Herpes-Infected Monkeys Are Increasing In Florida And There Is No Plan To Stop Them


Madison Dapcevich


Madison Dapcevich

Freelance Writer and Fact-Checker

Madison is a freelance science reporter and full-time fact-checker based in the wild Rocky Mountains of western Montana.

Freelance Writer and Fact-Checker

One infant and two adult female rhesus macaques in Florida's Silver Springs State Park. Today, there are likely between 200 and 300 macaques in the area. Jane Anderson/University of Florida

A group of invasive herpes-carrying monkeys is expanding its range in central Florida and officials have yet to put a management plan in place to mitigate and control their spread.

Rhesus macaques have been making headlines in the sunshine state ever since their inaugural appearance at Silver Springs State Park (SSSP) in the 1930s. At the time, a boat operator released 18 individuals on an island to bolster local tourism, not knowing they could swim to surrounding areas, according to the University of Florida. But now, the charismatic primates appear to be spreading beyond their initial grounds without a plan in place to mitigate their impact. Just a few weeks ago, a monkey “showed up” in Jacksonville, Florida. Others have been spotted along the northeast coast of Florida


“My guess is that a monkey that has left one of the established groups has set off on its own, and that sort of thing may be more and more common, creating more and more potential for human interaction,” Dr Steve A. Johnson, associate professor at the Department of Wildlife Ecology & Conservation at the University of Florida, told IFLScience in an interview.

Macaca mulatta are highly adaptable and can thrive in a number of environments, often wreaking havoc when introduced to new habitats. Thousands of macaques released on Morgan Island, South Carolina, for biomedical research elevated the risk of E. coli and the introduction of the monkeys in the Florida Keys destroyed red mangroves, leading to shoreline erosion. In central Florida today, macaques are known to eat eggs from native bird nests, as well as eat around 50 native plant species, and frequent coastal environments during the weekend when recreational boaters show up to illegally feed them.

The macaques also carry herpes B virus.

“We know that [the monkeys] carry herpes B virus and we know that herpes B virus is lethal in people, so that sets up the possibility that if the population increases and they interact with people more, someone may be hurt,” said Johnson, adding that there is a low risk and likelihood that such interaction would occur, but such incidents would carry with them a high consequence. Herpes B in humans can degrade one's quality of life, present neurological issues, and prove fatal.

Figure 6. Rhesus macaque in an aggressive stance to a woman attempting to feed it. Jane Anderson/University of Florida

It is unknown whether herpes B can spread to people in the wild. Despite 18 reports of macaque bites or scratches in Florida, there has not been a single monkey-to-person transmission in the state. However, there are some 50 cases of human herpes B virus infections from macaques in laboratory settings, almost exclusively from bites and scratches from infected animals – half of these cases were fatal. Any risk of exposure to the potentially fatal pathogen should prompt management plans to limit the transmission of the virus, advises the Centers for Disease Control and Prevention.

But Johnson says that there is currently no management plan in place. Between 1998 and 2012, a private trapper sponsored by the government caught more than 800 monkeys in the SSSP area to be sold to research facilities, but public outcry soon halted the operation. Today, the population continues to increase with between 200 and 300 individuals in the 1,860-hectare park (4,600 acres), and without a plan in place, researchers estimate that the population will double from its 2015 population by 2022.

“It’s a challenge and I’m hoping that through all of this attention the general public realizes that while [the monkeys] are cute and it’s not their fault that they are there, they are there and they are carrying a disease that is potentially fatal to people,” said Johnson. “They are not native and they shouldn’t be here.”

Florida has the most non-native wildlife species introduction of any state, and the management and mitigation of those species cost more than $500 million annually. Macaques aren’t the only primates in the state either; Florida is also home to established populations of squirrel and vervet monkeys, as well as Burmese pythons and other invasive reptiles, as well as feral cats and pigs.

A juvenile rhesus macaque consuming vegetation in Silver Springs State Park. Jane Anderson/University of Florida


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