Sorologia e pesquisa viral para doença de Newcastle em galinhas de quintal na microrregião de Feira de Santana, Bahia - Brasil

Abstract

Creating village chickens is a common practice in developing countries, and Newcastle disease a limiting factor in their productivity. Caused by an RNA virus, the avian paramyxovirus type 1, Newcastle disease affects several species of birds, the chicken is the domestic species most susceptible. The virus is classified according to the pathogenicity in chickens, the most virulent form is notifiable, and requires emergency measures, and it is a major health barrier to free global trade in animals and animal products. Brazil squad in the commercial poultry is considered free of the disease, but serologic studies have suggested the circulation of vaccine virus or field in unvaccinated birds in Bahia. This study aimed measure antibody titers against Newcastle disease virus by indirect ELISA in village chickens in main poultry hub cities of Bahia. Serum samples from 875 birds, belonging to 92 farms, located near to commercial farms were analyzed. All samples in the farm were subjected to conventional viral research, as official diagnosis, when they had at least one antibody titer higher than 5,000. Antibody titers were detected with extreme values ranging 1-14,919 and high coefficient of variation (CV = 129%). These data suggest that there was circulation of vaccine or country virus, but the birds were not eliminating the virus at the time of sample collection, as detected by RT-PCR in real time and viral isolation methods. It is considered that the proximity of the commercial poultry farms and village chicken, flaws management and deficiencies in biosecurity adopted in the two systems may promote the circulation of the virus of Newcastle disease, representing a risk to poultry in the region studied.