Map shows US states most badly affected by Cyclospora 'explosive diarrhea' outbreak

If you've been following the rather grim saga of the Cyclospora outbreak in the US, you might be wondering how far that nasty parasite has spread.

Well, a new map released by the US Centers for Disease Control and Prevention (CDC) offers a clearer picture of the states currently dealing with cases of the illness.

Health officials are still investigating the source of the outbreak, which has left more than 4,000 people dealing with some uncomfortable symptoms, to say the least.

The Cyclospora parasite can cause stomach cramps, nausea, fatigue, and the dreaded 'explosive diarrhoea'.

A map of Cyclospora infections in the US (US Centers for Disease Control and Prevention)

Some people unlucky enough to catch the illness have reported severe dehydration as a result, while others ended up needing hospital treatment to deal with the symptoms.

The CDC's interactive map gives a clearer picture of where Cyclospora cases have been reported across the US, with darker shades of blue highlighting the states with the highest number of infections.

States shown in lighter shades have recorded fewer cases, while those marked in grey have not reported any infections so far this year.

With that in mind, Michigan is clearly suffering the worst right now.

According to the CDC's latest figures, the state has reported between 901 and 2,100 cases of Cyclospora - making it the area with the highest reported numbers so far.

Ohio follows behind with between 301 and 500 cases, while New York, North Carolina and Indiana have each reported between 161 and 300 cases.

The FDA declared the detection of Cyclospora in lettuce from Taylor Farms as a false positive (Justin Sullivan/Getty Images)

Meanwhile, a number of states have not reported any cases so far this year, including New Mexico, Maine, South Carolina, South Dakota, Montana and Oregon.

While the map gives us a better idea of where cases are being reported, health officials are still working to understand exactly why some areas have seen larger clusters than others.

Investigations into the possible food sources are already underway, with officials looking at everything from leafy greens to fresh herbs.

Early reports looked at a possible link between the recent burst of Cyclospora cases and lettuce.

But health officials in North Carolina have named parsley and cilantro as ingredients that 'keep showing up repeatedly' in interviews with people who have fallen ill.

Food producer Taylor Farms was pulled into the investigation after an initial test suggested Cyclospora had been detected in a lettuce sample from one of its facilities in Mexico - only for that result to later be confirmed as a false positive by the FDA.

With no single source confirmed as of yet, individuals who are starting to experience symptoms are advised to consult a medical professional as soon as possible. If symptoms of the illness are left untreated, the infection can last for week.