Scientists have found more than a quarter of monkeys in Florida carry the deadly herpes B virus, which causes mild disease in macaques but can be fatal to humans.
Although 25 percent of the population carries the virus, fewer were actually infectious. The virus lies dormant in nerves between flare-ups, similar to cold sores in humans. Researchers reported in the journal Emerging Infectious Diseases that between 4 and 14 percent of the monkeys released the virus in their spit during their fall breeding season while the wild monkeys’ excrement turned out to be unspoiled, as far as herpes B was concerned.
Study author Samantha Wisely, a wildlife biologist at the University of Florida, calls the virus a low-risk but high-consequence: “there’s really a lot we don’t know about herpes B in wild monkeys. There’s really a low-risk of you getting it, but if you get it, there are going to be very high consequences.”
Native to southern and eastern Asia, Florida’s feral rhesus macaque monkeys, for the purpose of tourism, were introduced between 1930 and 1950 to central Florida’s Silver Springs State Park, where they multiplied. By 2012, 1,000 rhesus macaques had been trapped and removed before public outcry stopped the control effort. At last count in 2015, some 175 macaques were living in Silver Springs State Park.
Macaques can become an annoyance in new environments as they destroy crops, contaminate water, and eat down on native birds’ eggs and chicks. They also can carry herpes B, which usually doesn’t have any effect on them, but sometimes causes cold sores, mouth ulcers, and eye irritation. The virus hides out in the animal’s nerves, after the initial infection, flaring up only when the monkey gets sick or stressed. When it does, the monkey can become contagious, secreting the virus in its spit, urine, and feces, which is how the virus can be spread to humans. According to CDC, herpes B causes a devastating brain disease in humans that is deadly about 70 percent of the time, especially without treatment.
Reported cases of herpes B were mainly found in lab workers or veterinarians who caught the virus from a bite or exposure to infected bodily fluids at work. There have been no reports of people who were bitten by a wild monkey. Since wild monkeys also poop everywhere, Wisely says there could be plenty of chances for the virus’ exposure.
To find out how common the herpes B virus was in Florida’s feral monkeys, Wisely’s team analyzed blood tests collected by trappers trying to control the population. They found that about 25 percent of the monkeys contained antibodies to the virus. While trappers targeted younger monkeys that probably hadn’t been exposed to the virus, about 75 percent of the older monkeys tested carried the virus.
The team also tested the monkeys’ spit during 2015 to show that carrying the virus did not necessarily mean a monkey was infectious, which they dipped cotton swabs in sugar water and lobbed them at the monkeys.
“It was kind of a targeted toss at particular monkeys,” Wisely says. “And then they chew on it for a while and go, ‘Wait, this isn’t food,’ and then spit it out.”
Wisely’s team estimated, as researchers couldn’t always track a spitball back to the monkey who made it, that between 4 and 14 percent of the monkeys shed the virus during the breeding season, causing stress for both the males and the females.
People should not be terrified about those herpes B-infected monkeys in Florida but rather be cautious. The Florida Fish and Wildlife Commission said in a statement that it supports “active management to remove these threats.” As for whether or not you want to touch, feed, or attempt a selfie with the wildlife, it is highly advised to not do so as Wisely says, “it doesn’t do the wildlife any good and it doesn’t do you any good.”
[via The Verge]