Control of Newcastle disease and identification of major constraints in village chicken production systems in Myanmar

• CSIRO Livestock Industries, Australia
• Ministry of Livestock and Fisheries, Burma (Myanmar)

Village chickens are the most important livestock species for many rural families in Myanmar, particularly poorer families. They are raised as a source of income and also to provide food for the Village chickens are the most important livestock species for many rural families in Myanmar, particularly poorer families. They are raised as a source of income and also to provide food for the household.

Newcastle disease is a viral disease of poultry with mortality rates of up to 100%; it is a serious problem for village chicken producers in Myanmar, where there are regular epidemics of the disease. Newcastle disease can be controlled by the use of an appropriate vaccine, known as I-2. Vaccines are available in liquid and freeze-dried forms, but the former are cheaper and easier to produce. The vaccine has been used successfully in several countries, but has not been as effective as expected in Myanmar.

Three potential problems have been identified. First, there are concerns about the difficulty of maintaining a 'cold chain' when the vaccine is moved from one place to another. Second, it is not always easy to catch chickens, which usually roam free and are not kept in enclosures at night. Third, rural farmers are not always aware of the problems caused by Newcastle disease and other poultry diseases.

The aim of this project was to improve village poultry production in Myanmar by improving the production, quality and distribution of Newcastle disease vaccine, to identify the major constraints to chicken production and provide villagers with better information about chicken production and diseases.

Technicians using specialised equipment measure vaccine temperatures under different conditions, at different locations and times, and with different types of packaging. They bought back some vaccinated chickens from villagers to determine whether the vaccination has induced protective levels of antibodies. When the liquid vaccine was deemed appropriate for Myanmar conditions, members of the project team investigated the best way to distribute it, comparing for instance the effectiveness and cost of sealed transfer pipettes instead of glass vials.

Australian scientists conducted a refresher course on vaccine production and use and a training course on diagnosis of poultry diseases. The project team also designed new extension materials based on a model used successfully in Mozambique.

The scientists surveyed selected villages to determine the total number of birds, the age structure of the flock, productivity and current disease status. This survey was accompanied by an intensive epidemiological survey comparing vaccinated and non-vaccinated birds and the development of an economic surplus model to gauge the socioeconomic impacts of different types of chicken management.

The scientists used samples collected from the village survey to genetically characterise field isolates of Newcastle disease virus. This enabled them to determine whether the circulation of virulent virus in particular geographic areas is restricted to particular strains and times.

There was limited information on the factors influencing village chicken health and production in Myanmar prior to this project, hence the need for a series of epidemiological studies to identify the major constraints to village chicken health and to evaluate strategies with the potential to improve village chicken production. Initially, a baseline survey confirmed the importance of chicken-keeping to rural farmers in Myanmar, ranking it as their second most important wealth-producing activity after crop production.

The survey also indicated that mortality in young chicks and deaths from Newcastle disease were two major constraints to improving chicken production in villages. This was confirmed in a 6-month longitudinal panel study. In this study, prevalence of protective titres (measuring antibody levels) from field exposure to Newcastle disease virus was 79%. High prevalence at village level appeared to be protective against mortality; mortality rates decrease by a factor of 0.88 for every 10% increase in prevalence of titres in the previous month.

These issues were then addressed in a 12-month intervention study with Newcastle disease vaccination and improved management applied to randomly selected flocks. This work demonstrated a significant increase in the number of birds sold after a period of six months in the group of farmers who introduced changes to the management of young chicks, and led to additional income from the sale of birds. The number of households consuming home-produced chicken meat also increased in this group. Molecular characterisation of ND viruses circulating in Myanmar revealed that genotype VII was predominant.

The project aimed to advise village farmers on simple and sustainable approaches to maintaining good village chicken health and production and to increase the general awareness amongst village farmers towards the economic benefits of chicken keeping. An extension program was developed, including the production of extension materials based on the outcomes of the epidemiological studies. A series of farmer meetings were conducted to demonstrate the production benefits of introducing chick management changes and Newcastle disease vaccination and to discuss the extension messages.

The extension work was expanded from the original involvement of 12 villages in the field studies to a total of 47 villages, encompassing three administrative divisions of Myanmar. Nearly 4000 farmers received training in village chicken health issues. Sustainability was a major obligation for the project. Key village people were identified in each of the 47 villages, and their task was to further support farmers by conducting training workshops on village chicken health, promoting I-2 ND vaccination and selling locally produced equipment to improve the management of young chicks (bamboo coops, creep feeders and starter feed).

The capacity impacts of this project were remarkable, with training provided to local scientists in epidemiology, pathology, vaccine production, extension methods, and molecular assays.

In summary the project team used a stepwise approach to conduct scientific investigations involving the village chicken-owning community and led a participatory development of extension material and services to increase the awareness of smallholder poultry owners towards village chicken health and production. Poor farmers were the direct beneficiaries of this project - by improving the survival rate of young birds, more were available for sale at the markets and for consumption in the village households.