Please use this identifier to cite or link to this item: http://ir.library.ui.edu.ng:8080/jspui/handle/123456789/586
Title: ISOLATION AND CHARACTERIZATION OF CHICKEN INFECTIOUS ANEMIA VIRUS IN SOUTHWESTERN NIGERIA
Other Titles: A THESIS IN THE DEPARTMENT OF VETERINARY MICROBIOLOGY AND PARASITOLOGY, SUBMITTED TO THE FACULTY OF VETERINARY MEDICINE IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY OF THE UNIVERSITY OF IBADAN
Authors: Oluwayelu, D. O.
Keywords: CAV
Isolation
Characterization
Sequence
Phylogenetic analysis
Issue Date: Jul-2006
Abstract: Chicken infectious anemia (CIA) is a disease of poultry of global economic importance. It causes poor growth, reduced production efficiency, increased mortality and increased condemnation rate at slaughter in affected chickens. The disease is relatively unknown in Nigeria. This study was designed to develop and use a modified blocking ELISA (MBE) as a cheaper option for serodiagnosis of CIA in Nigeria, isolate chicken anemia virus (CAV) from suspected CIA cases in southwestern Nigeria, characterize the isolates obtained, and compare them with reference CAV strains in an effort to determine the genetic relatedness between Nigerian CAV isolates and those from other parts of the world. Serum and tissue samples from commercial and indigenous chicken flocks in Lagos, Ogun, Ondo, Osun and Oyo States were collected over a IS-month period. The sera were assayed for CAV antibodies using the developed MBE, the performance of which was compared with those of the IDEXX ELISA (IDE), indirect ELISA (IE), indirect immunofluorescence (IIF) and polymerase chain reaction (PCR). Results obtained in developing the MBE were analyzed using the Statistical Analysis System package. DNA extracted from tissue samples were amplified by PCR and positive samples used for virus isolation in MDCC-MSB1 cell line. Isolates obtained were typed with four CAV-specific monoclonal antibodies (Mabs). One isolate (NGR-1) was quantified and used for in vivo pathogenicity studies in specific-pathogen-free chickens. CAV obtained from commercial chickens and cloned indigenous chicken DNA were sequenced. Sequence data obtained were analyzed using Informax Vector NTI advance 9 software. The neighbor joining method of the PHYLIP package was used for phylogenetic analysis of Nigerian and reference CAV strains. Optimum absorbance values were obtained for the developed MBE using 1:200 dilution coating antigens, 1:100 serum, 1:20000 Mab, 1:2000 conjugate and PBS- Tween 20 with milk powder as conjugate dilute. A high CIA prevalence rate of 59.0% was obtained in chickens tested. There was 99.3%, 87.0%,96.2% and 89.9% agreement between the MBE and the IDE, IE, IIF and PCR respectively. Four Nigerian isolates grew in cell culture and Mab typing showed that they were antigenically related to the reference Cux-1 CAV. NGR-1 had a titer of 106.0 TCID50/0.1ml and was more pathogenic than the Cux-1 virus. Nucleotide sequence alignment showed that 93-100% homology exists between Nigerian CAV isolated obtained in this study and Cux-1 virus. Two isolates (NGR-1 and NGR-4) had 98.0% identity with a Malaysian and a Bangladeshi strain respectively. A maximum of 7% nucleotide diversity was observed among Nigerian strains, resulting in only 3% diversity at the amino acid level. Phylogenetic analysis revealed that the Nigerian isolates belong to four genetic groups at the nucleotide level and three genetic groups at the amino acid level. This work has established that CAV circulates in both commercial and indigenous chickens in Nigeria, and that Nigerian isolates belong to the same serotype as other known CAV isolates. Vaccination of layer and broiler breeders to minimize vertical transmission of the virus and consequently prevent virus dissemination is therefore advocated.
URI: http://hdl.handle.net/123456789/586
Appears in Collections:Academic Publications in Veterinary Microbiology and Parasitology

Files in This Item:
File Description SizeFormat 
ui_thesis_oluwayelu_isolation_2006_07.pdf24.06 MBAdobe PDFView/Open


Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.