R2 Talk

Zoonotic Diseases

Ian Kidder, MD

Mentor: Poorani Sekar, MD

Zoonoses Handout

·         Zoonoses are infections acquired by direct or indirect contact with animals

·         6 out of 10 infections are zoonotic

Household pets (cats and dogs)

·         Pasteurella

o   Normal part of feline oral flora = contract from cat bites

o   Cellulitis + purulent drainage + lymphangitis

o   Treat with amoxicillin-clavulanate

·         Rabies

o   Bites from infected animals

o   Negri bodies on histology

o   CNS infection w/ hydrophobia and aerophobia

o   Exposure treatment = rabies immunoglobulin + vaccination

·         Capnocytophaga

o   From dog bites/licks

o   Asplenia or liver disease = risk of cellulitis –> sepsis + DIC, loss of limbs

o   Treat with ampicillin-sulbactam

·         Bartonella (“cat-scratch disease”)

o   Due to cat scratch or bite

o   Painless papule/pustule at inoculation site + subacute regional lymphadenopathy

o   Treatment = drainage of LN purulence + azithromycin (if extensive)

Farm animals

·         Coxiella (“Q fever”)

o   Infection from aerosolized amniotic fluids of livestock

o   Acute presentation = flu-like, pneumonia, and hepatitis

o   Persistent localized infection = endocarditis, bone/joint or vascular infections

o   Treat with doxycycline (add hydroxychloroquine for persistent localized infxn)

·         Brucella (“undulant fever”)

o   Infection from unpasteurized dairy products or birth product aerosols

o   Undulating pattern of fevers + non-specific systemic symptoms (often MSK pain)

o   Associated with culture-negative infections (including endocarditis)

o   Treat with doxycycline + rifampin or streptomycin

Other exposures

·         Leprosy (Mycobacterium leprae)

o   Route of transmission uncertain (but not typically skin-to-skin contact)

o   Tuberculoid leprosy (Th1 response) = hypopigmented + numb macules/plaques

o   Lepromatous leprosy (Th2 response) = skin nodules/plaques + leonine facies

o   Treat with dapsone + rifampin

·         Tularemia

o   Found in rodents and ticks

o   Portals of entry = inhalation, mucous membranes, skin (think bites)

o   3 primary presentations:

§  Ulceroglandular/glandular = +/- ulcer w/ regional lymphadenopathy

§  Oropharyngeal/oculoglandular = pharyngitis, cervical lymphadenopathy, conjunctivitis

§  Pneumonic = imaging shows infiltrates, hilar lymphadenopathy, pleural effusions

o   Treat with streptomycin, doxycycline, or tetracycline

·         Yersinia (plague)

o   Transmission from rodents to humans via fleas

o   In US, mostly western states and “Four Corners” area

o   Three forms: bubonic, septicemic, and pneumonic

o   Treat with streptomycin

·         Leptospira

o   Source = rodent urogenital tract

o   Contract from contaminated water (e.g. via a cut or scrape)

o   Usually presents as mild flu-like illness

o   Severe cases = hemorrhagic diathesis, jaundice, and AKI (aka Weil’s syndrome)

o   Treatment = IV penicillin