emirates7 - Nearly 1,000 people in Michigan have been diagnosed with a parasitic infection, making it the largest such outbreak in state history and one of the nation’s largest in years.

No deaths have been reported, and the source of the cyclospora infections hasn’t been identified. Meanwhile, investigations into similar illnesses have been going on in 28 other states, including Ohio, where people just across the Michigan border are also becoming sick.

Michigan officials first announced the outbreak last week, when they were aware of more than 170 cases — all in the southeastern corner of the state — since 22nd June. Michigan usually identifies only about 50 cases each year.

On Wednesday, the state reported the number had grown to 992, including about 40 hospitalisations. Just across the state line, Lucas County, Ohio, reported 306 cases as of Wednesday. Northwest Ohio has seen more than 500 cases.

Cyclospora surges can be tricky to investigate, and food-poisoning sources can be hard to establish. But “there is clearly a linked outbreak happening right now,” Dr. Natasha Bagdasarian, Michigan’s Chief Medical Executive, told The Associated Press on Wednesday.

Cyclospora is a microscopic, spherical parasite that commonly causes watery diarrhea “with frequent and sometimes explosive bowel movements,” according to the US Centres for Disease Control and Prevention. The illness, called cyclosporiasis, is not usually life-threatening and is typically treated with antibiotics. Outbreaks tend to occur most often in the late spring and summer.