Serological and Virological Study of Newcastle Disease and Avian Influenza in Chickens in Rural Areas in Senegal

Abstract

Serological survey on the prevalence of Newcastle disease (NCD) virus antibodies using haemagglutination inhibition test (HI) and virological detection by RT-PCR of highly pathogenic avian influenza (HPAI) H5N1, were carried out in 6 regions of Senegal from June to November 2008. Rural chickens were raised in free ranging traditional and backyard systems. A total of 668 birds were sampled and 150 cloacae swabs from wild birds were used for the study. Data on medical care (treatments) and hygiene were collected using a questionnaire. The overall seroprevalence of NCD virus antibodies was 54.4% in these rural chickens but the prevalence of protective Newcastle disease virus antibodies in vaccinated chickens was 70.6% and in unvaccinated chickens 43.8%. These results suggest that for the “vaccinated chickens” group, the vaccination was not well carried out, furthermore the results also imply the possibility of circulation of a wild strain of NCD virus. There was a significant difference in prevalence between regions and the use of antibiotics for vaccinated and unvaccinated chickens. Multiple correspondence analysis classified regions in four sectors in which emphasis has to be laid on vaccination or training. To further understand the epidemiology of NCD in rural chickens in Senegal, characterisation of isolates and risk factor studies should be conducted. No HPAI H5N1 virus was detected in our study. This confirms the negative status of Senegal for HPAI H5N1. Guinea fowls, Ducks, Turkeys and chickens were positive to the HI test.

Keywords: Prevalence, Newcastle disease, Avian Influenza, Rural chickens, Senegal