Infection caused by Corynebacterium diphtheriae; outbreaks raise mortality risk if untreated.
The diphtheria outbreak in Australia has reached multiple states and territories, with the Northern Territory reporting hundreds of cases and at least one death. Health authorities warn vaccination rates are driving transmission, while Indigenous communities are disproportionately affected. Officials say cases are now decreasing after peaking earlier in 2026.
The CDC reports an early West Nile virus surge with dozens of cases across multiple states, including Arizona. Authorities warn of higher risk this summer and emphasize bite prevention as mosquito activity rises.