Chicken Astrovirus Infection: Minireview and Preliminary Serologic Evidence of Antigenically and Genetically Distinct Chicken Astroviruses in Nigerian Indigenous Chickens

Poultry have gradually assumed a very important role in the economy of many industrialized and developing countries. However, with the continued discovery of new viral agents affecting the poultry industry worldwide, it is important that stakeholders in the industry in Nigeria be updated about these emerging viral threats in order to better understand the dynamics of health and disease that affect the industry. This knowledge will engender research into the prevalence, distribution, pathogenicity and economic losses caused by these diseases, and ultimately lead to the design of prevention strategies and formulation of policies for effective control. This paper includes a review on chicken astrovirus (CAstV), a recently emerged virus that causes enteritis, retarded growth and poor productivity in chickens, with particular emphasis on the history, economic importance, epidemiology, diagnosis and control. In addition, the result of a preliminary serological survey of CAstV antibodies in Nigerian indigenous chickens in Ibadan, Oyo State is reported. Using the indirect immunofluorescence test with CAstV 612- and CAstV 11672-infected cells respectively, only 4% and 8% of the tested sera were positive for CAstV antibodies. Our findings provide the first serologic evidence of CAstV infection in Nigeria and indicate the circulation of, at least, two antigenically and genetically distinct CAstVs in the Nigerian poultry population. We conclude that the runting-stunting, retarded growth and poor productivity commonly seen in Nigerian indigenous chickens could be due, among other factors, to CAstV infections

Cross Reactivities of Rabbit Anti-Chicken Horse Radish Peroxidase Conjugate with Sera of Some other Avian Species in ELISA System

The cross reactivities of rabbit anti chicken horse radish peroxidase (conjugate) was tested with sera of Chicken, Ducks, Geese, Guinea fowl, Hawks, Pigeons and Turkeys in indirect enzyme linked immunosorbent assay (ELISA) technique. Sera from mammalian species (Bat, Equine and swine) were used as negative controls. The conjugate was coated on wells of ELISA micro titer plate and sera from the avian and mammalian species added. Reactivity was detected with OPD. There were losses of reactivities when sera were diluted as from 1\\78125. Chicken and Turkey sera reacted with the conjugate without loss of reactivities when either normal rabbit serum (NRS) or bovine serum albumin (BSA) was used as blocking agent. Sera of other avian species and mammals did not react with the conjugate. It is concluded that rabbit anti chicken Horse radish peroxidase could be used to detect antibodies in chickens as well as Turkey and that BSA and NRS could be used as blocking agent without loss of reactivities

Pandemic influenza A/H1N1 virus incursion into Africa: countries, hosts and phylogenetic analysis

Swine origin influenza A/H1N1 virus was first detected in Mexico in April 2009. It thereafter spread to over a hundred countries in five continents including Africa and was declared a pandemic by the WHO. The disease was estimated to have caused 18,500 laboratory - confirmed deaths worldwide among millions of infected people within the first year. Though Africa was late in detecting and reporting pandemic H1N1, information on the incursion of the virus into Africa and its molecular features are important for planning control measures between countries and to understand inter-host and genetic relationship of influenza viruses detected in Africa. We studied time and events of the detection of 2009 pandemic Influenza A/HIN1 virus in Africa and selected viral HA and NA gene sequences from the GenBank and GISAID data bases . Nucleotide sequence alignment and construction of phylogenetic trees were carried out with MEGA version 5 bioinformatics software and the neighbor-joining ClustalW method with 1000 bootstrap replicates. Earliest human cases of pandemic H1N1 in Africa were detected  by June 2009 in Egypt, Morocco, South Africa and later cases in Ghana, Nigeria and Cameroon, with varying phylogenetic clusters. Following cases of Influenza A/H1N1 pandemic in humans, infections in pigs earlier reported in America, Europe and Asia were also observed in Cameroon, Nigeria, Togo and Kenya, apparently transmitted from humans by reverse zoonoses. Adoption of an integrated, cross-sectoral and transboundary approach to zoonotic diseases surveillance and management in the context of One-Health in Africa is advocated. Africa particularly needs to be better prepared to prevent or mitigate outbreaks and spread of emerging diseases.Keywords: Influenza virus incursion, Pandemic, Africa, Phylogeny, One-Healt

Sequence and phylogenetic analysis of chicken anaemia virus obtained from backyard and commercial chickens in Nigeria : research communication

