Newcastle disease in intensive poultry industries can be controlled by repeated applications of suitable vaccines. The process is expensive and requires good vaccines, proper storage conditions for the vaccines and a high level of technical expertise. The control methods that are effective for commercial poultry are neither feasible nor affordable in rural villages (Ideris et al., 1990). The control of NCD in village flocks has been a challenge for decades due to the specific problems associated with vaccinating multi-age flocks containing relatively low numbers of chickens that frequently scavenge for much of the day in locations with no or unreliable vaccine storage conditions (Alders and Spradbrow, 2001). The challenge has been to develop an effective NCD control programme for the family poultry sector that was sustainable, both economically and socially (Alders, 2003). This had to be achieved in the absence of a viable cold chain to support the distribution of potent vaccines (Alders, 2014) and overcome the difficulty of delivering small quantities of vaccine, suitable for village flocks (Bensink and Spradbrow, 1999). Initial NCD control research efforts and activities, therefore, focussed on the development of NCD vaccine that was suitable for use in difficult rural conditions where the cold chain is often absent or unreliable (Alders and Spradbrow, 2001). In circumstances where the cold chain is weak or absent, the only reliable option is the use of thermotolerant NCD vaccines (Alders, 2003).
Attempts over the past few decades to improve the control of NCD in village poultry have included development of NCD vaccines that have thermotolerance and hence are suitable for village poultry. The heat tolerant V4 (Spradbrow et al., 1988) vaccine against NCD has been developed to control NCD in village chickens in tropical countries. Implementation of this vaccine brought a promising result in some African countries (Alders and Spradbrow, 2001). Later in an effort to develop NCD vaccine, I-2 NCD vaccines, a seed
virus similar to V4-HR, that could be made available to laboratories in developing countries (Bensink and Spradbrow, 1999) was developed. The I-2 NCD vaccine produced in freeze-dried form will maintain its activity for eight weeks when stored below 30°C (Alders, 2003), and hence may be suitable for village poultry systems. Studies on the application of these vaccines in village poultry across developing countries have demonstrated that it is possible to effectively control NCD (see Copland and Alders, 2005b; Msoffe et al., 2010; Wambura et al., 2000).
More recently Lal et al. (2014) reported the development of low-dose, fast-dissolving tablet vaccines, each containing up to 50 doses of vaccine and weighing about 50 mg, that could maintain virus stability for more than six months at 4°C. This fast-dissolving tablet vaccine format allows for compact and cost-effective packaging and hence it could provide a promising option to control NCD in village poultry across developing countries. Despite the development of thermostable NCD vaccines for village poultry and the need to control NCD in village chickens, it has been difficult to achieve a sustainable control programme. It became apparent that to make NCD control activities sustainable, attention had to be given to the social and economic implications of NCD control in communities (Copland and Alders, 2005a). Implementation of a successful and sustainable NCD control programme requires economic sustainability, based on the commercialisation of the vaccine and vaccination services and delivery of effective extension materials and methodologies among others (Alders et al., 2010).
The application of suitable NCD vaccines in the developing world has greatly reduced the impact of this disease in family poultry (FAO, 2014). However, implementation of NCD vaccine programmes in village chicken in developing countries, particularly in sub-Sahara African countries, is limited. One of few examples of implementation of an effective NCD control programme in African countries is that of Mozambique, which resulted in increased chicken stocks, increased purchasing power for the poor to meet basic needs, improved households’ food security and access to nutritious food and increased decision- making power for women (Bagnol, 2001; Woolcock et al., 2004).
No adequate scientific documentation exists on village level implementation and impact of NCD vaccination schemes in Ethiopia. It is, however, believed that the country has promising innovations in vaccine technologies and there is a capacity to produce millions
of doses of NCD vaccines (Anebo et al., 2013). NCD vaccinations have routinely been provided to commercial poultry producers, but there is no comprehensive policy to control NCD in village poultry, which is by far the most important poultry sector in the country. To the best of our knowledge, only few studies have been reported about implementation of NCD vaccination in village poultry production systems in the country. Trial of V4 vaccine conducted in 1993 and 1995 (Rushton, 1995) ,both on-station and on the field, is the early application of NCD vaccine in Ethiopia. The result from this trial, particularly result from on-station, was encouraging. Evaluation of I-2 vaccine in village poultry in three districts of Amhara region of Ethiopia (Nega et al., 2012) is the other related work . Result from the study shows that antibody titer response to I-2 vaccine was 90.4%. It is therefore imperative for Ethiopia, a country where egg and chicken are predominantly supplied from village poultry, to have a well-thought and well-designed policy on NCD control that gives due emphasis to village poultry. Like any other public policy, NCD prevention policies and resultant interventions can be meaningful when they address the needs of the target community. When designed based on public interest, the interventions will be quickly adopted and hence welfare impacts happen. Formulation of effective NCD control programmes that are desirable to farmers requires detailed understanding of the key aspects of possible vaccine programmes that influence farmers’ opinions towards the disease and the prevention interventions. However, attributes of a vaccine programme that influence farmers’ choice of possible vaccine services in Ethiopia remain unknown, as the service is not yet marketed or tested.
5.2 Using Choice Experiment to elicit preference for attributes of NCD vaccination