Monitoring of Lassa virus infection in suspected and confirmed cases in Ondo State, Nigeria

Introduction: Lassa virus (LASV), the causative agent of Lassa fever (LF), an endemic acute viral haemorrhagic illness in Nigeria, is transmitted by direct contact with the rodent, contaminated food or household items. Person-to-person transmission also occurs and sexual transmission has been reported. Thus, this study investigated the presence of LASV in body fluids of suspected and confirmed cases. Methods: this was a cross-sectional study between March 2018 and April 2019 involving 112 consenting suspected and post ribavirin confirmed cases attending the Lassa fever treatment center in Ondo State. Whole blood was collected from 57 suspected and 29 confirmed cases. Other samples from confirmed cases were 5 each of High Vaginal Swab (HVS) and seminal fluid; 12 breast milk and 4 urine. All samples were analyzed using reverse transcription-PCR (RT-PCR) targeting the S-gene of LASV. Results: analysis of whole blood by RT-PCR showed that 1/57 (1.8%) suspected and 1/29 (3.4%) confirmed post ribavirin treated cases were positive. While LASV was detected in 2/5 (40%) post ribavirin treated seminal fluids and 1/11 (8.3%) breast milk. However, LASV was not detected in any of the HVS and urine samples. Conclusion: the detection of LASV in seminal fluid and breast milk of discharged post ribavirin treated cases suggests its persistence in these fluids of recovering Nigerians. The role of postnatal and sexual transmissions in the perennial outbreak of LF needs to be further evaluated

Saliva all positive figures.

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Age and sex distribution of study participants (n = 299).

Age and sex distribution of study participants (n = 299).</p

SARS-CoV-2 positivity by gender and sample type.

SARS-CoV-2 positivity by gender and sample type.</p

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Raw data and analysis.

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Fig 1 -

Cycle Threshold (Ct) values for SARS-CoV-2 positivity to (A) E-gene, (B) N-gene, and (C) Orf1ab gene respectively, show good comparison on both the Saliva and the Nasopharyngeal swab: The median Cycle Threshold (Ct) values for the three SARS-CoV-2 genes (E, N, and Orf1ab) of the positive samples (Ct 40) from both the nasopharyngeal swab and saliva samples were compared using the Wilcon signed rank exact test. The p values of 0.07715, 0.8438, and 0.2293 were determined for the E, N, and Orf1 ab genes respectively. There were no statistically significant differences between the median SARS-CoV-2 E-gene, N-gene, and Orf1ab gene Ct values detected for the Nasopharyngeal swab and Saliva samples.</p

Relationship of SARS-CoV-2 positivity with gender and age groups.

Relationship of SARS-CoV-2 positivity with gender and age groups.</p