Newcastle disease (ND) is a notifiable disease affecting chickens and other avian species caused by virulent strains of Avian paramyxovirus type 1 (APMV-1). While outbreaks of ND can have devastating consequences, avirulent strains of APMV-1 generally cause subclinical infections or mild disease. However, viruses can cause different levels of disease in different species and virulence can evolve following cross-species transmission events. This report describes the detection of three cases of avirulent APMV-1 infection in Great Britain (GB). Case 1 emerged from the ‘testing to exclude’ scheme in chickens in Shropshire while cases 2 and 3 were made directly from notifiable avian disease investigations in chicken broilers in Herefordshire and on premises in Wiltshire containing ducks and mixed species, respectively). Class II/genotype I.1.1 APMV-1 from case 1 shared 99.94% identity to the Queensland V4 strain of APMV-1. Class II/genotype II APMV-1 was detected from case 2 while the class II/genotype I.2 virus from case 3 aligned closely with strains isolated from Anseriformes. Exclusion of ND through rapid detection of avirulent APMV-1 is important where clinical signs caused by avirulent or virulent APMV-1s could be ambiguous. Understanding the diversity of APMV-1s circulating in GB is critical to understanding disease threat from these adaptable viruses.

Newcastle disease is one of the most important diseases of poultry with wide distribution and high fatalities. An infection with a virulent strain can cause up to 100% fatality in a susceptible flock, with devastating economic losses. In-feed antibiotics are not directly effective against Newcastle disease virus (NDV), but they may assist in prevent associated production problems. With in-feed antibiotics being controlled or banned, prebiotics, particularly those sourced from spices, and probiotics have been investigated as potential alternatives for maintaining seroconversion in poultry vaccinated against NDV. Certain prebiotics have a positive effect on anti-NDV antibodies but using spices as sources of prebiotics gave no clearly defined results. Garlic extract was reported to increase the mean haemagglutination inhibition (HI) titre of NDV by 0.6 after two weeks of supplementation, increasing titres by 4.0 in the vaccinated group compared to an increase of 3.4 in vaccinated unsupplemented group. However, onion-based compounds did not improve anti-NDV antibodies. The majority of studies have found that probiotics improved antibody levels and seroconversion to NDV vaccines in poultry. A commercial probiotic, containing a mixture of Bacillus species and Saccharomyces boulardii when used at a concentration of 100 g/ton was found to significantly increase the anti-NDV titre (log2) from 5.00 to 5.50. Another commercial probiotic, consisting of a combination of bacteria, reduced mortality by 6.6% at a concentration of 1 g/kg. Additional studies are needed to define the conditions and forms in which both the pre- and pro-biotics work best with respect to NDV control.

Newcastle Disease (ND) is regarded as one of the major diseases of poultry because of the devastating losses that the virulent form of the ND virus can impose on both commercial and domestic chickens. However, the disease can be controlled through the administration of effective vaccines. Almost all the commercially available ND vaccines require refrigeration and begin to deteriorate rapidly after 1-2 hours if left at room temperature (around 25°C). Subsequently, because maintaining an adequate supply of refrigerated facilities may be a difficult task in many countries with unreliable electrical supplies, the development and large scale production of an effective thermostable ND vaccine seems imperative to support the poultry industry. Such vaccines should be resilient to damage associated with either very cold or hot environments so there are no concerns about the viability of the vaccine in response to temperatures fluctuations that can occur in extreme environments when the difference in temperature during cold and warm seasons can vary greatly. In the following review paper, the development of such a vaccine is discussed, including molecular characterisation, organ tropism of vaccine strains, production, as well as administration methods and their efficacy. It addition, the potential payback has been calculated alongside opportunities provided by removing vaccines from cold chain storage.

Newcastle disease (ND) continues to be a problem in many developing countries. Successful disease control and diagnosis is often difficult because of a lack of biosecurity at farm level, cost-effective field-based diagnostics and seromonitoring tests. The use of fixed chicken red blood cells has been reported to be useful for haemagglutination (HA) and haemagglutination inhibition (HI) tests to avoid the cumbersome process of regular blood collection and processing of cells. However, virus isolation and biological characterisation or molecular tests such as polymerase chain reaction followed by sequence analysis are still essential for rapidly pathotyping the epizootic virus isolates. The demonstration of Newcastle virus (NDV) along with case history and clinical signs is of diagnostic importance in unvaccinated flocks. Monoclonal antibodies are not always very effective. The need for the collection of suitable specimens has been reviewed in this study. The disease is mainly controlled by using live vaccines when vaccinating the flock. The live virus vaccines persisting in the poultry house environment seem to be gaining virulence. Efficacy of the vaccine to be assessed reflects the immune status of the vaccinated birds. Filter paper sampling method of sample collection and HI test are reported to be successful for large scale seromonitoring programmes. This review concentrates on different diagnostic tests and their usefulness under field conditions for rapid identification of the disease so that control measures can be implemented at an early stage.

