A new study in the Journal of Wildlife Management looks at the population estimates and management options for introduced rhesus macaques in Florida.

Rhesus macaque Image/Rlevse
Rhesus macaque

According to researchers from the University of Florida, Department of Wildlife Ecology and Conservation:

Approximately 12 rhesus macaques (Macaca mulatta) were introduced to the forests along the Silver River, central Florida, USA, between 2 introductions in the 1930s and 1940s to increase tourism; this land is now Silver Springs State Park (SSSP). By the mid‐1980s the population along the Silver River reached nearly 400 individuals. Approximately 1,000 animals were trapped and removed from 1984 to 2012 to reduce population growth and mitigate negative macaque‐human interactions. This practice was halted due to extensive public controversy, and consequently no population management has been implemented since 2012.

As of 2015, they think there are some 176 macaques and suggest this population was growing and will likely double in size by 2022 without management intervention.

There is a concern of dangerous infectious agents carried by macaques, as the National Geographic points out:

Earlier this year, scientists from the U.S. Centers for Disease Control and Prevention discovered that around 30 percent of these monkeys carry herpes B, a rare and highly virulent virus that can be deadly to humans. Only about 50 human cases of herpes B have ever been documented, though as far as we know none of these derived from wild macaques. In 1997, one 22-year-old research assistant died after accidentally getting bodily fluids from a captive monkey in her eye and contracting the disease.

B virus infection is caused by a herpes virus. B virus is also commonly referred to as herpes B, monkey B virus, herpesvirus simiae, and herpesvirus B.

The virus is found among macaque monkeys, including rhesus macaques, pig-tailed macaques, and cynomolgus monkeys (also called crab-eating or long-tailed macaques). Macaque monkeys are thought to be the natural host for the virus.

The CDC notes infection with B virus is extremely rare in humans. When it does occur, the infection can result in severe brain damage or death if the patient is not treated soon after exposure. Infection in humans is typically caused by animal bites or scratches or by mucosal contact with body fluid or tissue.

Untreated B virus infections in humans result in an extremely high mortality rate (∼80%) and, consequently, present unique and potentially lethal challenges for individuals handling macaque monkeys or macaque cells and tissues.

The odds of catching herpes from a wild rhesus macaque are “really, really low, but the consequence is really, really high—sort of like the lottery,” says Steve Johnson, associate professor of wildlife ecology at the University of Florida.