Beware: May is prime tick season

The number of tick-borne diseases in Minnesota reached record numbers last year, including two people who died of infections, the state Department of Health said Friday.

Bites from black-legged ticks, also called deer ticks, led to 1,239 cases of Lyme disease; 322 cases of human anaplasmosis, a bacterial infection, and 24 cases of babesiosis, a malaria-like illness caused by a parasite.

Those numbers were substantially higher than the previous high-water marks: 1,023 cases of Lyme disease in 2004, 186 for human anaplasmosis in 2005 and 18 cases of babesiosis in 2006, the Health Department said.

"Minnesota continues to be one of the highest-risk states for diseases from black-legged ticks," said Melissa Kemperman, an epidemiologist for the Minnesota Department of Health.

Last year, one person died from complications from anaplasmosis and another from babesiosis infection, she said. Dozens of others were hospitalized.

The two infections, while more rare than Lyme disease, can cause high fever, chills, headache and muscle aches, and, if untreated, can lead to organ failure. Lyme disease generally is not considered deadly, but it can cause serious complications if left untreated, Kemperman added.

"If you visit or live in forested parts of Minnesota during late spring or early summer, you must protect yourself from tick bites to avoid developing Lyme disease or other tick-borne illnesses," she said.

Kemperman noted that deer ticks are so small that it's often difficult to see them so it's essential to try to prevent bites by using repellents and covering up in wooded or bushy areas.

The prime season for tick-borne illnesses begins in May, but ticks remain active through October. This year's prolonged winter is not likely to reduce the risk from tick-borne diseases as the typical numbers of adult ticks that are feeding have been observed this spring, Kemperman said.

Not all black-legged ticks carry the organisms that cause disease, and prompt removal of infected ticks can prevent disease transmission. If an infected deer tick bites you, it needs to be attached at least 12 to 24 hours to transmit human anaplasmosis bacteria and 24 to 48 hours to transmit Lyme disease bacteria, the Health Department said.

Anybody experiencing an expanding rash, fever, headache, chills, muscle pain, joint pain and fatigue after a tick bite should seek medical attention immediately. Sometimes the symptoms don't appear until days or weeks after the bite.

Kemperman said that repellents containing DEET or permethrin offer the best protection and that wearing long pants and light-colored clothing as well as staying on trails can minimize the risk.

Staff writer Maura Lerner contributed to this report. Tim Harlow • 612-673-7768