Mexico City — Infectologist Alejandro Macías has warned that the parasite Cyclospora cayetanensis, responsible for a severe diarrhea outbreak affecting 34 U.S. states, could reach Mexico in the coming weeks.
Macías said the parasite may arrive due to the humidity and temperature conditions typical of the rainy season. He noted that he has treated cases in Mexico, though they are not directly linked to the U.S. outbreak.
According to the U.S. Centers for Disease Control and Prevention (CDC), the outbreak has recorded 1,645 confirmed cases since May, four times more than the same period in 2025.
Macías explained that the parasite is not transmitted from person to person. It needs about a week in the environment to become infectious and typically spreads through water used for irrigation.
Symptoms and Diagnosis
The specialist urged the public to watch for symptoms such as explosive, profuse diarrhea that can last several days. He recommended informing doctors about the possibility of Cyclospora cayetanensis infection.
Macías noted that the parasite is often not detected in standard stool tests, so a specific request to the laboratory is needed for confirmation.
“If someone has explosive, abundant diarrhea beyond what is normally known, discuss it with your doctors and let them know you’ve heard about this, so they can specifically look for it in the lab,” he said.
Risky Vegetables
Macías identified lettuce, cilantro, and parsley as the vegetables with the highest risk of transmitting the parasite, as their structure makes it difficult to completely remove contamination even after thorough washing.
While U.S. authorities continue investigating the outbreak’s origin, Macías called for strengthened hygiene measures and epidemiological surveillance to detect possible cases in Mexico promptly.
