Seroprevalence and risk factors for Lassa virus infection in South-West and North-Central Nigeria: a community-based cross-sectional study.

BACKGROUND: Understanding the level of exposure to Lassa virus (LASV) in at-risk communities allows for the administration of effective preventive interventions to mitigate epidemics of Lassa fever. We assessed the seroprevalence of LASV antibodies in rural and semiurban communities of two cosmopolitan cities in Nigeria with poorly understood Lassa epidemiology. METHODS: A cross-sectional study was conducted in ten communities located in the Abuja Municipal Area Council (AMAC), Abuja, and Ikorodu Local Government Area (LGA), Lagos, from February 2nd to July 5th, 2022. Serum samples collected from participants were analyzed for IgG and IgM antibodies using a ReLASV® Pan-Lassa NP IgG/IgM enzyme-linked immunosorbent assay (ELISA) kit. A questionnaire administered to participants collected self-reported sociodemographic and LASV exposure information. Seroprevalence of LASV IgG/IgM was estimated overall, and by study site. Univariate and multivariate log-binomial models estimated unadjusted and adjusted prevalence ratios (aPRs) and 95% confidence intervals (CI) for site-specific risk factors for LASV seropositivity. Grouped Least Absolute Shrinkage and Selection Operator (LASSO) was used for variable selection for multivariate analysis. RESULTS: A total of 628 participants with serum samples were included in the study. Most participants were female (434, 69%), married (459, 73%), and had a median age of 38 years (interquartile range 28-50). The overall seroprevalence was 27% (171/628), with a prevalence of 33% (126/376) in Abuja and 18% (45/252) in Lagos. Based on site-specific grouped LASSO selection, enrollment in the dry season (vs. wet; aPR, 95% CI: 1.73, 1.33-2.24), reported inconsistent washing of fruits and vegetables (aPR, 95% CI: 1.45, 1.10-1.92), and a positive malaria rapid test (aPR, 95% CI: 1.48, 1.09-2.00) were independently associated with LASV seropositivity in Abuja, whereas, only a self-reported history of rhinorrhea (PR, 95% CI: 2.21, 1.31-3.72) was independently associated with Lassa seropositivity in Lagos. CONCLUSIONS: The LASV seroprevalence was comparable to that in other areas in Nigeria. Our findings corroborate those from other studies on the importance of limiting human exposure to rodents and focusing on behavioral factors such as poor hygiene practices to reduce exposure to LASV.

Evaluation of Performance of Two Rapid Tests for Detection of HIV-1 and -2 in High- and Low-Prevalence Populations in Nigeria.

The availability of reliable human immunodeficiency virus types 1 and 2 (HIV-1/2) rapid tests in resource-limited settings represents an important advancement in the accurate diagnosis of HIV infection and presents opportunities for implementation of effective prevention and treatment interventions among vulnerable populations. A study of the potential target populations for future HIV vaccine studies examined the prevalence of HIV infections at six selected sites in Nigeria and evaluated the use of two rapid diagnostic tests (RDTs) for HIV. The populations included market workers at sites adjacent to military installations and workers at highway settlements (truck stops) who may have a heightened risk of HIV exposure. Samples from 3,187 individuals who provided informed consent were tested in parallel using the Determine (DT) and Stat-Pak (SP) RDTs; discordant results were subjected to the Uni-Gold (UG) RDT as a tiebreaker. The results were compared to those of a third-generation enzyme immunoassay screen with confirmation of repeat reactive samples by HIV-1 Western blotting. One participant was HIV-2 infected, yielding positive results on both RDTs. Using the laboratory algorithm as a gold standard, we calculated sensitivities of 98.5% (confidence interval [CI], 97.1 to 99.8%) for DT and 98.1% (CI, 96.7 to 99.6%) for SP and specificities of 98.7% (CI, 98.3 -99.1%) for DT and 99.8% (CI, 99.6 to 100%) for SP. Similar results were obtained when the sites were stratified into those of higher HIV prevalence (9.4% to 22.8%) versus those of lower prevalence (3.2% to 7.3%). A parallel two-test algorithm requiring both DT and SP to be positive resulted in the highest sensitivity (98.1%; CI, 96.7 to 99.6%) and specificity (99.97%; CI, 99.9 to 100%) relative to those for the reference laboratory algorithm.

