An Iowa resident has died after contracting a suspected case of Lassa fever, health officials said.

The patient was diagnosed Tuesday after returning to the United States from West Africa earlier this month, according to the Centers for Disease Control and Prevention (CDC) and the Iowa Department of Health and Human Services (IDHHS).

The patient was hospitalized in isolation at the University of Iowa Health Care Medical Center in Iowa City and died Tuesday afternoon, officials said.

Health officials said the risk to the public from the disease is low, and cases typically only occur in West Africa.

Here’s what you need to know about Lassa fever, how it spreads and how it is treated:

What is Lassa fever?

According to the World Health Organization, Lassa fever is “an acute viral hemorrhagic disease caused by the Lassa virus.”

“Lassa fever is a potentially life-threatening viral disease,” said Dr. Albert Ko, the Raj and Indra Nooyi Professor of Public Health at the Yale School of Public Health, told ABC News. “The virus, which belongs to this class of families called arenaviruses, is harbored by rats, and rats specifically in the western part of Africa.”

According to the CDC, the virus is primarily spread by multi-tamed rats belonging to the genus Mastomys.

Only multi-tamed rats in West African countries – such as Guinea, Liberia, Nigeria and Sierra Leone – are known to carry the virus. But people living in neighboring countries are also at risk of infection with the Lassa virus.

The first documented case was identified in 1969 in Lassa, Nigeria, which gave the disease its name, the CDC said.

In the past 55 years, there have been only eight travel-related cases of Lassa fever in the US, according to the IDHHS, making its occurrence in the US very rare.

How is Lassa fever spread?

Lassa fever is often spread by coming into contact with the urine or feces of infected rats. Multimammate rats often live in areas where food supplies are stored. Such contact can occur by touching contaminated objects, eating contaminated food, getting the virus in an open cut or sore, eating infected rodents, or breathing air contaminated with infected urine or feces, such as when cleaning or swiping, according to the CDC.

Lassa fever can also be transmitted from person to person by coming into contact with the blood or body fluids of an infected person, or through sexual contact.

“It’s not because of the air. It’s not like COVID,” Dr. Robert Murphy, professor of infectious diseases at Northwestern University Feinberg School of Medicine, told ABC News. “(Lassa fever), it has to be a liquid. … So you don’t have to worry about being in the same room with someone, but you do have to worry if you’ve touched that person or interacted with that person and are exposed to all the fluids they have.”

What are the symptoms of Lassa fever?

According to the CDC, symptoms of Lassa fever typically appear one to three weeks after a person is first infected.

About eight in 10 people who contract Lassa fever have mild symptoms, including low-grade fever, fatigue, weakness and headache, or they experience no symptoms at all and are never diagnosed, according to the CDC. The remaining 20% ​​will experience severe symptoms including bleeding, facial swelling and vomiting, as well as pain in the chest, back and abdomen, breathing difficulties and shock.

Complications can include hearing loss and acute kidney failure, the experts said. If a pregnant person is infected, there is a high risk of miscarriage, with about 95% of fetuses not surviving, according to the CDC.

Less than 1% of people who contract Lassa fever die. However, of those who become seriously ill and are hospitalized, the mortality rate is approximately 15%.

“Once they get really sick, death is quite rapid, usually within seven to 14 days,” Murphy said.

He added that diagnosing Lassa fever can be challenging because testing for the virus is not routine. The people handling samples need to be careful in case they come into contact with them and become infected, Murphy said.

How is Lassa fever treated?

Patients who suffer from Lassa fever can be given an antiviral medicine called Ribavirin. According to the CDC, it is most successful if given to the patient soon after they become ill and show symptoms.

Supportive care, including rest, hydration, and treatment of the symptoms of the virus, is also recommended.

Tips to prevent Lassa fever

There are currently no vaccines to prevent infection with the Lassa virus.

If anyone is traveling to West Africa, the CDC says the most important method to prevent infection with Lassa fever is to stay away from rats.

The CDC further recommends storing food in rat-proof containers and keeping the house clean. One should also avoid eating rats and catch and dispose of rats in and around houses.

That said, most Americans don’t have to worry about Lassa fever, said Dr. Ko of the Yale School of Public Health.

“This is a disease that is really a major public health problem, but it is in West Africa,” he said. “It’s not a disease that spreads easily from one place to another, unlike some other diseases we’ve dealt with like Zika and COVID, and that’s because people are usually not contagious until they start developing symptoms , and often we can screen and know, you know, identify and isolate people who are sick before they travel.”