UK Warns of 'Explosive Diarrhoea' Parasite as Cases Rise After Mexico Travel
The UK Health Security Agency (UKHSA) has issued a stark warning to holidaymakers after a sharp rise in cyclosporiasis cases, a nasty intestinal infection caused by the Cyclospora parasite. Since April, 67 cases have been reported across the UK, with the majority linked to travel to Mexico, particularly the popular resort areas of Riviera Maya and Cancún. The agency stresses that the parasite does not naturally occur in the UK, and there is no risk of person-to-person spread, but the symptoms can be severe, including explosive, watery diarrhoea that can last for weeks if untreated.
Of the 52 cases with travel information available, 48 had recently returned from Mexico, many staying at all-inclusive resorts. The UKHSA notes that affected individuals stayed in a range of hotels and consumed a variety of food and drink within their resorts, making it difficult to pinpoint a single source. Investigations are ongoing, and health officials anticipate more cases as summer travel peaks.
The US Outbreak: 18,000 Sickened and a Lettuce Recall
The UK cases come amid a much larger outbreak in the United States, where an estimated 18,000 people have been infected across 45 states. The Centers for Disease Control and Prevention (CDC) and the Food and Drug Administration (FDA) are investigating six separate outbreaks and have identified shredded iceberg lettuce served at Taco Bell as a potential source. Taylor Farms, the supplier, has recalled all iceberg lettuce sourced from central Mexico from the U.S. market, affecting restaurants and retailers, including Walmart.
At least 423 people have been hospitalized, though no deaths have been reported. The outbreak has been particularly concentrated in the Midwest, but cases are surging nationwide. The CDC notes that cyclosporiasis cases typically rise in the summer months, but this year's numbers are dramatically higher than the usual 3,000 annual cases. Investigators are also looking into whether other produce items are contributing to the surge.
Why This Matters: A Parasite That Hits Holidaymakers and Restaurants Hard
For UK travellers, the warning is timely. The UKHSA advises that while the infection is not life-threatening, it can cause significant distress. Symptoms include watery diarrhoea, stomach cramps, bloating, fatigue, and weight loss. In severe cases, people may need to use the toilet up to 20 times a day. Treatment with antibiotics is available for those with prolonged or severe illness.
Dr Philip Veal from the UKHSA said: "If you develop symptoms after returning from travel, such as watery diarrhoea, loss of appetite, weight loss, stomach cramps or pain, bloating, increased wind, nausea, fatigue or other flu-like symptoms, please seek medical attention and inform your healthcare professional of your travel history."
The outbreak is also shaking the restaurant industry in the US. Taco Bell voluntarily removed shredded iceberg lettuce from its menus on July 17, and customer visits have plummeted by 21%. Other salad-focused chains, like Chopt and Sweetgreen, have seen a dip in sales even though they have not been linked to the outbreak. Food safety expert Craig Hedberg of the University of Minnesota noted that the growing number of cases suggests that Taco Bell was not the only source of contaminated lettuce, adding that the FDA is likely to identify additional sources.
How the Parasite Spreads and How to Stay Safe
Cyclospora is a microscopic parasite that is carried in human faeces. It can contaminate food and water, particularly fresh produce like lettuce, herbs, and soft fruits. The parasite is not killed by typical washing, but it is killed by cooking or freezing. Health officials recommend that travellers to affected regions, including Mexico and parts of the US, follow strict food and water hygiene: drink bottled water, eat thoroughly cooked food, and avoid fresh uncooked berries, herbs, unpeeled fruit, and salad items. These precautions apply even in high-end all-inclusive resorts.
For those in the US, the FDA has advised consumers to check for recalled lettuce and to avoid eating shredded iceberg lettuce from Taylor Farms. The recall affects both restaurant and retail products. The CDC has also published a map of affected states, and is urging anyone with symptoms to seek medical care and to report their food history.
The Bigger Picture: Record Outbreaks and Food Safety Challenges
The current outbreak highlights the vulnerabilities in the global food supply chain. The cyclospora parasite is not new, but the scale of this summer's outbreak is unprecedented. Climate changes, increased travel, and the complex distribution networks of fresh produce are likely contributing factors. The UKHSA's warning to holidaymakers underscores how quickly such infections can spread internationally.
This is not the first time lettuce has been at the center of a major food safety crisis. In 2018, romaine lettuce was linked to two major E. coli outbreaks that sickened hundreds across the US and Canada. The current cyclospora outbreak serves as a reminder that fresh produce, while healthy, can carry hidden risks. The FDA is working with producers to identify contamination points, but the investigation is ongoing.
As summer continues, health authorities on both sides of the Atlantic are urging vigilance. For travellers, the message is clear: if you develop symptoms after returning from a trip, mention your travel history to your doctor or healthcare provider. For the public, monitoring recalls and following safe food handling practices can reduce risk. The outbreak is a sobering reminder that even in an era of advanced food safety technology, a tiny parasite can cause outsized disruption.
UK Case Breakdown and What to Do
According to the UKHSA, between 30 April and 15 July 2026, there have been 30 cases in England, 27 in Scotland, and 10 in Wales. The agency is working with public health authorities in Mexico and the US to identify the source. It is also coordinating with the European Centre for Disease Prevention and Control. For anyone who has recently travelled to Mexico and is experiencing symptoms, the UKHSA advises to contact your GP or NHS 111, and to mention your travel history. Most people recover without treatment, but antibiotics can shorten the illness.
Recent Developments in the US and the Impact on Restaurants
In the US, the CDC is actively investigating the largest cyclospora outbreak in the nation's history. The Taylor Farms recall has been expanded to include all iceberg lettuce from central Mexico, and the FDA is using whole-genome sequencing to trace the strain. Taco Bell has stated it is cooperating with authorities and has removed the affected lettuce from all its restaurants. The impact on the restaurant industry is significant, with visits to Taco Bell falling by 21% as of July 23, according to Placer.ai. Salad chains like Chopt and Sweetgreen have also seen a dip, despite no link to the outbreak. This consumer caution is a familiar pattern in food safety scares, but the scale is notable.
The Economic Ripple Effect on Lettuce Prices
The outbreak has also affected lettuce prices. Government data shows the retail price of iceberg lettuce climbed nearly 20% between January and June, and fresh lettuce prices were about 33% higher last month than a year earlier. Grocery stores advertised iceberg lettuce for an average of $1.86 per head, up 25 cents from the same week in 2025. The combination of a poor growing season and the recall has tightened supply, adding to the economic strain on restaurants and consumers. Food safety experts say that while the cost may be temporary, the long-term impact on consumer trust could linger.
What This Means for the Future of Food Safety
This outbreak, while severe, is part of a broader trend of emerging foodborne illnesses. The rise in international travel and the global trade in fresh produce mean that a contamination event in one country can quickly become a multinational concern. The UK's warning to travellers is a direct result of the US outbreak, and similar advisories have been issued by Canada and other European countries. As the world becomes more interconnected, so too does the risk of these outbreaks. Health officials are calling for improved surveillance and rapid sharing of data across borders.
In the meantime, consumers can take steps to protect themselves: wash hands thoroughly, avoid raw produce in high-risk areas, and stay informed about recalls. The Product Recalls Surge: Cyclospora, Salmonella, Allergen Alerts Hit U.S. article provides a broader look at the scale of food recalls this year. The situation is fluid, and more cases are expected. The cyclospora outbreak is a wake-up call for both the travel industry and the food supply chain, prompting questions about how to better prevent such infections in the future.
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