Federal health authorities are mobilizing resources to address two distinct parasite-related public health and agricultural challenges currently unfolding in the United States. One involves a significant rise in foodborne cyclosporiasis cases, while the other concerns the unexpected re-emergence of the New World screwworm in southern border livestock—marking the first return of the destructive pest in decades.
The Centers for Disease Control and Prevention (CDC) is tracking a sharp increase in cyclosporiasis, an intestinal illness caused by the parasite Cyclospora cayetanensis. As of July 7, Michigan has reported more than 708 confirmed cases, far exceeding its typical annual total of around 50. Ohio has recorded at least 170 cases since late June, with Indiana, New York, and North Carolina each surpassing 100 recent infections.
The illness, typically transmitted through contaminated fresh produce or water, produces severe watery diarrhea, stomach cramps, nausea, vomiting, loss of appetite, and low-grade fever. At least 20 people have been hospitalized nationwide, though no fatalities have been reported. Officials note that the true case count is likely substantially higher due to underdiagnosis and underreporting. Investigations by the CDC, Food and Drug Administration (FDA), and state health departments are underway to identify potential sources, but there is currently no evidence of a single nationwide outbreak linked to all cases.
Simultaneously, federal and state agencies are intensifying efforts to contain the New World screwworm (Cochliomyia hominivorax), a flesh-eating fly eradicated from the United States in the 1960s. The first domestic detection occurred on June 3, 2026, when larvae were found in a three-week-old calf in Zavala County, Texas. Subsequent cases have been confirmed in cattle, goats, sheep, and one dog across Texas and New Mexico.
The screwworm lays eggs in open wounds or mucous membranes of warm-blooded animals. Hatched larvae burrow into living tissue, causing painful myiasis that can be fatal to livestock and wildlife if untreated. Federal officials stress that the risk to humans remains very low, with no domestically acquired human cases reported, provided wounds are properly cared for.
In response, the CDC activated a Level 3 Emergency Operations Center in mid-June. Texas Governor Greg Abbott declared a statewide disaster, enabling additional resources. Authorities have implemented quarantine zones, expanded trapping, and increased sterile male fly releases to disrupt breeding. The FDA has issued an Emergency Use Authorization for pet treatments.
Health officials emphasize that the cyclosporiasis surge and screwworm incidents are unrelated. Both responses continue as agencies work to safeguard public health and the nation’s agricultural industry and food supply.
