Among the many animals infected with the bacterial species of Bartonella, dogs and cats represent a large reservoir for human infection because most Bartonella species are zoonotic, meaning that they can be transmitted from pet to human. While the role of dogs as a reservoir of Bartonella infection for humans is less clear, transmission from cats via bites/scratches and through fleas are believed to be the more common scenario.
The most common Bartonella species transferred from cat to human is known as cat scratch disease, as typically cat scratches or bites in those cats positive for Bartonella may result in human infection. Cat scratch disease can be a serious human health threat, so it is important that any person scratched or bitten by a cat be evaluated as soon as possible by their physician.
Approximately 20% of healthy cats living in the United States may be positive for Bartonella. Although many cats may show no clinical symptoms, these cats remain infected for years or for the life of the pet. While the bacteria may cause varied systemic symptoms in affected cats, oral, respiratory or eye symptoms are the most common ones seen in some cats and may include gingivitis/stomatitis, upper respiratory symptoms such as sneezing and discharge, as well as inflammation of the cornea and inner chambers of the eye. Occasionally, chronic digestive tract symptoms may occur, as well as enlarged lymph nodes on exam and fevers of unknown origin.
All healthy cats should be tested, especially those with some of these symptoms, as well as especially those cats from shelter or high stress situations, and cats with flea infestations where infection rates are highest. There are special blood antibody tests, as well as PCR testing that may identify positive cats. Treatment of infected cats includes not only several weeks of Doxycycline antibiotic therapy, but also the implementation of strict flea control. With early detection and diagnosis, prognosis for recovery is usually excellent