Bacterial Zoonoses
A bacterium is a member of a large group of unicellular microorganisms which have cell walls but lack organelles and an organised nucleus. The diseases caused by bacteria are known as bacterial diseases.
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Cat Scratch Disease
Cat scratch disease is an infection caused by a bacterium known as Bartonella henselae. The cat fleas usually transmit to cats and they, in turn, transmit the disease to humans by bites or scratches. There are not many studies about this disease in India. This disease closely resembles tuberculosis and haematological malignancies. In India, it is a cause of fever and lymphadenopathy in children. This disease is considered an emerging disease worldwide.
Asymptomatic cats with Bartonella henselae in their mouth act as vectors of this disease. They spread it by clawing and butting the skin. Horizontal transmission from cat to cat occurs via cat fleas (Ctenocephalides felis). These fleas or ticks can also transmit the disease to humans in rare cases. This disease is more common in children than in adults. It is usually a self-limiting disease.
In humans-
- A primary skin lesion that starts as a vesicle at the inoculation site
- tender, regional, unilateral lymphadenopathy
- Lymph nodes may eventually develop pus
- Body ache, malaise, anorexia and fever can be observed
- Lymphadenopathy may be observed for months
- Rare cases of meningoencephalitis, endocarditis and ocular involvement may be observed.
- Seizures may occur that are self-limiting but can last up to a year.
In animals-
- Cats may get a fever for 2-3 days following the infection but are usually asymptomatic.
- Other animals like dogs may show signs like-
- Fever
- Vomiting
- Lethargy
- Red eyes
- Swollen lymph nodes
- Decreased appetite
Serology by Indirect Fluorescent Assay or ELISA may be performed. PCR is another technique used to diagnose this disease.
Cats and dogs should ideally be placed on preventative flea medication such as Fipronil or methoprene. Permethrin should not be used on cats. You should contact your vet to discuss the right preventative measure for your pet. An immunocompromised individual should avoid hanging out with cats. Strict hand hygiene rules should be followed at homes especially the ones with animals. As of now, no vaccines are available for the treatment of this disease.