Lassa fever is an acute viral illness caused by the Lassa virus, endemic in several West African countries. Transmitted mainly through contaminated food or contact with infected rodents, the disease has a 1% case fatality rate, increasing up to 15% in severe cases. Early supportive care can reduce mortality. There are no approved antiviral treatments or vaccines, though research is ongoing. Prevention focuses on hygiene practices and healthcare precautions.
Key Facts about Lassa Fever
Lassa fever is a viral illness caused by the Lassa virus, predominantly found in West Africa, including countries like Benin, Ghana, Guinea, Liberia, Mali, Nigeria, and Sierra Leone. The virus primarily transmits through contact with contaminated food or items, particularly those contaminated by rodent urine or feces. Although the average case fatality rate is around 1%, it can rise to over 15% in patients with severe conditions. Early supportive care significantly improves survival rates.
Overview of Lassa Fever
Identified in 1969, Lassa fever is a zoonotic disease linked to the Mastomys rodent species, which typically carries the virus without showing symptoms. About 80% of infections present mild or no symptoms, while 20% can lead to severe illness affecting multiple organs. Early detection, isolation, and hygiene practices are crucial for curtailing disease spread in communities.
Transmission of the Virus
Human infections primarily occur through exposure to contaminated food or direct contact with infected Mastomys rodents. While person-to-person transmission is less common, it can occur, particularly in healthcare settings through direct contact with infected bodily fluids. The virus may remain in the semen of male survivors for several months, though no transmission via semen has been documented. There is no evidence of airborne spread.
Symptoms of Lassa Fever
Symptoms typically appear between 2–21 days post-exposure, beginning with fever, weakness, and malaise. Severe cases may escalate to serious complications including bleeding, shock, seizures, and low blood pressure. Maternal mortality rates are particularly high among pregnant women in their third trimester. Lasting effects post-recovery may include hearing loss and neurological complications, warranting ongoing medical care for affected individuals.
Diagnosis
Distinguishing Lassa fever from other infectious diseases can be challenging. Diagnostic confirmation typically employs methods such as RT-PCR, ELISA, and viral isolation techniques. Due to the biohazard risk posed by samples, testing must occur under strict safety protocols in specialized facilities.
Treatment Options
Currently, there is no specific antiviral drug for Lassa fever, although ribavirin has been administered with uncertain efficacy. Patients should ideally participate in clinical trials for potential treatments. No licensed vaccine exists yet, but research is ongoing to develop effective vaccines.
Preventive Measures
Preventing Lassa fever focuses on minimizing rodent-human contact and ensuring proper hygiene in the community. Measures include using rodent-proof containers for food, maintaining clean living spaces, and ensuring safe food preparation. In healthcare environments, standard infection control precautions should always be practiced. Timely recognition and treatment of suspected cases can enhance survival rates and reduce transmission risks.
Travel Considerations and WHO’s Role
Healthcare providers should consider Lassa fever in febrile patients returning from endemic regions. WHO collaborates with affected countries to bolster preparedness and response initiatives, enhancing surveillance, clinical management, laboratory services, and community engagement. Expanding knowledge on diagnostics and therapeutics remains crucial for effective management and mortality reduction.
Lassa fever poses significant health risks, particularly in endemic regions of West Africa. Its transmission primarily through contact with infected rodents highlights the critical importance of public health measures, including hygiene and quick case recognition. Current treatment options are limited, necessitating continued research and development of vaccines and effective therapeutics. The role of health authorities, including the WHO, is essential in coordinating responsive efforts to mitigate the spread and impact of Lassa fever.
Original Source: www.who.int
