Lassa Fever: an Emerging and Re-emerging Fatal Viral Disease of Public Health Concern

Lassa fever is a life threatening infectious zoonosis of public health significance, and is caused by a single-stranded, linear, bi-segmented RNA virus belonging to the Arenaviridae family. The disease is transmitted by rodents, particularly the Natal mastomys (Mastomys natalensis). In terms of public health impact, Lassa fever outperforms Ebola, Marburg, and all other hemorrhagic fevers except Dengue. Lassa fever is endemic in Benin, Ghana, Guinea, Liberia, Mali, Sierra Leone, and Nigeria, although it is also thought to exist in other West African countries. Each year, it is thought to be responsible for up to 300,000 new infections and 5000 deaths in Western Africa. Lassa virus disease was named one of the world's top bio-threats by the global Coalition for Epidemic Preparedness (CEPI) in 2017. Humans are most typically infected through the ingestion or inhalation. Nosocomial infection is also noticed. Very recently, an outbreak of Lassa fever was confirmed in Togo. However, when symptomatic, fever, general malaise and weakness, headache, hemorrhaging (in the gums, eyes, or nose, for example), respiratory distress, frequent vomiting, face swelling, discomfort in the chest, back, and abdomen; and shock occur. Deafness is the most common complications of Lassa fever. The fatality rate in the hospitalized patients may reach 15 to 20 %. There are a variety of virus diagnostic techniques available, ranging from viral culture to serological and molecular diagnostic testing. There are currently no FDA-approved vaccinations for Lassa fever, and therapy options are exceedingly restricted. Early supportive care, such as rehydration and symptomatic treatment, improves survival prospects.