Study links cat fleas to rise in murine typhus cases in Texas
Researchers found Rickettsia typhi DNA in cat fleas from the Rio Grande Valley, confirming a potential pathway for the flea-borne disease that has hospitalized hundreds in South Texas.
A study by Texas A&M College of Veterinary Medicine and Biomedical Sciences detected the bacterium Rickettsia typhi in cat fleas collected from domestic cats in the Rio Grande Valley. DNA from the pathogen was found in fleas from six of 167 sampled cats, providing direct evidence that pets can serve as reservoirs for murine (flea-borne) typhus.
The Texas Department of State Health Services reports more than 6,700 cases of the disease in the region between 2008 and 2023. Hospital records from the University of Texas Medical Branch show that 119 of 149 adult patients diagnosed between 2019 and 2023 required hospitalization, with 33 admitted to intensive care and two deaths recorded.
"Metro Health monitors reports of flea-borne murine typhus, which is endemic in Bexar County. Our data dashboard shows rates above pre-pandemic levels in 2023 and 2024," a spokesperson for the City of San Antonio Metropolitan Health District said, adding that residents should use insect repellents, treat pets for fleas and limit rodent contact.
Experts emphasized a "One Health" approach, noting that while cats rarely show severe illness, controlling fleas on pets is a simple preventive measure for humans. Dr. Sarah Hamer of Texas A&M warned that increased numbers of pet and stray cats, limited access to affordable flea control and warmer temperatures likely contribute to the resurgence.
Murine typhus, once nearly eliminated in the United States after 1940s vector-control campaigns, has re-emerged in parts of Texas and California, prompting public-health officials to monitor and advise on flea-prevention strategies.