Experiments were conducted to determine the effects of Newcastle disease on chicken fat metabolism. Thirty black-bone chickens were infected intraocularly with the Newcastle disease virus (NDV). Six birds were killed at 0, 12, 24, 48 and 72 h post infection, respectively. Results showed that the NDV infection decreased concentration of high-density lipoprotein cholesterol and increased concentrations of total cholesterol and low-density lipoprotein cholesterol in the plasma. Concentrations of triglycerides and free fatty acid were decreased after their initial increase. NDV infection also dramatically raised the activities of lipoprotein lipase (LPL), hepatic lipase and lipases in the serum. Furthermore, PCR results showed that the incipient infection up-regulated mRNA expression of LPL, adipose triglyceride lipase and nuclear factor peroxisome proliferator-activated receptor alpha (PPARα), but down-regulated them at later stage. Similarly, mRNA expression of fatty acid synthase, acetyl-CoA carboxylase and nuclear factor PPARγ, fatty acid transport protein 1 (FATP1), and 4(FATP4) decreased, whereas fatty acid translocase and fatty acid-binding protein increased initially. Data from Western blotting analysis showed that the changes in protein levels were consistent with mRNA expression. These results indicated that fat metabolism of the chicken was affected by the NDV infection. At the beginning of NDV infection, lipogenesis was inhibited, whereas lipolysis was strengthened. After lipolysis was strengthened, fat metabolism was found to be maximally depressed.

Village chickens can be found in all developing countries and play a vital role in the livelihood strategies of many poor rural households. The implementation of effective village poultry production programmes in Asia, Africa and Latin America has resulted in increased poultry numbers, household purchasing power, home consumption of poultry products and decision-making power for women.

The rapid and wide geographical spread of highly pathogenic avian influenza subtype H5N1 has drawn attention to the neglect of village poultry health. This crisis has presented an opportunity to invest in improved village poultry husbandry that can make a positive contribution to human development in rural areas across a range of endeavours including: empowerment of women (increased productivity, knowledge, participation in community life as vaccinators, etc); HIV/AIDS mitigation; wildlife conservation through a reduction in bushmeat consumption; improved understanding of disease transmission, prevention and control, human nutrition and hygiene; and, most importantly building trust between communities and government agencies.

Key recommendations to support technically sound and sustainable Newcastle disease control programmes in village chickens include encouraging veterinary pharmaceutical manufacturers to develop and observe a code of conduct that supports the supply of appropriate vaccine with an adequate shelf life, giving instructions in local languages, using temperature indicators in vaccine containers and discouraging the payment of commission on the purchase of vaccine. Quality assurance activities should be built into all vaccination programmes to improve cost-efficiency, and should include post-vaccination serological monitoring of a representative sample of birds, especially when a new vaccine or new disease control programme is introduced. Also required is the participation of farmers (male and female) in monitoring and evaluating the effectiveness of vaccination campaigns; and active collaboration with the Ministries of Agriculture, Health and Education in village poultry improvement programmes.

Village poultry make a significant contribution to poverty alleviation and household food security in many developing countries. This contribution by village poultry to livelihoods can also support HIV/AIDS mitigation and wildlife conservation initiatives. Appropriate interventions focussing on the factors limiting productivity of the different production systems must be tailored according to country and local conditions. The contrast between the type of support in relation to the production systems that might be promoted in export-oriented countries such as Thailand, in comparison to others such as Mozambique and Lao PDR is discussed. A review of the benefits and costs of inputs comparing small scale commercial poultry and scavenging village poultry production systems in different countries taking into account the bio-risks for each production system demonstrates the overall efficiency of the village production system and provides an insight into why this system has continued to thrive into the 21st century.

Newcastle disease is a major constraint to poultry production in Africa, in both commercial and village rearing systems. A ten-year review (January, 1996-December, 2005) of case reports in respect of Newcastle and other poultry diseases diagnosed at the veterinary clinics in Kaduna, Nigeria was conducted. A total of 3164 outbreaks were documented with 1050 outbreaks diagnosed as ND. There were significant (P>0.05) associations in the distribution of Newcastle disease and age, breed, season, type of bird and management system of poultry in Kaduna. ND outbreaks were most prevalent during the dry season (December – March). Poultry kept in confined conditions, broilers, pullets, layers and birds between 3-4 weeks and 13-15 weeks of age were at greatest risk of suffering from ND outbreaks. Single vaccination had a significant effect (P<0.05) on reducing incidence of disease compared to birds that were not vaccinated or had multiple ND vaccinations. These findings have an impact on the correct approach to immunization practices using to control disease under African conditions.

