The Centers for Disease Control opened an investigation into the death of a traveler upon returning home to Iowa from West Africa. Previously, reports stated that the traveler died of an “Ebola-like” virus. Further Nebraska Laboratory Response Network testing confirmed that the patient tested positive for Lassa fever.

Lassa Fever

Lassa fever occurs in West Africa and is carried by the Mastomys or “multimammate” rat. The first documented cases occurred in Lassa, Nigeria, in 1969. Much like other diseases, most people infected only experience mild symptoms and are not diagnosed, and the overall mortality rate is one percent. These cases account for eighty percent of all human infections.

That other twenty percent of infections? Those are the cases best studied and include more serious symptoms such as difficulty breathing, vomiting, bleeding, facial swelling, trunk pain, and shock. However, the infection may be asymptomatic for up to three weeks and is non-infectious during this time.

The virus spreads through contaminated body fluids from both rats to humans and between humans. Many infections occur due to rat urine contamination in food supplies in its endemic regions of West Africa. Particulates from rat droppings containing the virus may also be inhaled and infect humans through sweeping and cleaning. It doesn’t spread through normal, close physical contact.

Iowa Case

Because the patient did not exhibit symptoms until after returning to the United States, the CDC considers the infection to have low to minimal risk of having infected any passengers on the traveler’s flight home. Upon hospitalization with symptoms, the University of Iowa Health Care Medical Center placed the patient in isolation to prevent any transmission. Unfortunately, the patient died at the end of October.

This patient is only the ninth confirmed case of Lassa Fever in the United States. The treatment is an antiviral drug called Ribavirin, also used to treat hepatitis C. At this time, local health officials are still tracing all potential contacts with the deceased patient who may be at risk.

Potential Complications

While Lassa Fever presents with severe disease in twenty percent of those infected, if a pregnant woman becomes infected, her unborn child has a ninety-five percent chance of miscarriage and death. The most common long-term complication of Lassa Fever is permanent deafness, occurring in one in three infected individuals, regardless of symptom severity.

Suppose you or a loved one has traveled to or from West Africa and experienced any illness-related symptoms. In that case, it is best practice to seek medical attention as some treatments are effective only if administered at disease onset. If traveling to or from this region, it may be better to overreact to mild symptoms than to end up hospitalized with an infection rarely seen in the United States.

Editor: Lucy Cafiero