A growing cyclosporiasis outbreak has sickened thousands of people across the United States, raising an unexpected question: What role is the weather playing in its explosive spread?

Here's what you need to know:

Cyclosporiasis is caused by the microscopic parasite Cyclospora cayetanensis. People typically become infected after eating fresh produce like leafy greens, herbs or berries that have been contaminated with the parasite.

So where does the weather fit in?

For starters, extreme heat and drought can put extra stress on farms, meaning crops need more water to survive, increasing reliance on irrigation. This increases the chances that contaminated water can carry Cyclospora onto fruits and vegetables before they ever reach the grocery store.

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The parasite itself also needs warm, moist conditions to become infectious in the first place, which is why historically, cases of cyclosporiasis tick up in the spring and summer months.

The bigger picture

It's important to note that heat doesn't create Cyclospora. And unlike bacteria, the parasite doesn't multiply rapidly just because temperatures climb. But hot, dry weather can influence the environment in ways that may increase opportunities for contamination.

(MORE: 8 health conditions affected by extreme heat)

That's why researchers are paying closer attention to how a changing climate could influence foodborne illnesses.

Rising temperatures, more frequent droughts and shifting rainfall patterns can affect water quality, farming practices and produce safety. 

But that doesn't mean every heat wave will trigger a cyclosporiasis outbreak, or that the weather is solely responsible.

Contaminated irrigation water and poor food handling practices remain the primary culprits. Think of heat as one factor that can make an already complicated food safety puzzle even more challenging.