Infection pattern, case fatality rate and spread of Lassa virus in Nigeria.

Affiliation

Yaro CA(1)(2), Kogi E(3), Opara KN(4), Batiha GE(5), Baty RS(6), Albrakati A(7), Altalbawy FMA(8), Etuh IU(9), Oni JP(9).
Author information:
(1)Department of Animal and Environmental Biology, University of Uyo, Uyo, Akwa Ibom, Nigeria. [Email]
(2)Department of Zoology, Ahmadu Bello University, Zaria, Nigeria. [Email]
(3)Department of Zoology, Ahmadu Bello University, Zaria, Nigeria.
(4)Department of Animal and Environmental Biology, University of Uyo, Uyo, Akwa Ibom, Nigeria.
(5)Department of Pharmacology and Therapeutics, Faculty of Veterinary Medicine, Damanhour University, Damanhour, AlBeheira, 22511, Egypt.
(6)Department of Biotechnology, College of Science, Taif University, P.O. Box 11099, Taif, 21944, Saudi Arabia.
(7)Department of Human Anatomy, College of Medicine, Taif University, P.O. Box 11099, Taif, 21944, Saudi Arabia.
(8)National Institute of Laser Enhanced Sciences
(NILES), Cairo University, Giza, 12613, Egypt.
(9)Department of Animal and Environmental Biology, Kogi State University, Anyigba, Nigeria.

Abstract

BACKGROUND: Lassa fever (LF) is a zoonotic infectious disease of public concern in Nigeria. The infection dynamics of the disease is not well elucidated in Nigeria. This study was carried out to describe the pattern of infection, case fatality rate and spread of lassa virus (LASV) from 2017 to 2020. METHODS: Weekly epidemiological data on LF from December, 2016 to September, 2020 were obtained from Nigeria Centre for Disease Control. The number of confirmed cases and deaths were computed according to months and states. Descriptive statistics was performed and case fatality rate was calculated. Distribution and spread maps of LF over the four years period was performed on ArcMap 10.7. RESULTS: A total of 2787 confirmed cases and 516 deaths were reported in Nigeria from December, 2016 to September, 2020. Increase in number of cases and deaths were observed with 298, 528, 796 and 1165 confirmed cases and 79, 125, 158 and 158 deaths in 2017, 2018, 2019 and 2020 respectively. Over 60% of the cases were reported in two states, Edo and Ondo states. The LF cases spread from 19 states in 2017 to 32 states and Federal Capital Territory (FCT) in 2020. Ondo state (25.39%) had the highest of deaths rate from LF over the four years. Case fatality rate (CFR) of LF was highest in 2017 (26.5%) with CFR of 23.7, 19.6 and 13.4% in 2018, 2019 and 2020 respectively. The peak of infection was in the month of February for the four years. Infections increases at the onset of dry season in November and decline till April when the wet season sets-in. CONCLUSION: There is an annual increase in the number of LASV infection across the states in Nigeria. There is need to heighten control strategies through the use of integrated approach, ranging from vector control, health education and early diagnosis.