Los Angeles County West Vector & Vector-Borne Disease Control District


    There is now evidence that ticks may be a significant transmitter of the Bartonella infection to humans.  A study in California showed that a minimum of 2.3% of a pool of 1253 Ixodes pacificus ticks tested positive for Bartonella.  Additionally, it appears that the Dermacentor species of ticks are also capable of transmitting the Bartonella bacteria.

    Early symptoms of Bartonella include a red, crusted, elevated skin lesion where the bacteria enters its host (which can mimic the Lyme disease enlarging rash), followed by flu-like symptoms of fever, muscle and joint aches/pains, nausea, vomiting, and chills.  Also, enlargement of the lymph nodes around the ears is often present.  More serious symptoms include encephalitis, which can result in headaches, dementia, seizures, coma, inflammation of the heart, abdominal pain, bone lesions, and loss of vision. Studies also indicate that some Lyme disease patients are also infected with Bartonella.  Treatment with multiple antibiotics is becoming more common in these situations.

    The genus Bartonella, a group of small, weakly-staining, gram-negative bacteria, includes two species currently of human medical importance in the United States.  These are B. henselae and B. quintana, .

  • CAT-SCRATCH DISEASE (B. henselae)
    (Cat-Scratch Fever)

    An infection caused by Bartonella henselae, characterized by regional lymphadenitis after a papule at the site of a cat scratch or tick bite. (see photo at right of cat scratch lesion on thumb)

    The domestic cat is a major reservoir for B. henselae. The prevalence of B. henselae antibodies in cats in the USA is 14 to 50%. In one study, 41% of pet cats had bacteremia, although all were asymptomatic. Most of the implicated felines are healthy. The cat flea may be an additional vector.

  • TRENCH FEVER   (B. quintana) 

    A bacterial infection recognized in soldiers in World War I has been reported uncommonly and sporadically around the world, including the United States.
        B. quintana rarely causes endocarditis in homeless, urban alcoholic men and bacillary angiomatosis, bacteremia, and other disseminated infections in AIDS patients. In patients with normal immune systems, trench fever caused by B. quintana presents as prolonged or recurrent fevers with a prolonged period of bacteremia, but with a low fatality rate. Body lice are a known vector for this disease.

Bartonella Infections in Immunocompromised Patients

    Disseminated B. henselae and B. quintana infections may cause several different pathologic entities in immunocompromised patients, most often those with AIDS. 

    The most common manifestation is bacillary angiomatosis, characterized by protuberant, reddish, berrylike lesions on the skin, often surrounded by a collar of scale. 

(Information on this page obtained from the Merck Manual of Diagnosis and Therapy)
(Photo provided by The Centers for Disease Control)

How Can Tick Borne Illnesses be Prevented?