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What to know about 'explosive diarrhoea' parasite outbreak in US
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Sareen Habeshian
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Nearly 7,000 people in the US may have a diarrhoea-causing parasite, the Centers for Disease Control and Prevention (CDC) has said.
Cyclosporiasis is an infection caused by a microscopic parasite, with the main symptom being frequent, watery and explosive diarrhoea. People can become infected by consuming food or water that contains the parasite.
The outbreak now spread to 34 states. Michigan and Ohio have been hit particularly hard, with the two states reporting more than 3,000 cases on Friday. More than 1,000 of those cases were diagnosed over the previous two weeks.
No deaths from the recent infections have been reported in the US. While the source has not yet been identified, past outbreaks have been linked to raw produce.
Where have cases been reported?
The CDC said on Tuesday that 1,645 people nationwide were confirmed to have cyclosporiasis. Another 5,100 cases were under investigation.
No deaths have been reported, and 141 patients have been admitted to hospital, the CDC added.
According to the CDC, more than 400 cases are linked in four Midwestern states: Michigan, Ohio, West Virginia and Kentucky.
'Explosive diarrhoea' outbreak remains a mystery as officials struggle to find sources
Michigan - 3,309 reported illnesses across the state since 9 July<br>New York - 510 cases reported in New York, with more than half coming from New York City alone<br>Ohio - More than 400 cases in the past month<br>North Carolina - 307 people have been sickened, with 13 cases requiring hospital admissions<br>Illinois - The state has reported 194 probable cases, calling it a "higher-than-average" figure for this time of year
Other states with a large number of cases include Indiana, Texas and New Jersey, according to the CDC.
The number of people sick with cyclosporiasis is likely higher than the number reported because some people recover without medical care and are not tested for the illness.
The CDC said it anticipates the case counts will continue to rise as new data comes in.
What is cyclospora?
Cyclosporiasis is an intestinal illness caused by a microscopic parasite, according to the CDC.
People can become infected by consuming food or water that contains the parasite.
The illness is not usually life threatening, according to the CDC, and is less common than other foodborne illnesses such as salmonella and E. coli.
People who are infected with cyclospora may or may not experience symptoms. The illness usually causes diarrhoea "with frequent and sometimes explosive bowel movements", says the public health agency.
If untreated, the illness may last from a few days to over a month, and symptoms may return after appearing to dissipate.
It usually takes about one week after infection to become sick.
Person-to-person transmission does not occur, according to Dr Caitlin Rivers, of the Johns Hopkins Center for Health Security.
The epidemiologist wrote in an 8 July newsletter that transmission was exclusively faecal-oral via ingestion of contaminated food or water.
What's causing the outbreak?
Those who were infected "became sick after eating food in the United States", the CDC said, and did not report any travel during the 14 days before they got sick.
No specific type of produce or any grower or supplier has been identified as the source.
"Contamination typically occurs at the farm or irrigation level, making traceback investigations difficult," Rivers wrote.
Previous cyclospora outbreaks in the US and Canada have been linked to bagged salad mixes and kits, fresh cilantro, fresh basil, raspberries, snow peas and green onions.
How to stay safe
Given the large and increasing number of cases, Michigan's health department has recommended restaurants and...