An investigation of a strategy for the vaccination of free ranging chickens against newcastle disease in Qwa-Qwa, South Africa

The primary aim of this study was to develop a strategy to control Newcastle disease in free ranging village chickens using the Nobilis® ND Inkukhu vaccine (Intervet South Africa). The study was conducted at Thibella village in Qwa-Qwa district of the eastern Free State province of South Africa, from April 2001 - October 2002. Three different routes of vaccination ( administration via eye-drop, drinking water and feed) were investigated and the most efficient route was determined. Haemagglutination inhibition test was conducted frequently after revaccinations in order to measure the antibody status of village chickens after immunisation against Newcastle disease. The study also sought to determine intervals for re-vaccinations. Trial challenges were conducted to determine the efficacy of the vaccine using a South African isolate of velogenic Newcastle disease virus. A questionnaire survey was also conducted to determine perceptions and knowledge on vaccines by free ranging chicken owners. The eye-drop vaccination route produced the highest haemagglutination inhibition (HI) titres ranging between 2.7 and 4.4, followed by drinking water vaccination route with HI titres ranging between 2.3 and 4.0. The lowest titres were from the feed vaccination route where HI titres ranged between 1.6 and 3.0. Following the trial challenge experiment, the entire control group died on the 3ʳᵈ and 4ᵗʰ day after infection. However 70 % of the chickens immunized with the Nobilis® ND Inkukhu vaccine by using either the eye-drop or drinking water route survived the trial challenge. Only 20 % of the chickens from the group immunized through the feed route survived the trial challenge. Evidently both the eye-drop and drinking water vaccination routes were efficient in preventing infection of Newcastle disease virus. The efficiency of the vaccine using either of the routes can be enhanced by having boosts at 3-month intervals on the first year of a vaccination campaign and then at 6-month intervals on the second year onwards. From the questionnaire survey, 96 % of the owners mentioned that the indigenous name in Sesotho for Newcastle disease is 𝗠𝗼𝗸𝗼𝗶𝘆𝗼. The questionnaire also revealed that outbreaks occur mainly in spring months between August and October. The majority of the respondents indicated that they would prefer to vaccinate their flocks using the drinking water route. They also proposed that extension officers should be involved in the vaccination exercises. It was evident that in the majority of households in Qwa-Qwa women were the ones who were primarily responsible for taking care of the chickens. It will be valuable in the future if village communities in Qwa-Qwa were educated in the control of poultry diseases, in particular on Newcastle disease. Through workshops and seminars, and also by assisting in vaccination programs, extension officers in rural areas can play a critical role in the growth of free ranging poultry farming in poor rural communities in South Africa.