About 100 chickens in each of three Cameroonian villages were vaccinated against Newcastle disease by eye-drop with the V4 heat-resistant strain and marked. In each of a further two villages another 100 chickens were marked and mock-vaccinated as controls. Each village was visited weekly for 18 weeks after vaccination, and all mortality and losses, sales and consumptions of the marked chickens were noted. A sample of about 20 serum samples was taken every 3 weeks from marked chickens in each village for 15 weeks for titration of antibodies against Newcastle disease. In the vaccinated villages a peak mean titre of greater than log(2)5 was observed 3 weeks after vaccination; the mean titres remained at least log(2)3 for 12 weeks after vaccination. There was no mortality due to Newcastle disease in the vaccinated villages. In the control villages an average of 15% of the chickens died of Newcastle disease during the observation period. Twenty weeks after vaccination a sample of ten study chickens was purchased from the vaccinated villages and ten were purchased from the control villages; these were challenged with the velogenic Italien strain of Newcastle disease virus. Four out of ten of the vaccinated chickens and one out of ten of the non-vaccinated chickens survived the challenge.

Although 65% of domesticated birds in the Cameroon are kept in traditional chicken farms, very little attention is given to this important sector by the administration as well as by the farmers themselves. This could be detrimental to the modern poultry sector where a lot of investments have been made during recent years. In order to estimate the danger of neglecting traditionally-raised chickens and the health threat they represent for the poultry population of the country, a study was conducted to evaluate the impact of Newcastle disease in traditional farms. A total of 180 chicken blood serum samples from three provinces of the Cameroon were submitted to the haemagglutination inhibition test; 51.66%, 48.33% and 46.66% of birds respectively from the East, West and North provinces reacted positively to the test. The consequences of such a situation are emphasised.