Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2024 Dec 18;24(1):3470.
doi: 10.1186/s12889-024-20840-y.

Descriptive epidemiology of Lassa fever, its trend, seasonality, and mortality predictors in Ebonyi State, South- East, Nigeria, 2018-2022

Adanna Ezenwa-Ahanene  1   2   3 , Adetokunbo T Salawu  4 , Ayo S Adebowale  4   5
Affiliations

Descriptive epidemiology of Lassa fever, its trend, seasonality, and mortality predictors in Ebonyi State, South- East, Nigeria, 2018-2022

Adanna Ezenwa-Ahanene et al. BMC Public Health. .

Abstract

Background: Nigeria is an epicenter for Lassa fever. Ebonyi state is located in the South-Eastern region of Nigeria where a high burden of Lassa fever has been reported. Therefore, this study was designed to assess the epidemiology of Lassa fever, its seasonality, trend, and mortality predictors in Ebonyi state, South-East, Nigeria.

Method: We analyzed data extracted from Ebonyi State Integrated Disease Surveillance and Response (IDSR) system over five years (2018-2022). A total of 1578 reported Lassa fever cases were captured in the IDSR out of which 300 were laboratory-confirmed. Data were analyzed using descriptive statistics, additive time series model, quadratic equation, and logistic regression model (α0.05). Spatial distribution of reported Lassa fever cases was conducted using Arc G.I.S.

Results: The mean age of the individuals with the reported cases of Lassa fever was 29.4 ± 17.8 years. Lassa fever showed a seasonal trend across the years. The quadratic model provided the best fit for predicting Lassa fever cumulative cases (R2 = 98.4%, P-value < 0.05). Projected cases of Lassa fever for the year 2023 were 123 in the 1st quarter, 23 in the 2nd quarter, 42 in the 3rd quarter, and 17 in the 4th quarter. The seasonality index was + 70.76, -28.42, -9.09, and -33.2 in the 1st, 2nd, 3rd, and 4th quarters respectively. The reported cases of Lassa fever followed a declining trend (slope = -0.1363). Farmers were 70% less likely to die from Lassa fever compared to those not working (aOR:0.3, CI: 0.17-0.83). The hot spots for Lassa fever were Abakaliki and Ezza Local Government Areas.

Conclusion: Although the reported Lassa fever cases followed a declining trend in Ebonyi state, there was a seasonality in the disease pattern. Being a farmer was protective against the risk of dying from Lassa fever. While efforts to eliminate and mitigate the spread of the disease in Ebonyi state should be strengthened, more attention should target the peak period of the disease.

Keywords: Ebonyi State; Lassa fever; Seasonality; Time series analysis.

PubMed Disclaimer

Conflict of interest statement

Declarations. Ethics approval and consent to participate: Ethical approval for this study was obtained by the data originators from the Ebonyi State Ministry of Health (EBSHREC/01/04/2022–02/04/2024). Consent for publication: Not applicable. Competing interests: The authors declare no competing interests.

Figures

Fig. 1
Fig. 1
Geographic distribution of Lassa fever in West Africa. Source: http://www.who.int/emergencies/diseases/lassa-fever/geographic-distribution
Fig. 2
Fig. 2
Flow of Integrated Disease Surveillance and Response (IDSR) data in Nigeria. Source: National technical guidelines for integrated diseases surveillance and response, Nigeria
Fig. 3
Fig. 3
Geographical Distribution of Reported and Confirmed Lassa Fever Cases by Local Government Areas in Ebonyi State, 2018 – 2022
Fig. 4
Fig. 4
Monthly Number and Trend Line of Reported Cases of Lassa-Fever in Ebonyi State, 2018 – 2022
Fig. 5
Fig. 5
Quarterly number and 3-Quarter Moving Average of Reported Cases of Lassa-Fever in Ebonyi State, 2018 – 2022
Fig. 6
Fig. 6
Lassa Fever Observed and Fitted Cumulative Cases in Ebonyi State, 2018–2022
Fig. 7
Fig. 7
Graphical Display of the Observed and Predicted Cumulative Reported Cases of Lassa Fever in Ebonyi State, 2018–2022
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

References

    1. Adebowale AS, Afolabi RF, Bello S, Salawu MM, Bamgboye EA, Adeoye I, Dairo MD, Kivumbi B, Wanyana I, Seck I, Diallo I, Leye MMM, Bassoum O, Fall M, Ndejjo R, Kabwama SN, Mapatano MA, Bosonkie M, Egbende L, … Fawole OI. Spread and seasonality of COVID ‑ 19 pandemic confirmed cases in sub ‑ Saharan Africa : experience from Democratic Republic. BMC Infect Dis 2023;1–12. 10.1186/s12879-023-08168-1 - PMC - PubMed
    1. Adebowale AS, Fagbamigbe AF, Akinyemi JO, Obisesan OK, Awosanya EJ, Afolabi RF, Alarape SA, Obabiyi SO. The spread of COVID-19 outbreak in the first 120 days : a comparison between Nigeria and seven other countries. 2021:1–8. - PMC - PubMed
    1. Agbonlahor DE, Akpede GO, Happi CT, Tomori O. 52 Years of Lassa Fever Outbreaks in Nigeria, 1969 – 2020: an epidemiologic analysis of the temporal and spatial trends. 2021;105(4):974–985. 10.4269/ajtmh.20-1160 - PMC - PubMed
    1. Akhmetzhanov AR, Asai Y, Nishiura H. Quantifying the seasonal drivers of transmission for Lassa fever in Nigeria. Philos Transact Royal Soc B: Biolog Sci 2019;374(1775). 10.1098/rstb.2018.0268 - PMC - PubMed
    1. Aloke C, Obasi NA, Aja PM, Emelike CU, Egwu CO, Jeje O, Edeogu CO, Onisuru OO, Orji OU, Achilonu I. Challenges, and future perspectives. 2023;1–25. - PMC - PubMed

LinkOut - more resources