US health officials warn cyclospora outbreak likely to worsen through summer

United States health officials are investigating a growing outbreak of cyclospora after infections increased sharply across the country this year.

According to the US Centers for Disease Control and Prevention (CDC), 1,645 domestically acquired cases have been confirmed since May 1, while more than 5,100 additional reports are being reviewed to determine whether they are linked to the outbreak, Caliber.Az reports via Al Jazeera.

Authorities expect the number of infections to continue rising through August.

Cyclospora is a microscopic parasite that causes an intestinal illness known as cyclosporiasis. The parasite infects the intestines after people consume contaminated food or water, typically resulting in symptoms about a week after exposure, although illness can develop anywhere from two days to two weeks later.

Unlike many other foodborne pathogens, cyclospora does not spread directly from person to person. After leaving the body through human waste, the parasite must spend several days or weeks in the environment before it becomes infectious.

The most common symptom is frequent watery diarrhoea, but patients may also experience stomach cramps, bloating, nausea, loss of appetite, weight loss, fatigue, vomiting, headaches and low-grade fever. While the illness is rarely life-threatening, symptoms can persist for weeks without treatment and are usually treated with antibiotics.

The CDC says infections are typically linked to food or water contaminated with human waste. Fresh produce eaten raw—including leafy greens, herbs and berries—has been associated with previous outbreaks because it may be exposed to contaminated irrigation or washing water.

Health officials have not yet identified the source of the current outbreak. The US Food and Drug Administration (FDA) is tracing several types of fresh produce through the supply chain, including lettuce identified by Michigan health officials as a possible source, although no specific grower, supplier or product has been confirmed.

As part of the investigation, the FDA is interviewing infected individuals about what they ate before becoming ill and tracing those food items back through distributors and suppliers to identify the source of contamination.

Foods previously linked to cyclospora outbreaks include lettuce, bagged salad mixes, cilantro, basil, raspberries, snap peas, coleslaw, vegetable trays and fresh fruit mixes. Taco Bell has also reportedly removed lettuce, cilantro, pico de gallo and guacamole from menus at some locations as a precaution while the investigation continues.

Health experts recommend practising good food hygiene to reduce the risk of infection. This includes washing hands before and after handling fresh produce, rinsing fruits and vegetables under running water—even if labelled "pre-washed"—using a produce brush for firm vegetables and fruits, and refrigerating cut or cooked produce within two hours. However, experts note that washing alone may not completely eliminate the parasite.

By Aghakazim Guliyev