Analysis of Culex and Aedes mosquitoes in southwestern Nigeria revealed no West Nile virus activity

Introduction: Amplification and transmission of West Nile virus (WNV) by mosquitoes are driven by presence and number of viraemic/susceptible avian hosts. Methods: in order to predict risk of WNV infection to humans, we collected mosquitoes from horse stables in Lagos and Ibadan, southwestern Nigeria. The mosquitoes were sorted and tested in pools with real-time RT-PCR to detect WNV (or flavivirus) RNA using WNV-specific primers and probes, as well as, pan-flavivirus-specific primers in two-step real-time RT-PCR. Minimum infection rate (MIR) was used to estimate mosquito infection rate. Results: Only two genera of mosquitoes were caught (Culex, 98.9% and Aedes, 1.0%) totalling 4,112 females. None of the 424 mosquito pools tested was positive for WNV RNA; consequently the MIR was zero. Sequencing and BLAST analysis of amplicons detected in pan-flavivirus primer-mediated RT-PCR gave a consensus sequence of 28S rRNA of Culex quinquefasciatus suggesting integration of flaviviral RNA into mosquito genome. Conclusion: While the latter finding requires further investigation, we conclude there was little or no risk of human infection with WNV in the study areas during sampling. There was predominance of Culex mosquito, a competent WNV vector, around horse stables in the study areas. However, mosquito surveillance needs to continue for prompt detection of WNV activity in mosquitoes.Pan African Medical Journal 2016; 2

Serologic Evidence of Exposure to West Nile Virus among Humans in Ibadan, Southwestern Nigeria

Background: Cases of fever without diagnoses of malaria and/or typhoid are usually regarded as undifferentiated febrile illness (UFI) in Nigeria. We studied the contribution of WNV (an arbovirus) to UFI in humans in southwestern Nigeria.Materials and methods: Sera from 188 consenting humans visiting two health care facilities in Ibadan, and 25 horse grooms from Lagos and Ibadan were screened for WNV antibodies by cELISA and a subset by PRNT. Pertinent demographic/clinical data were collected and blood samples screened for Plasmodium spp, Salmonella typhi and S. paratyphi antibodies. Student’s t-test and binary logistic regression were used for data analysis.Results: Overall, 156 participants (73.2%, 95% CI: 67.3-79.2 [n=213]) were positive for WNV antibodies. Being clinically ill was associated (p=0.001) with WNV seropositivity while “active” and “non-active” participants had comparable (p=0.21) seroprevalence of 74.6% and 62.5%, respectively. Forty-five percent (18/40) of febrile participants had WNV antibodies only, thereby accounting for UFI. The 18-66 year olds had higher (75.8%) seroprevalence than those ≤ 17 years (47.4%) while seropositivity obtained for the horse grooms (56.0%) was significantly lower than for the remaining 188 individuals (75.5%). Participants were mostly exposed to WNV (75.5%) than Plasmodium (33.5%) and S. typhi (39.9%) while PRNT showed that 10.5% of tested humans had protective WNV antibodies.Conclusions: This study revealed serologic evidence of exposure of the participants to WNV and contribution of the virus (or related flaviviruses) to UFI in the study area. High prevalence of the antibodies indicates endemicity of southwestern Nigeria for WNV.Key words: Humans, anti-WNV antibody, prevalence rate, undifferentiated febrile illness, southwestern Nigeria

Coconut Milk - Citrate As Extender For West African Dwarf Buck Spermatozoa At Room Temperature

We studied the proportions of coconut milk and sodium citrate buffer suitable for extension of West African dwarf (WAD) buck spermatozoa at room temperature. Semen was collected from clinically healthy buck certified free of obvious andrological defects. Eight trials of semen extension were carried out using 0.1 ml of semen plus 0.5 ml buffer as individual extender. In the extenders D1 to D7, while the buffer (sodium citrate) was decreasing, the coconut milk was increasing. Statistical analyses from 5 trials showed that D2 containing 20% coconut milk and 80% citrate buffer that supported mean sperm cell motility of 52.6% was highly significant (p = 0.018) at 2 hours post-extension in preserving motility of extended buck semen un-refrigerated compared to both D3 (40% coconut milk and 60% citrate buffer) and D4 (50% coconut milk and 50% citrate buffer). D2 also maintained mean sperm cell motility of 45% and was highly superior (p = 0.012) to both D3 and D4 at 3 hours post-extension. However, in D2, there was no statistical difference (p = 0.693) between 2 hours and 3 hours storage time in mean motility of extended sperm cells. Similarly, there was no difference (p = 0.106) in mean sperm cell motility between D2 at 3 hours and D3 at 2 hours post extension. We concluded therefore, that D2 was superior to others with which it was compared; and that it preserved extended buck semen for more than 2 hours storage at room temperature

