The CDC and the Iowa Department of Health are investigating a possible case of Lassa fever, diagnosed today in an Iowa resident who recently returned to the U.S. from West Africa. The patient showed no symptoms during travel, so the risk to fellow airline passengers remains very low. They were hospitalized in isolation at the University of Iowa Health Care Medical Center and passed away earlier this afternoon. Preliminary testing at Nebraska’s Laboratory Response Network lab indicated a likely positive result for Lassa fever, with confirmatory tests planned.
Lassa fever is a viral disease common in West Africa but is rarely seen in the U.S. In West Africa, the virus is carried by rodents and spread to humans through contact with the urine or droppings of infected animals. Rarely, the virus can transmit from person to person via contact with blood or body fluids of an infected person, through mucous membranes, or through sexual contact. The virus does not spread through casual contact, and individuals are generally not contagious before symptoms appear. Each year, there are approximately 100,000 to 300,000 Lassa fever cases and about 5,000 deaths in West Africa.
If confirmed, this case would mark the ninth recorded instance of Lassa fever in a traveler returning to the U.S. since 1969.
The CDC is assisting Iowa state and local public health officials in investigating how the patient might have contracted the virus, with initial information suggesting potential contact with rodents in West Africa. Federal support has been extended to Iowa, and efforts are underway to identify and monitor individuals who had close contact with the patient after symptoms appeared. Identified close contacts will be monitored for a 21-day period.
More updates will be provided as additional information becomes available. For more details on Lassa fever, visit the CDC website at About Lassa Fever | CDC.