This work reports the first molecular analysis study of chicken anaemia virus (CAV) in backyard chickens in Africa using molecular cloning and sequence analysis to characterize CAV strains obtained from commercial chickens and Nigerian backyard chickens. Partial VP1 gene sequences were determined for three CAVs from commercial chickens and for six CAV variants present in samples from a backyard chicken. Multiple alignment analysis revealed that the 6 % and 4 % nucleotide diversity obtained respectively for the commercial and backyard chicken strains translated to only 2 % amino acid diversity for each breed. Overall, the amino acid composition of Nigerian CAVs was found to be highly conserved. Since the partial VP1 gene sequence of two backyard chicken cloned CAV strains (NGR/Cl-8 and NGR/Cl-9) were almost identical and evolutionarily closely related to the commercial chicken strains NGR-1, and NGR-4 and NGR-5, respectively, we concluded that CAV infections had crossed the farm boundary

Cross reactivities of rabbit anti-chicken horse radish peroxidase conjugate with sera of some other avian species in elisa system

The cross reactivities of rabbit anti chicken horse radish peroxidase (conjugate) was tested with sera of Chicken, Ducks, Geese, Guinea fowl, Hawks, Pigeons and Turkeys in indirect enzyme linked immunosorbent assay (ELISA) technique. Sera from mammalian species (Bat, Equine and swine) were used as negative controls. The conjugate was coated on wells of ELISA micro titer plate and sera from the avian and mammalian species added. Reactivity was detected with OPD. There were losses of reactivities when sera were diluted as from 1\\78125. Chicken and Turkey sera reacted with the conjugate without loss of reactivities when either normal rabbit serum (NRS) or bovine serum albumin (BSA) was used as blocking agent. Sera of other avian species and mammals did not react with the conjugate. It is concluded that rabbit anti chicken Horse radish peroxidase could be used to detect antibodies in chickens as well as Turkey and that BSA and NRS could be used as blocking agent without loss of reactivities

Prevalence of Avian Origin H5 and H7 Influenza Virus Antibodies in Dogs in Ibadan and Sagamu, Southwestern Nigeria

Highly pathogenic avian influenza H5N1 subtype was recently reported in some states of Southwestern Nigeria including Oyo and Ogun states. As part of ongoing influenza surveillance efforts in livestock and companion animals in Nigeria, a study was conducted to investigate the prevalence of avian H5 and H7 influenza virus antibodies in exotic and Nigerian village dogs in Ibadan and Sagamu, two cities in Oyo and Ogun states respectively. One hundred and sixty two (162) dogs comprising 85 exotic dogs from Ibadan and 77 Nigerian village dogs from Ibadan and Sagamu were screened for the presence of avian H5 and H7 influenza virus antibodies. Using the hemagglutination inhibition (HI) test, none of the samples from exotic dogs had HI antibodies to both virus strains while all 77 Nigerian village dog samples were negative for H5 antibodies but two (2.6%) were positive for H7 antibodies at a titre of 1:32. The presence of H7 influenza virus antibodies in Nigerian village dogs, although at a low rate, suggests that these dogs had naturally been infected with the virus. It is possible that the dogs acquired the infection through consumption of dead chickens or internal organs of animals killed during hunting. The close contact between these dogs and their owners, domestic poultry and wildlife underscores their importance in the epidemiology of influenza in Nigeria

THE PATHOLOGY OF INFECTIOUS BURSAL DISEASE IN CROSSBREEDS OF HARCO COCKS AND INDIGENOUS NIGERIAN HENS

An outbreak of infectious bursal disease (IBD) occurred in a flock of 11-week old crossbreeds of Harco cocks and indigenous Nigerian hens (referred to as exotic and locals respectively in the text). Clinical signs observed include depression, anorexia, ruffled feathers and diarrhoea. Haemorrhages were present in the bursa of Fabricius, muscles and proventriculus-gizzard junction, while the bursae and kidneys were enlarged. Oedema, lymphocytic depletion and presence of remnants of dead lymphocytes were observed in histopathological sections of the bursae and spleen. IBD viral antigen was detected by the agar gel preciptin test (AGPT) in suspensions of the bursae of dead birds. Sera obtained from survivors were also positive for IBD virus precipitins in the AGPT. These observations appear to be the first description of IBD in crossbreed chickens in Nigeria and confirm that they are susceptible to clinical IBD. (Af. J. of Clinical and Experimental Microbiology: 2002 3(2): 91-94