NIGERIAN FEVER!

Released: April 25, 2012

What Is the Current Situation?

The Nigerian Federal Ministry of Health has reported an increased number of cases of Lassa fever. Nineteen of the country's 36 states have reported cases since the beginning of 2012. As of April 13, 2012, there were reports of 818 suspected cases, including 84 deaths. At this time, 131 cases have been confirmed by laboratory testing. Seven deaths have also been reported among health care workers.  Cases have occurred in the states of Edo, Bauchi, Plateau and Taraba. The number of reported cases of Lassa fever in Nigeria is greater this year than in previous years. However, cases in previous years could have been underestimated due to the lack of laboratory and disease investigation systems.

The Nigerian government is responding to the outbreak by improving the disease investigation, treatment of patients, and conducting awareness campaigns among affected populations. Security and availability of resources are proving to be a major challenge. WHO does not advise or recommend any restrictions on travel or trade with Nigeria.

What Is Lassa Fever?

Lassa fever is a viral illness that is spread by rats. People get the disease through direct contact with rat droppings or urine and through touching objects or eating food contaminated with rat droppings or urine. Lassa fever may also spread though person-to-person contact. This happens when a person comes into contact with an infected person's blood, tissue, or body fluids. The symptoms include fever, pain behind the chest, sore throat, back pain, cough, abdominal pain, vomiting, diarrhea , and bleeding from the mouth or nose. People with Lassa fever may also experience hearing loss, tremors, swelling of the face and eyelids, and swelling of the brain. Pregnant women with Lassa fever often have bleeding from the genitals and miscarriage and may die from the illness.

Lassa fever is seen in West Africa. Cases have been documented in Guinea, Liberia, Sierra Leone, and Nigeria. However, the rats that spread Lassa fever also live in other countries in Africa. The number of Lassa virus infections per year in West Africa is estimated at 100,000 to 300,000, with approximately 5,000 deaths. These numbers are estimates because cases are not investigated everywhere. In some areas of Sierra Leone and Liberia, 10%-16% of people admitted to hospitals have Lassa fever, which indicates the serious impact of the disease on the population of this region. Lassa fever can occur all year long, but most cases occur from January to May.  

How Can Travelers Protect Themselves?

Avoid contact with rats, especially rat urine and feces.

• Put food away in rodent-proof containers.
• Keep the home clean and rodent proof.
• Trap rats in and around homes.
• Do not eat rats.

Stay away from germs:

• Wash hands well and often with soap, and teach children to wash their hands, too.
• Do not share eating or drinking utensils.
• Clean surfaces that are frequently touched (such as toys, doorknobs, tables, and counters) regularly with soap and water or with cleaning wipes.
• Avoid close contact with sick people.

Seek Medical Care:

• If you have traveled to the area and develop symptoms of fever, headache, sore throat, muscle pain, chest pain, nausea, vomiting, diarrhea, and abdominal pain, see a doctor or healthcare provider right away. Be sure to tell your doctor or healthcare provider that you have recently traveled to Nigeria.

Clinician Information

When caring for patients with Lassa fever, follow Viral Hemorrhagic Fever isolation precautions and barrier nursing precautions.

Lassa fever is most often diagnosed by using reverse transcription-polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent serologic assays (ELISA), which detect IgM and IgG antibodies as well as Lassa antigen. The virus itself may be cultured in 7 to 10 days. Immunohistochemistry performed on tissue specimens can be used to make a post-mortem diagnosis.

Ribavirin, an antiviral drug, has been used with success in Lassa fever patients. It has been shown to be most effective when given early in the course of the illness. Patients should also receive supportive care consisting of maintenance of fluid and electrolyte balance, oxygenation, and blood pressure, as well as treatment of any other complicating infections.

Additional Information:

• Lassa fever (CDC, Special Pathogens Branch)
• Viral Hemorrhagic Fevers (CDC Yellow Book, Health Information for International Travel)