Where Did Florida's Herpes Monkeys Come From? Infected Rhesus Macaques Pose Fatal Threat to Humans

At least 12 feral rhesus macaque monkeys, who could be infected with a deadly form of herpes, have been spotted for the first time in northern Florida. According to ABC-affiliate First Coast News, the animals were seen in six neighborhoods in the city of Jacksonville. But how did members of this species, which originates from Asia, end up in the Sunshine State?

The brown and gray creatures, characterized by their pink, hairless faces, were introduced to the state in the 1930s by a man named Colonel Tooey, who ran a glass bottom boat tour on the Silver River in central Florida. Tooey bought half a dozen of the animals and released them on an island to add interest to his attraction, according to the Florida Fish and Wildlife Conservation Commission (FWC). Outside Florida, the animals live in Afghanistan, Nepal, Thailand, Pakistan, India, Southeast Asia, and China.

Unbeknownst to Tooey, the animals can swim and were able to escape to the nearby forests where they rapidly multiplied. About a decade later, Tooey, who owned Silver Springs Park, noticed how popular the animals had become with tourists, and released a further six monkeys to the north shore of the river. In the mid-1980s the population spiked to almost 400. Between 1984 and 2010, around 1,000 were trapped and killed in an attempt to control the population.

In the 1970s, a laboratory animal supply company introduced rhesus macaques to the Florida Keys, but they were removed between 1990 and 2000 after they ruined red mangroves, causing a loss of vegetation and eroded the shoreline.

Now, the animals, which can live for over three decades in the wild in groups of between 10 to 80 monkeys, have been spotted in the Julington Creek, St. Johns, St. Augustine, Palatka, Welaka and Elkton areas of northeast Florida, according to First Coast News.

Dr. Steve Johnson, an expert in primates at the University of Florida, told First Coast News, "The potential ramifications are really dire."

Referring to footage of a macaque obtained by the outlet, he said, "A big male like the one in that video in Jacksonville—that's an extremely strong, potentially dangerous animal."

The FWC told First Coast News they believe the reports are credible and the monkeys likely came from Central Florida. This is particularly concerning as some macaques from Silver Springs have tested positive for the Herpes B virus, which can be spread through bites, scratches and contact with bodily fluids. Around a quarter are infected, The Guardian reported.

rhesus macaque monkey, hong kong,
A rhesus macaque monkey look on as he drinks from a bottle in Hong Kong on April 30, 2011. Wildlife experts say monkeys come into conflict with humans when their natural habitat in forests is destroyed. AFP PHOTO/ED JONES (Photo credit should read Ed Jones/AFP via Getty Images) Ed Jones/AFP via Getty Images

According to the FWC, there have been around 18 reported incidents of rhesus macaques biting or scratching people in Florida. And while there have been 50 confirmed cases of humans catching herpes B from macaques, the wild variety are not thought to have passed the infection to people. Of those 50 cases, 21 were fatal, while the reaming cases suffered permanent brain damage. In 2017, the FWC banned people from feeding any wild monkeys in Florida to prevent the spread of herpes B and other injuries.

Carrie Bennett, who lives in Julingotn Creek, told First Coast News, "That is definitely a concern because I walk the dogs at like 5:30 in the morning and its pitch blackout.

"If they bit me, if they came after and bit you, you don't know what they have, what they're carrying."