Crash course: Zoonoses Flashcards by Georgia Leggett

What causes Brucellosis? What is it contracted from? When does it present?

Brucella spp.
Contracted from raw dairy + farm animals
After 2w incubation

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Give 3 features of brucellosis presentation

Sudden onset high fever, rigours, headache, malaise, myalgias

Back/ joint pain, hepatosplenomegaly, FLAWSy

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Which 2 ‘buzzword’ symptoms are associated with brucellosis

BACK PAIN as causes epidural abscess

EPIDIDYMO-ORCHITIS

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Give 3 serious manifestations of brucellosis

Endocarditis
Osteomyelitis
CNS infection

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What is used to diagnose and treat Brucellosis?

Dx: Cultures

Tx: Doxycycline + Streptomycin

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What causes Rabies? How is it contracted? When does it present?

Various Lyssaviruses
Contracted from animals: dogs + bats
After 1-3m incubation

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How does rabies present?

Initially: fever, headaches, malaise

Within days affects CNS: furious + dumb rabies

Excessive salivation, hydrophobia

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How is rabies diagnosed?

Often clinically
Dx: Fluorescent antibody test
CSF PCR possible (bad sign)
Biopsy from nape of neck

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What is pathogonomic for rabies?

Negri body on histology
(inclusion body in infected neurons)

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How is rabies treated?

Only before symptomatic

If bitten: pre-emptive rabies vaccine + immunoglobulins

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What causes plague? What is it contracted from? When does it present?

Yersinia pestis
Rat fleas
After hours- couple of days

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Give 4 features of bubonic plague

Fevers
Rigors
Buboes: massive LNs, when aspirated contain dense black fluid
Dry gangrene

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Give 4 features of pneumonic plague

Fevers
Rigors
Cough + bloody sputum
ARDS

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Give 4 features of septicaemic plague

Fevers
Rigors
DIC
Peripheral gangrene

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How is plague diagnosed and treated?

Dx: Microscopy, culture or PCR

Tx: Aminoglycosides or Doxycycline

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What causes Leptospirosis? What is it contracted from? When does it present?

Leptospira spp.
Rat urine
After 1w incubation

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What scenario may leptospirosis be contracted in?

swimming in lake with rat pee in (stagnant water)

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How can leptospirosis present?

Fevers, chills, rigors, myalgia, pharyngitis ± haemoptysis

Conjunctival suffusion, jaundice, meningitis

Pulmonary or GI haemorrhages, renal failure, haemolysis

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Give 2 buzzword symptoms of leptospirosis

JAUNDICE

CONJUNCTIVAL SUFFUSION (Dry conjunctivitis, no exudate)

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What causes Bartonellosis? How is it contracted? When does it present?

Bartonella henselae
Cat scratches
After 1w incubation

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How does Bartonellosis present?

Painless erythematous crusted papule at scratch site

Lymphadenopathy proximal to inoculation site

Fevers, malaise

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What presentation is pathogonomic for Bartenollosis?

Parinaud oculoglandular syndrome:
Conjunctivitis + enlarged LN in front of ear

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What causes Lyme disease? How is it transmitted? When does it present?

Borrelia spp.
Ixodes tick
After days-weeks incubation

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How does early localised Lyme disease present?

Erythema migrans, esp. inoculation site
“Bulls-eye” or “target” rash

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How does early disseminated Lyme disease present?

Fevers Myalgias Arthralgias CNS: headache, meningitis Cardiac: palpitations, heart block

How does late disseminated Lyme disease present?

Arthritis Skin lesions Polyneuropathies

How is Lyme disease diagnosed and treated?

Dx: Clinically if erythema migrans + exposure or rash biopsy/ serology Tx: Doxycycline Ceftriaxone if CNS involvement

What causes Leishmaniasis? How is it transmitted?

Leishmania spp. Sand fly bites

How does cutaneous Leishmaniasis present?

Well demarcated lesion at site of inoculation

How does mucocutaneous Leishmaniasis present?

Follows cutaneous, destructive lesions around face

How does diffuse cutaneous Leishmaniasis present?

Widespread nodular rash

How does visceral Leishmaniasis present?

Gradual onset fever Hepatosplenomegaly Pancytopenia Die of secondary infections if not treated

How is Leishmaniasis diagnosed and treated?

Dx: Microscopy Tx: Amphotericin B (for visceral- the form that will kill) Cutaneous harder to treat

What causes Anthrax? What is it found in? How is it spread?

Bacillus anthracis Found in farm/ wild animals Spread by spores in hair

What are the 3 major forms of presentation of Anthrax?

Cutaneous GI Pulmonary

How does cutaneous Anthrax present?

Boil that develops into an eschar Lymphadenopathy

How does GI Anthrax present?