We surveyed south polar skuas (Catharacta maccormicki Saunders) in Antarctica for antibodies to a series of viral agents using blood serum and cloacal swabs from 124 adult skuas. There were no ticks on the subjects and we were unable to isolate virus from any individual. Skuas, however, were seropositive to some avian viruses: 16.9% (20/118) had antibodies to infectious bursal disease virus and 10.5% (11/105) were seropositive for Newcastle disease. We found 1.0% (1/98) had antibodies to avian influenza, no evidence of egg drop syndrome (0/48), but 27.8% (10/36) had antibodies to flaviviruses. Clearly south polar skuas encounter a variety of pathogens either in Antarctica or during their migration in the non-breeding season. There was no evidence of disease in skuas, but the presence of antibodies to pathogens indicates the need to continue to search for the origins of these immunological challenges.

The main objective of this work was to describe the characteristics of and major constraints to village chicken production in Myanmar. Data on village chicken production, health, husbandry and marketing were collected in 296 households in 10 villages in the Yangon division of Myanmar in November 2003. The average flock size in the study area was about 30 birds, comprising 12 chicks, 12 growers, 4 hens and 2 cocks. Disease as a cause of mortality was more prominent in growers and adults, while predation and exposure to unfavourable environmental conditions were major causes of mortality in chicks. The main predators identified were: birds, rats, snakes, dogs and cats in 32, 31, 17, 15 and 3% of households respectively. Two main strategies were identified to improve village chicken production: vaccination as a means of protecting birds against Newcastle disease and confinement rearing and supplementary feeding of chicks, as a means of reducing the attrition rate of young chicks. This is the first survey conducted describing village chicken population structure and productivity in Myanmar.

It appears possible for free-flying native or feral wild birds to be responsible for direct or indirect spread of infectious agents from contaminated poultry product wastes to susceptible commercial poultry. Direct spread involves infected wild birds gaining access to commercial poultry. Indirect spread involves secondary spread to other free-flying birds that may subsequently gain access to commercial poultry.

In analysing the level of risk of such spread consideration is given to three elements. These are the susceptibility of wild birds to infection by the agents concerned, the opportunity for susceptible species coming into direct or indirect contact with both poultry product wastes and commercial poultry, and the occurrence of actual cases of such spread.

The scenario being considered is one in which poultry product wastes contain an infective dose of one of the agents of concern, namely avian influenza, Newcastle disease or infectious bursal disease. A review of the literature was undertaken to assist in assessing the likelihood of spread of these agents by wild birds.

Exposure of wild birds, to any of the three viruses of concern at product waste disposal sites, is a potential threat but the likelihood of spread to commercial poultry appears to be low. More obvious means of spread occur in the poultry industry, as biosecurity is often rudimentary. Spread of infectious agent by fomites, live poultry and infected wild birds could well be involved in transmission of disease agents between farms. Where live bird poultry markets or semi-feral village poultry exist they provide an obvious means of spread of these agents and involvement of access of wild birds to poultry product wastes is probably of little importance.

The likelihood of wild bird involvement in virus spread from poultry products could increase if a susceptible species with gregarious habits (flocking behaviour) leading to high population densities, were to frequent both poultry product waste disposal sites and commercial poultry premises. Some passerines are likely to frequent waste disposal facilities and poultry premises, but it appears that different species congregate at poultry premises than at waste disposal sites.

There is little evidence of spread of disease from waste poultry products to commercial poultry premises having occurred.

Rural poultry flocks in developing countries make little use of conventional vaccines or therapies. Appropriate vaccines must be robust, cheap and suited for local production in relatively unsophisticated laboratories. Only diseases producing high mortalities warrant attention. Appropriate therapies depend on local ethnoveterinary knowledge.

Newcastle disease is the most important constraint to the productivity of village chicken flocks. The Australian Centre for International Agricultural Research (ACIAR) initiated projects on vaccines to control this disease in rural flocks in 1984. Thermostable variants of the avirulent strains V4 and I-2 were developed and shown to be safe and effective in laboratory and village trials. Master seed of I-2 vaccine is made available without cost to developing countries. Vaccine is produced by a seed-lot system and involves allantoic sac inoculation of non-SPFeggs. Harvested allantoic fluid is the basis of the vaccine. Sustainable vaccination campaigns require components other than an appropriate vaccine. Appropriate extension messages must be developed to target the neglected village flocks, and the women who usually control them. Systems of cost recovery must be developed. Appropriate training must be available at all levels – to administrators, laboratory staff and village vaccinators. With the control of Newcastle disease, villagers can be convinced of the full potential of their flocks to produce food and income. Other interventions including housing, nutrition and control of otherdiseases can be introduced.

