The Centers for Disease Control and Prevention (CDC) and the Iowa Department of Health are currently probing a potential case of Lassa fever in Iowa. The disease was identified in an Iowa resident who recently returned from West Africa earlier this month. Fortunately, the patient was not symptomatic during their journey, indicating a very low risk of transmission to fellow airline passengers.
Upon returning to the U.S., the patient was admitted to the University of Iowa Health Care Medical Center and placed in isolation. Sadly, the individual succumbed to the illness earlier today. Initial testing conducted by the Nebraska Laboratory Response Network indicated a presumptive positive result for Lassa fever, with further confirmation testing planned.
Lassa fever, a viral disease prevalent in West Africa, is rarely encountered in the U.S. In West Africa, the virus is typically transmitted to humans through contact with the urine or droppings of infected rodents. Human-to-human transmission is uncommon but can occur through direct contact with the blood or bodily fluids of an infected person, mucous membranes, or sexual contact. Importantly, the virus is not transmissible through casual contact, and individuals are not considered infectious before symptoms appear.
Annually, West Africa reports between 100,000 to 300,000 Lassa fever cases, resulting in approximately 5,000 deaths. If confirmed, this suspected Iowa case would mark only the ninth recorded occurrence of Lassa fever in travelers returning to the U.S. since 1969.
The CDC is collaborating with Iowa's state and local public health authorities to investigate the potential infection source. Preliminary findings suggest the patient may have had exposure to rodents during their time in West Africa. Federal assistance has been extended to Iowa by the CDC and other agencies as needed.
Lassa fever transmission only occurs when individuals exhibit active symptoms. Consequently, the CDC is working closely with state health officials to trace individuals who had contact with the patient after symptom onset. Identified close contacts will undergo monitoring for a 21-day period. Further updates will be provided as more information becomes available.
