Predictors, Prevalence and Spatial Analysis of Lassa Virus among Household Rodents in a Low Socioeconomic Community in Southwestern Nigeria

Lassa fever is an acute viral endemic disease of public health importance in West Africa. The main reservoir for Lassa virus is the multimammate mouse, Mastomys natalensis. Due to increased outbreaks of Lassa fever, investigations for the presence of this virus in household rodents are pertinent. This study assessed the predictors and prevalence of the Lassa virus, providing spatial analysis of the virus among household rodents. Atotal of 35 households were systematically sampled. Traps were placed in each of the sampled households for four weeks and rodents captured were identified using morphological characteristics. The viral screening was done on trapped rodents using reverse transcriptase-polymerase chain reaction (RT-PCR) with primers targeting the s-gene of the virus. Maps arising from the spatial analysis were generated using ArcMap 10.1 to show rodentinfested areas and areas prone to an outbreak of the disease. The frequency of rodents captured was presented in percentages. A total of forty-four (44) rodents were captured. Three species of rodents were trapped from the selected households with Rattus rattus(43.2%) being the dominant species in the households followed by Rattus fuscipes (38.6%) and Rattus norvegicus (18.2%). From the PCR results, two samples of the Rattus rattus tested positive followed by Rattus fuscipes and Rattus norvegicus which had one rodent each, respectively testing positive for the virus. Geo-spatial maps were generated to show rat infestation density and areas prone to an outbreak.Common household rodents such as Rattus rattus, Rattus fuscipes, and Rattus norvegicustested positive and these species of rodent were previously not known to be a host. Therefore, awareness should be encouraged.