African swine fever (ASF) was first introduced into Nigeria through Lagos state in 1997. The disease rapidly spread to Ogun state in 1998 and extended to the Niger Delta (Delta, Rivers and Akwa Ibom states) in the same year. In 1998, Kaduna, Plateau and Benue states all north of the country experienced ASF for the first time. Poor farm biosecurity, bad abattoir practices and extensive/free range pig farming systems led to extensive spread of the diseases to about 16 Nigerian states excluding the far northwest and north east. A total of 1036 field samples collected over a 6-year period covering 19 Nigerian states were analysed during the period under review; 805 samples were PCR positive and 231 negative. Positive samples were detected in all three surveillance phases and from all agroecological zones across the country. For the first time since its incursion, ASF was identified in some states; Bauchi, Adamawa Taraba and Gombe with chances of control very slim and further spread of the virus northward envisaged. Outbreaks of the disease are now a perennial problem with an increasing disease burden in areas where high numbers of pigs are produced in the country. The National Veterinary Research Institute (NVRI), Vom, since 2002 investigated ASF based on tissue submissions and reports made by individuals, private & commercial farms and agricultural bodies. We present an analysis of geographical and temporal distribution of ASF in the country from 2002 to 2007 and a review of historic outbreaks since the first incursion. Risk factors and prospects for control are discussed.
Prevalence and molecular identification of Campylobacter species isolates from poultry and humans were conducted using culture, biochemical reaction and Polymerase Chain Reaction (PCR) techniques. A total of 798 (506 poultry and 292 human) samples were identified biochemically, out of which 312(39.1%) were positive for Campylobacter species. Campylobacter jejuni, C. coli and C. lari had 38 (23.8%) out of 160, 63(39.4%) out of 160, 59(36.9%) out of 160 prevalence rates, respectively in humans while 29(19.1%) out of 152, 79(52.0%) out of 152 and 44(28.9%) out of 152 were the rates for the species in the same order in poultry. Campylobacter isolates were kept at -20 o C in 15% glycerol and 85% tryptone broth until used while some were identified 24hrs post isolation. Single and multiplex PCR were used to confirm the genus Campylobacter and three Campylobacter species, respectively. All the 130(100 stored and 30 fresh) isolates were members of the genus Campylobacter. The single PCR band view of stored isolates also revealed other bands in addition to 439 bp which is specific for the genus Campylobacter, while the fresh isolates had distinct bands at 439bp only. Multiplex PCR revealed 2(6.7%) out of 30 were positive for stored isolates out of 30, 1(50%) each for C. jejuni and C. Coli. However, 1 of the stored isolate was positive for both spp. On the other hand, 6(20.0%) of out 60 fresh isolates were positive, with 5(83.3%) and 1(16.7%) for C. jejuni and C. coli, respectively. The possibilities of improper identification using conventional method have been revealed in the study. PCR can identify Campylobacter species more accurately than biochemical method, though storage of isolates, integrity of extracted DNA and PCR conditions can affect result. However, the use of both methods should be encouraged in regular and effective surveillance of Campylobacter species in poultry and humans.
Reverse transcription polymerase chain reaction (RT-PCR) and partial sequencing of the VP2 hypervariable region was performed on clinical samples from two infectious bursal disease (IBD) outbreaks in Plateau state, Nigeria. IBD virus RNA was detected in all four bursa of Fabricius samples. Nucleotide sequencing and analysis of the four samples revealed high similarity to previous IBDV sequences from northern and southern Nigeria. The deduced amino acid sequences were compared to reference IBDV strains retrieved from the GenBank; virulence markers A222, I256, and I294 were conserved in both outbreak and reference sequences. Amino acid residue S254 was conserved in the outbreak viruses and previous viruses from northern Nigeria. Phylogenetic analysis revealed that all four viruses were very virulent IBDVs. These viruses clustered with vv2-1 variant viruses from Oyo and Ogun states and less closely with vv2-2 isolates from Tanzania. The nucleotide identity of the sequences in this study ranged from 99.6 to 100 % with each other. These findings are further evidence of IBD outbreaks in vaccinated chicken flocks in Nigeria.
Aim: Characterization of Infectious bursal disease viruses (IBDV) from the two outbreaks in Jos Nigeria, using reverse transcriptase polymerase chain reaction/restriction fragment length polymorphism (RT-PCR/RFLP) technique. Materials and Methods:A total of 40 bursa samples were collected from two outbreaks in November 2011 from two farms of 6-8 weeks old pullets within Jos South Local Government Area, with mortality between 60 -74.2 % in commercially reared layer chicken flocks experiencing signs typical of infectious bursal disease (IBD). All the samples were found to contain IBDV genome by One Step RT-PCR using VP2 gene specific primers. Result:The assay amplified a 743bp fragment from 701-1444 nucleotides. RT-PCR product was further subjected to restriction digestion using TaqI, MvaI and SacI Restriction enzymes to differentiate classical from very virulent phenotypes. The RFLP profile was found similar for all eight isolates with TaqI and MvaI enzyme but different for SacI. All eight TaqIpositive Viruses were further found positive for MvaI digestion and yielded RFLP profile similar to vvIBDV in Europe whereas one isolate was SacI positive and had a RFLP profile similar to classic IBDV strains. Conclusion:The clinical history of high mortality and TaqI and MvaI restriction enzyme positivity revealed that vvIBDV strains still exist in Jos, North central Nigeria.
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