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Available from: Sunday Omilabu, Oct 02, 2015
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    • "Understanding the incidence and distribution of LF has been hampered by lack of easily-available diagnostics and limited public health surveillance infrastructure in the region [5]. LF is best characterized in areas with research programs focusing on the disease, particularly central and southern Nigeria and eastern Sierra Leone [5], [6]. Beyond these focal areas of surveillance activity, estimates of LASV distribution are coarse, providing little basis for inference into intervening areas of West Africa. "
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    ABSTRACT: Lassa fever is a disease that has been reported from sites across West Africa; it is caused by an arenavirus that is hosted by the rodent M. natalensis. Although it is confined to West Africa, and has been documented in detail in some well-studied areas, the details of the distribution of risk of Lassa virus infection remain poorly known at the level of the broader region. In this paper, we explored the effects of certainty of diagnosis, oversampling in well-studied region, and error balance on results of mapping exercises. Each of the three factors assessed in this study had clear and consistent influences on model results, overestimating risk in southern, humid zones in West Africa, and underestimating risk in drier and more northern areas. The final, adjusted risk map indicates broad risk areas across much of West Africa. Although risk maps are increasingly easy to develop from disease occurrence data and raster data sets summarizing aspects of environments and landscapes, this process is highly sensitive to issues of data quality, sampling design, and design of analysis, with macrogeographic implications of each of these issues and the potential for misrepresenting real patterns of risk.
    PLoS ONE 08/2014; 9(8):e100711. DOI:10.1371/journal.pone.0100711 · 3.23 Impact Factor
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    ABSTRACT: Recent Lassa virus strains from Nigeria were completely or partially sequenced. Phylogenetic analysis revealed the predominance of lineage II and III strains, the existence of a previously undescribed (sub)lineage in Nigeria, and the directional spread of virus in the southern part of the country. The Bayesian analysis also provided estimates for divergence times within the Lassa virus clade.
    Journal of clinical microbiology 12/2010; 49(3):1157-61. DOI:10.1128/JCM.01891-10 · 3.99 Impact Factor
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    ABSTRACT: To estimate the burden of Lassa fever in northern and central Edo, a state in south Nigeria where Lassa fever has been reported. Blood samples were obtained from 60 patients hospitalised at the Irrua Specialist Teaching Hospital (ISTH), Irrua, with a clinical suspicion of Lassa fever and from 451 febrile outpatients seen at the ISTH and hospitals in Ekpoma, Iruekpen, Uromi, Auchi and Igarra. All samples were tested retrospectively by Lassa virus-specific RT-PCR. Outpatients were additionally screened for Lassa virus-specific antibodies by indirect immunofluorescent antibody assay. Lassa virus was detected in 25 of 60 (42%) patients with a clinical suspicion of Lassa fever. The disease affected persons of all age groups and with various occupations, including healthcare workers. The clinical picture was dominated by gastrointestinal symptoms. The case fatality rate was 29%. Lassa virus was detected in 2 of 451 (0.44%) febrile outpatients, and 8 (1.8%) were positive for Lassa virus-specific IgG. Lassa fever contributes to hospital mortality in Edo State. The low prevalence of the disease among outpatients and the low seroprevalence may indicate that the population-level incidence is not high. Surveillance for Lassa fever should focus on the hospitalised patient.
    Tropical Medicine & International Health 05/2012; 17(8):1001-4. DOI:10.1111/j.1365-3156.2012.03010.x · 2.33 Impact Factor
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