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BARTONELLA HENSELAE (Cat Scratch Disease)

Note for Pet Owners:
Bartonella henselae is a zoonosis. Zoonoses are diseases that are transmissible between animals and humans. Some of these diseases are extremely serious and potentially life-threatening others cause only transient, mild disease. At the time an animal appears ill there is no way of knowing whether or not it is a zoonosis. For this reason it is important to follow basic hygiene precautions such as washing hands after handling animals, not allowing animals to soil eating implements or plates. If your animal is ill use protective plastic gloves and clear up and dispose of any mess (eg urine and faeces) as soon as possible .

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Description

Cat scratch disease is a self-limiting condition in humans in which a local lymphadenopathy (inflammation and painful enlargement of the lymph nodes) occurs following a cat bite, scratch and possibly licks. In humans, most cases of cat-scratch disease occur in children aged of 2 to 14, and in veterinarians, and  most cases occur in the autumn or winter months.

Cause

The most common cause of this syndrome  is the arthropod-transmitted gram-negative bacterium Bartonella spp, usually B.henselae, but also B.clarridgeia.   Bartonella spp live inside red blood cells (erythrocytes) and apparently healthy cats often carry the organism in their blood without showing any clinical signs.  It can be transmitted to other cats by blood transfusion.

B.vinsonii subsp berkoffi may be transmitted by the brown dog tick and it has been associated with endocarditis cases, and with granulomatous lymphadenitis in dogs.

Afipia felis is a gram-negative pleomorphic bacterium that has been isolated from a few human patients with cat-scratch disease, and which used to be thought to be the main cause.

Other Bartonella include :
Bartonella species Reservoir Disease
Bartonella bacilliformis human Carrionīs disease/Verruga peruana
Bartonella quintana human Trench fever, bacteraemia, bacillary angiomatosis, endocarditis
Bartonella henselae cats Cat scratch disease, bacillary angiomatosis, bacteremia, endocarditis
Bartonella elizabethae rats Endocarditis
Bartonella grahamii Retinitis
Bartonella vinsoni dogs Endocarditis, bacteremia
Bartonella washonsis rodents Myocarditis
Bartonella clarridgiae cats Bacteremia
Bartonella rochalimae human Carrionīs disease like syndrome

 

 

Breed Occurrence
There is no reported breed predilection, although most cases are thought to occur following contact with a young kitten.. 

The overall prevalence rate in cats in the USA is 28% with geographical variability from 4% (Midwest) to 60% (SE) and infection rates are higher in cats with fleas and those living in  warm, high humidity environments.

Signs

Cats : Many cats can carry the organism in their blood (called bacteraemia) for long periods (years) without showing any signs. If they do show signs these may be fever (48-72 hours), lethargy, depression, staring into space, postural deficits in limbs, reduced appetite, lymph node enlargement, inflammatory lesions in multiple organs.

Humans : 3-30 days (usually 7-12 days) following a bite, scratch or lick pimples occur near to the site and these can last for 4 weeks. Local lymph nodes swell and become painful. Some discharge pus. This stage may be accompanied by fever , headache, and reduced appetite. Swelling of the lymph nodes usually goes down within 6 weeks, but it has been reported to last up to 1 year. 

Complications


Humans : Immunocompromised patients may develop complications beyond the lymph node enlargement, including :

  • AIDs encephalopathy (proposed)
  • Arthritis
  • Bacillary angiomatosis
  • Endocarditis
  • Granulomatous hepatosplenic syndrome
  • Papilloedema (optic nerve swelling)
  • Peliosis
  • Pulmonary granuloma (transplant patients)
  • Relapsing fever (with bacteraemia)
  • Retinitis

Diagnosis

Humans : Diagnosis is made from the clinical signs and history, and confirmed by detecting antibodies or isolation of the organism from blood samples, or aspirates or biopsies taken from the lymph nodes.

Treatment

Cats : Amoxicillin, amoxicillin-clavulanate, doxycycline and enrofloxacin may be effective in reducing the bacteraemia due to Bartonella spp, but to avoid development of resistant species antibiotic treatment is best reserved for cats owned by immunocompromised people.

Humans : The disease is self-limiting and no treatment is necessary, however antibiotics (usually doxycycline, erythromycin and rifampin) may shorten the course of the disease.

Control of fleas and other potential vectors is an important part of prevention of infection for both cats and humans.

Prognosis

Good

Long term problems

None reported. Cats used as blood donors should be screened for this disease.

 

Updated January 2016