Welcome to the twenty-sixth edition of FOI Clinical. Each week, we'll send you a briefing on outbreak news. When something urgent breaks, you'll get an alert the same day.
In this edition
Cyclosporiasis — Measles — West Nile virus — Vibrio vulnificus: Florida — Dengue: Florida + Virginia — Tularemia: Long Island — Legionnaires': New York City (closed) — Ebola
National Interest
Cyclosporiasis
On August 3, the Michigan Department of Health and Human Services announced that two Michigan residents, both of whom had serious underlying medical conditions, died "in connection with" cyclosporiasis and dehydration. These are the first confirmed deaths from cyclosporiasis ever recorded in the United States, in this outbreak or any previous one. The department said it would not release further details about the two cases.
Illnesses have now been reported in 45 states, and the CDC has called this the largest cyclosporiasis outbreak on record in the United States. A typical year sees 3,000-4,000 cases reported to the National Notifiable Disease Surveillance System.
National surveillance data through the week ending July 25 show the heaviest burden in Michigan (4,843 cases), Ohio (2,905), New York City (554), Kansas (448), and Florida (264).
Case counts reported by state and federal agencies as of early August:
| Jurisdiction | Cases | Hospitalized | Reported as of |
|---|---|---|---|
| Michigan | 11,234 | 193 | August 3 (2 deaths) |
| Ohio | 4,013 | — | July 31 |
| Kansas | 289 | 12 | July 22 |
| Nine-state cluster under CDC investigation | 1,947 | 98 | July 27 |
| National suspected total | ~18,200+ | 423 | ~July 29 |
| Cases reported to CDC by state health departments, year to date | 11,877 | — | Week ending July 25 |
The Taylor Farms de México recall of iceberg lettuce distributed to 27 states, issued July 17, remains the only recall currently in effect. No food source has been confirmed by laboratory testing.
An investigation into a nine-state cluster, which accounts for 1,947 cases and 98 hospitalizations, is ongoing.
Measles
The CDC's July 30 update put the national total at 2,371 confirmed cases across 45 jurisdictions. That tally exceeds the total for all of 2025 (2,289) and represents the highest annual count since 1991. Recent state activity:
- Pennsylvania — 202 cases and the largest active outbreak in the country. Lancaster County accounts for roughly 92 cases; 28 people have been hospitalized statewide.
- Virginia — 177 cases, unchanged for a second week. Buckingham and Cumberland Counties remain under active outbreak status.
- Delaware — 5 cases linked to an outbreak declared on July 22. All are adult men in Kent County, four of them unvaccinated.
The Pan American Health Organization has postponed its review of U.S. measles elimination status until November 2026. The United States will likely lose the elimination status it achieved in 2000. Canada, which is also experiencing extensive outbreaks, lost its status last year.
West Nile virus — first death outside Arizona; national cases climb
National surveillance recorded 143 confirmed human cases across 23 states as of August 4, up from 113 the week before. The count is running roughly five to nine times higher than is typical for this point in the season.