Wisconsin measles reaches 142; WHO limits Ebola vaccine to research: Health risk update, Aug. 29–Sep. 4, 2026

The week's signal

From August 29 through September 4, 2026, the clearest domestic signal was measles spreading locally in southwest Wisconsin: the state reported 136 confirmed and 6 probable cases across Grant, Iowa, and Lafayette Counties on September 4. Pennsylvania reported 540 confirmed cases in 36 counties on September 2, while Illinois opened an alert after at least four linked cases in Douglas County. 1 2 3

The immediate household action is to check MMR records and keep anyone with possible measles symptoms away from public spaces until a clinician gives instructions. The immediate travel action is to review CDC notices before a Nicaragua or central African itinerary. The immediate clinical action is to know which exposed patients qualify for measles post-exposure prophylaxis and which returning travelers need call-ahead evaluation.

WHO also issued new vaccine guidance for Bundibugyo virus disease and announced a global mpox vaccine stockpile. CDC added a Level 2 chikungunya notice for Nicaragua on September 3. 4 5 6

Actions for households, travelers, and clinical teams

Alert	Who should act	What to do now
Measles in southwest Wisconsin	Residents and visitors in Grant, Iowa, and Lafayette Counties, especially people without documented immunity	Check vaccination records. Anyone who may have been exposed should stay home and monitor for symptoms for 10–21 days. A person with fever, cough, runny nose, red eyes, or rash should call a clinic before visiting. Wisconsin reported 136 confirmed and 6 probable cases as of September 4. 1
Pennsylvania measles outbreak	Residents and visitors across Pennsylvania, especially people without full MMR protection	Review MMR records and arrange vaccination through a healthcare provider or local health department. The September 2 update reported 540 cases in 36 counties, 91 hospitalizations, and 2 deaths. A symptomatic person with a possible exposure should call a provider or 877-PA-HEALTH before arrival. 2
Douglas County, Illinois measles outbreak	Illinois residents with a possible exposure and people planning international travel	Illinois reported at least four linked cases on September 2. Eligible nonimmune people age 6 months and older may receive measles post-exposure prophylaxis within 72 hours of first exposure. Immune globulin is an option for some high-risk people who cannot receive MMR or who missed that window; clinicians should assess infants, pregnant people, and immunocompromised patients. 3
Jalapeño-linked Salmonella recall	Consumers, restaurants, and retailers that handled recalled jalapeños or prepared foods	Do not eat, sell, or serve recalled products. Wisconsin's September 4 page identifies recalled Walmart pico de gallo products with UPC 681131276351 or 681131276344 and best-if-used-by dates from August 8–16, 2026; the page also points to Whole Foods prepared-food recalls. Discard or return affected products and wash surfaces that they touched. 1
Bundibugyo virus disease travel restrictions	People traveling to the Democratic Republic of the Congo (DRC), Uganda, or South Sudan; travel and clinical teams	CDC says to avoid all travel to Ituri and Nord-Kivu in the DRC, avoid nonessential travel to Haut-Uélé and Tshopo, and use enhanced precautions elsewhere in the DRC and in Uganda. A person who has been in the DRC within 21 days of a flight to the United States cannot board a commercial flight with a U.S. destination. Travelers returning from Uganda or South Sudan without DRC travel must use designated U.S. airports for enhanced screening. 7 8
Chikungunya in Nicaragua	Travelers to Nicaragua, particularly pregnant travelers and people at higher risk of severe disease	CDC's September 3 notice is Level 2: practice enhanced precautions. Prevent mosquito bites with repellent, long sleeves, and screened or air-conditioned rooms. CDC recommends chikungunya vaccination for travelers visiting an outbreak area; pregnant travelers should discuss the risks and benefits with a clinician. 6
WHO Ebola vaccine guidance	Outbreak-response teams, clinicians, and public-health officials working with Bundibugyo virus disease	WHO says Ervebo, the only licensed Ebola vaccine, should be used against Bundibugyo virus disease only within research protocols. The available evidence suggests possible cross-protection but remains insufficient to establish clinically meaningful protection in humans. Maintain proven outbreak-control measures and communicate the uncertainty about vaccine effectiveness. 4

