Cat-scratch disease is a worldwide epidemic, first identified in 1889. The cat is the only natural host of the pathogen of this disease and the source of infection. This disease is caused by people being scratched by the cat or infected by its feces, which is characterized by local chronic lymph node enlargement.

When people are infected, the symptoms are local lymph node inflammation, swelling, pain, purulence, increased body temperature, rash on the limbs, and sometimes even meningitis. Serious systemic disease can occur in 3% of patients. Most cases are benign and self-limiting, and usually resolve within 2 to 4 months.

Etiology

• Bartonella henselae is the main pathogen of cat scratch disease. It is a Gram-negative Campylobacter. It is small and belongs to the Bartonella family of Rickettsia.

Modes of Transmission

• The main source of infection is cats, especially kittens and newly adopted cats, as well as dogs, monkeys and rabbits. There are no reports of human-to-human transmission. Cats with pathogens don't get sick.
• More than 90% of the patients have contact with cats or dogs, and 75% have been scratched or bitten by the animals. The mode of transmission is direct contact with pathogens, 50% of which can be caused by various injuries, resulting in infection, and 25% of which have no obvious skin damage.

Incubation Period

• The incubation period of cat scratch disease is 3 to 10 days.

Clinical Manifestations

• The clinical manifestations of the disease are diverse, with mild cases making up a large proportion.
• Primary skin lesions: 3 to 10 days after cat's scratch and bite, one to several erythematous papules appear locally, with no significant pain. A few papules turn to blisters or pustules, occasionally break through to form small ulcers. After 1-3 weeks, they leave a short period of pigmentation or scab and heal. Skin lesions are more common in the hands, forearms, feet, legs, face, eyes and other places, but can be ignored because of their mild symptoms.
• Systemic symptoms: mostly mild, with fever (>38.3°C), fatigue and anorexia, nausea, vomiting, abdominal pain and other gastrointestinal reactions, weight loss, headache, splenomegaly, sore throat and conjunctivitis. Conjunctivitis with preauricular lymph node enlargement is one of the important features of cat scratch disease.

Therapy

• Although the efficacy of antibiotic therapy has not been proven, Gentamicin 5 mg/kg/d intravenous drips for 5 days have been used to successfully treat adult systemic cat scratch disease. Other antibiotics that might be used include azithromycin, Rifampin, and Ciprofloxacin. In most cases, lymphadenopathy resolves spontaneously during follow-up visits. Aspiration of exudates can be used to prepare intradermal antigens and improve symptoms

Disease Distribution

• The disease is found throughout the world. It can occur in preschoolers and adults, but more than 60% of cases occur between 5 and 21 years of age.
• Travelers at risk for cat scratch disease: travelers are at low risk of catching the disease.

Prevention

• Reduce contact with cats, avoid being scratched or bitten when in contact with cats and dogs, immediately apply tincture of iodine or mupirocin ointment to the wound after being accidentally scratched or bitten, and observe the scratch and nearby lymph nodes frequently.
• In addition, limiting the exposure of pet cats to pathogens, such as restrictions on going out, can also play a certain role in prevention.