The height of tick season is done, but now is when some people who caught tick-borne illnesses are starting to feel their effects.

Since 2009, tick-borne illnesses have been on the rise, and researchers have found another bacterial strain: ehrlichia, which causes ehrlichiosis. The symptoms of ehrlichiosis are similar to other tick-borne illnesses, with fatigue, fever and weakness. However, researchers are still unsure if the disease has any long-term effects, but they know it can be treated with antibiotics.

“If it behaves similar to anaplasmosis (a tick-borne illness), we wouldn’t expect to have too many long-term affects,” said Dave Neitzel, an expert in vector-borne diseases at the Minnesota Department of Health.

To date, thousands of blood samples from across the United States have been screened by the Mayo Clinic, but the bacterium has been found only in Wisconsin and Minnesota — in 25 patients. Thousands of ticks across the country also have been studied, but, again, only ticks from the two Upper Midwest states have been carriers.

Minnesota’s three most common tick-borne diseases come from the blacklegged tick, often called the deer tick. According to a news release from Minnesota Department of Health (MDH), the three most common tick diseases, Lyme disease, Babesiosis and anaplasmosis, all increased in 2010.

• Lyme disease: 1,293, up 21 percent from 2009 and slightly above the 2007 level of 1,239.

• Human anaplasmosis: 720 (more than double the 300-plus cases in recent years).

• Babesiosis: 56, up from 31 in 2009.

Perhaps the most serious tick-borne illness researchers have discovered is Powassan virus, which can’t be treated with antibiotics. Medics can only try to alleviate symptoms until the person’s immune system fights off the illness. Neitzel said some people are affected worse than others, and Minnesota saw its first death from the disease at the end of June 2011.

Officials recommend outdoor enthusiasts continue using repellents through the warm months, especially in brushy areas where ticks are found. Furthermore, keeping mosquitoes away prevents West Nile virus; however, that virus has significantly declined in the past three years in Minnesota.