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Cat or dog ownership and seroprevalence of Ehrlichiosis, Q fever, and cat-scratch disease.

Article Excerpt
Concerns have been raised about the role of domestic cats or dogs in the acquisition of zoonoses, in particular in pregnant women or immune-suppressed persons. We report that cat or dog ownership is not associated with an increased seroprevalence of antibodies to Anaplasma phagozytophilum, Coxiella burnetii, and Bartonella henselae in symptom-free persons in Styria, Austria.

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Keeping pet cats and dogs is very popular in Austria. However, these animals can serve as reservoirs for the agents of important bacterial infectious diseases and as a potential source of infection for humans, even though the infectious animals may be asymptomatic. Infections are potentially transmitted from domestic animals to humans by scratches, bites, or close contact. Examples for such infections include human granulocytic ehrlichiosis (Anaplasma phagocytophilum), cat-scratch disease (CSD, Bartonella henselae), and Q fever (Coxiella burnetii).

Cats are known to be the most important source of infections for B. henselae (aeroprevalence in Austrian cats is 33%) (1). However, dogs may also transmit B. henselae (2). Animals are contagious through their blood, which may contaminate saliva in cases of gum bleeding. Fleas from infected animals may contain the infectious agent, and bites from these fleas can transmit CSD. Typically, CSD is a benign and self-limiting disease in humans, occurring with lymphadenopathy, low-grade fever, primary cutaneous inoculation lesion, and weight loss, lasting 6-12 weeks. Rarely observed atypical signs and symptoms include erythema nodosum, figurate erythemas, thrombocytopenic purpura, Perinaud's oculoglandular syndrome, encephalopathy, hepatic granulomas, osteomyelitis, pulmonary disease, and optic neuritis (3). These severe manifestations occur in immunocompetent patients, whereas bacillary angiomatosis or peliosis hepatitis are more likely to develop in immunosuppressed patients.

C. burnetii infection has been associated with a chronic fatigue like syndrome (4). Both cats and dogs are well-described reservoirs for C. burnetii (5). In humans, C. burnetii infection usually is asymptomatic (60%) or manifests as a mild disease with fever, headache, myalgias, and spontaneous recovery (5). However, this infection may lead to serious complications and even death in patients with acute disease, especially those with meningoen-cephalitis and myocarditis and, more frequently, in chronically infected patients with endocarditis. Q fever in pregnancy has been associated with abortion, premature birth, and low weight in newborns (6,7).

Within the past several decades, the number of Ehrlichia and Anaplasma spp. recognized to infect cats, dogs, and humans has expanded substantially (8). The agent of human granulocytic ehrlichiosis (HGE) has recently been classified as A. phagozytophilum (9). The disease has influenzalike symptoms with variable degrees of anemia, thrombocytopenia, leukopenia, and elevated liver enzymes. Dogs are thought to be sentinels for assessing risk for HGE in humans (10). Cases of HGE in the United...