Welcome to the thirty-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
Measles: a sixth death in Pennsylvania – Influenza: early-season activity – National surveillance, week 39 – Baylisascariasis: a fatal pediatric case in Los Angeles County – Powassan virus: a New York case, and a national count already at 46 – Dengue: Florida reaches 296, and Hillsborough extends its emergency – Ebola: a second case in Kenya, and a first vaccine trial – Russia: WHO’s assessment of the Irkutsk death
National interest
Measles: a sixth death in Pennsylvania
CDC's measles page, updated October 9, reports 4,080 confirmed cases. CDC's yearly incidence table shows this is the worst year since 1991, when 9,643 cases were reported. The 2025 total was 2,289. The chart below starts the following year, 1992, when 2,126 cases were reported.
There have been 42 outbreaks this year, 96% of cases are outbreak-associated (3,897 of 4,080), and 10% of patients have been hospitalized (414 of 4,080). CDC's national death count still says two.
The regional picture is worse. On October 9 the Pan American Health Organization rated the risk of measles spread in the Americas as very high, in part because of religious mass gatherings in South America that are expected to increase travel. The region reported 55,792 confirmed cases and 77 deaths in 17 countries and territories between January 4 and October 3, 4.8 times the same period last year. Guatemala, Mexico, the United States, Peru and Canada accounted for 99.5% of them.
In other news, Pennsylvania has reported a sixth measles-associated death in a 39 year old woman. According to the Franklin County Coroner, she had underlying health conditions. In an interview with NBC News, pediatrician and vaccine expert Dr. Paul Offit estimated that the state could have “closer to 6,000 cases,” based on the number of reported deaths.
State updates:
- Pennsylvania: the state's measles dashboard showed 1,222 cases on October 14, including 157 in the preceding seven days. Cases have been reported in 42 counties, with Lancaster and Mifflin counties most affected. To date, 225 people have been hospitalized, just under a fifth of all cases, and 34% of cases are in people under 18.
- Wisconsin: state health services confirmed 267 cases statewide on October 13. The southwest outbreak in Grant, Iowa, Lafayette and Vernon counties accounts for 237 confirmed and six probable. A new cluster has appeared in Rock County: five probable cases, linked to one another but not to the southwest outbreak, with the source unknown and laboratory confirmation still pending. Marathon County has six cases and Chippewa 11, both attributed to out-of-state travel.
Influenza: early season activity
CDC's FluView for week 39, published October 9, says seasonal influenza activity is increasing in many parts of the country but remains low overall. Early-season activity is higher than typically observed at this time of year. Clinical laboratory positivity rose to 3.6%; 1,435 positives from 39,317 specimens. The highest activity is on the West Coast, particularly in HHS Region 9, where test positivity is nearing 10%.
Of 127 influenza A specimens subtyped at public health laboratories in week 39, nearly all (125) were H1N1pdm09. Since week 21, 80.5% of influenza A viruses reported have been H1N1pdm09, most of them the D.3.1.1 HA subclade. Week 39 also ends the 2025–26 surveillance season; the 2026–27 season began on October 4.