Haemorrhage necrotic ulcers Lymphadenopathy Perforation

How does pulmonary Anthrax present?

Chest pain Haemoptysis SOB Haemorrhagic mediastinitis

What is an eschar?

Painless necrotic skin lesion Deep, dark, black

What 2 buzzword symptoms/ signs are associated with anthrax?

Eschars Widened mediastinum

List 4 dermatophytoses that can be treated topically

Tinea pedis – Athletes foot Tinea cruris – Groin Tinea corporis – Body Tinea manuum – Hands/ palms

Give 2 dermatophytoses that require systemic treatment

Tinea capitis – Scalp/ hair Tinea unguium – Finger/ toenails

Name 1 organism causing Tinea infection

Trichophyton rubrum

What causes Pityriasis versicolor? How does this present?

Malassezia furfur Multiple brown/ tan/ hypopigmented lesions across trunk, abdo + face

What is the treatment for Pityriasis versicolor?

Ketoconazole 2% shampoo

What are 2 topical treatments for tinea infections?

Clotrimazole 1% Terbinafine 1%

What are 2 oral treatments for tinea infections?

Itraconazole Terbinafine

What causes candidiasis?

Candida spp.

How does candidiasis most commonly present?

Vaginal candidiasis (thrush) + skin infections

Which population is oral candidiasis associated with?

Asthmatics- use steroid inhalers (thus encourage to wash mouth out after use)

Which population is oesophageal candidiasis associated with?

Severe immunosuppression- HIV

Which population is disseminated candidiasis associated with?

Those with a central line

What tests are diagnostic of candidiasis?

Beta-D-glucan +ve Galactomannan -ve

How can severe candidiasis be treated?

Amphotericin B

What causes Aspergillus?

Aspergillus spp

What is an aspergilloma? In which patients are these seen?

Ball of aspergillus that forms in pre-exisiting cavity Occur in patients with pre-existing cavity e.g. TB, squamous cell lung cancer, bronchiectasis

What does invasive aspergillosis involve? In which patients does this occur?

Pulmonary + extra pulmonary Immunocompromised/ those with a line infection

What is allergic bronchopulmonary aspergillosis?

Hypersensitivity reaction to colonisation Seen in asthmatics, profound inflammatory response NOT infection with aspergillus

What tests can be used to detect aspergillus?

Beta-D-glucan: +ve Galactomannan: +ve

What is the treatment for aspergillosis?

Aspergilloma: Surgical removal Invasive aspergillosis: Amphotericin B ABPA: Prednisolone

What causes sporotrichosis? How is it contracted?

Sporothrix schenckii Contracted from ROSE THORNs- seen in gardeners/ farmers

Describe presentation of sporotrichosis

Proximally spreading nodular necrotic rash from inoculation site Can disseminate, producing abscesses in bone, joints, CNS

What causes Mucormycosis? In which patients is it seen?

Rhizopus + Mucor spp. Patients that had covid esp. diabetics

Describe presentation of Mucormycosis

Rhinocerebral infection, necrotic, destroys tissue Vascular invasion follows Very high mortality

What is PrPc? What is its secondary structure?

Protein expressed on surface of neurones of brain 2 structure: Alpha-helical

What can PrPc misfold into? What causes this? What does this cause?

PrPSc: change in secondary structure: beta pleated sheets Sporadically, familially or infectiously Difficult to degrade, water-insoluble, forms big lumps of protein. Accumulation results in neuronal cell death

How does PrPSc interact with normal PrPc?

PrPSc can make PrPc misfold = propagation of protein that can't be moved or degraded + are neurotoxic

What is the most common form of prion disease?

Creutzfeldt-Jakob disease

What are the 3 forms of CJD?

Sporadic: 85% = unknown endogenous cause Familial: 5-15% = genetic mutation Acquired: <1%

How can CJD be acquired?

Acquires first dose of misfolded protein exogenously Iatrogenic: thus surgical instruments must be autoclaved Variant: acquired from eating beef with mad-cow disease (prion disease)

What is the proper name for mad cow disease?

bovine spongioformencephalopathy

How is CJD diagnosed?

Clinically + supported by imaging Can only be confirmed on biopsy postmortem

In which form of CJD can an alternative investigation be used to diagnose?

variant CJD Prion protein found in tonsils Ix: Tonsillar biopsy

Other than CJD, name 3 prion diseases

Kuru Gerstmann-Sträussler-Scheinker disease Fatal Familial Insomnia

What is Kuru disease?

Prion disease seen in Papau New Guinea Spread through ritual cannibalism

What is Gerstmann-Sträussler-Scheinker disease?

Autosomal DOMINANT familial prion disease Slower progression than others Life expectancy 5y

What is Fatal Familial Insomnia?

Autosomal DOMINANT familial prion disease Features prominent insomnia, paranoia, hallucinations