Probably best known these days for their beloved – and slooooow – appearance in the Disney film Zootopia, sloths are once again taking center stage. Unfortunately, that’s not necessarily good news.

Oropouche fever, once contained almost exclusively to the Amazon rain forest, has mutated and is rapidly spreading through South, Central and North America. The disease is popularly known as Sloth Fever because it primarily affects sloths, birds and primates. It was first identified nearly 70 years ago, but since late 2023 has exploded across the American continents.

Of the 8000 known cases so far this year from the current outbreak, most are in Brazil. However, travelers appear to have carried the mutated strain to other areas with infections in Peru, Bolivia, Colombia, Cuba, Europe and even our own Sunshine State.

The disease is spread primarily by biting midges, but this new variation is also transmitted by a very well-known insect around these parts – the mosquito.

A Potentially Exponential Problem

Both the Centers for Disease Control and the Florida Department of Health have issued warnings. Florida has reported 20 travel-related cases, almost half of which popped up in the last week of August. That may seem tame considering our experiences with Zika and some other mosquito-borne viruses. But considering 2023 had fewer than 850 global cases all year, and we’ve already seen more than ten times that many infections in the first eight months of this year, it could be cause for concern.

The picture gets even worse when you realize that for the first time in generations, the sloth virus has made its way into Europe. Nearly 20 citizens of Spain, Italy, and Germany carried Oropouche fever to their homelands from Brazil and Cuba.

And whether its spread by mosquitoes or its traditional host, Culicoides paraensis (very similar to our noseeums), scientists say our area could be prime breeding ground. 

Dr. Peter Hotez, the co-director of the Texas Children's Hospital Center for Vaccine Development and dean of the National School of Tropical Medicine at Baylor College of Medicine, told ABC News, "There is a possibility that it could gain a foothold in the southern U.S., especially in Gulf Coast states."

Reaction Time Is a Factor

The disease is transmitted by the bite of a midge or mosquito. Once it’s in your bloodstream it can quickly penetrate the blood-brain barrier and affect your nervous system.

Oropouche virus causes a flu-like fever in infected people, along with a headache, muscle aches, stiff joints, nausea, chills, sensitivity to light and vomiting. In severe cases it can cause meningitis. Two people have died in the past year, but those are the only known deaths since its discovery in 1955.

Typically, the symptoms appear three to ten days after being bitten. After three to seven days, it appears to have left your system, but for approximately 60% of those affected, they relapse a few days later.

Along with other Zika-like symptoms, Sloth fever can also lead to babies being born to infected mothers exhibiting microcephaly – a birth defect where the baby's head is smaller than expected - and may be connected to a miscarriage. There are five cases being investigated and the CDC cautions pregnant women to avoid nonessential travel to areas of infection just in case.

Despite the clever name, the wild animal who is the primary host for the virus is yet to be identified.

Changes for the Worse

The biggest worry for the doctors and scientists looking at the issue right now is the mutation.

The virus tends to accumulate in the brain and liver. To get there, it employs a Trojan horse approach. Sloth fever contains a single strand of genetic RNA wrapped in a protein shell. Scientists believe it slips into immune cells that don’t resist the protein coating, using them to get to the tissues and organs it targets.

A recent analysis of the virus, currently undergoing peer review, puts forth the theory that the genetic code of Orthobunyavirus oropoucheense has been altered or reshuffled so that it now replicates more efficiently in infected cells and spreads faster in a host. That, along with various gradual changes to our global climate, may mean Oropouche fever could pose a larger threat in the future. Thankfully, the current outbreak is being tracked with a molecular surveillance diagnostic system, an option we didn’t have in the past.

There is no cure for Sloth Fever. Once infected, the Pan American Health Organization recommends treating the symptoms with rest, fluids and painkillers.

The best defense is a direct offensive – making sure you have screens with small openings, wearing long sleeves and pants, and using organic insect repellants.

Another approach is to ensure mosquitoes don’t bite you in the first place. Our No Bite Zones Mosquito Protection Program transforms biting momma mosquitoes and their offspring into vegans. It’s effective, affordable and easy to install in your backyard.

For more details on this or any of our effective, green pest control solutions, please give us a call! And leave the sloths alone. This isn’t their fault!