The number of Legionnaires’ disease cases in north central Marshalltown has risen to 34, according to the latest update from the Iowa Department of Health and Human Services on Tuesday.

UPDATE: September 16, 2025:

MARSHALLTOWN, Iowa — Health officials in Iowa continue to investigate a growing outbreak of Legionnaires' disease in Marshall County. Since August, there have been 61 reported cases.

Experts are focusing on cooling towers in north-central Marshalltown as a potential source of the outbreak after mapping out where patients spent most of their time before falling ill.

Officials are urging building owners to disinfect all cooling centers on their properties. The exact cause of the disease remains unknown.

UPDATE - September 15, 2025:

MARSHALLTOWN, Iowa — The latest numbers from

See Full Page