Lassa Fever in a Time of Coronavirus in Nigeria

These are still early days for coronavirus in Nigeria, whose first case was reported on February 25. As of the morning of March 24, Nigeria had forty-two confirmed cases and one confirmed death, according to coronavirus tracking by Johns Hopkins University. But an outbreak of Lassa fever, caused by a more common virus, has been active in Nigeria for the past few months and has even prompted calls for the declaration of a national health emergency.

Between January 1 and March 15, the Nigerian Center for Disease Control reported 161 deaths of Lassa fever patients, with 3,735 suspected cases and 906 confirmed cases, across twenty-seven of Nigeria’s thirty-six states. For the same period in 2019, Lassa killed 114 with 1801 suspected cases and 455 confirmed cases across twenty-one states, but the 906 confirmed cases for 2020 is already greater than the 810 confirmed cases for all of 2019. Lassa fever is known to have a case fatality rate as high as 23 percent, much higher than the 3.4 percent estimated by the WHO for COVID-19 as of March 5. There have even been calls for the Nigerian government to declare a state of emergency for Lassa fever. Explanations for the rising number of Lassa fever cases since 2015, when there were just sixty-four confirmed cases, includes both better diagnosis and increasingly poor sanitation and living situations. Thus far, there is no evidence of a link between the two diseases. 

Lassa fever is named after the Nigerian town where it was first identified in 1969. It is an acute viral disease of animal origins with early symptoms similar to malaria and COVID-19. It is now found in other West African countries. Epidemics have historically occurred during the dry season, which runs roughly from November to April. According to the U.S. Centers for Disease control, during various periods, Lassa fever patients accounted for between 10 and 16 percent of hospital admissions in parts of Sierra Leone and Liberia. Though crude, such estimates help illustrate the potential impact outbreaks of Lassa fever can have on West African health systems. 

In Nigeria, as elsewhere, the disease is disproportionately found among younger adults, between twenty and thirty years of age. The most devastating consequences of the disease can be deafness. The most common vector for the disease is the urine and feces of the multimammate rat, a rodent found in rural areas that colonizes areas where people live and where food is available. The disease can be transmitted from human to human through contact with bodily fluids, but not as easily as Ebola or coronavirus. Lassa can be treated with an antiviral drug and by supportive care. Its victims in hospitals are typically isolated, so that they may compete for space with coronavirus patients. 

The spread of coronavirus has led to the World Health Organization, African governments, and non-governmental organizations to publicize the underdeveloped public health systems in most African countries and to request international assistance. There has been already some international response. But for many Africans, the coronavirus, like the much deadlier Ebola or HIV/AIDS epidemics, are seen in the context of more common diseases that sicken many more people, have high mortality rates, but that do not receive sustained attention from outsiders. Indeed, many observers are concerned that the appearance of the high profile disease caused by coronavirus, COVID-19, will divert precious resources away from the more commonplace killers. This season’s outbreak of Lassa fever—the worst such outbreak in years—is a case in point.