Trends in Reported Babesiosis Cases-United States, 2011-2019

What is already known about this topic?Babesiosis is an emerging zoonotic tickborne parasitic disease in the United States and occurs primarily in the Northeast and Midwest.What is added by this report?During 2011-2019, U.S. babesiosis incidence significantly increased in northeastern states. Three states (Maine, New Hampshire, and Vermont) that were not considered to have endemic babesiosis had significantly increasing incidences and reported case counts similar to or higher than those in the seven states with known endemic transmission.What are the implications for public health practice?As case rates rise in multiple states, tick prevention messaging, provider education, and traveler risk awareness should be emphasized.

Automated summary

This report reveals a significant increase in babesiosis incidence in the northeastern states of the United States from 2011 to 2019. In addition to the known endemic areas, three states (Maine, New Hampshire, and Vermont) that were not considered to have endemic transmission also experienced a significant increase in incidence, with case counts similar to or higher than the seven known endemic states. Public health practice should focus on strengthening tick prevention messaging, provider education, and traveler risk awareness.