NAME: Bartonella henselae
SYNONYM OR CROSS REFERENCE: Formerly Rochalimaea henselae. Cat-scratch diseaseFootnote 1-Footnote 3, cat-scratch fever Footnote 4, and zoonotic bartonellae Footnote 3 are caused by Bartonella henselae. Infection may cause bacteremia, endocarditis, bacillary angiomatosis, bacillary hepatis, peliosis hepatis Footnote 5.
CHARACTERISTICS: B. henselae is of the Bartonellaceae family, and appear as fastidious aerobic, short, Gram-negative rods (0.2 to 0.6 µm by 0.5 to 1.0 µm) Footnote 3, Footnote 4. They can be found in capillary walls near site of entry upon infection Footnote 4. The optimal growth temperature varies from 35°C to 37°C Footnote 3.
PATHOGENICITY/TOXICITY: Cat-scratch disease: In 50 % of the cases, a small skin lesion appears at the inoculation site, and evolves from a papule to a vesicle and partially healed ulcers Footnote 3. Symptoms include low grade fever and lymphadenopathy 2 weeks after cat scratch, lick, or bite of cat flea bite Footnote 1, Footnote 4. Headaches, sore throat and conjunctivitis, malaise, anorexia, and chills are common Footnote 3, Footnote 4. Atypical manifestations occur in 5-10% of those infected Footnote 3, Footnote 6. The most common is Parinaud's oculoglandular syndrome (periauricular lymphadenopathy and palpebral conjunctivitis); Meningitis, encephalitis, osteolytic lesions, and thrombocytopenic purpura may occur. Encephalopathy is one of most serious complications of cat-scratch disease and usually occurs within 2-6 weeks after onset of lymphadenopathy and usually resolves with complete recovery. New clinical presentations associated with immunocompromised patients have been reported Footnote 3, Footnote 6. Neuroretinitis or bacteremia can lead to chronic fatigue syndrome Footnote 3. One case of aggressive endocarditis has been linked to B. henselae in a cat owner Footnote 3. Bacillary angiomatosis is characterized by vascular proliferative lesion observed, mainly in patients with AIDS Footnote 3, Footnote 6. B. henselae has been linked to HIV-associated brain lesions, meningoenchephalitis, encephalopathy, dementia, and neuropsychological decline Footnote 3. Rheumatic manifestations are also related to Bartonella infection in humans, including erythema nodosum, leukocytoclastic vasculitis, and fever of unknown origin with myalgia and arthralgia Footnote 3.
EPIDEMIOLOGY: Worldwide distribution Footnote 3. It is estimated that approximately 20,000 human cases of cat-scratch disease /annum occur in US Footnote 3, Footnote 4 where one third of cats carry the bacterium Footnote 4. Fifty five to eighty percent of cat-scratch disease cases occur in patients under 20 years old Footnote 3, Footnote 6. Immunosuppressed individuals in the general population are at an increased risk of bacillary angiomatosis infection Footnote 4. The prevalence of infections is usually highest in warm and humid climates, where cat fleas are abundant Footnote 3. There is a seasonal pattern, with most cases seen in fall and winter Footnote 3, Footnote 6.
INFECTIOUS DOSE: Unknown.
MODE OF TRANSMISSION: The cat flea (Ctenocephalides felis) is thought to be the major vector by which the cat becomes infected Footnote 2, Footnote 3. Humans become infected with B. henselae by direct or indirect contact with kittens or cats harboring the organism. Humans rarely become infected following exposure to animals other than cats Footnote 1, Footnote 7. The role of cat fleas in human transmission seems limited Footnote 3, Footnote 7. Human infection results from inoculation of infective flea feces at time of injury Footnote 3.
COMMUNICABILITY: Human-to-human transmission has not been documented.
RESERVOIR: Cats Footnote 3, Footnote 4, Footnote 6 and dogs Footnote 7.The domesticated housecat, Felis catus, is the most important natural host for B. henselae. Approximately 10% of pet cats and 33% of feral cats are bacteremic with the organism Footnote 1.
VECTORS: The cat flea (Ctenocephalides felis) is the major vector for animal hosts Footnote 1, Footnote 4; there is some evidence suggesting cat flea bites may lead to human infection Footnote 1, Footnote 7.
