Pandemiology Watch (July 29-August 4, 2026)
Leggionaire’s disease
According to the New York City Department of Health on July 30, 2026, a community cluster of Legionnaires’ disease is under investigation in the Upper East Side neighborhoods of Carnegie Hill and Yorkville. A total of 92 cases, including seven deaths, have been reported. Testing identified live Legionella bacteria in 59 cooling towers across 58 buildings, which have been cleaned and disinfected.
Ebola
According to the INRB-UMIE BDBV on August 1, 2026, Epidemic Dashboard, the Bundibugyo Ebola outbreak in the Democratic Republic of the Congo has reached 3,748 confirmed cases and 1,657 confirmed deaths. Health authorities are also investigating 227 suspected cases and 91 suspected deaths.
According to the World Health Organization (WHO) on August 1, 2026, the Bundibugyo Ebola outbreak in the Democratic Republic of the Congo continues to intensify. The outbreak has expanded from a single health zone in Ituri Province to multiple health zones across five provinces, making it the largest Ebola outbreak ever recorded in the country. WHO warned that ongoing transmission, conflict-related insecurity, and cross-border movement continue to challenge response efforts and increase the risk of further spread
Cyclospora
According to the Michigan Department of Health and Human Services on August 5, 2026, officials are investigating an ongoing cyclosporiasis outbreak that has resulted in more than 12,000 cases and two deaths. Lettuce or salad greens are considered a potential source of the outbreak, although the exact source has not yet been identified. Health authorities continue to work with local partners to investigate cases and monitor the situation
Measles
US
As of July 31, 2026, the United States has reported 2,371 measles cases so far in 2026, according to the Center for Disease Control. In 2026, the age group 5-19 accounts for 49% of the cases (1,161), and children under 5 years account for 20% of the cases (469). Of the cases reported in 2026, 93% were unvaccinated or had an unknown vaccination status and 7% of the cases have been hospitalized (161). A total of 4,660 measles cases and three deaths have been reported to date.
Canada
According to the Public Health Agency of Canada on August 4, 2026, Canada has reported 1,109 measles cases (1,027 confirmed and 82 probable) in 2026 as of July 25. 61% of the cases occurred in children (668). Manitoba accounts for 61% of the cases (677), and Alberta accounts for 28% of the cases (311) reported so far in 2026. 86% of the cases reported in 2026 were unvaccinated (953), and 7% required hospitalization. A total of 6,534 measles cases and two deaths have been reported to date.
Influenza
According to the Centers for Disease Control and Prevention on July 31, 2026, 190 pediatric influenza deaths have been reported in the United States during the 2025-2026 flu season. In the latest weekly influenza surveillance report, two additional child deaths linked to influenza were reported.
H5N1
As of August 4, 2026, the Centers for Disease Control and Prevention has not reported any cases of person-to-person transmission of H5N1 in the United States. The total remains at 71 confirmed human cases and two deaths.
Mpox
From July 29-August 4, 2026, there have been no significant updates on mpox outbreaks worldwide.
Hantavirus
As there have been no significant updates for several weeks, Hantavirus will only be included in the report if new developments are reported.