Lassa - A Latent Threat to West Africa: How Ready Are We?

Sir,

The 2013–2016 Ebola virus epidemic in West Africa has unfortunately become a costly lesson in dealing with an infectious disease outbreak in situations when both the exposed population and the international community are unprepared.[1] Lassa virus belongs to the Old World complex of the family Arenaviridae that causes hemorrhagic fever in humans. It is endemic in Sierra Leone, Nigeria, Guinea, and Liberia. Since its discovery in 1969 in Nigeria, rural and nosocomial outbreaks have been reported to occur repeatedly in Sierra Leone: Panguma and Kenema; Liberia: Zorzor, Phebe, and Ganta, and Nigeria: Jos, Onitsha, Zonkwa, Vom, Imo, Lafia, Irrua, and Abakaliki [Figure 1].[2] The reservoir host of the virus is the multimammate rat Mastomys natalensis. An epidemiological study revealed that majority of the cases occurs between October and February, suggesting epidemic favorable by dry season and reported fatality rate of 29%.[3] A more recent oversea cross-border infection has been reported in February 2 and March 3, 2016 in Germany.[4] As of June 9, 2017, a total of 501 suspected cases including 104 deaths have been reported since the onset of the current Lassa fever outbreak season in 2016 in Nigeria. Of these reported cases, 175 have been confirmed including 59 deaths.[5] More so, Benin Republic and Togo have reported new cases on February 20 and February 26, respectively.[5]

Figure 1

Risk map of Lassa fever

European governments have been summoned to mobilize resources to challenge Ebola outbreak in West Africa. In similar vein, we call on West African governments to rise up to this public health concern and as well prepare for eventual widespread epidemic like the last Ebola virus epidemic. The initial interest following the report of Lassa fever epidemic in 1969 waned considerably.

While the Lassa crisis is still latent, we identify the need for field-based laboratories, epidemiological surveillance resources, public health education, and diagnostic equipment. As revealed by the last Ebola outbreak, the West African subregion is vulnerable considering the lack of adequate health-care infrastructure required for such public health challenge.

Unlike North America and Europe where Biosafety Level-4 (BSL-4) laboratories do network, such concrete partnership is still loose and scanty in the West African subregion. BSL-4 laboratories should design proper communication channels with all the health institutions to ensure containing probable cases and as well network with each other to brainstorm emergency response program.

In the event of Lassa outbreak, in the West African subregion, it could be catastrophic considering the fact that region is a malaria-endemic region. Early differential diagnosis of the Lassa fever from other causes of febrile fever (including malaria) may result in large number of deaths in the initial stage. Point-of-care testing using rapid diagnosis kits such as ReLASV would be very useful for screening of suspicious cases while at the same time build network with lesser logistic bottlenecks with standard test centers.

It is of necessity to coordinate this West African crusade against Lassa in synergy with international organizations such as World Health Organization, United States Agency for International Development, European Centre for Disease Prevention and Control, and more. The West African Health Organization should champion this cause.

In synchronization with the fight against HIV/AIDS, we urge all West African governments to wake up to this call. Lassa epidemic is a public health concern. If the latest state is unchecked, we may have another regional and even global outbreak. The Lassa virus has lived long with us.

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Conflicts of interest

There are no conflicts of interest.