Rare Lassa Fever Case Found in US

Lassa fever infection identified in US patient who recently traveled to West Africa

/ Author:  / Reviewed by: Joseph V. Madia, MD Beth Bolt, RPh

(RxWiki News) Traveling can expose people to new cultures and sights, but sometimes it can also expose people to diseases not typically seen at home. This is expected to be the case for one US patient.

The patient has been diagnosed with Lassa fever, a rodent-borne infectious disease that is rarely seen in the US, but common in certain parts of West Africa.

Health officials are investigating the illness and identifying people who may have had close contact with the patient.

"Store food in rodent-proof containers."

According to the Centers for Disease Control and Prevention (CDC), Lassa fever was discovered in a Minnesota man who had recently returned to the US from West Africa.

Most Lassa fever patients have mild symptoms like fever, weakness and headache. However, CDC reported that around 20 percent of patients experience more severe symptoms like excessive bleeding, breathing troubles, vomiting, hearing loss and swelling of the brain. An estimated 1 percent of Lassa fever patients die from the infection. 

CDC reported that the US patient entered a Minnesota hospital on March 31 with fever and confusion. After blood sample tests, the patient was diagnosed with Lassa fever on April 3.

The disease, which is common in some parts of West Africa, including Sierra Leone, Liberia, Guinea and Nigeria, is typically spread through rats who carry the disease.

Humans usually become infected through contact with the urine or droppings of an infected rodent. CDC noted that in rare cases, direct contact with the bodily fluids of an infected person can lead to person-to-person transmission.

“Given what we know about how Lassa virus is spread to people, the risk to other travelers and members of the public is extremely low,” said Martin Cetron, MD, MPH, Director of CDC’s Division of Global Migration and Quarantine, in a press release.

However, CDC did report that it is investigating and identifying people who might have had close contact with the patient, including during his travel back to the US.

“This imported case is a reminder that we are all connected by international travel. A disease anywhere can appear anywhere else in the world within hours,” said Tom Frieden, MD, MPH, Director of CDC, in a press release.

CDC recommended avoiding contact with rodents, especially when in regions where Lassa fever is common.

"Putting food away in rodent-proof containers and keeping the home clean help to discourage rodents from entering homes. Using these rodents as a food source is not recommended," said CDC.

The US patient is reported as stable and recovering in Minnesota. 

Review Date: 
April 7, 2014
Last Updated:
April 8, 2014