The Nigerian Military Public Health Response to COVID-19: A 14-Month Appraisal.

The COVID-19 pandemic has caused significant morbidity and mortality since its emergence in December 2019. In Nigeria, the government inaugurated the Presidential Task Force on COVID-19 to coordinate resources while the Nigeria Centre for Disease Control led the public health response. The Nigeria Ministry of Defence Health Implementation Programme (MODHIP), in partnership with the US Army Medical Research Directorate - Africa/Nigeria, responded immediately to the pandemic by establishing a public health emergency operations center to coordinate the military response in support of national efforts. MODHIP has 5 functional units and 6 pillars that coordinate testing, surveillance, case management, risk communication, logistics, research, and infection prevention and control. It developed an incident action plan and each pillar had its own terms of reference to guide specific response activities while preventing duplication of efforts within the military and the Nigeria Centre for Disease Control. In addition, awareness and sensitization sessions were conducted on preventive practices for COVID-19 and infrastructure was provided for hand hygiene and screening at all military facilities. Military laboratories were configured for SARS-CoV-2 testing while selected military health facilities were equipped and designated as COVID-19 treatment centers. Research proposals aimed at better understanding the disease and controlling it were also developed. The traditional combat role of the military was redirected to complement this public health emergency response. In this article, we highlight gaps, opportunities, and lessons to improve military participation in public health emergency response in the future. More funding and multisectoral collaboration with civilian institutions are key to strengthening military public health emergency preparedness and response capabilities.

Reference intervals of common clinical biochemistry analytes in young Nigerian adults.

BACKGROUND: Reference intervals are assessment tools for interpretation of clinical test results. These intervals describe the dispersion of test parameter values of apparently healthy persons in defined populations as health status indicators. Using reference intervals obtained and validated in populations outside the geographical region of derivation for medical decision-making may impact negatively on clinical interpretation and patient management. Many countries have established their reference values, current studies on these data for Nigeria are however scarce. Determination of clinical biochemistry reference intervals for young Nigerian adults which is of particular importance in routine clinical management and conduct of clinical trials in response to existing and emerging diseases will add significantly to the existing body of knowledge. OBJECTIVE: The objective was to establish reference intervals for 24biochemistry analytes among Nigerians aged 18 to 26 years. METHODS: This was a cross-sectional study among 7,797 consenting male and female military applicants aged 18 to 26 years from 37 States of Nigeria. It was a total study among volunteers for military service. Blood samples were collected and subjected to serological testing for HIV-1 and 2, hepatitis-B, malaria, pregnancy and haematuria to restrict our study population to apparently healthy participants. Biochemical assays were performed on 6,169 participant samples that met the inclusion criteria. Generated data was entered into MS Excel® and exported into SPSS® software version 16 for analysis. Statistical tools used were frequencies, median, mid 95th percentile range with 2.5th and 97.5th percentiles as limits. Reference intervals were estimated using nonparametric methods. No intergender statistical comparison was made. RESULTS: Complete records were obtained for 6,169 eligible participants. Median values and associated reference intervals were similar in both genders. CONCLUSION: The findings from this study will help in clinical decision-making and play a significant role in supporting the current global rapid expansion of clinical trials in response to the urgent need for preventive and therapeutic solutions to existing and emerging diseases.

Strengthening service integration for effective linkage of HIV-positive mothers to antiretroviral treatment: a cross-sectional study in two military health facilities in Kaduna, Nigeria, 2014.

