2016/2017 Lassa fever outbreak in Nigeria: age and sex have no effect on treatment outcome

Abstract

Introduction : lassa fever is an endemic Viral Hemorrhagic Fever (VHF) in Nigeria. Improvements in case detection and treatment outcome could be achieved by understanding the transmission dynamics better and applying the lessons from previous outbreaks considering the resource constrained setting. This study assessed age-sex disparities in treatment outcome using data from 2016/2017 lassa fever outbreak surveillance in Nigeria. Methods : lassa fever surveillance and outcome data from December 2016 to May 2017 from 14 States was extracted from the VHF platform. Univariate and bivariate analysis were carried out using Epi info 7 for socio-demographics and treatment outcome. Possible association between treatment outcome and selected variables (age, sex) were analyzed using Chi square at 0.05 level of significance. Results : there were 168 confirmed cases of Lassa fever during the study period, data was complete for 139 (82.7%). More men were affected (56%), as 61 of the 139 patients (46%) were female. The median age for all the patients treated was 32 years (IQR 25 - 44). Symptoms at presentation prior to treatment included fever (67%), nausea and vomiting (34.5%), diarrhea (14.4%), and intense fatigue (39%) while only 10.8% experienced unexplained bleeding. A total of 75 (54%) patients were treated and discharged alive, while 64 (46%) died. No significant association was found between gender and treatment outcome (p value = 0.976). Although survival was higher among patients aged 15 to 24 years (72%) and lowest among patients who were 45 years and above (35%), age of the patient was not significantly associated with the adverse treatment outcome (p-value = 0.06). Conclusion : for the 2016/2017 lassa fever outbreak in Nigeria, age and sex did not influence the treatment outcome of the recorded cases. There is a need for further analysis and more large scale studies on Lassa fever treatment outcomes.