Traveling ticks, some possibly carrying Lyme disease, could use rivers to move from Illinois to Missouri, researchers at the University of Illinois reported recently.

After creating maps to track tick migration, researchers ventured into the outdoors and collected ticks to determine where they were from and whether they brought Lyme disease with them.

The maps, published in last month’s on line version of Emerging Infectious Diseases, a Centers for Disease Control journal, show ticks are moving south along the Mississippi and Illinois rivers.

"We think that because the Illinois River empties into the Mississippi River, those ticks could travel into Missouri," said Roberto Cortinas, a research associate at the university’s College of Veterinary Medicine and an author of the study. "The river might act as a barrier for a while, it may slow it down, but it will not stop it."

A similar migration has already happened in Wisconsin and Illinois, bringing more cases of Lyme disease to Illinois. The disease, however, often acts differently in different habitats, so the migrating Illinois ticks might not cause an increase of Lyme disease cases in Missouri, Cortinas said.

Missouri health officials estimate there were 27 cases of Lyme disease for the first 11 months of 2001, compared with 47 cases in 2000. The state’s 2001 estimates only include cases that fully meet the Centers for Disease Control definition of Lyme disease.

"We have a bunch more that are probable and pending, but we only report the ones that meet that definition because there are other diseases that are similar," said Liz Klithermes, an assistant section chief at the Missouri Department of Health’s section of Communicable Disease Control and Veterinary Public Health.

The most interesting research being conducted on Lyme disease in Missouri, however, involves one of those diseases that causes symptoms similar to Lyme disease, Cortinas said. Harvard researchers are crediting Ed Masters of Cape Girardeau with describing a rash illness carried by southern ticks. Lone Star ticks, the most common human biting tick in Missouri, transmit the disease, while deer and bird ticks transmit Lyme disease.

Southern-associated rash illness, now called Masters’ disease, provokes the same bulls’-eye rash, fatigue and muscle or joint pain as Lyme disease.

"We believe that the bacteria that is causing our Lyme or Lyme-like illness here in the South is related but somewhat different than the bacterium in the Northeast," Masters said. "It may be like a first or second cousin; it’s not an identical twin. To the patients it makes no difference."

More research on Masters’ disease is necessary, Masters said, adding he and his team have yet to culture the disease or to complete his DNA research.

For now, those who enjoy the outdoors should remember to pull their socks over their pant legs and to check their bodies thoroughly for ticks after spending any time outside during warm months, Cortinas said.

"Most disease transmission takes place within 24 hours," Cortinas said. "If you can catch the tick within 24 hours, the likelihood of getting the disease is very small."

Cortinas also advised against using nail polish, gasoline or other toxins to remove a tick. The toxins can make the tick ill and cause it to expel the contents of its stomach into the host’s blood.