Feline Bartonella Infection: Signs, Diagnosis, Treatment, and Prevention
Sun, April 18, 2021

Feline Bartonella Infection: Signs, Diagnosis, Treatment, and Prevention



Domestic pets are susceptible to infection with different Bartonella species, said CDC (Centers for Disease Control and Prevention), a national public health institute in the US. Bartonella can also infect humans. As of this writing, there are over 36 recognized Bartonella species that are transmitted by various vectors like fleas and ticks, said Dr. Jason Stull of DVM 360, a news source dedicated to publishing content on veterinary practice needs.

Many of them are zoonotic, causing diseases in both animals and humans. Cats and dogs are the hosts for many Bartonella species, but other animals like rodents can also harbor Bartonella. Bartonella is well-known as the carrier of cat scratch disease (CSD), which is caused by the bacteria Bartonella henselae. Cats can have CSD if they are infected by the cat flea (Ctenocephalides felis). For Dr. Stull, CSD only scratches the surface of Bartonella infection.  


Molecular Survey of Bartonella Species In Shelter Cats In Rio De Janeiro (2019)

Juliana M. Raimundo and colleagues of the American Journal of Tropical Medicine and Hygiene, a monthly peer-reviewed journal, found that 83 of the 208 shelter cats sampled were positive for Bartonella species based on ITS and gltA gene results. The distribution of the Bartonella species infection in Rio de Janeiro, Brazil (Group 1) was 22.1%. In Group 2, which consisted of Duque de Caxias and other municipalities, the frequency distribution was (48.6%). Bartonella DNA was observed in fleas from cats infected by the bacteria. The researchers also found that felines were more frequently infected by Bartonella species during the period of March to June (52.2%) than from December to March (27.7%).

Of the 51 positive samples selected, sequencing confirmed B. henselae (68.6%), B. clarridgeiae (23.5%), and B. koehlerae (17.6%) infections in cats. Cases involving ITS and gltA sequences from a single same cat that corresponded to various feline Bartonella species were considered co-infections. Therefore, 5.9% and 3.9% of cats were concurrently infected with B. henselae plus B. clarridgeiae and B. clarridgeiae plus B. koehlerae, respectively. Further, cat fleas harbored B. henselae and B. clarridgeiae DNA. In fleas, no B. koehlerae species was detected.



Regarding the analysis of factors linked with Bartonella species bacteremia in felines, those that had present ectoparasite infestation were likely to have bacterial infection than those who don’t (42.5% and 22.2%). Cats that had a past ectoparasite infestation were more likely to be infected (45.2% and 32.1%). Those with present flea infestation were likely to be infected (47.2% and 32%). Both males (42.9%) and females (37.3%) had similar chances of getting infected with Bartonella species, so as with the age of the cats (young (≤1 year) 41.2%; adult (>1 year) 39.3%).

38.6% of symptomatic and 42.1% of asymptomatic cats had similar chances of becoming infected. Cats that exhibited respiratory signs (42.6%) or that were afflicted with Sporothrix species infection (39.3%) had bacterial infection. However, bacterial infection was less commonly seen in cats with oral (28.6%) or ocular (20%) signs and chronic diarrhea (16.7%). With regard to the hematological results for Bartonella infection, eosinophilia was found in 63.9% of Bartonella infection positive cats, along with hyperproteinemia (62.7%), thrombocytopenia (24.1%), and lymphopenia (2.4%).



Signs and Diagnosis of Bartonella Infection

Cats infected with Bartonella species do not exhibit clinical signs, noted Maria Grazia Pennisi and colleagues of the European Advisory Board on Cat Diseases (ABCD), an online advisory board on feline diseases. There are also cases when infected cats show “vague intermittent” signs that may manifest together with stress, immunocompromise, co-infection with another pathogen or concurrent illness. Bartonella infection has also been implicated as causing keratitis, conjunctivitis, uveitis, blepharitis, and chorioretinitis, explained Northwest Animal Eye Specialists, an animal hospital.

Conjunctivitis associated with Bartonella infection is commonly chronic and refractory “to a variety of treatments.” However, the infection can respond quickly to oral azithromycin therapy. It can be difficult to prove that Bartonella infection is the root cause of a feline’s clinical signs. However, your veterinarian will perform a diagnosis to evaluate the clinical signs along and a blood test to check for high level of antibodies.

However, using this technique can entail false negatives. When a false negative occurs, this means that the cat is infected but the antibody is negative. False negatives occur up to 11% of the time. Further, positive titers might only suggest exposure to Bartonella and not necessarily an active infection. Your veterinarian can also perform other diagnostic tests like blood culture and PCR. Like the above-mentioned technique, these diagnostic tests have their own disadvantages and can be more time-consuming and expensive.



Six months after the therapy, it is recommended to have your cat undergo repeat blood testing to assess the treatment plan’s adequacy, know as an “antibody titration test.” Titers are determined by serial dilutions on pre- and post-treatment blood samples. The test can be costlier and more time-consuming, as it can take as long as one month to get the results. On the other hand, initial tests only take about 10 to 14 days. Exposure history can also be used to confirm diagnosis. Screening a healthy cat (or dog) is generally not advised, even if it is sometimes requested due to zoonotic concerns, particularly if the owner is immunocompromised.


Treatment for Bartonella Infection

Azithromycin, an oral antibiotic, helps treat Bartonella infection, which can take three weeks. The side effects of this therapy include gastrointestinal issues such as decreased appetite, diarrhea, and vomiting. Managing flea problems are also helpful in preventing re-infection. Cats should be kept indoors to prevent the transmission of Bartonella. Keeping your cat indoors will reduce its risk of flea infestation and contact with stray cats.

Doxycycline or a combination of antimicrobials is advisable for treating Bartonella. Therapy is helpful, but bear in mind that it is infrequently curative. In fact, therapy is used to reduce bacterial load, relieve symptoms, and improve your cat’s quality of life. Treatment is advisable for animals exhibiting overt clinical signs of infection. To avoid scratches. avoid engaging in rough play with cats, especially kittens and free-roaming feral cats. This is important for individuals with weakened immune systems. If you or your loved one is scratched, wash the wound promptly with soap and water. Discourage immunocompromised individuals from owning or playing with young cats. Presently, there is no vaccine against Bartonella infection.



Bartonella can affect both dogs and cats. Since there is no vaccine, owners should focus on minimizing contact with fleas and other vectors. Owners should also take additional precautionary measures like avoiding bites and discouraging immunocompromised individuals from owning or playing with young cats.