The thermostable vaccines have been tested in at least 30 developing countries and produced on a large scale in at least 9. International agencies otherthan ACIAR and various NGOs have supported the projects. The next village vaccine could be fowlpox, with virus adapted to production in the allantoic cavity.

The major killing disease of duck flocks in Asia is duck plague. An ACIAR project has seen the development of an improved vaccine in Vietnam The vaccine, adapted to grow in cultured chick embryo fibroblasts, is registered foe use throughout Vietnam. Various remedies, mainly herbal, are used on village flocks to improve performance. These probably do not assist in treating established disease.

The commercial industry could ask, are our vaccines too sophisticated and expensive, is there a place for food vaccines, should we investigate herbal remedies and how can we help the rural poor?

Village poultry play a vital role in many poor rural households. They provide scarce animal protein (in the form of meat and eggs) and can be sold/bartered to meet essential family needs such as medicine, clothes and school fees. They also provide manure and pest control as well as being used in traditional ceremonies. Village poultry are generally owned and managed by women and children and improving their production can provide the first step out of poverty for the rural poor.

The Australian Centre for International Agricultural Research (ACIAR) has supported village poultry research in many countries since 1984. This research has had some significant outcomes including: the control of Newcastle disease (ND) using Australian derived live thermotolerant vaccines in a variety of poultry production systems in several countries; description and quantification of the scavenging feed resource base of low input/low output systems; development of gender-sensitive extension materials and methodologies suitable for use in remote rural areas in Asia and Africa; and the development and registration of a new duck plague vaccine in Vietnam.

The thermotolerant ND I-2 vaccine remains viable for periods away from the cold chain, can be administered by various routes and induces an acceptable level of protection under village conditions. The vaccine master seed, together with the ND Laboratory Manual, is made available without cost by ACIAR.

In developing countries where ND is endemic, outbreaks regularly result in high mortalities and in countries where it is not endemic, sporadic outbreaks make vaccination advisable. The implementation of an effective ND control programme in countries in Africa and Asia has resulted in increased chicken numbers, increased household purchasing power, increased home consumption of chicken products and increased decision-making power for women.

However, sustainable programmes for the control of ND in village chickens have been difficult to achieve, often due to limited appreciation by official agencies of the benefits of village poultry. Experience has shown that a sustainable ND control programme is composed of five essential components: a) an appropriate vaccine and vaccine technology; b) effective extension materials and methodologies that target veterinary and extension staff, community vaccinators and farmers; c) simple evaluation and monitoring systems; d) economic sustainability based on the commercialisation of the vaccine and vaccination services and the marketing of surplus chickens and eggs; and e) support and coordination by relevant government agencies for the promotion of vaccination programmes.

Details of ND control in village poultry are provided on the ACIAR website, www.aciar.gov.au and by the Australian Agency for International Development www.ausaid.gov.au.

Throughout the continent of Africa the keeping of indigenous fowl by village communities has been practised for many generations. These birds, which are generally kept on a free range system, currently make up more than 80% of the continent's poultry flock. Although requiring minimal resource input and considered secondary to other agricultural activities by farmers, this type of production has an important role in supplying local populations with additional income and high quality protein. However, high mortality, especially in growers, constitutes the greatest constraint on development. Indigenous fowl are not a particular variety but are the result of erratic crosses between local and imported stocks. Growth and egg production of the indigenous birds are low and their limits of performance are rapidly reached when feeding and management are improved. However, the meat and eggs are much preferred by the consumers and fetch premium prices compared with commercial birds. The genetic potential of the indigenous stocks could be improved through crossing with selected but still robust varieties.

The effect of vitamin A deficiency or the lentogenic La Sota strain of Newcastle disease virus (NDV) infection, or both, on immunoglobulin (IgA and IgM) levels in bile and plasma were investigated. In addition, tissue distribution of IgA-, IgG- and IgM-containing cells was studied to establish the source of these Ig. Chickens (1-d-old) with limited vitamin A reserves were fed ad lib. on diets containing either marginal or adequate levels of vitamin A. At 4 weeks of age, half the chickens in each group were infected with NDV. The number of IgA- and IgM-containing cells was not significantly affected by vitamin A deficiency, demonstrating that neither class-switching nor homing of Ig-containing cells is influenced by vitamin A deficiency. Although bile IgM levels were not significantly different in vitamin A-deficient chickens compared with normal chickens, IgA levels were significantly lower. This decrease was even more pronounced in deficient NDV-infected chickens, despite the higher number of IgA-containing cells found in these birds. These results, together with the slightly increased levels of IgA in plasma of vitamin A-deficient chickens, suggest that the hepatobiliary transport of IgA is impaired by vitamin A deficiency and possibly also by NDV infection, although disturbed secretion by IgA-containing cells cannot be excluded