INTRODUCTION: strong PMTCT-ART service linkages ensure continuity of care for healthier mothers and children born HIV free. Program data showed weak PMTCT- ART linkages in military health facilities. We conducted a study to assess the PMTCT-adult ART service linkage in two Nigerian military health facilities in Kaduna State. METHODS: we conducted a cross-sectional study using mixed methods (interviews and FGDs) in 44 Nigeria Army Reference Hospital (NARH) and 1 Division Hospital, Kaduna. We studied 372 HIV-positive mothers after a delivery of their babies, referred for ART services from January 2009 to December 2013. We conducted FGDs among ANC, PMTCT and ART clinics staff. We analysed data using descriptive and inferential methods. A p-value of < 0.05 was considered significant with 95% confidence intervals (CI) for estimates. RESULTS: of the 372 respondents studied, 320 (86%) accessed PMTCT services from the 44 NARH. Most respondents (206,55.4%) respondents aged < 25 years. One in six (16.7%) respondents had no record of referral. Delivering baby in a separate facility from where PMTCT services were accessed, increased the likelihood of not accessing ART services (odd ratio [OR]: 6.7, 95% CI= 3.3 -13.6). The qualitative study identified poor service integration between PMTCT and ANC clinics. CONCLUSION: the key factors hindering PMTCT-ART linkage in military health facilities included poor service integration, clients delivering of a baby in a facility separate from where PMTCT services were accessed. The Ministry of Defence HIV programme should strengthen ANC-PMTCT-ART service integration through a centrally coordinated client information management system.

Establishment of reference values for selected haematological parameters in young adult Nigerians.

BACKGROUND: Haematological reference values are necessary for accurate diagnosis of diseases, clinical decision-making, treatment monitoring and clinical research. Due to unavailability of pan-Nigerian reference values, local results interpretation is based on the use of Western values. OBJECTIVE: This study aims to establish national reference values for some haematological parameters in apparently healthy young adult Nigerians. METHODS: Seven Thousand, Seven Hundred and Ninety-Seven (7,797) volunteers aged 18 to 26 years participated in the study. Participants' interviewer-administered questionnaires and blood samples were collected, analyzed and those with confounding factors (HIV infection, Hepatitis B sero-positivity, Malaria and Pregnancy) were excluded from statistical analysis. The 95-percentile reference range was determined for each haematological parameter using SPSS Version 16®. The result obtained was reviewed with reference to already established reference values in two West African and Western countries. RESULTS: Blood specimens from 6153 (78.9%) participants [comprising 5915 (96.1%) males and 238 (3.9%) females] were analyzed after exclusion of 1,644 (21.1%) participants with confounding variables. Reference ranges among males and females varied and these were consistent with findings from two other West African countries. The median platelets count in this study was 218 x 109/l while commonly used Western value is 280 x 109/l. Other haematological parameters in the study were similar to Western values. CONCLUSION: The findings of this study will improve clinical and research decision-making. Considering that this study is limited to young adult participants, there is a need to conduct future pan-Nigerian studies that will include all age groups.

Virological Suppression and Patterns of Resistance Amongst Patients on Antiretroviral Therapy at 4 Nigerian Military Hospitals.

BACKGROUND: In resource-constrained settings, plasma HIV-1 RNA quantification has not been routinely available for the monitoring of response to antiretroviral therapy. This study evaluated virological suppression rates amongst patients on first-line ART in four Nigerian military hospitals. METHODS: We conducted a cross-sectional study of 325 randomly selected adult clinic clients (≥18 years old) on first-line ART regimens at four Nigerian military hospitals. Plasma HIV-1 RNA was assayed using a Roche COBAS TaqMan48 with High Pure System. Virological failure was defined as HIV-1 RNA >1000 copies/ml. Specimens with HIV-1 RNA >1000 copies/ml were referred for genotyping. RESULTS: HIV-1 RNA results were obtained in 322 participants. Two hundred and seventy-eight study participants (86.3%) had HIV viral RNA < 1000 copies/ml, including 273 (84.8%) with HIV- 1 RNA <400 copies/ml. HIV drug resistance genotyping results were obtained in 35 of 44 study participants with HIV-1 RNA >1000 copies/ml. Only 14% (5/35) had no resistance mutations. Of the remainder, 10% (3/30) had no nucleoside analogue mutations while 33% (10/30) had only M184V along with non-nucleoside reverse transcriptase inhibitor (NNRTI) mutations (K103N or Y188C). 25% (5/25) of participants failing on Zidovudine had more than two thymidine analogue mutations (TAMs). CONCLUSION: We observed a high virological suppression rate among the study participants. However, a large proportion of virologically unsuppressed clients had identifiable resistance mutations. The study demonstrates that viral load monitoring is feasible at Nigerian military hospitals and supports the current WHO HIV treatment guidelines which emphasize virological monitoring of patients on ART for early detection of treatment failure.

