![\"A](\"https:\/\/www.newsbeep.com\/us-tx\/wp-content\/uploads\/2026\/07\/Dr.-Hamer_Dr.-Balasubramanian_feline-flea-research-20260616-NP-25-1408x939.jpg\")
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Dr. Sarah Hamer (left), a professor in the Department of Veterinary Integrative Biosciences, and Dr. Sujata Balasubramanian, an associate research scientist, review research data as part of a study examining flea-borne pathogens in South Texas cat populations.<\/p>\n
Credit: Nadya Pichkasova\/Texas A&M University College of Veterinary Medicine and Biomedical Sciences<\/p>\n
As human cases of flea-borne murine typhus continue to occur in South Texas, researchers\u00a0are working to better understand the role cats and their fleas may play in the disease\u2019s transmission cycle.<\/p>\n
In\u00a0a recent study<\/a>, researchers at the\u00a0Texas A&M College of Veterinary Medicine and Biomedical Sciences (VMBS)<\/a> detected DNA from\u00a0Rickettsia typhi\u00a0\u2014 the bacterium that causes flea-borne murine typhus \u2014 in cat fleas (Ctenocephalides felis) collected from domestic cats in the Rio Grande Valley, a region that consistently reports some of the highest numbers of human cases of murine typhus in Texas.<\/p>\n The findings provide new insight into the pathogens carried by cat fleas and demonstrate how closely animal, human and environmental health are linked.<\/p>\n Tracking an emerging threat<\/p>\n Flea-borne murine typhus is a bacterial disease that can infect humans when flea feces containing\u00a0R. typhi\u00a0enter the body through a bite site or mucous membrane and can typically be treated with antibiotics. Its incidence has steadily increased in Texas over the past decade, particularly in South Texas \u2014 with more than 6,700 cases being reported in the region between 2008 and 2023, according to the Texas Department of State Health Services.\u00a0\u00a0<\/p>\n \u201cThe last time flea-borne typhus was rampant, rats and rat fleas were the main reservoir and vector,\u201d said Dr. Sujata Balasubramanian<\/a>, an associate research scientist in the VMBS and first author of the study. \u201cNow, there is a layer of cat fleas contributing to this uptick.\u201d<\/p>\n Despite the Rio Grande Valley consistently reporting some of the state\u2019s highest numbers of flea-borne typhus cases, relatively little is known about the prevalence of\u00a0R. typhi\u00a0among cats and cat fleas in the region.<\/p>\n \u201cPeople have cats as pets and often befriend and feed stray cats,\u201d Balasubramanian said. \u201cDespite the awareness that cat fleas can carry and transmit\u00a0R. typhi, we do not have a good understanding of\u00a0R. typhi\u00a0carriage in cats or cat fleas, not even in the areas of higher incidence of flea-borne typhus.\u201d<\/p>\n Fleas reveal multiple zoonotic pathogens<\/p>\n When the research team tested fleas collected from domestic cats for several disease-causing pathogens, it detected\u00a0R. typhi\u00a0in fleas removed from six of the 167 cats sampled, providing some of the first data on the pathogen\u2019s presence in cat flea populations in the region.<\/p>\n Cat fleas collected as part of a Texas A&M study are examined for the presence of disease-causing bacteria, including Rickettsia typhi, the pathogen responsible for flea-borne murine typhus.<\/p>\n Credit: Nadya Pichkasova\/Texas A&M University College of Veterinary Medicine and Biomedical Sciences<\/p>\n Researchers also identified\u00a0Bartonella henselae\u00a0and\u00a0Bartonella clarridgeiae\u00a0in the fleas and cats. Both bacteria are associated with cat scratch disease, a zoonotic infection that can be transmitted from cats to humans.<\/p>\n Although\u00a0R. typhi\u00a0was detected in fleas from a relatively small number of cats, researchers say the findings help fill an important knowledge gap about the pathogens carried by cat fleas in an area where human cases of murine typhus continue to occur.<\/p>\n While the study did not directly examine transmission between cats, fleas and people, the findings provide a clearer picture of the pathogens circulating within flea populations in a region where human cases continue to occur.