The doctrine of unintended consequences is alive and well and swinging from the trees in Florida.

A sizable population of wild monkeys is sweeping across the state after being introduced during the 1939 filming of “.”

There are now thought to be 1,000 rhesus monkeys roaming the Sunshine State — all descended from three males and three females released together in the late 1930s.

It seems that one , the tour operator behind the promotion, didn’t know that the monkeys could swim. They quickly escaped from the so-called “Monkey Island” on which they had been marooned and began breeding.

Nearly 80 years later, some of the small primates have been seen as far away as Jacksonville and Sarasota, more than 100 miles from Silver River State Park in Central Florida, where they began their American sojourn.

Now the question is, what to do about them.

The jury is still out on how much of a danger to people they present.

Virus can be deadly

A by the Centers for Disease Control and Prevention (CDC) in their journal Emerging Infectious Diseases found that some of the animals excrete a virus that can be dangerous to people.

The rhesus macaques in Silver Spring Park are known to carry herpes B. Now it seems some of the monkeys have the virus in their saliva and other bodily fluids, raising the risk to humans.

Worldwide, 50 people — mostly lab workers — have contracted herpes B as a result of macaque bites and scratches, according to the CDC. Of those, 21 people died from complications from the disease.

The CDC expressed fear that the more interaction there was between the monkeys and people, the more scratches or bites may occur.

Researchers from universities in Florida and Washington decided to warn Florida’s wildlife agency that the infected monkeys should be considered a public health concern.

Dr. Carol Hood, an immunologist who has worked in nonhuman primate research, said that in a laboratory setting or when the monkeys are housed together in close quarters, 100 percent will test positive for the virus.

In the wild, there isn’t 24-hour exposure.

“There will be fewer human outbreaks,” Hood told Healthline. “It’s similar to what happens with chicken pox and shingles.”

Many are exposed, but not all come down with the same symptoms.

What’s important in this situation, according to Hood, is more research.

“The strain may be very virulent in the lab and less so in the wild,” she explained.

The danger to humans

The problem in Florida is still in its early stages.

According to Dr. Antonio Crespo, an infectious disease specialist at Orlando Health, “B virus infection is a serious infection caused by a herpes simplex-like virus that is frequently found in macaque monkeys.”

In an email to Healthline he explained, “People can get infected by contact with secretions from these primates as well as by bites or scratches. It can cause a serious disease in humans that if untreated can be fatal in more than 70 percent of the cases, causing an encephalomyelitis.”

“Prophylaxis with drugs such as acyclovir and valacyclovir is very effective in preventing the disease after an exposure,” he added. “Early treatment if the disease is diagnosed is also very important in preventing serious complications and death. It is very important to educate the population about the seriousness of this disease and to avoid contact with wild monkeys.”

There’s a somewhat different situation in Indonesia that raises more questions than answers.

“In Indonesia, tourists come in close contact with rhesus monkeys,” Hood said.

There are few reports of bad reactions, mostly a few headaches, but nothing life-threatening has been reported.

Is the strain of herpes B in Indonesia the same as in Florida? Do people have receptors that can bind with the virus?

State wildlife officials are taking a serious look at the implications.

“Without management action, the presence and continued expansion of non-native rhesus macaques in Florida can result in serious human health and safety risks, including human injury and transmission of disease,” said Thomas Eason, assistant executive director of the Florida Fish and Wildlife Conservation Commission, in a statement.

He didn’t specify what action might be taken, but a spokesperson for the commission said the group is in favor of ridding the state of the invader monkeys.

In defense of monkeys

The trouble is that the macaques have their defenders, too.

That includes tourists who think they’re cute.

The CDC study summed it up like this: “Human visitors to the park are most likely to be exposed through contact with saliva from macaque bites and scratches or from contact with virus shed through urine and feces.”

Some nature lovers aren’t worried. A charter boat captain advertised his tour on the Silver River for 35 years with the cries of “Monkey, monkey, monkey!”

More than two dozen monkeys eventually responded to his shouts and appeared in trees on the riverbank. Within minutes, curious kayakers and other boat tour operators pulled close to shore for a better look and to snap photos.

A wildlife photographer on a river tour had advice for fellow tourists.

“They are not a pest to people. People are pests to the macaques. People feed them and this is not cool. You should never feed wildlife.”

In other words, it’s not safe to monkey around.