An Evaluation of Selected Populations for HIV-1 Vaccine Cohort Development in Nigeria.

Development of a globally effective HIV-1 vaccine will need to encompass Nigeria, one of the hardest hit areas, with an estimated 3.2 million people living with HIV. This cross-sectional Institutional Review Board (IRB) approved study was conducted in 2009-12 at four market sites and two highway settlements sites in Nigeria to identify and characterize populations at high risk for HIV; engage support of local stakeholders; and assess the level of interest in future vaccine studies. Demographic, HIV risk data were collected by structured interviewer-administered questionnaires. Blood samples were tested on site by HIV rapid diagnostic tests, followed by rigorous confirmatory testing, subtype evaluation and testing for HBV and HCV markers in a clinical reference laboratory. Of 3229 study participants, 326 were HIV infected as confirmed by Western Blot or RNA, with a HIV prevalence of 15.4%-23.9% at highway settlements and 3.1%-9.1% at market sites. There was no observable correlation of prevalence of HIV-1 (10.1%) with HBV (10.9%) or HCV (2.9%). Major HIV-1 subtypes included CRF02_AG (37.5%); G (27.5%); G/CRF02_AG (25.9%); and non-typeable (8.9%), with 0.3% HIV-2. Univariate analysis found age, gender, marital status, level of education, and sex under substance influence as significant risk factors for HIV (p<0.001). Educating and winning the trust of local community leadership ensured high level of participation (53.3-77.9%) and willingness to participate in future studies (95%). The high HIV prevalence and high risk of HIV infection at highway settlement and mammy markets make them well suited for targeting future vaccine trials in Nigeria.

Significant contribution of subtype G to HIV-1 genetic complexity in Nigeria identified by a newly developed subtyping assay specific for subtype G and CRF02_AG.

While abundant sequence information is available from human immunodeficiency virus type 1 (HIV-1) subtypes A, B, C and CRF01_AE for HIV-1 vaccine design, sequences from West Africa are less represented. We sought to augment our understanding of HIV-1 variants circulating in 6 Nigerian cities as a step to subsequent HIV-1 vaccine development.The G/CRF02_AG multi-region hybridization assay (MHA) was developed to differentiate subtype G, CRF02_AG and their recombinants from other subtypes based on 7 HIV-1 segments. Plasma from 224 HIV-1 infected volunteers enrolled in a cohort examining HIV-1 prevalence, risk factor, and subtype from Makurdi (30), Abuja (18), Enugu (11), Kaduna (12), Tafa (95), and Ojo/Lagos (58) was analyzed using MHA. HIV-1 genomes from 42 samples were sequenced to validate the MHA and fully explore the recombinant structure of G and CRF02_AG variants.The sensitivity and specificity of MHA varied between 73-100% and 90-100%, respectively. The subtype distribution as identified by MHA among 224 samples revealed 38% CRF02_AG, 28% G, and 26% G/CRF02_AG recombinants while 8% remained nontypeable strains. In envelope (env) gp120, 38.84% of the samples reacted to a G probe while 31.25% reacted to a CRF02 (subtype A) probe. Full genome characterization of 42 sequences revealed the complexity of Nigerian HIV-1 variants.CRF02_AG, subtype G, and their recombinants were the major circulating HIV-1 variants in 6 Nigerian cities. High proportions of samples reacted to a G probe in env gp120 confirms that subtype G infections are abundant and should be considered in strategies for global HIV-1 vaccine development.