Epidemiological Trends of Lassa Fever Outbreaks and Insights for Future Control in Nigeria

Abstract

The pattern of Lassa fever outbreaks in Nigeria over the years is worrisome and increasingly becoming more challenging with frequent and widening geographical spread. Lassa fever is endemic and fast becoming hyper-endemic in Nigeria. It affects the largest number of people, creating a geographical network of endemic foci encompassing a population of perhaps 180 million from Guinea to Nigeria. Lassa fever presents signs and symptoms indistinguishable from those of febrile illnesses such as malaria and other viral haemorrhagic fevers such as Ebola. Frequent human exposure to the virus is therefore possible due to the human population explosion in the endemic area and therefore given opportunities for infection with this virus, and subsequently the disease. Clinical diagnosis of Lassa fever is difficult however it should be suspected in patients showing fever with temperature (≥ 38°C) not responding adequately to antimalarial and antibiotic treatments. Laboratory diagnosis by serological, cell culture and molecular techniques is reliable although very expensive. For now there is supportive treatment but no licensed vaccine yet; therefore, public awareness and advocacy are vital in educating and sensitizing the citizenry on the risk associated with overcrowding and unhygienic practices both in our communities and health institutions in Nigeria and its environs. This review summarizes the trends and pattern of outbreaks of Lassa fever in Nigeria and other aspects of diagnosis and prevention including reasons for the lack of a vaccine and proposes plans to prevent future outbreaks.