Molecular Detection of Leptospira spp. in Rodents Trapped in the Mozambique Island City, Nampula Province, Mozambique

EC Microbiol. 2018 Dec;14(12):813-821. Epub 2018 Nov 27.


Introduction: Leptospirosis is a neglected zoonotic disease caused by a bacteria of the genus Leptospira. In Africa it is frequently mistaken for frequently occurring conditions such as malaria. The aim of this study was to identify rodent species involved in the transmission of the disease, the prevalence of pathogenic Leptospira spp. in selected rodent species and risk factors for human leptospirosis.

Material and methods: We conducted a descriptive and exploratory epidemiological and molecular study in Mozambique Island city in 2015. Six neighborhoods, comprising 30 households each were randomly selected. People from the selected 180 households were interviewed regarding their awareness of the disease, the presence of rodents in their houses, chemicals used to eliminate them, sewage disposal, water supply system, and other key issues related to the disease. In each neighborhood we trapped 10 rodents for morphometric study to identify their species and for molecular isolation of Leptospira DNA. We extracted kidneys from 57/60 of rodents trapped, and performed nested polymerase chain reaction targeting rrs 16S ribosomal DNA and lipL32 genes for identification of Leptospira genus and pathogenic Leptospira spp. respectively.

Results: Of the 180 participants 92 (51%) reported having heard of leptospirosis; 107 (59%) have had the disease; 151 (83%) reported the existence of rats in their house; 100 (56%) had latrines; 118 (66%) used chemicals to kill the rats; 102 (57%) used well water and 114 (63%) used trash containers. The most prevalent rodent species captured was Rattus norvegicus 36/60 (60%), followed by Rattus rattus 19/60 (31.67%) and Mus musculus 3/60 (5%). rrs 16S ribosomal DNA was identified in 20/57 (35.%) rodents. Out these two were positive for lipL32 gene, giving an overall pathogenic Leptospira infection of 3.5% (2/57). The rodent species identified as carriers of pathogenic Leptospira were Rattus norvegicus (1) and R. rattus (1).

Conclusion: This is the first study in Mozambique to identify the presence of pathogenic species of Leptospira using molecular tools. Leptospirosis risk factors in Mozambique Island city are rodent's infestation, limited disease awareness, lack of access to clean water, insufficient resources for waste collection, greater clustering of households, poor sanitation environment and degradation of living conditions. Pathogenic Leptospira spp. are present in the area studied and at least two species of rodents, the R. rattus and R. norvegi-cus are potentially involved in the transmission of the causal agents of the disease.

Keywords: Leptospirosis; Mozambique; Nested-PCR; Rodents Species; lipL32; rrs16S.