BITE TRANSMITTED ZOONOSES: Cat Scratch Disease

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BITE TRANSMITTED ZOONOSESCat Scratch Disease

• Etiologic agent
• Cat scratch disease
• Bartonella (Rochalimaea) henselae
• B. clarridgeiae recently reported
• Afipia felis (no clear link has been established
  yet name is acronym for Armed Forces Institute
  of Pathology)
• Bartonellosis (Carrions disease, Oroya fever)
• B. bacilliformis
• Trench fever, endocarditis, septicemia
• B. quintana
• Bacillary angiomatosis/bacillary peliosis
• B. henselae, B. quintana

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BITE TRANSMITTED ZOONOSESCat Scratch Disease

• Microbiology
• Bartonella (Rochalimaea) henselae
• gram negative rod
• not readily cultured - incubated 5-15 days at
  35C, 5 CO2
• small bacilli (2mm x 0.5mm)
• stain best with Gimenez
• indirect fluorescent antibody (IFA) - developed
  by CDC from Houston-1 isolate - used to detect
  establish organism as causative and to establish
  cats as reservoirs
• PCR diagnosis preferred but not readily available

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BITE TRANSMITTED ZOONOSESCat Scratch Disease

• Microbiology
• EM of B. henselae (x 50,000)

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BITE TRANSMITTED ZOONOSESCat Scratch Disease

• Epidemiology
• Reservoir
• B. henselae and B. clarridgeiae isolated from
  domestic cats worldwide
• seroprevalence studies indicate 14-44 of cats
  have antibodies to B. henselae
• infection in cats is asymptomatic with bacteremia
  lasting for several months

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BITE TRANSMITTED ZOONOSESCat Scratch Disease

• Epidemiology
• Transmission
• transmitted by bite or scratch from cat - termed
  traumatic cat contact
• kittens and cats lt 1 year of age may pose
  greatest risk
• fleas have been implicated as vectors, but their
  role in transmission is unclear
• fleas may play a role by facilitating reservoir
  maintenance in certain populations (cat to cat
  transmission?)

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BITE TRANSMITTED ZOONOSESCat Scratch Disease

• Epidemiology
• Incidence
• very common, encountered frequently by
  pediatricians
• CDC estimates that 22,000 visits each year 10
  which result in hospitalization
• in US, estimated to be from 1.8 to 9.3 cases per
  100,000
• difficult to ascertain due to lack of reliable
  diagnostic test and self-limiting nature of
  disease
• males possibly at greater risk than females
• up to 40 of cats in various studies have been
  found to be bacteremic

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BITE TRANSMITTED ZOONOSESCat Scratch Disease

• Epidemiology
• Risk factors
• cat ownership/contact
• young age (especially lt 20 yrs)
• contact with kitten poses greater risk
• flea-infested cats, particularly those living for
  the most part outdoors
• immunocompromised patients, particularly AIDS
  patients

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BITE TRANSMITTED ZOONOSESCat Scratch Disease

• Diagnosis
• CSD criteria (3 of 4 required for confirmed
  diagnosis)
• 1. history of cat traumatic contact
• 2. lymphadenopathy, exclusion of other causes
• 3. positive CD skin test
• 4. characteristic lymph node lesions (necrotizing
  granulomas surrounded by infiltrates and giant
  cells - best characterized by silver stain)
• skin test positive in 90 of cases, but false
  and false - are a problem, as is standardization
  being replaced with PCR
• serology - positive predictive value reported to
  be 91

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BITE TRANSMITTED ZOONOSESCat Scratch Disease

• Clinical manifestations
• Typical features (90 of cases)
• incubation period between 7 - 12 days (up to 30
  days)
• hallmark feature chronic lymphadenitis lasting
  4-6 weeks, may persist for up to 12 months
• fever up to 41C (106F) for 1-7 days
• headache, malaise, fatigue
• one or more small papules at site (2-5mm)
• typically benign, self-limiting, lasting 6-12
  weeks without treatment

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BITE TRANSMITTED ZOONOSESCat Scratch Disease

• Clinical manifestations
• papule at site of inoculation

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BITE TRANSMITTED ZOONOSESCat Scratch Disease

• Clinical manifestations
• regional swelling around scratch

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BITE TRANSMITTED ZOONOSESCat Scratch Disease

• Clinical manifestations
• Atypical features (up to 14 of cases)
• Perinauds oculoglandular syndrome
• conjunctival granuloma and adenopathy - painless,
  resolves spontaneously within 2-4 months
• encephalopathy
• rare complication, occurs in 1-7 of cases 2-6
  weeks after classic CSD
• encephalitis recently reported in 5 children in
  FL (19954)
• others (osteitis, thrombocytopenia purpura,
  hepatic granulomas, pulmonary disease)

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BITE TRANSMITTED ZOONOSESCat Scratch Disease

• Management
• Treatment
• supportive - antipyretics and analgesics
• antibiotics only in severe cases (gentamicin)
• local heat to involved lymph nodes
• if suppurated, aspiration to relieve pain
• incision and drainage should be avoided - could
  leave scar or draining fistula
• prognosis - generally benign, self-limiting
  (except in AIDS patients)
• patients with CNS involvement will completely
  recover within 1 year without neurologic sequelae

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BITE TRANSMITTED ZOONOSESCat Scratch Disease

• Management
• Prevention and control
• proper first aid and hygiene applied to all bites
  and scratches
• discourage rough play, particularly for children
• treatment of bacteremic cats may help reduce risk
• not necessary to remove cat from household unless
  in the presence of immunocompromised person, in
  which case testing, treatment, and long term
  monitoring of blood cultures may be viable
  alternatives to removal