Search Results (3)

In Nigeria, hepatitis B virus (HBV) infection remains a significant public health issue. The emergence of immune escape mutants (IEMs), basal core promoters, and precore (BCP/PC) mutants among asymptomatic individuals has enabled the continuous evolution of the virus in the country. In this study, we used Sanger sequencing of the S gene and the BCP/PC region to investigate the genetic diversity, phylogenetic relationships, and mutational profiles of HBV strains detected in two regions in Nigeria. A total of 178 HBsAg-positive samples confirmed by ELISA underwent viral DNA extraction and PCR amplification of the surface and BCP/PC genes, and 76 and 60 sequences were found to be exploitable for S and BCP/PC genes, respectively, which were used for HBV genotyping and mutational analysis. We detected various mutations in the major hydrophilic loop (target of neutralizing antibodies), including vaccine escape mutants (VEMs) (L127P/R, S140T/L, and G145A), HBV immunoglobulin resistance mutants (T131N, S143T, and W156R), and mutations previously reported in patients with reactivated infections (T115N, G159A/R, and F161Y). We also identified a high proportion of C1741T in 34/42 (81%) along with A1762T or G1764A mutation in 14/42 (33%) and 18/42 (43%) as the dominant variants in the BCP region. The predominant classical PC G1896A and G1899A variants were identified in 26/42 (62%) and 17/42 (40%) participants in this study. Two HBV genotypes were identified (A and E). However, HBV genotype E was the most frequently identified genotype, and is still the dominant strain circulating in Nigeria. We report the circulation of HBV IEMs and the preponderance of BCP and classical PC variants among asymptomatic carriers. Our findings suggest that the spread of these HBV mutant variants among asymptomatic carriers may have an impact on the effectiveness of diagnostic immunoassays and the success of HBsAg-based vaccinations. This highlights the need for robust surveillance. Full article

Dogs live in close contact with humans as pets, for hunting, for security, and as a source of income. In addition, the meat is also consumed by some tribes in Nigeria. Dogs could therefore serve as reservoirs, carriers, and transmitters of zoonotic diseases. This review evaluates the literature from 2000 to 2020 for the prevalence and incidence of zoonotic pathogens associated with dogs in Nigeria. The results obtained show that overall, parasites constituted a majority (64%) of the zoonotic pathogens (or species) identified in dog hosts. A good number of studies have examined the role of ticks in the transmission of tick-borne pathogens. Further, bacteria make up 22% of the zoonotic pathogens. From this study, it appears that rabies is the major pathogen in dogs for which there is reliable evidence linking contact between humans and dogs. Oyo State in southwestern Nigeria and Plateau State in north-central Nigeria were the most frequently studied states, while prevalence/disease surveillance studies constituted 80% of the overall papers assessed. Interdisciplinary collaborations as well as research and diagnosis policy amendments are missing links to fully appreciate the role of dogs in the transmission of zoonotic diseases in Nigeria. Policies should integrate a one health approach in the Nigerian health system, whereby diagnostic screening of humans and animals by physicians and veterinarians includes zoonotic pathogens for more accurate diagnosis and control. Full article

Babesiosis is a significant tick-borne disease that causes varying degrees of losses to animals and humans, as well as a severe economic impact. In Nigeria, there have been several reports on the prevalence of Babesia infection in sheep; however, to date, there is no documented report on the molecular characterization of Babesia ovis in sheep. Here, we determined the prevalence of Babesia infection in sheep using microscopy and PCR and further characterized Babesia ovis in sheep in Nigeria. In this study, 198 blood samples were collected from Abuja and Abeokuta, Nigeria. Microscopic and polymerase chain reactions were used to detect the presence of B. ovis in sheep. Genomic DNA was extracted from blood samples, and generic RLB forward and reverse primers were used to amplify the 18S rRNA segment of B. ovis. Sequence analysis of the generic molecular marker was used to determine the genetic characteristics of B. ovis in sheep in Nigeria. The prevalence of B. ovis infection using microscopy and PCR was 61.1% and 36.9%, respectively. There was a higher prevalence of Babesia infection in Abeokuta (38.4%) than in Abuja. Study animals of one and half years to three years had the highest percentage (45.8%) of Babesia infection, and higher infection of B. ovis was recorded in male animals (37.5%), balami breeds (40.0%), white coat colors (44.4%), emaciated animals (75.0%), and polycythaemic animals (57.1%). Sequencing analysis indicated that B. ovis 18S rRNA from southwestern Abeokuta and north-central Abuja, Nigeria, showed 90–95% identity of documented isolates from other countries. BioEdit and MEGAX software was used to clean sequences and construct a phylogenetic tree to show evolutionary relationships. In conclusion, the findings from this study offer significant information on the molecular characteristics of B. ovis infection for the first time in Nigeria, as well as its present prevalence status. Furthermore, sheep have been identified as a potential reservoir for this tick-borne pathogen; thus, the information from this study can serve as a basis to formulate effective control strategies for tick-borne pathogens circulating amongst the ruminant population in Nigeria and Africa by extension. Full article