What the counts mean

The Wisconsin measles figure is a cumulative outbreak total as of September 4. The number combines 136 confirmed and 6 probable cases; it describes case classification, not the number of people infected during one day or one week. Wisconsin also reported measles virus in wastewater collected from treatment facilities serving Lafayette and Iowa Counties during the week of August 24. The state uses wastewater alongside case data to monitor possible spread; wastewater cannot identify a person or pinpoint a transmission site. 1

Pennsylvania's 540 cases are also cumulative. The September 2 release says 43 new positive cases had been added since August 31, then gives the cumulative total, 91 hospitalizations, and 2 deaths. The two dates answer different questions: August 31 anchors the new-case interval, while September 2 dates the public update. 2

The jalapeño recall carries a similar date distinction. Wisconsin's current page was revised September 4, while the linked product recalls began August 9 and August 12. The page keeps the consumer action current: check the product identifiers, discard or return recalled food, and clean surfaces that touched it. The page reports the associated outbreak count as 431 people in 32 states, with 57 hospitalizations and no deaths, using CDC data current as of August 19. 1

Travel and vaccine watch

WHO's August 31 guidance addresses a specific question for outbreak teams: whether Ervebo can be used against Bundibugyo virus disease. WHO's conclusion keeps that use inside research protocols because the evidence does not yet establish clinical protection in humans. The guidance calls for a ring randomized controlled trial, continued outbreak-control measures, clear communication about unknown efficacy, and faster development of Bundibugyo-specific vaccines. 4

WHO's September 2 announcement covers a different vaccine action. A global mpox vaccine stockpile, approved by Gavi's board in 2025 and coordinated by the International Coordinating Group on Vaccine Provision, is scheduled to begin operations later in September. WHO reported 190,683 confirmed mpox cases and 529 deaths across 145 countries and territories from January 1, 2022, through July 31, 2026. The announcement changes the global supply mechanism for outbreak response; it does not change the routine U.S. vaccination schedule. 5

CDC's September 3 Nicaragua notice adds a destination-level action for travelers. The notice recommends enhanced precautions, mosquito-bite prevention, and chikungunya vaccination for travelers visiting an outbreak area. Symptoms usually begin 3–7 days after an infected mosquito bite and include fever and joint pain; a traveler who develops symptoms during or after the trip should seek medical care. 6

CDC's travel-notice page continues to list Level 4 for Ituri and Nord-Kivu, Level 3 for Haut-Uélé and Tshopo, and Level 2 for Uganda and other DRC provinces outside those areas. Travelers should match the province, entry route, and 21-day timing to the current notice rather than rely on a country name alone. 7 8

State and clinical signals

Wisconsin's September 4 update says measles is spreading locally in the three-county area. Wastewater samples from Lafayette and Iowa Counties were positive during the week of August 24, and an earlier positive Grant County sample remained part of the state's monitoring picture after a later retest was negative. A wastewater result signals virus presence in a sewershed; it does not identify a specific infected person. 1

Illinois gives clinicians a time-sensitive exposure pathway. Post-exposure prophylaxis can be given to eligible nonimmune people age 6 months and older within 72 hours of first exposure. Immune globulin can help certain high-risk people who cannot receive MMR or who missed that interval. A patient with possible measles symptoms should call ahead so staff can protect other patients and healthcare workers. 3

The CDC DRC notice gives a matching call-ahead rule for clinicians. People who develop fever, headache, muscle pain, weakness, diarrhea, vomiting, stomach pain, or unexplained bleeding or bruising during travel or within 21 days after leaving an affected area should isolate, avoid travel, contact local health authorities or a healthcare facility, and call before arrival. 7

Bottom line

Check MMR records for everyone in a household, especially before travel or after a possible measles exposure.
Keep a person with possible measles symptoms at home and call the clinic before arrival.
In Illinois, ask a clinician about measles post-exposure prophylaxis within 72 hours; high-risk patients may need immune globulin.
Check recalled jalapeño products and prepared foods for the listed UPCs and dates; discard or return them and sanitize contact surfaces.
For Nicaragua, use mosquito-bite precautions and discuss chikungunya vaccination before departure.
For DRC, Uganda, or South Sudan, check the province, travel route, entry restrictions, designated airport rules, and 21-day symptom-monitoring period before departure.
Clinical and outbreak teams should treat Ervebo as a research-protocol option for Bundibugyo virus disease while continuing established control measures.