The benefit
When most pet owners think about tick-borne diseases, dogs tend to come to mind first. But a new study suggests that cats—often overlooked in conversations about tick-borne illness—may be carrying these pathogens at surprisingly high rates. Understanding what researchers found could help you better protect your cat and, in some cases, your entire household.
The science
Ticks transmit a range of pathogens (disease-causing microorganisms) to the animals they feed on. Among the most studied in veterinary medicine are Anaplasma species—bacteria that infect white blood cells and can cause fever, lethargy, and joint pain—and Hepatozoon species, single-celled parasites that invade white blood cells and muscle tissue. Both are spread primarily through tick bites, and both have been documented in dogs in many parts of the world.
Cats are known to interact with ticks, yet they receive far less attention in tick-borne disease research. This gap matters because cats that carry these pathogens may serve as silent reservoirs—hosts that sustain pathogens in the local environment without always showing obvious clinical signs. If cats are frequently infected but rarely tested, the true scope of tick-borne disease in pet populations may be underestimated.
What the study did
Researchers screened blood samples from 93 shelter cats using PCR (polymerase chain reaction)—a molecular test that detects tiny traces of pathogen DNA even when the animal shows no symptoms. PCR is widely considered the most sensitive method for identifying tick-borne pathogens in blood, making it more reliable than antibody tests in cases of early or low-level infection.
The study population consisted entirely of shelter cats, providing a cross-section of cats that had likely had varied outdoor or semi-outdoor exposure before entering the shelter. By testing this group, the researchers aimed to assess how common tick-borne pathogen DNA was among cats in a real-world, non-clinical setting.
Key findings
The study found high rates of Anaplasma DNA in the shelter cat population—a finding the authors described as exceeding what might typically be expected. Hepatozoon DNA was also detected in a portion of the cats screened. Together, these results show that multiple tick-borne pathogens can circulate among cats at meaningful prevalence levels.
Equally significant was what this implies about cats’ ecological role. Because cats are often allowed to roam outdoors, interact with wildlife, and encounter ticks in a wide range of environments, they may act as bridge hosts—animals that carry pathogens between wildlife reservoirs and domestic settings. This positions cats as a potentially important, if underappreciated, link in the chain of tick-borne disease transmission in the areas where they live.
Real-world application
For cat owners, these findings carry a clear message: tick prevention is not just a dog issue. Cats that spend time outdoors—or even cats that share a home with dogs who go outside—may be at real risk of acquiring tick-borne pathogens. And because infected cats may not display obvious symptoms, illness can go undetected without deliberate screening.
At the same time, the public health dimension is worth noting. Tick-borne pathogens that circulate among local animal populations can, in some cases, affect human health as well. Cats that bring ticks indoors from outdoor environments can potentially introduce infected ticks into the home. Reducing the tick burden on your cat is therefore not only about your pet’s health—it may reduce risk to the whole household.
How to implement
- Ask your veterinarian about tick prevention products specifically approved for cats. Some products safe for dogs are toxic to cats, so never use dog tick preventatives on a cat without veterinary guidance.
- If your cat goes outdoors—or even spends time on a screened porch, patio, or in a garden—discuss regular tick checks and parasite screening at wellness visits.
- For cats that hunt small mammals or birds, the risk of tick exposure is especially high. These cats may warrant more frequent parasite monitoring.
- If your cat develops unexplained fever, lethargy, loss of appetite, or joint stiffness, mention the possibility of tick-borne illness to your veterinarian, even if you have not seen ticks on your pet.
- Indoor-only cats are at lower risk, but ticks can occasionally enter the home on clothing, bags, or other pets—so some vigilance remains appropriate.
What to expect
Most cats infected with Anaplasma or Hepatozoon do not develop severe disease, and some remain entirely asymptomatic. However, cats with underlying health conditions or compromised immune systems may be more vulnerable to illness. Regular veterinary wellness exams, which can include bloodwork and parasite screening, are the most reliable way to catch subclinical (no-symptom) infections before they progress.
Potential concerns
- Tick prevention compliance in cats can be challenging. Some cats resist topical products, and not all owners are aware that tick preventatives are available and recommended for cats.
- Shelter environments may not be representative of all domestic cat populations. Cats in shelters may have had more outdoor exposure prior to intake, which could mean the prevalence detected here is higher than in a purely indoor pet population.
- The detection of pathogen DNA by PCR does not always indicate active disease. A positive result means the pathogen’s genetic material is present; it does not confirm that the cat is clinically ill or infectious to others.
Study limitations
The study was conducted in a shelter setting, which means the findings may not directly reflect the prevalence of tick-borne pathogens in all domestic cats. Shelter cats may have had higher outdoor exposure and therefore higher tick contact than the average household cat. The researchers noted that the results may not be representative of all domestic cat populations, and broader surveys across different settings and regions would help clarify how widespread these findings are. The study also did not assess clinical outcomes, so the health impact of these infections on the individual cats was not determined.
Bottom line
A PCR study of 93 shelter cats found high rates of Anaplasma and Hepatozoon DNA—two tick-borne pathogens—in blood samples, and the results suggest that cats may play a more significant role in local tick-borne disease cycles than many pet owners and clinicians currently appreciate. The practical takeaway is straightforward: cats in tick-prone environments need consistent, veterinarian-approved external parasite control, and owners should be aware that tick-borne illness is not limited to dogs. Discuss tick prevention and screening options for your cat at your next veterinary visit, especially if your cat spends any time outdoors.
Disclaimer
This article summarizes peer-reviewed research for educational purposes. Always consult with your veterinarian for personalized advice about your pet’s health and behavior.