Molecular Detection and Characterisation of Lassa Fever Virus among Patients Attending Tertiary Hospitals in Jos, Central Nigeria

Background: Lassa fever is a highly contagious viral haemorrhagic fever that was first identified in 1969 following lethal infection of a missionary in Lassa, North eastern Nigeria.

Aim: The aim of the study was to carry out molecular detection and characterisation of Lassa viruses in Jos.

Study Design: Cross sectional study.

Materials and Methods: We targeted patients presenting with Lassa fever-like symptoms, including people who had lived in close association with them in Jos, central Nigeria. A total of 156 blood samples were collected from consented participants.

Results: Lassa IgG and IgM was detected using ELISA technique while S- RNA gene of Lassa virus was detected using RT-PCR. Partial sequencing and phylogenetic analysis of the S-RNA gene was done using appropriate tools. A Lassa virus seroprevalence of 24% was established in the study area. RT-PCR detected Lassa virus S-gene in 8 (5.1%) samples, while gene sequencing and phylogenetic analysis showed Lassa virus strains aligning with lineages II and III of Lassa viruses in the GenBank. Statistically, a positive correlation (r=0.057) among suspected cases and exposed subjects was established. Also, a negative correlation (r= -0.005) was seen among outcome of serology and molecular detection among suspected cases while a positive correlation (r= 0.086) was observed in the sub-population of suspected cases with regards to outcome of serology and molecular detection.

Conclusion: The discovery of Lassa strains aligning with lineage II Lassa viruses in GenBank is novel and remains the first report on the strains in central Nigeria. Similar work is recommended in other regions of the country.