Cyclospora Outbreak In US: What Is Food-Borne Parasite And Does It Pose Risk In India?

The United States (US) is investigating a major outbreak of Cyclospora, a microscopic parasite that spreads through contaminated food and water.

The White House has said it is closely monitoring the situation and is working with the Centers for Disease Control and Prevention (CDC), the Food and Drug Administration (FDA), and state authorities to trace the source.

White House Press Secretary Karoline Leavitt said there are "typically thousands of cases" every year, but the current outbreak has seen an unusually high number of infections, Reuters reported.

What Is Cyclospora And Why Is It Different?

Cyclospora cayetanensis is a single-celled protozoan parasite that infects the small intestine. Unlike bacterial food poisoning, which usually settles within a few days, cyclosporiasis can last for weeks and often returns after the patient appears to recover, hepatologist and public health researcher Dr Cyriac Abby Philips told The Indian Express.

The illness usually appears about a week after exposure. Patients commonly suffer from watery diarrhoea, abdominal cramps, bloating, loss of appetite, weight loss and prolonged fatigue. Vomiting is less common. Standard antibiotics used for routine food poisoning do not work.

Instead, the infection responds to co-trimoxazole. Routine stool tests may also miss the parasite unless doctors specifically request testing for Cyclospora.

Does Cyclospora Pose A Risk In India?

Experts say Cyclospora is not unknown in India, but it is often overlooked. Dr Philips said the country does not know the true burden because "almost nobody looks" for the parasite.

The most useful evidence comes from a 2025 study by the ICMR-National Institute of Cholera and Enteric Diseases in Kolkata. The study found Cyclospora cayetanensis in around 2% of diarrhoeal patients across eastern India.

The figure rose to 7% during July and August, while children aged between five and 12 years recorded the highest prevalence at 18%. Poor household sanitation and rural residence were linked to higher infection rates.

How Does It Spread?

Cyclospora spreads through contaminated food and water, especially fresh produce. Unlike many food-borne infections, it requires one to two weeks outside the human body before it becomes infectious. This makes direct person-to-person transmission unlikely.

Dr Philips said outbreaks usually begin because of environmental contamination, such as contaminated irrigation water, rather than poor hygiene in restaurant kitchens.

The parasite's outer shell survives for weeks in soil and water and resists chlorine, allowing it to remain on fresh produce. Thorough cooking at 70°C is considered the only reliable way to kill it.

What Does The US Outbreak Mean?

The current US outbreak has once again exposed the challenges of tracking Cyclospora. Outbreak investigations are often delayed by four to eight weeks, leaving little contaminated produce available for testing.

Poor supply-chain documentation further complicates efforts to trace the original source. Current laboratory methods also cannot distinguish between live and dead parasite spores.

Public health advocates have also noted that delays in tracking the 2026 outbreak coincided with a reduction in CDC surveillance, according to Times of India.

For Indian travellers, the outbreak is a reminder to be cautious while consuming raw fresh produce abroad. For India, experts say the larger lesson is the need for better surveillance, routine laboratory testing and stronger farm-level sanitation to detect infections that may otherwise go unnoticed.