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Background Lassa fever, killing thousands of people annually, is the most reported viral zoonotic disease in Nigeria. Recently, different rodent species carrying diverse lineages of the Lassa virus (LASV) in addition to a novel Mobala-like genetic sequence were detected within the country. Here, screening 906 small mammal specimens from 11 localities for IgG antibodies and incorporating previous PCR detection data involving the same populations, we further describe arenavirus prevalence across Nigeria in relation to host species and geographical location. Methods Small mammals were trapped during the period 2011–2015 according to geographical location (endemic and non-endemic zones for Lassa fever), season (rainy and dry seasons between 2011 and 2012 for certain localities) and habitat (indoors, peridomestic settings and sylvatic vegetation). Identification of animal specimens from genera such as Mastomys and Mus ( Nannomys ) was assisted by DNA sequencing. Small mammals were tested for LASV IgG antibody using an indirect immunofluorescence assay (IFA). Results Small mammals were infected in both the endemic and non-endemic zones for Lassa fever, with a wider range of species IgG-positive ( n = 8) than those which had been previously detected to be PCR-positive ( n = 3). IgG-positive species, according to number of infected individuals, were Mastomys natalensis ( n = 40), Mastomys erythroleucus ( n = 15), Praomys daltoni ( n = 6), Mus baoulei ( n = 5), Rattus rattus ( n = 2) , Crocidura spp. ( n = 2), Mus minutoides ( n = 1) and Praomys misonnei ( n = 1) . Multimammate mice ( Mastomys natalensis and M. erythroleucus ) were the most ubiquitously infected, with animals testing positive by either PCR or IgG in 7 out of the 11 localities sampled. IgG prevalence in M. natalensis ranged from 1% in Abagboro, 17–36 % in Eguare Egoro, Ekpoma and Ngel Nyaki, up to 52 % in Mayo Ranewo. Prevalence according to locality, season and age was not, however, statistically significant for M. natalensis in Eguare Egoro and Ekpoma, localities that were sampled longitudinally. Conclusions Overall, our study demonstrates that arenavirus occurrence is probably more widely distributed geographically and in extent of host taxa than is currently realized. This expanded scope should be taken into consideration in Lassa fever control efforts. Further sampling should also be carried out to isolate and characterize potential arenaviruses present in small mammal populations we found to be seropositive.

The aim of this study was to evaluate the use of a capture enzyme-linked immunosorbent assay (ELISA) for the detection of LASV-reactive IgG antibodies in Mastomys rodents. The assay was used for laboratory-bred Mastomys rodents, as well as for animals caught in the wild in various regions of West Africa. The ELISA reached an accuracy of 97.1% in samples of known exposure, and a comparison to an immunofluorescence assay (IFA) revealed a very strong agreement between the ELISA and IFA results (Cohen’s kappa of 0.81). The agreement is valid in Nigeria, and in Guinea and Sierra Leone where the lineages II and IV are circulating, respectively. Altogether, these results indicate that this capture ELISA is suitable for LASV IgG serostatus determination in Mastomys rodents as an alternative to IFA. This assay will be a strong, accurate, and semi-quantitative alternative for rodent seroprevalence studies that does not depend on biosafety level 4 infrastructures, providing great benefits for ecology and epidemiology studies of Lassa fever, a disease listed on the Research and Development Blueprint of the WHO.

We phylogenetically compared sequences of the zoonotic Lassa virus (LASV) obtained from Mastomys rodents in seven localities across the highly endemic Edo and Ondo States within Nigeria. Sequencing 1641 nt from the S segment of the virus genome, we resolved clades within lineage II that were either limited to Ebudin and Okhuesan in Edo state (2g-beta) or along Owo-Okeluse-Ifon in Ondo state (2g-gamma). We also found clades within Ekpoma, a relatively large cosmopolitan town in Edo state, that extended into other localities within Edo (2g-alpha) and Ondo (2g-delta). LASV variants from M. natalensis within Ebudin and Ekpoma in Edo State (dated approximately 1961) were more ancient compared to those from Ondo state (approximately 1977), suggesting a broadly east-west virus migration across south-western Nigeria; a pattern not always consistent with LASV sequences derived from humans in the same localities. Additionally, in Ebudin and Ekpoma, LASV sequences between M. natalensis and M. erythroleucus were interspersed on the phylogenetic tree, but those from M. erythroleucus were estimated to emerge more recently (approximately 2005). Overall, our results show that LASV amplification in certain localities (reaching a prevalence as high as 76% in Okeluse), anthropogenically-aided spread of rodent-borne variants amidst the larger towns (involving communal accommodation such as student hostels), and virus-exchange between syntopic M. natalensis and M. erythroleucus rodents (as the latter, a savanna species, encroaches southward into the degraded forest) pose perpetual zoonotic hazard across the Edo-Ondo Lassa fever belt, threatening to accelerate the dissemination of the virus into non endemic areas.

