What is the “sloth fever” virus?

There’s a new virus in the United States, and while it has a cute name, it’s not something to be underestimated. Oropouche virus, sometimes called “sloth fever,” can be fatal.

The Centers for Disease Control and Prevention (CDC) recently issued health advisories regarding the virus, which so far has affected several Florida residents. The good news is that the cases in the United States are related to travel. But families and pregnant women also need to know the following.

What is sloth fever and how does it spread?

According to the Centers for Disease Control and Prevention (CDC), sloth fever dates back to 1955, when it was first detected in Trinidad and Tobago. Overall, this is a virus endemic in the Amazon basin, the agency said.

As the CDC explains in its recent health advisory, the virus is typically spread in forested areas through endemic transmission between mosquitoes and other non-human vertebrate hosts, such as sloths (hence the name, discussed below). Detailed introduction), non-human primates, domestic and wild birds, and even rodents.

However, it is possible for humans who travel to forested areas to contract the virus from the insects, and the CDC says it is this type of transmission that is most likely to bring sloths into densely populated urban environments. The CDC says once an infected person enters an urban area, the virus can continue to spread to uninfected people. This is because biting insects can spread the virus from an infected person to an uninfected person.

Brian Labus, PhD, MPH, REHS, assistant professor in the Department of Epidemiology at the University of Nevada, Las Vegas School of Public Health, explains: “The virus is spread through the bites of small flies called midges and possibly mosquitoes. “Biostatistics.” “It is impossible for this virus to be transmitted directly from person to person without insects.”

According to the CDC, the current outbreak of sloth fever appears to be originating not only in endemic areas of the Amazon but also in new areas of South America and the Caribbean. Countries that have recently reported cases include Brazil, Bolivia, Peru, Colombia and Cuba.

From the beginning of 2024 to August 1, more than 8,000 cases were reported, including 2 deaths. There were also five cases of what the CDC calls “vertical transmission” of the virus linked to fetal death or congenital malformations.

Current cases in the U.S. are related to travel

Importantly, the CDC states, “Although travel-related cases have been identified in the United States, there is currently no evidence of local transmission within the United States or its territories.”

This is a key point to emphasize. The current cases in the country are travel-related cases affecting individuals in one of the countries where the disease has been reported.

All nine cases of Oropouchi fever reported in Florida are linked to international travel by these individuals. All 20 cases of Oropouchi fever reported in 2024 were travel-related.

“Unless you have recently traveled to an area where the disease may be found, such as Brazil or Cuba, there is no reason to think you are infected with Oropouche virus,” Dr. Labus said. “This is not something you picked up in your backyard. ”

Why is it called sloth fever?

When the virus was first discovered in Trinidad and Tobago, it was found in an area near the Oropouche River, hence the name Oropouche virus. However, it first appeared in Brazil a few years later, where it was found in a three-toed sloth.

“The name ‘sloth fever’ is more likely to be accepted by people,” Dr. Labus said.

However, the name “sloth fever” may be a bit misleading, as the virus is actually spread through insect bites, not through contact with the sloths themselves. Despite this, it is still referred to as sloth fever by some because mosquito bites can transmit the virus to other vertebrate non-human hosts, including sloths.

It’s an unfortunate name, and Linda Yancey, MD, an infectious disease specialist at Memorial Hermann Health System in Texas, suggests it should be changed.

“This shouldn’t be called sloth fever,” she said. “The World Health Organization has stopped the practice of naming diseases after animals as this often leads to animal cruelty and people needlessly killing innocent animals, as we saw with the 2008 swine flu outbreak.”

sloth fever symptoms

The CDC says nearly 60 percent of people infected with sloth fever will develop symptoms. The incubation period before such symptoms appear can be as short as three days or as long as ten days.

“The initial clinical manifestations are similar to those caused by dengue, Zika, and chikungunya viruses, with acute fever, chills, headache, myalgia, and arthralgia,” the CDC said.

Other common symptoms may include:

• Retroorbital (eye) pain
• Photophobia (light sensitivity)
• nausea
• Vomit
• diarrhea
• fatigue
• maculopapular rash
• dilation of blood vessels in the eye
• stomach ache

In affected countries, the virus is spread among people exposed to midges or mosquitoes, the CDC said. But people who have other viral infections, are 65 years or older, or have other underlying medical conditions (including immunosuppression, high blood pressure, diabetes, or cardiovascular disease) are most likely to develop severe Oropouche disease.

What should a family member do if they think they are infected?

Importantly, medical experts note that the Oropouche virus does not actually exist in the United States at this time. What’s more, this is a disease spread by midges and mosquitoes, so the only way to contract the disease is to be bitten by these insects in areas where the virus is found. To wit: bitten in South America, Central America or the Caribbean.

“If you and your child have not traveled to these areas recently, you do not have Oropouche infection,” Dr. Yancey confirmed. “If you have recently traveled to one of these areas and are concerned, you can contact your primary care provider.”

But be aware, Dr. Yancey added, that there are no commercial tests for Oropush yet. “The only testing is through the local health department,” she said.

Dr. Zachary Hoy, a board-certified pediatric infectious disease specialist at Pediatrix Medical Group, adds that if you think your child may be infected, the first step is to contact their health care provider and schedule an evaluation.

“Some common issues to watch out for are dehydration caused by not wanting to eat or drink often,” Dr. Hoy explains.

Like Dr. Yancey, he emphasized that while sloth fever can be diagnosed, there is no antiviral treatment. But this reality does not change the way the virus is managed after it is discovered.

“The most commonly used drugs are nonsteroidal anti-inflammatory drugs (NSAIDs), such as Motrin or naproxen sodium,” Dr. Hoy said. “This can help relieve muscle and joint pain.”

What pregnant women need to know about sloth fever

The CDC recommendations make clear that the virus has the potential to be “vertically transmitted,” meaning it can be passed from a pregnant woman to her fetus. The occurrence of this condition is associated with fetal death or congenital malformations. This means that pregnant people should be aware of the necessary precautions.

“As of July 2024, the Brazilian Ministry of Health issued a report identifying four cases of microcephaly (a birth defect) in newborns born to mothers infected with the Oropouche virus. Fetal deaths were observed, possibly related to Mother-to-child transmission has been implicated,” said Suraj Sagar, DO, chief of the Division of Infectious Diseases at Holy Name Medical Center in New Jersey. “Those who are pregnant or may become pregnant should reconsider travel plans to countries with ongoing cases.”

In its recommendations, the CDC advises pregnant women to reconsider non-essential travel plans to areas affected by the virus and under a Level 2 travel health notice.

If you decide to make this type of trip, it’s important to take precautions against insect bites when visiting affected countries, including using mosquito repellent and looking for one that’s safe for pregnant women.