Evidence of Infection by H5N2 Highly Pathogenic Avian Influenza Viruses in Healthy Wild Waterfowl

The potential existence of a wild bird reservoir for highly pathogenic avian influenza (HPAI) has been recently questioned by the spread and the persisting circulation of H5N1 HPAI viruses, responsible for concurrent outbreaks in migratory and domestic birds over Asia, Europe, and Africa. During a large-scale surveillance programme over Eastern Europe, the Middle East, and Africa, we detected avian influenza viruses of H5N2 subtype with a highly pathogenic (HP) viral genotype in healthy birds of two wild waterfowl species sampled in Nigeria. We monitored the survival and regional movements of one of the infected birds through satellite telemetry, providing a rare evidence of a non-lethal natural infection by an HP viral genotype in wild birds. Phylogenetic analysis of the H5N2 viruses revealed close genetic relationships with H5 viruses of low pathogenicity circulating in Eurasian wild and domestic ducks. In addition, genetic analysis did not reveal known gallinaceous poultry adaptive mutations, suggesting that the emergence of HP strains could have taken place in either wild or domestic ducks or in non-gallinaceous species. The presence of coexisting but genetically distinguishable avian influenza viruses with an HP viral genotype in two cohabiting species of wild waterfowl, with evidence of non-lethal infection at least in one species and without evidence of prior extensive circulation of the virus in domestic poultry, suggest that some strains with a potential high pathogenicity for poultry could be maintained in a community of wild waterfowl

Preliminary findings on the thermostability of three immunogenic strains of newcastle disease virus under regimen of high temperature

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Detection of Infectious Bursal Disease Virus (IBDV) in naturally infected chickens in Nigeria by the Reverse Transcription-Polymerase Chain Reaction (RT-PCR)

The Reverse Transcription - Polymerase Chain Reaction (RT-PCR) was used for the identification of Infectious bursal disease virus (IBDV). The technique was applied on bursa of Fabricius of infected chicken. Some of these bursae have been kept in the freezer for 16years under conditions of regular electric power fluctuations. A commercially produced IBD vaccine and two freeze dried IBD viruses grown on chicken embryo fibroblast cell were used as known source of IBD viruses. One pair of primers was produced from published sequences of serotype1 IBDV targeted at the VP2 region of the genomic RNA. These primers were designed to generate a product of 1325bp size. Out of 45 samples tested, IBD viral RNA could be detected in 43 samples by the RT-PCR. No reaction was obtained from the RNA extracted from the control bursae. The use of PCR for the diagnosis of diseases is fairly new in this country though the technology has been in use in most developed and some developing countries. It\'s application has been found to improve the efficiency and accuracy of disease diagnosis as the test is very specific. The Viral RNA gemone of IBDV could be detected even in bursal samples found to have degenerated due to storage problems. KEY WORDS: Infectious bursal disease virus, diagnosis, reverse transcription Polymerase Chain Reaction, chicken Nigerian Veterinary Journal Vol.24(2) 2003: 1-

Paired Chicken and Mammalian Erythrocyte Indicator Systems for Haemagglutination Test and Diagnosis of Newcastle Disease

Three levels of erythrocytes suspensions, 1.5%, 1% and 0.5% respectively from goat and guinea pig, were compared to conventional 0.5% chicken erythrocytes, in an attempt to investigate the suitability for the two sources of mammalian erythrocytes as indicators for Newcastle disease virus haemagglutination (HA) tests. The results showed that the guinea pig erythrocytes, were associated with the same HA titre (8 log 2); with HA times being 30, 50 and 35 minutes respectively and elusion times were 120, 85 and 105 minutes respectively. The data therefore established biometric and qualitative similarities between the control and these two test dilutions of erythrocytes. In HI tests on sera from commercial poultry, the guinea pig indicator was consistently associated with 2 to 5 fold higher HI titres than the other indicators in some of the flocks tested. A retrospective flock health analysis revealed that the higher titres were associated with confirmable Newcastle Disease (ND) outbreaks in the affected flocks. These findings therefore suggested that the use of standardised guinea pig erythrocytes in parallel with chicken erythrocytes as indicators, might facilitate field ND diagnosis and thus obviate the problem posed by the delay in the requirement for paired sera from acute and convalescent phases of outbreaks in vaccinated flocks, as in existing procedure. The generally recognised simplicity and economy of HI serology would continue to favour its application in preference to other laborious and complicated virologic techniques, especially in medium scale laboratories, as well as in rural developmental and epidemiologic studies. Key Words: Mammalian erythrocytes, haemagglutination tests, diagnosis, Newcastle disease. Trop. Vet. Vol.22: (1) 26-32 (2004

Common Leg Aliment Of Poultry In Plateau State, Nigeria

A study was carried out to investigate the occurrence and causes of leg ailment in poultrythrough questionnaire survey and farm visitation. Post mortem and laboratory examination were also conducted. The results showed that different species of poultry were affected with varous types of leg ailments; out of which local chickens had the highest incidence 175(30.49 %), followed by broilers and commercial laying chickens 153(26.67 %) and least in ostrich 16(6.75 %). Swollen legs were recorded thus: local chickens 65(36.72 %), commercial layer chicken 51(28.81 %) and broilers 33(18.64 %). Incoordinaton, another common leg ailment were observed in broilers 40(33.33%), layer chickens 39(32.50 %), local chickens 24(20.0 %), and turkeys 4(14.81 %) Physical injuries due to trauma, burns, trampling (smothering) and accidents were recorded in broilers 28(30.77 %), commercial laying chickens 25(27.47 %), local chickens 21(23.08 %), cockerels 17(18.68 %), guinea fowls 15(39.47 %) and ostriches2(5.26 %). Curled toes, mange, Newcastle disease, Mareks disease and Clostridia infections resulting in leg ailments were also observed. Keywords: Leg ailments, Poultry, Implication, Plateau State Animal Research International Vol. 1 (3) 2004 pp. 208-21

Avian Influenza

Avian influenza (AI) is a viral disease of birds that can be transmitted to other animals including humans. Outbreaks of highly pathogenic avian influenza (HPAI) subtype H5N1 occurred in poultry in Africa for the first time in 2006 following its emergence in Asia. Subsequent spread of the infection, multiple introductions, and fatal transmission to humans globally and in some African countries and connected regions underscore the importance of this transboundary animal disease to livestock, livelihoods, and public health. The prevention and control of future AI outbreaks in order to mitigate its socioeconomic and public health impact cannot be overemphasized. Repeated incursions of HPAI into Africa and intermingling of multiple susceptible hosts could drive emergence of pathogens at the interface between humans and animals in a shared environment. Intersectoral synergy for the control and mitigation of avian influenza based on the principles of One Health is therefore desirable. The need to understand the nature of the disease, its epidemiology, distribution, applied surveillance strategies, diagnosis, and measures for its control are germane and discussed in this chapter as it applies to Sahelian Africa and connected regions. Basic knowledge of influenza virus and its impact on human and animal health would help to better prepare the next generation of professionals to cope with the rapidly evolving challenges posed by this infectious disease of global reckoning