Beware of Lassa Fever

Mar 1, 2012 at 11:33 am in Featured, General, Health, Lagos by mayowa O. · Tags: , ,

There have been reported cases of Lassa fever outbreak in some parts of Lagos state and we wanted to bring it to your knowledge and also to discuss ways to avoid getting the disease.

The disease, Lassa viral haemorrhagic fever, is an acute illness of 1-4 weeks duration that occurs in parts of West Africa including Nigeria. The virus, which is a single-stranded RNA virus belonging to the virus family Arenaviridae, is a zoonotic disease; meaning that humans become infected from contact with infected animals. The host, of Lassa virus is a rodent of the genus Mastomys, commonly known as the “multimammate rat.” Mastomys infected with Lassa virus do not become ill, but they can shed the virus in their excreta (urine and faeces).

About 20% of human infections have severe multi-system disease, where the virus affects several organs in the body, such as the liver, spleen and kidneys. The incubation period of Lassa fever ranges from 6-21 days. The onset of the disease is usually gradual, starting with fever, general weakness, and malaise but after a few days, headache; sore throat; muscle pain; chest pain; nausea; vomiting; diarrhea; cough; and abdominal may follow. Severe cases may progress to show facial swelling, fluid in the lung cavity, bleeding from mouth, nose, vagina or gastrointestinal tract, and low blood pressure. Protein may be noted in the urine. Deafness, Shock, seizures, tremor, disorientation, and coma may be seen in the late stages.

Certain varieties of Mastomys often live in human homes, the virus is easily transmitted to humans. Health care workers are at risk if proper barrier nursing and infection control practices are not maintained.

Transmission: Transmission to humans occurs via direct contact with rat urine, feces, and saliva; via contact with excretion- or secretion-infected materials; or via ingestion of excretion-contaminated food. Lassa virus may also be spread between humans through direct contact with the blood, urine, faeces, or other bodily secretions of a person with Lassa fever. There is no concrete evidence supporting airborne spread between humans. Person-to-person transmission occurs in both community and health care settings, where the virus may be spread by contaminated medical equipment, such as re-used needles. Sexual transmission of Lassa virus has also been reported.

Diagnosis: Lassa fever is difficult to distinguish from many other diseases which cause fever, including malaria, shigellosis, typhoid fever, yellow fever and other viral haemorrhagic fevers. Unfortunately the symptoms of Lassa fever are so varied and non-specific that clinical diagnosis is often difficult, especially early in the course of the disease. The key to effective treatment is early diagnosis, within six days of infection.

Prevention: The prevention of Lassa fever in the community centers on promoting good “community hygiene.” This will discourage rodents from entering homes. Other measures include storing grain and other foodstuffs in rodent-proof containers, disposing of garbage far from the home and maintaining clean households. Prevention of rodents from your surroundings is key.

Family members and health care workers are advised to be careful to avoid contact with blood and body fluids while caring for sick persons. Routine barrier nursing precautions probably protect against transmission of Lassa virus in most circumstances. However, for added safety, patients suspected to have Lassa fever should be cared for under specific “isolation precautions,” which include the wearing of protective clothing such as masks, gloves, gowns, and face shields, and the systematic sterilization of contaminated equipment.


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