruses are currently the most significant Influenza A virus. It is associated with up to 100% mortality in affected flocks. Transmission is by contacts, aerosols and formites (Jordan and Pattson, 1999; Webster et al, 2006). The transmission and spread of AI in Nigeria has been primarily associated with wild and feral birds (Ducatez et al, 2006) while secondary spread possibly caused by human related activities sustain the virus in the environment (Salzberg et al, 2007). Poultry farming in some parts of the country is largely rural and subsistence providing food and additional income for the family. The farms are most often mixed, with multiple species of animals at different ages kept together. The introduction of new birds to an existing stock is a common practice but is often followed by devastating consequences as described in this particular case. This presents a serious challenge to the control of the disease. An outbreak of the HPAI (H5NI) was reported in a mixed poultry farm in Kano State in December 2006.This happened after the introduction into the farm, a goose bought from a life bird market. The goose died shortly after with signs of avian influenza. Afterward, other birds in the farm became sick and started to die. Carcasses sent to National Veterinary Research Institute, Vom were found positive for HPAI virus by isolation and identification. Affected flock was culled and bio security measures taken to curtail the spread of the disease. HPAI is becoming endemic in spite of on-going effort to contain it due to unwholesome farm practices that favour reservoir of infection in feral birds, ducks, geese etc wherever they are traded and raised.

Keywords: HPAI, Mixed farming, Waterfowl

Nigerian Veterinary Journal Vol. 28 (3) 2007 pp. 67-69