ABSTRACT
The present study analyzed the occurrence of Newcastle disease in the commercial poultry population in all major regions of Minas Gerais, Brazil. The main objective was to investigate the impact of regional patterns of production on the epidemiology of the disease. The study was based on data collected from 797 diagnosis files of laboratory results of samples processed from 1988 up to 1998. The small number of cases of virus isolation encountered suggest that the incidence of Newcastle disease in Minas Gerais was very low over the period, although sporadic foci have occurred. The vaccination antibody titer responses were adequate and within the recommended standards. Some marked regional differences were found. In the region Triângulo Mineiro/Alto Paranaíba, Brazil, the incidence of HI titers indicative of contact with the virus was very low, confirming that vaccination is not carried out and natural challenge rarely occurs. Conversely, vaccination is a common practice in the other regions studied, but the incidence of contact with wild virus was significantly (p > 0.05) higher than in the former region. Vaccinated broilers HI antibody titers indicative of protection were found in adequate proportions
KEY WORDS
Newcastle disease; vaccinal proteccion; hemagglutination inhibition; broiler