UF veterinarian: More reptilian pets may mean more threat from ticks

Exotic reptiles are being imported into the country in massive numbers as lizard lovers and other pet aficionados clamor for the creatures, but an unwanted companion — ticks — often hitch a ride, a University of Florida professor warns.

That’s a problem because ticks can carry and spread diseases that threaten the health of domestic animals, native wildlife, and, in some cases, people, said veterinarian Mike Burridge, Ph.D., an expert on tick-borne diseases.

“Recently, the pet trade has become a significant importer of live reptiles, and in 2000 it was estimated that 8.6 million reptiles and amphibians were kept as pets in the United States,” Burridge said. “In addition to the legal trade, the worldwide illegal trade in live reptiles is substantial and profitable.”

Since 1997, when they discovered more than 100 African tortoise ticks on a leopard tortoise admitted to UF’s Veterinary Medical Teaching Hospital, Burridge and his colleagues have found at least 11 exotic tick species have been imported into Florida on reptiles. At least seven of those species have spread beyond importation facilities, and at least five spread within the state to other captive reptiles.

Two species were known carriers of heartwater, an often-fatal circulatory infection that affects livestock in Africa and the eastern Caribbean, and another two were later confirmed as capable of transmitting the organism that causes it. In one shipment of leopard tortoises imported from Africa to a reptile facility in Central Florida, Burridge and his colleagues found 15 of 38 ticks on the tortoises to be infected with the organism that causes heartwater. Although Burridge’s team managed to safely eradicate the ticks at the Central Florida reptile facility through a series of chemical treatments, the experience was a wake-up call, he said.

Burridge’s longtime research program, which has components in several African countries, has focused on the prevention and treatment of tick-borne diseases, specifically heartwater. But with the Centers for Disease Control and Prevention reporting that the number of U.S. residents traveling to Africa increased by 70 percent between 1986 and 1996, and the international reptile trade growing by leaps and bounds, Burridge’s focus has broadened in recent years to include a problem he feels poses a much more immediate threat to U.S. agriculture, and possibly to humans as well.

“In general, the problem of exotic ticks entering Florida is not just that they are coming here, but that they are reproducing,” said Petey Simmons, B.S., a UF wildlife biologist working with Burridge. “We managed to eradicate the ticks at the Central Florida facility through a protocol of chemical treatments we developed, but for the most part, these methods are not being used.”

A notable exception is the Miami Metro zoo, where exotic ticks that had plagued the zoo’s Komodo dragons were eradicated this year with help from Burridge and Simmons.

“We knew they were a reptile tick specific to Komodo dragons,” said the zoo’s veterinarian, Christine Miller, D.V.M. “We have plenty of reptiles here, however, and I didn’t want to be introducing a new species of tick.”

Miller added that although none of the ticks afflicting the Komodo dragons were ever identified on other zoo reptiles, after several years zoo personnel still hadn’t been able to eradicate the ticks.

“Dr. Burridge took a personal interest, and made several visits on his own time along with Simmons and the manufacturer of the chemical,” Miller said. “They examined the ticks and the animals, took samples and confirmed that these ticks had not spread to other animals. We made the decision not to treat the animals directly, but to treat the environment in which they lived.”

In 2001, a Florida woman returned from a short trip to Southern Africa to discover a tick on the back of her knee. She sent the tick to Burridge’s laboratory, where it was tested and found to be of a species known to carry both heartwater and a disease known as African tick bite fever, which affects humans. Fortunately, the tick tested negative for the organisms that cause both infections, and the woman never became ill. It was only the second record of this tick species being introduced into the United States on a human host, Burridge reported in the Journal of Parasitology in 2002.

Meanwhile, UF scientists are working with colleagues at the University of Tampa to trap and eradicate thousands of giant Nile monitors on the loose in Cape Coral. Scientists don’t know how the carnivorous lizards, which are native to Africa and can grow up to 7 feet long, were introduced, although in all likelihood they were either escapees from the pet trade or deliberately released when they became too large to handle. Burridge said he is concerned about the ticks these reptiles are known to carry.

“Giant lizards on the loose in an urban area?” he said. “Who would believe it? This is just an example of how out of control the situation is. We have found exotic ticks to be breeding in a number of different locations in Florida.”

Leroy Coffman, D.V.M., state veterinarian and director of Florida’s Division of Animal Industry, said the biggest problem officials face is keeping up with new reptile importers and new areas of the globe from which the reptiles are originating.

“That, and finding the resources to do this in ways we can adequately measure,” he said. “Shipments can and have contained prohibited species. The method of detection so far has been by our working relationship with the importing industry — and by accident.”