Lassa fever is a viral hemorrhagic illness responsible for thousands of human deaths in West Africa yearly. Rodents are known as natural reservoirs of the causative Lassa mammarenavirus (LASV) while humans are regarded as incidental, spill-over hosts. Analysis of genetic sequences continues to add to our understanding of the evolutionary history, emergence patterns, and the epidemiology of LASV. Hitherto, the source of data in such investigations has mainly comprised human clinical samples. Presently, a rise in the quantity of virus strains accessed through ecological studies over the last 15 years now allows us to explore how LASV sequences obtained from rodents might affect phylogenetic patterns. In this study, we phylogenetically compared LASV sequences obtained from both rodents and humans across West Africa, including those from two localities highly endemic for the disease: Ekpoma in Nigeria and Kenema in Sierra Leone. We performed a time-calibrated phylogeny, using a Bayesian analysis on 198 taxa, including 102 sequences from rodents and 96 from humans. Contrary to expectation, our results show that LASV strains detected in humans within these localities, even those sampled recently, are consistently ancient to those circulating in rodents in the same area. We discuss the possibilities connected to this preliminary outcome. We also propose modalities to guide more comprehensive comparisons of human and rodent data in LASV molecular epidemiological studies.

Context: Multifunctional food protein-derived peptides attract a great deal of research interest due to their health-promoting benefits. Particularly, peptides that have both antihypertensive and antioxidant properties are desired, since both effects can be synergistic in prevention of cardiovascular diseases. Aim: The aim of this study was to investigate the angiotensin-I-converting enzyme (ACE) inhibitory and 2,2′-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activities of two species of the Nigerian periwinkles: Pachymelania aurita and Tympanotonus fuscatus. Methods: The ACE inhibitory and 2,2′-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activities of simulated gastrointestinal digestion (SGID) hydrolysates and ultrafiltered (UF) fractions of T. fuscatus var. radula and P. aurita were determined. Human SGID of the protein extracts of T. fuscatus and P. aurita was carried out using pepsin, trypsin, and chymotrypsin, and the hydrolysates were fractionated into two by centrifugal ultrafiltration. The ACE inhibitory and DPPH radical scavenging activities of the crude hydrolysates and UF fractions were tested. The UF permeates were observed to have relatively higher activities and was subjected to gel filtration chromatography on Sephadex G-50. The chromatographic fractions showed absorbance at 215, 225, and 280 nm and were assayed for DPPH radical scavenging activity. Results: The inhibitory effect of the fractions on ACE activity was reported as the minimum concentration of extract that caused 50% of the inhibition (IC50), where the IC50 values of P. aurita UF permeate and P. aurita UF retentate were 65.2 ± 6.4 and 301.9 ± 59.1 μg/ml, respectively, and that of T. fuscatus UF permeate (TFUFP) and T. fuscatus UF retentate were 54.93 ± 2.83 and 291.7 ± 8.6 μg/ml, respectively. Conclusion: This study suggests the potential health benefits of consuming T. fuscatus var. radula and P. aurita in health maintenance.

Aims: This study aimed to describe the prevalence and pattern of lipid abnormalities among antiretroviral therapy (ART)-naive HIV patients, understand if there is any relationship to virologic and immunologic status, and discuss the implications for care. Methods: This was a cross-sectional study in which baseline demographic, clinical, and laboratory data of all ART-naive HIV-infected individuals recruited into the adult ARV clinic, University College Hospital, Ibadan, between January and December 2006, were analyzed. Results: In total, 1316 ART-naive HIV-infected persons were recruited in the period. Females subjects and participants aged ≦35 years accounted for 67.1% and 57.7% of all participants, respectively. At least 1 abnormal lipid fraction was seen in 73.3% of participants. It was observed that in 11.5% participants the total cholesterol (TC) was ≧5.2 mmol/L, in 2.7% the low-density lipoprotein cholesterol (LDL)-C was >4.1 mmol/L in 56.5% the high-density lipoprotein cholesterol (HDL)-C was <1.0 mmol/L, and in 27.6% the triglyceride (TG) was >1.7 mmol/L. The TC, LDL-C, and HDL-C were all significantly positively correlated with CD4 counts and negatively correlated with viral load. On the contrary, the TG levels were negatively correlated with CD4 counts and positively correlated with viral load. Multivariate linear analysis showed a significant relationship between all the lipid parameters and viral load. CD4 counts were only significantly associated with TC. Conclusions: A significant burden of dyslipidemia exists among ART-naive HIV-infected persons. Low HDL-C was the most frequently observed abnormality. The abnormalities related more with viral load levels than with CD4 counts. Dyslipidemia screening should be done in ART-naive HIV-infected persons. Simple healthy lifestyle changes should be emphasized, with other care given to those with the disorder.