Welcome to the nineteenth 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

World Cup - Measles - Cyclosporiasis - Botulism - Listeria - Plague - Leptospirosis - Tick-borne diseases - West Nile virus - Ebola - Hantavirus: MV Hondius

National interest

FIFA World Cup 2026: heat dominates Week 1

The FIFA World Cup tournament opened June 11. Heat illness is proving a major public health threat.

At the Houston FIFA Fan Festival on opening day, 22 people were treated for heat-related illness and 4 hospitalized among 30,000+ attendees. Another 85 were treated at an onsite cooling center. In Miami, the heat index exceeded 100°F during the first match, with 10 heat-related medical calls and 2 hospital transports. More than a third of the tournament's 104 matches have been flagged for dangerously hot or humid conditions. FIFA mandated 3-minute hydration breaks each half regardless of weather.

No confirmed communicable disease cases linked to World Cup venues. The Georgetown/MedStar HSOC is producing daily situation reports for 350+ enrolled organizations; wastewater surveillance detected rotavirus, hepatitis A, and norovirus signals in some host metros during Week 1, but no clinical clusters. No Ebola screening hits at the four designated airports. We covered the full preparedness landscape in Issues 17 and 18.