DRUG SUSCEPTIBILITY/RESISTANCE: B. henselae is susceptible to several antibacterial agents Footnote 1. Rifampin, ciprofloxacin, gentamicin, trimethoprim, and sulfamethoxazole have the greatest effect Footnote 1. Erythromycin, doxycycline, isoniazid, and rifampin have been effective in treatment of bacillary angiomatosis in immunocompromised patients Footnote 1.
DRUG RESISTANCE: Penicillins, cephalosporins, tetracycline, and erythromycin have little to no clinical effect in cat-scratch disease. Resistance to macrolides Footnote 8 and to fluoroquinolones Footnote 9 has been observed.
SUSCEPTIBILITY TO DISINFECTANTS: Information specific to B. henselae is not available, but most bacteria have been shown to be susceptible to low concentrations of chlorine, 70% ethanol, phenolics such as orthophenylphenol, ortho-benzyl-paua-chlorophenol, 2% aqueous glutaraldehyde, peracetic acid (0.001% to 0.2%) Footnote 10, Footnote 11.
PHYSICAL INACTIVATION: Information specific to B. henselae is not available, but most bacteria can be inactivated by moist heat (121°C for 15 min - 30 min) and dry heat (160-170°C for 1-2 hours) Footnote 12.
SURVIVAL OUTSIDE HOST: Unknown.
SURVEILLANCE: Monitor for symptoms. Identification can be done by histology tests of lymph node biopsy sample, indirect fluorescent antibody assay (IFA), polymerase chain reaction (PCR) assay, restriction fragment length polymorphism (RFLP) assay, and serological tests Footnote 3, Footnote 6, Footnote 7.
Note: All diagnostic methods are not necessarily available in all countries.
FIRST AID/TREATMENT: The majority of cases of cat-scratch disease occurring in normal hosts do not require anti-infective therapy for resolution of infection Footnote 1. Cat-scratch disease is usually self-limiting within several weeks Footnote 3, Footnote 6 If an antibiotic regime is required tetracycline or erythromycin are effective treatments Footnote 4.
LABORATORY-ACQUIRED INFECTIONS: No documented cases Footnote 7.
PRIMARY HAZARDS: Scratches, bites, and/or licks from infected laboratory animals Footnote 7.
SPECIAL HAZARDS: None.
RISK GROUP CLASSIFICATION: Risk Group 2 Footnote 13.
CONTAINMENT REQUIREMENTS: Containment Level 2 facilities, equipment, and operational practices for work involving infectious or potentially infectious materials, animals, or cultures.
PROTECTIVE CLOTHING: Lab coat. Gloves when direct skin contact with infected materials or animals is unavoidable. Eye protection must be used where there is a known or potential risk of exposure to splashes Footnote 14.
OTHER PRECAUTIONS: All procedures that may produce aerosols, or involve high concentrations or large volumes should be conducted in a biological safety cabinet (BSC). The use of needles, syringes, and other sharp objects should be strictly limited. Additional precautions should be considered with work involving animals or large scale activities Footnote 14.
SPILLS: Allow aerosols to settle and, wearing protective clothing, gently cover spill with paper towels and apply an appropriate disinfectant, starting at the perimeter and working towards the centre. Allow sufficient contact time before clean up Footnote 14.
DISPOSAL: Decontaminate all wastes that contain or have come in contact with the infectious organism before disposing by autoclave, chemical disinfection, gamma irradiation, or incineration Footnote 14.
STORAGE: The infectious agent should be stored in leak-proof containers that are appropriately labelled Footnote 14.
REGULATORY INFORMATION: The import, transport, and use of pathogens in Canada is regulated under many regulatory bodies, including the Public Health Agency of Canada, Health Canada, Canadian Food Inspection Agency, Environment Canada, and Transport Canada. Users are responsible for ensuring they are compliant with all relevant acts, regulations, guidelines, and standards.
UPDATED: November, 2010
PREPARED BY: Pathogen Regulation Directorate, Public Health Agency of Canada
Although the information, opinions and recommendations contained in this Pathogen Safety Data Sheet are compiled from sources believed to be reliable, we accept no responsibility for the accuracy, sufficiency, or reliability or for any loss or injury resulting from the use of the information. Newly discovered hazards are frequent and this information may not be completely up to date.
Public Health Agency of Canada, 2010