Analysis of Clinical Manifestation of Newcastle Disease in Traditional Poultry of Chad

Abstract

Since its discovery in 1926, the virus of Newcastle disease (NDV) has been well described by several authors. But the control of this disease remains today a topical issue. It causes economic losses in industrialized and developing countries. The clinical manifestation of NDV differs from one species to another. This article places a state of clinical manifestation of the virus of Newcastle disease in traditional avian population, raised in the same breeding conditions. That avian population has been made up of chickens, ducks, guinea fowl and pigeons. The clinical manifestation of NDV has been observed by species, age and in epidemiological units (EpUn). The choice of EpUn has been done randomly. A total of 372 EpUn with a workforce of 13608 volatile have been observed. Young people aged at least 6 months have been 51.5% , 5.6%, 0.4% and 1.3% of the total, for chickens, ducks, guinea fowl and pigeons respectively. According to this order, adults over 6 months represented 28%, 5.4%, 4.8% and 3%. The clinical manifestation of the NDV has been observed in all domestic poultry species. Mortality varied between 26 and 99% in chickens; 17 and 75% in ducks; 8 and 100% in guinea fowls, and 11 and 100% among pigeons. Young volatiles have been more sensitive to NDV than adults. Mortality varied between 33 and 99% in young chickens, 21 and 75% in young ducks; 22 and 100% in young guinea fowl; 18 and 100% among young pigeons. In adults the rate varied respectively between 26 and 78%; 17 and 47%; 8 and 26%, 11 and 73% in the same species. Among this population of young volatiles, ducklings have been less sensitive than other young. Maternal antibodies seem to persist beyond a month and a half, while the chicks aged a month could present the clinical manifestations of the disease. Animal concentration, climatic changes, socio-economic activities of man and other emergence of ND factors seem to play an important role in the clinical manifestation of NDV from traditional domestic poultry. Knowledge of the clinical manifestation of this disease among the traditional bird population is one of the essential elements of its control.