kIncubation period: 1-3 weeks

kEpidemiology: Lassa fever occurs in West Africa mainly in the countries of Guinea, Liberia, and Sierra Leone. The virus was discovered in 1969 in Nigeria. In areas where the virus is endemic it is a significant cause of morbidity and mortality. Up to 20% of cases involve severe multisystem disease and up to 50% of cases are fatal during epidemics.

kSymptomology and Outcomes: Symptoms of Lassa Fever include fever, retrosternal pain, sore throat, back pain, cough, abdominal pain, vomiting, diarrhea, conjuctivitis, facial swelling, proteinuria, and mucosal bleeding. The varied symptoms caused by this virus make clinical diagnosis difficult. In 80% of cases, there are either mild or no observable symptoms. Complications of LV include deafness/hearing loss (in one third of cases) and spontaneous abortions. Lassa virus has a mortality rate of 1% but is highly fatal in pregnant women and 95% fatal in fetuses.

kPathology and Pathogenesis: Virus titers are highest in the brain, liver, ovary, pancrease, uterus, and placenta, however no significant pathological or functional lesions are found in these locations

kPrevention and Management: Lassa virus is best prevented by avoiding contact with Mastomys rodents, the rodents that carry the virus. Food should be kept in rodent proof containers to deter rodent infestation. Also, person-to-person contact should be avoided with infected patients. Treatment for the virus is supportive for symptoms. The antiviral, ribavirin can be administered in the early stages of infection to curb the viruses effects.