<\/p>\n The study also highlights the importance of a One Health approach, which recognizes the connections among animal health, human health and the environment.<\/p>\n \u201cLike all vector-borne diseases, there are many pieces of the puzzle needed for the successful transmission of murine typhus,\u201d said Dr. Sarah Hamer<\/a>, a professor in VMBS\u2019\u00a0Department of Veterinary Integrative Biosciences<\/a>. \u201cWe must think about the ecology of the disease, which includes the interactions of the right species of flea with cats or opossums \u2014 both of which can serve as hosts for the fleas and bacteria. Humans serve as an accidental host when hungry fleas find us instead of an animal.\u201d<\/p>\n Several factors may be contributing to the continued presence of flea-borne murine typhus in South Texas.<\/p>\n \u201cThere are only a few places in the U.S. where murine typhus is recognized to be transmitted with some regularity and, unfortunately, that includes South Texas,\u201d Hamer said. \u201cThe increased abundance of pet cats and stray or feral cats, socioeconomic conditions that prevent access to affordable flea protection on cats, and warming temperatures likely all promote flea infestation of cats and transmission of the bacteria that causes typhus.\u201d<\/p>\n Because the disease depends on interactions among fleas, animals, people and the environment, researchers say understanding those relationships is essential for identifying risks and developing effective prevention strategies.<\/p>\n Protecting pets and people<\/p>\n Although cats typically do not become seriously ill from\u00a0R. typhi, controlling flea infestations remains an important step in protecting both animal and human health.<\/p>\n Dr. Sarah Hamer holds a cat in her office. Hamer studies vector-borne diseases and the role of animals and arthropods, including fleas, in the transmission of zoonotic pathogens.<\/p>\n Credit: Nadya Pichkasova\/Texas A&M University College of Veterinary Medicine and Biomedical Sciences<\/p>\n \u201cIf we can help to control flea infestations on cats, we also reduce the chance that fleas will become infected with the bacteria and reduce the chance that infected hungry fleas will hop onto a human instead of a cat,\u201d Hamer said. \u201cWhat we do to help animal health can also protect human health.\u201d<\/p>\n Rather than indicating that cats themselves post a threat to people, the findings highlight the importance of controlling flea populations.<\/p>\n \u201cFleas and other ectoparasites can spread disease agents that not only make our pets sick, but they can make us sick as well,\u201d she said. \u201cKeeping cats indoors where they can\u2019t interact with wildlife and working with your veterinarian to provide flea and tick control for cats can help minimize chances of disease transmission.\u201d<\/p>\n Continuing the search for answers<\/p>\n Researchers say the study is only the beginning of efforts to better understand how flea-borne murine typhus circulates among animals, fleas and people in South Texas.<\/p>\n \u201cWe know rats, rat fleas, cats, cat fleas and opossums can carry\u00a0R. typhi,\u201d Balasubramanian said. \u201cMore sampling and more studies are imperative.\u201d<\/p>\n Future work would focus on identifying factors that influence its circulation and determining how risks vary among pet, stray and feral animal populations.<\/p>\n \u201cBecause of all the changes in wildlife populations, climatic conditions and human land use, continued surveillance and research is the only way we can gather data to understand these changing risks for human and animal health,\u201d Hamer said.<\/p>\n More information: Rickettsia typhi, Bartonella henselae, and related zoonotic agents in fleas from domestic cats (Felis catus) from the Rio Grande Valley, Texas![\"A](\"https:\/\/www.newsbeep.com\/us-tx\/wp-content\/uploads\/2026\/07\/Dr.-Hamer_Dr.-Balasubramanian_feline-flea-research-20260616-NP-18-1408x939.jpg\")
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DOI: 10.1186\/s13071-026-07421-1<\/a>
https:\/\/link.springer.<\/a>com\/article\/10.1186\/s13071-026-07421-1<\/a><\/p>\n