Zoonoses

Question 1

Define zoonoses

Answer 1

Diseases that pass between living animals and humans (where animals are the source of the disease)

Question 2

What are anthroponoses?

Answer 2

Diseases spread from humans to animals

Question 3

Give examples of anthroponoses

Answer 3

Influenza (virus infecting pigs, birds), strep throat (bacteria infecting dogs), leishmaniasis (parasite infecting dogs), chytridiomycosis (fungus affecting amphibians)

Question 4

Toxoplasmosis only tends to infect humans when they are what?

Answer 4

Immunosupressed

Question 5

What are the common zoonoses in the UK?

Answer 5

Salmonella
Campylobacter
Toxoplasmosis
Psittacosis
Q-fever
Ringworm

Question 6

What causes psittacosis?

Answer 6

Chlamydophilia psittaci

Question 7

What causes Q-fever?

Answer 7

Coxiella burnetti

Question 8

What causes ring worm?

Answer 8

Dermatophytes

Question 9

What zoonoses are rarely seen in the UK now?

Answer 9

Anthrax
Rabies
Bubonic plague

Question 10

What is anthrax?

Answer 10

Bacteria spread by contact with bacterial spores (often in infected animal products)
Can lead to skin/lung/GI disease

Question 11

What is bubonic plague spread by?

Answer 11

Insects & small animals

Question 12

What is tularaemia?

Answer 12

Bacterial infection transmitted by ticks, deer flies, infection animals
Presents with fever, skin ulcer, tenderness, regional lymphadenopathy

Question 13

Define emerging zoonoses

Answer 13

Zoonosis that is newly recognised/evolved/that previously occurred but now shows an increase in incidence/expansion in geographical/host/vector range

Question 14

Give examples of emerging zoonoses

Answer 14

Avian influenza
Nipah virus (SE Asia --> severe encephalitis) 
Rabies
Brucellosis
Moneypox

Question 15

What is monkey pox?

Answer 15

Similar to small pox

Flu like stage –> eruption of maculopapules which develop into vesicles –> pustules & crusts

Question 16

What is rabies infection with?

Answer 16

Lyssavirus

Question 17

How is rabies spread?

Answer 17

Transmission via saliva from bite by infected animal

Question 18

What animals tend to be carriers for rabies?

Answer 18

Mostly dogs and bats

Also monkeys, foxes, racoons, skunks, wolves, cats

Question 19

What is the incubation period for rabies?

Answer 19

2wks-several months

Question 20

How does rabies virus spread in the body?

Answer 20

Travels to brain via peripheral nerves

Further the bite is away from brain, the longer it will take to travel

Question 21

Once rabies reaches the CNS what is the prognosis?

Answer 21

100% fatal

Question 22

What is the clinical presentation of rabies?

Answer 22

Acute encephalitis:
Malaise, headache, fever, mania, lethargy, coma
Unable to swallow
Hydrophobia (involuntary pharyngeal muscle contraction when try to drink - pathognomic)

Question 23

How do most people die of rabies?

Answer 23

Respiratory failure

Question 24

How do you diagnose rabies?

Answer 24

PCR of saliva/CSF

Mostly confirmed on post-mortem brain biopsy

Question 25

How do you Rx rabies?

Answer 25

Immediately after bite give PEP: Cleaning & debridement Human rabies Ig (esp around wound if poss.) 4 doses of rabies vaccine over 14 days

Question 26

Who did brucellosis used to affect?

Answer 26

Farmers, vets, slaughterhouse workers

Question 27

Where are the brucellosis organisms excreted?

Answer 27

Milk, placenta, aborted foetus

Question 28

When are humans at risk of being infected with brucellosis?

Answer 28

Milking/birthing infected animals Handling carcasses of infected animals Drinking unpasteurized diary products

Question 29

When sending a suspected brucellosis sample to the lab what must you do?

Answer 29

Warn them as it may spread in lab

Question 30

How do you diagnose brucellosis?

Answer 30

Culture with prolonged intubation time & serology

Question 31

What kind of microorganism is brucellosis?

Answer 31

Small, gram -ve coccobacilli

Question 32

What are the three species of Brucella and where do they mostly come from?

Answer 32

Melitensis - goat, sheep, camel Suis - pig Abortus - buffalo, cattle

Question 33

What is the incubation period for Brucella?

