Stephen Obekpa Abah

Lassa fever remains a major public health threat in West Africa, yet the household and behavioural determinants of prior Lassa virus exposure are not sufficiently understood. This study examined environmental, behavioural, and demographic factors associated with Lassa virus IgG seropositivity among residents of selected states in North-Central Nigeria. Analysis was carried out on baseline data from 958 participants enrolled in the first phase of an ongoing longitudinal cohort study, which collected information on rodent exposure, house integrity, food safety practices, and household composition. Formative indices were constructed and standardised, and logistic regression models with 1000-iteration bootstrap estimation were used to identify predictors of IgG positivity. Seroprevalence of Lassa virus IgG was 19%, while IgM positivity was 1.15%. Rodent activity around and within homes was widespread, with more than 86% of participants reporting rodent presence. Logistic regression analysis showed that rodent exposure (standardised coefficient 0.20, 95% CI 0.02–0.43) and participant age (0.20, 95% CI 0.05–0.35) were significant predictors of IgG seropositivity. Household size demonstrated a strong inverse association (−0.41, 95% CI −0.68 to −0.20). House integrity and food safety formative indices exhibited weak and non-significant effects. Model performance was acceptable (AUC 0.63; Brier score 0.148), and variance inflation factor values confirmed negligible multicollinearity. These findings emphasised the continuing role of rodent exposure and demographic factors in Lassa virus transmission risk. This implies that there is a need to strengthen community-level rodent control and household-based prevention strategies, which can help to reduce exposure.

Lassa fever (LF), a severe hemorrhagic disease endemic to West Africa, is primarily transmitted by rodents of the genus Mastomys, particularly Mastomys natalensis, which serve as the main reservoirs of Lassa virus (LASV). There have been reports of high prevalence of LF in Nigeria, and outbreaks tend to be recurrent yet geographically restricted, implying that additional ecological or epidemiological factors influence the distribution of the disease beyond the mere presence of M. natalensis. However, national-scale data on LASV prevalence in rodent populations remain scarce. To address this gap, a targeted small mammal survey was conducted over a four-month period (May to August 2024) in Otukpo Local Government Area (LGA) of Benue State, north-central Nigeria. Rodents and other small mammals were trapped across three purposively selected wards identified as high-risk areas based on prior reports of occurrence of such small mammals in the areas and the informal settlements in which the selected wards were located in in Otukpo LGA. Analysis of the samples revealed no statistically significant variation in LASV prevalence among the study sites, indicating a relatively uniform, low-level exposure risk across the LGA and region. However, a marginally significant difference in LASV detection between plasma and serum samples suggests that sample type and storage conditions may influence serological sensitivity. These findings highlight the importance of refining diagnostic protocols, broadening surveillance to include additional rodent hosts, and integrating ecological data with public health strategies to improve early warning systems and strengthen Lassa fever control efforts.

In 2011, the United Nations Environment Programme discovered high levels of hydrocarbon pollution in drinking water wells in Nsisioken Agbi Ogale Rivers State, Nigeria. However, the level of polycyclic aromatic hydrocarbons (PAHs) in the same community's water supply was unknown. A comprehensive study of PAHs in three household dug wells and three boreholes was conducted using Agilent 7890B gas chromatography and 5975A mass spectrometry. The detected PAHs were mainly 4 - 5 ringed PAHs, such as Chrysene, Fluoranthene, Pyrene, Benzo[a]anthracene, and Benzo[b]fluoranthene. The total mean concentration was 5.8 ± 2.3 μg/L, with values ranging from not detected in borehole 3 to 8.0 μg/L at well 2. Source identification analysis suggested that the PAHs originated from fuel and biomass combustion. The incremental lifetime cancer risk for children and adults due to groundwater ingestion and skin contact ranged from ND to 7.448 × 10−3 and ND to 1.83 × 10−3 respectively. The Risk index (RI) values from ingestion and dermal routes were 1.5 ×10-2 and 2.4 × 10-2, indicating high risk of cancer. The hazard quotient for the two non-carcinogenic PAHs was greater than 1, indicating high toxicity. The PAH concentrations exceeded the maximum contamination limits set by the World Health Organization and the U.S. environmental Protection Agency, highlighting potential health risks associated with water use in the community. Authorities should provide a safe alternative water source for the community.

Introduction: Healthcare workers (HCWs) are daily exposed to HBV infections from the blood and body fluids of patients and clients they care for in the health sector. Unfortunately, many of these HCWs are not vaccinated for hepatitis B. This study aimed to assess the factors influencing knowledge of hepatitis B vaccination amongst HCWs in a rural tertiary health facility in Edo State, Southern Nigeria. Methods: A descriptive cross-sectional study design was used in this study, and data were collected using the quantitative approach. 280 HCWs were administered with pre-tested, semi-structured interviewer-administered questionnaires. The obtained data were analyzed using IBM SPSS version 21.0, and the level of significance – alpha (α) was set at 5% (0.05). Results: The mean age of HCWs was 34.90(±9.46) years. Just above half of the HCWs, 146 (52.1%), had a good knowledge of the hepatitis B (HB) vaccine.  Work type (pConclusion: There was poor knowledge of hepatitis B vaccination amongst HCWs with work type and category of HCW as determinants. Priority should be given to ensure targeted health promotion programmes that will improve knowledge, with a view to enhance optimal uptake of hepatitis B vaccine amongst HCWs.

There is fast-growing epidemiologic evidence of the effects of environmental chemicals on respiratory health. Polycyclic aromatic hydrocarbons (PAHs) have been linked with airway obstruction common in asthma and/or asthma exacerbation, and chronic bronchitis and emphysema. A systematic review of the association between exposure to PAHs and obstructive lung diseases is not yet available. The present systematic review aims to evaluate the evidence available in epidemiological studies that have associated PAHs with obstructive lung diseases such as asthma, chronic bronchitis, emphysema. We performed a systematic literature search on PubMed, Google Scholar, and Scopus databases using relevant keywords and guided by predesigned eligibility criteria. From the total of 30 articles reviewed, 16 articles examined the link between PAHs and lung function in both adults and children. Twelve articles investigated the association between PAHs and asthma, asthma biomarkers, and/or asthma symptoms in children. Two articles studied the relationship between PAHs and fractional exhaled nitric oxide (FeNO), a biomarker of airway inflammation and the relationship between PAHs and obstructive lung diseases and infections, respectively. One study assessed exposure to daily ambient PAHs and cough occurrence. Twenty-seven studies found an association between PAHs and asthma and reduced lung function. In children it is reinforced by studies on prenatal and postnatal exposure, whereas in adults, reductions in lung function tests marked by low forced expiratory volume in 1 second, (FEV₁), forced vital capacity (FVC), and forced expiratory flow (FEF_25–75%) were the major health outcomes. Some studies recorded contrasting results: insignificant and/or no association between the two variables of interest. The studies reviewed had limitations ranging from small sample size, to the use of cross-sectional rather than longitudinal study design. The literature reviewed in the present study largely suggest positive correlations between PAHs and obstructive lung diseases marked mainly by asthma and reduced respiratory function. This review was registered with PROSPERO (Registration no: CRD42020212894) The authors declare no competing financial interests.