Lassa fever thrives in Edo, Ondo, and Bauchi states in the past 5 years

Ondo, Edo, Bauchi, and occasionally Kogi and Ebonyi still have the highest prevalence of Lassa fever in Nigeria. The majority of Lassa fever cases and related fatalities have occurred in these states.

In the latest data from the Nigeria Centre for Disease Control and Prevention (NCDC) for the epidemic week 27 in 2023, 170 people died from Lassa fever.

The majority, 73 per cent, of all confirmed Lassa fever cases were reported from these three states (Ondo, Edo, and Bauchi) so far in 2023. 

In contrast, 27 per cent were reported from 25 states with confirmed Lassa fever cases. 

Lassa fever is an acute viral disease transmitted by the common African rat and is animal-borne. There are areas in West Africa where it is endemic, including Sierra Leone, Liberia, Guinea, and Nigeria. 

This disease was first identified after the deaths of two missionary nurses in Nigeria in 1969. The virus is called after the Nigerian town where the initial cases were reported.

Since the beginning of 2023, the Nigeria Center for Disease Control and Prevention (NCDC) has reported about 990 cases in 108 local governments and 28 states. 170 deaths were recorded among the 990 epidemic cases from week 1 to week 27. 

Lassa fever history during the past five years

In 2023, These three states, Ondo, Edo, and Bauchi, accounted for 73% of all confirmed Lassa fever cases. Ondo reported 33% of the 73% verified cases, Edo reported 29%, and Bauchi reported 11%.

For 2022, 111 Local Government Areas in 27 States had at least one confirmed case. 71% of confirmed cases originated in Ondo (33%), Edo (25%), and Bauchi (13%).

In 2021, 68 Local Government Areas in 17 States had at least one confirmed case reported. 84% of all reported cases originate from Edo (42%), Ondo (34%), and Bauchi (8%).

244 fatalities were recorded in 2020. At least one verified case has been reported by 27 States from over 131 Local Government Areas. A 75% of confirmed cases were from the states of Ondo (36%), Edo (32%) and Ebonyi (7%).

Why is Lassa fever more prevalent in these states?

Ecological factors in these states might be responsible for the widespread Lassa fever in Ondo, Edo, Bauchi and Ebonyi. Mastomys natalensis, also known as multimammate rats are known to carry the Lassa virus. The ecological circumstances of Ondo, Edo, and Bauchi states are ideal for these rodents, which makes it simpler for the virus to circulate and propagate.

Underreporting illnesses and delays in receiving necessary medical care can also be another reason for the high rate of Lassa fever in these states; this may be caused by insufficient access to healthcare facilities, a lack of knowledge about Lassa fever, and difficulties in diagnosing the condition. 

Poor hygiene and sanitation practices, population, and cultural and agricultural practices are other factors that might be responsible for the high prevalence of Lassa fever in some areas.

Research on the variables influencing the increased prevalence in these areas which would aid in the development of preventative and control efforts is currently needed in these areas.

Controlling Lassa fever in Nigeria necessitates a thorough and multifaceted approach that includes various strategies for prevention, surveillance, education, and treatment and sustained efforts and resources from various stakeholders, including government organisations, healthcare providers, communities, and international partners.