HBV INFECTION AMONG HIV-INFECTED COHORT AND HIV-NEGATIVE HOSPITAL ATTENDEES IN SOUTH WESTERN NIGERIA

Background: Prevalence, association and probable mode of acquisition of HBV and HIV dual infections have not been fully explored. Thus, HBV intervention plan and services are sometimes exclusively targeted towards HIV-infected population. We investigated HBV infection among HIV-infected cohort in comparison with HIV-negative hospital attendees to ascertain dual infectivity pattern; thereby encouraging appropriate allotment of intervention services. Materials and Methods: A total of 349 (M=141; F=208; Mean=33.98 years; Range= 0.33-80 years) plasma specimens from two virus diagnostic laboratories in south-western Nigeria were analysed. These include 182 HIV-positive and 167 HIV-negative specimens from ART and GDV laboratories respectively. The specimens were initially screened for detectable HIV antigen/antibody, and subsequently HBsAg by ELISA technique. Results: Overall, HBsAg was detected in 20.92% (95% CI: 16.65-25.19%) of the patients. Also, 24.82% (95% CI: 17.69-31.95%) and 18.27% (95% CI: 13.02-23.52%) HBsAg positivity was recorded for males and females respectively. CHI square analysis showed no association (P=0.14) between gender and prevalence of HBsAg. Similarly, comparison of prevalence of HBsAg by age groups shows no significant difference (P=0.24). Overall, no significant difference (P=0.59) was observed in the prevalence of HBsAg among the HIV-infected cohort and HIV-negative hospital attendees. Conclusions: Results of the study confirm endemicity and comparable rates of HBV infection independent of HIV-status

The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance.

Investment in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing in Africa over the past year has led to a major increase in the number of sequences that have been generated and used to track the pandemic on the continent, a number that now exceeds 100,000 genomes. Our results show an increase in the number of African countries that are able to sequence domestically and highlight that local sequencing enables faster turnaround times and more-regular routine surveillance. Despite limitations of low testing proportions, findings from this genomic surveillance study underscore the heterogeneous nature of the pandemic and illuminate the distinct dispersal dynamics of variants of concern-particularly Alpha, Beta, Delta, and Omicron-on the continent. Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve while the continent faces many emerging and reemerging infectious disease threats. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

Adult Males and Females in Osogbo, Osun State, Nigeria Manifest Extremely Low Level of Rubella Virus Susceptibility: Herd Immunity Implication

Introduction: Despite the epidemic-prone nature of rubella and absence of its vaccine in routine immunization in Nigeria, there have been no reported cases of rubella outbreak in Osogbo, capital city of Osun State. We therefore hypothesized that susceptibility to rubella viral infection was low among males and females attending LAUTECH Teaching Hospital, Osogbo. Methodology: To verify this, 89 sera of consecutively selected consenting males and females in the General-Out-Patient Department of LAUTECH Teaching Hospital were tested for presence of protective level of anti-rubella virus IgG antibody using ELISA. Relevant socio-demographic/clinical data were obtained with interviewer-administered questionnaires. The serologic results were analyzed vis-à-vis the participants’ data. Results: The 89 participants were aged 3-85 years (mean age: 39.4 years) with 38.2% as males (mean age: 36.3 years). Overall rubella virus IgG seropositivity was 97.8%. Consequently, the rubella viral infection susceptibility rate was 2.2%, with group-specific susceptibility ranging from 0.0% to 4.2%. The susceptibility for males and females were 2.9% and 1.8% respectively. None of the participants’ variables was statistically associated with the susceptibility; this was mainly due to zero susceptibility of most groups of the participants. The 11 pregnant women and the 7 participants reporting skin rash had zero susceptibility to rubella. Conclusion: The study concludes that males, as well as females, had very low level of susceptibility suggestive of herd immunity against the virus which apparently was responsible for absence of rubella outbreaks in Osogbo, Osun State. As the high positivity rate indicated rubella endemicity, we recommend inclusion of rubella virus-containing immunization in national routine immunization for children and young adults, as well as, public enlightenment regarding rubella in Osogbo, Osun State.</jats:p

CD4+ T Cell Response to Lamivudine, Stavudine and Nevirapine in Human Immunodeficiency Virus Infected Antiretroviral-Naive Men in Nigeria

Increase of (≥) 50 CD4(+) T cells/μl in post-commencement of highly active antiretroviral therapy (HAART) is acceptable as indicator of therapeutic success (TS). We therefore hypothesized that median change in CD4 count of the TS and therapeutic failure (TF) groups were comparable after 3 months; and that no associations existed between HAART outcome and adherence to therapy. One hundred Human immunodeficiency virus (HIV) infected antiretroviral (ARV) naive men on lamivudine + stavudine + nevirapine at Federal Medical Centre (FMC), Lokoja, Kogi State, Nigeria were studied. Data of the men were obtained with interviewer-administered questionnaire forms. Their ethylene diamine tetra acetic acid (EDTA)-treated whole blood samples were analysed with Partec CyFlow(®) Counter for pre-HAART and follow-up CD4 counts. Adherence to the ARV regimen was recorded for each patient as self-reported. We used Mann–Whitney U test, Kruskal–Wallis, Wilcoxon’s matched pair and CHI(2) statistical tests for analyses. Overall adherence rate was 95.0%. Though the median follow-up CD4 count was higher (P = 0.001) than the pre-HAART value; only 85% of the men attained TS (increase of ≥50 cells/μl) at follow-up. Median change in CD4 count (+104.0 cells/μl; n = 85) of the TS was higher (P = 0.001) than that (−8.0 cells/μl; n = 15) of TF group; the two groups were however, comparable in age (P = 0.17) and body weight (P = 0.96). Only adherence and pre-HAART CD4 counts were associated (P = 0.001) with HAART outcome; while only age apparently influenced (P = 0.01) adherence rate. Eighty-five percent of the men benefited from the HAART. The success was apparently due to adherence and less than or (≤) 200 pre-HAART CD4 counts; while age ≥40 years appearently reduced adherence level