Answer 33

5-30d

Question 34

What are the symptoms of brucellosis?

Answer 34

Acute (1-3wk): high, undulant fever, weakness, headaches, drenching night sweats, splenomegaly Subacute (>1m): fever & joint paints (knee, hip, SI joints) Chronic (m-yrs): flu like symptoms, malaise, depression, chronic arthritis, endocarditis, epididymo-orchitis, rarely meningism, splenomegaly Subclinical (most common)

Question 35

What should make you think brucellosis?

Answer 35

Unspecific acute presentation, sweating, travel Hx, nonresponsive to antibx

Question 36

How do you Rx brucellosis?

Answer 36

Long acting doxycycline for 2-3m & rifampicin/IM gentamycin for first weeks Add cotrimoxazole for 2 weeks if CNS dx

Question 37

What causes leptospirosis?

Answer 37

Spirochaete Leptospira interrogans | Mostly L. hardio from cattle

Question 38

What symptoms does L. hardio leptospirosis lead to?

Answer 38

Fever, meningism

Question 39

What are the life cycle of leptospira like?

Answer 39

Survive in environment for weeks/months | Direct transmission to humans via broken skin/mucous membrane & contact with infected animal urine

Question 40

Why is the incidence of leptospirosis increasing?

Answer 40

Recreational, e.g. increased white water rafting etc. Unexplained emergence in Thailand Climate change/disaster assoc, e.g. floods

Question 41

What is the incubation period of leptospirosis?

Answer 41

2-10d

Question 42

What are the symptoms of leptospirosis?

Answer 42

Undifferentiated fever, myalgia, headaches, abdominal pain

Question 43

How do you manage leptospirosis?

Answer 43

85% get better & don't need Rx 10-15% get severe dx: Weil's disease/pulmonary haemorrhage

Question 44

What triad do you get in Weil's disease?

Answer 44

Jaundice, AKI, bleeding

Question 45

When should you think about leptospirosis?

Answer 45

Fever in cattle farmer Exposure to rats/water Someone who works in an abattoir Vets/sewage workers

Question 46

What tests should you do for leptospirosis?

Answer 46

Culture (blood/CSF), serology & PCR

Question 47

How do you Rx leptospirosis?

Answer 47

Doxycycline for mild dx IV penicillin for severe Haemodialysis Mechanical ventilation

Question 48

What causes lyme disease?

Answer 48

Borrelia burgdirferi (spirochaete) found in wild deer

Question 49

What transmits lyme disease?

Answer 49

Tick (lxodes Ricinus) which active above 4C | Usually nymph that carries it

Question 50

What are the stages of lyme disease?

Answer 50

``` Early, localised (3-30d): target board erythema migrans Early disseminated (wks-months): borrelial lymphocytoma (bluish/red plaque/nodule - check earlobes, nipples, genitalia), may also get neuroborreliosis or cardiac disorders (peri-myocarditis/heart block) & arthritis (more in USA) Late disseminated (months-yrs): acrodermatitis chronica atroficans, lyme arthriris, peripheral neuropathy ```

Question 51

What is ACA?

Answer 51

Focal inflammation then atrophic skin | Caused by infection with B. afzelii

Question 52

What is lyme arthritis?

Answer 52

Bluish-red discolouration of extensor surfaces of extremities most commonly

Question 53

How do you diagnose lyme disease?

Answer 53

EM can be diagnosed clinically ELISA - if +ve/equivocal --> immunoblot test to confirm ELISA -ve - repeat in 4-6 weeks if still suspected ACA/lymphocytoma - clinical and high serology titres Arthritis - serology titres from synovial fluid/PCR

Question 54

How do you Rx lyme disease?

Answer 54

Oral doxycycline/amoxicillin IV ceftriaxone if disseminated Treat 21 days (28 for arthritis/ACA)

Question 55

How is leptospirosis 'classically' spread?

Answer 55

Infected rats urine

Question 56

What is leptospirosis aka?

Answer 56

Weil's disease (although this term is sometimes reserved for the most severe cases associated with jaundice)

Question 57

What reaction is sometimes seen after initiating antibiotics to treat Lyme disease?

Answer 57

Jarisch-Herxheimer reaction