Lassa fever
| Lassa fever | |
|---|---|
| Lassa hemorrhagic fever | |
 |
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| Specialty | infectious disease |
| Symptoms | fever, headaches, bleeding |
| Usual onset | 1–3 weeks following exposure |
| Causes | Lassa virus |
| Risk factors | exposure to rodents in West Africa |
| Differential diagnosis | Ebola, malaria, typhoid |
| Treatment | supportive, ribavirin |
| Frequency | ~400,000 cases per year |
| Deaths | ~5,000 deaths per year |
| Classification | |
|---|---|
| External resources |
Lassa fever, also known as Lassa hemorrhagic fever (LHF), is a type of viral hemorrhagic fever caused by the Lassa virus. Many of those infected by the virus do not develop symptoms. When symptoms occur they typically include fever, weakness, headaches, vomiting, and muscle pains. Less commonly there may be bleeding from the mouth or gastrointestinal tract. The risk of death once infected is about one percent and frequently occurs within two weeks of the onset of symptoms. Among those who survive about a quarter have deafness which improves over time in about half.
The disease is usually initially spread to people via contact with the urine or feces of an infected multimammate rat. Spread can then occur via direct contact between people. Diagnosis based on symptoms is difficult. Confirmation is by laboratory testing to detect the viruses RNA, antibodies to the virus, or the virus itself in cell culture. Other conditions that may present similarly include Ebola fever, malaria, typhoid fever, and yellow fever. The Lassa virus is a member of the Arenaviridae virus family.
There is no vaccine. Prevention requires isolating those who are infected and decreasing contact with the rats. Efforts include having a cat to hunt vermin, and storing food in sealed containers. Treatment is directed at addressing dehydration and improving symptoms. The antiviral medication, ribavirin may be useful when given early. These measures improve outcomes.
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Wikipedia