- As if Lyme disease wasn't worrisome enough, ticks are increasingly spreading a malaria-like parasite to humans which infects red blood cells, and has been fatal.
The parasite, Babesia microti, is turning up mostly in the northeastern United States and the upper Mid-West, spread by the same pesky deer tick, also known as the blacklegged tick, as Lyme disease.
Blacklegged ticks are in Florida, including Palm Beach County, entomologists say. But is Babesiosis also here? That's unclear, because it's not a disease that state health officials track, and research on tick-borne diseases has been minimal.
The tick that spreads Babesiosis is so small, the size of a poppy seed, that people often don't realize they've been bitten. Healthy people appear able to fend off the parasite, most without knowing they've been infected. But the parasite can linger in them for months or even years, and federal health officials are concerned that it's turning up in the blood supply, sickening transfusion recipients.
According to officials from the U.S. Centers for Disease Control and Prevention, more than 100 cases of transfusion-based Babesiosis have been reported.
People who lack functioning spleens seem most vulnerable to severe illness, along with the elderly and people who are HIV positive.
The symptoms are similar to many other illnesses: fever, chills, sweats, headache, body aches, loss of appetite, nausea, or fatigue, and so CDC officials are concerned that doctors who are seeing sick transfusion patients aren't considering the possibility of Babesiosis. It can cause anemia as red blood cells are infected, and the infection can be seen under a microscope. If diagnosed properly, it can be treated. It was added to the list of national notifiable diseases this year, so that outbreaks will be better tracked.
Babesiosis is well-established in Wisconsin and Michigan, as well as New York, New Jersey, Connecticut, Massachusetts and Rhode Island, the CDC says. But there has never been a survey for it in Florida ticks, said Dr. Cynthia Lord, associate professor of entomology at the Florida Medical Entomology Laboratory in Vero Beach. More research is needed, she added.
"We really don't have a good idea," she said. "I would like to have a better understanding of the distribution of tick-borne pathogens in the state."
The biggest issue for South Floridians may be the blood supply. With many snowbirds from the northeastern United States traveling here and donating, blood bank officials are on alert. An approved test to screen for Babesiosis in blood donations doesn't exist yet.
"It's got to be something we are all concerned about, because people travel, snowbirds from the north east come down here seasonally and donate blood," said Pat Michaels, a spokesman for Florida's Blood Centers. "Testing companies are actively working to develop a test to detect it for screening purposes in blood banks."
Both Lime disease and Babesiosis are carried by the blacklegged tick, aka Ixodes scapularis, a smallish tick found on deer, raccoons, rodents, and in Florida, lizards and skinks. It's abundant in northern woods where deer congregate, and is blamed for sickening about 29,000 people a year, with fewer than 100 of them based in Florida. Half the Lime disease cases diagnosed in Florida are likely acquired elsewhere, health officials estimate. That so few of those cases originate here may be attributable to the different feeding habits of ticks here. It appears that lizards don't readily pass along the parasite, entomologists said.
The ticks can be tough to spot. The female blacklegged tick is reddish with a black spot toward her head, while the male is darker, with a lighter edge encircling its back. After feeding, the ticks drop to the forest floor and lay eggs in leaf litter. Once hatched, the nymphs climb onto an animal again to feed and grow. Once a female reaches adulthood, she can lay 1,000 to 3,000 eggs in leaf litter. The entire life cycle can take two years.
"It has been found in most Florida counties, and in the counties where it hasn't been found, I suspect people haven't looked," Lord said. "Nobody has gone out and done the research."