Zoonoses

Question 1

What is the WHO definition of zoonoses?

Answer 1

Infections that are naturally transmitted between vertebrate animals and humans

Question 2

Malaria, Schistosomiasis, Oncoceriasis and elephantiasis are NOT zoonoses. Why do these not classify as zoonoses?

Answer 2

Even though they are transmitted from animals, they depend on human host as part of life cycle

Question 3

What are examples of an anthroponosis (humans infecting animals. ‘Reverse zoonoses’?

Answer 3

> Influenza (virus infecting birds, pigs)
‘Strep throat’ (bacteria affecting dogs)
Leishmaniasis (parasite infecting dogs)
Chytridiomycosis (fungus affecting amphibians)

Question 4

List some examples of bacterial zoonoses? [7]

Answer 4

• Salmonella
• Campylobacter
• Shigella
• E. coli
• Leptospirosis
• Plague
• Psittacosis

Question 5

List some examples of viral zoonoses? [4]

Answer 5

• Rabies
• Avian influenza
• Ebola
• West Nile fever

Question 6

List some examples of parasite zoonoses? [4]

Answer 6

• Toxoplasmosis
• Cysticercosis
• Echinococcosis
• Visceral larva migrans

Question 7

What are fungal 2 and prion 1 zoonoses?

Answer 7

Fungal

• Dermatophytoses
• Sporotrichosis

Prions
-CJD

Question 8

What are examples of more common zoonoses in the UK? [5]

Answer 8

• Salmonella
• Campylobacter
• Toxoplasma
• Psittacosis: Chlamydophila psittaci
• Q fever: Coxiella burnetti
• Ringworm

Question 9

What are examples of rarely seen zoonoses in the UK? [5]

Answer 9

• Rabies
• Bubonic plague
• Tularaemia
• Acute brucellosis

Question 10

List some emerging zoonoses? (newly evolved/occurred previously but shows increase in incidence/expansion in geographical, host or vector range) [5]

Answer 10

• Avian influenza
• Nipah virus
• Rabies
• Brucellosis
• Monkeypox

Question 11

What is rabies and how is it transmitted?

What are 4 animals that are involved in its route of transmission

Answer 11

Viral infection (lyssavirus) transmitted via animal bite

Animals include dogs (97%), bats, monkeys, foxes, racoons

Question 12

What is the incubation period of rabies?

Answer 12

Can be 2 weeks to several months

Question 13

Rabies travels to brain via peripheral nerves. What does it then cause?
4 points
Death by…

Answer 13

Acute encephalitis

• Malaise, headache and fever
• Progress to mania, lethargy and coma
• Overproduction of saliva and tears
• Can’t swallow and hydrophobia
• Death by resp failure

Question 14

What is the diagnosis [2] and treatment [4] of Rabies?

Is diagnosis easy/difficult? When is a diagnoses most commonly made in reality?

Answer 14

Diagnosis

• PCR of saliva/CSF
• Difficult, often found on post mortem

Treatment

• Wash wound and immediately give post exposure prophylaxis: even if already previous vaccinated
• If previous immunization, 2 further doses of vaccine
• No previous immunisation, give human rabies immunoglobulin and full course of vaccination, around wound

Full course - 4 doses of rabies vaccine over 14d

Question 15

Brucellosis causing organisms are excreted in milk, placenta and aborted foetuses of livestock. When can humans become infected? [4]

Answer 15

> During milking infected animals
During parturition
Handling carcasses of infected animals
Consumption of unpasteurized dairy products

Question 16

Describe the Brucella organisms microscopic appearance

Answer 16

Small, gram negative coccobacilli

Question 17

Discuss the following about Brucella Melitensis (1st of 3 Brucella organisms)

• Human virulence
• Animal host
• Geographic area

Answer 17

• Most virulent in humans out of 3 organisms
• Goats, sheep and camels are hosts
• Mediterranean area

Question 18

Discuss the following about Brucella Suis (2nd of 3 Brucella organisms)

• Human virulence
• Animal host
• Geographic area

Answer 18

• Relatively virulent in humans
• Pigs are hosts
• N/S America, SE Asia

Question 19

Discuss the following about Brucella Abortus (3rd of 3 Brucella organisms)

• Human virulence
• Animal host
• Geographic area

Answer 19

• Least virulent in humans out of 3 organisms
• Cattle, buffalo are hosts
• Worldwide

Question 20

What is the incubation period of Brucellosis?

Answer 20

5-30 days (up to 6m)

Question 21

What do you see in an acute presentation of Brucellosis? (lasts 1-3 weeks) [4]

Answer 21

• High ‘undulant’ fever
• Weakness, headaches
• Drenching sweats
• Splenomegaly

Question 22

What do you see in a subacute presentation of Brucellosis? (>1m) [2]

Answer 22

• Fever

- Joint pains (knee, hip, back)

Question 23

What do you see in a chronic presentation of Brucellosis? (months/years) [5]

Answer 23

• Flu like symptoms, Malaise, Splenomegaly, Chronic arthritis
• Endocarditis
• Depression
• Epididymo-orchitis
• Rarely meningism

Question 24

In subclinical brucellosis, how many have positive serology?

Answer 24

50%

Question 25

What is the treatment for Brucellosis? [3] What would you give in CNS disease?

Answer 25

>Long acting Doxycycline 2-3 months >Rifampicin >IM gentamycin for first weeks Add cotrimoxazole for 2 weeks in CNS disease

Question 26

Regarding leptospirosis, what organisms cause it and how is it transmitted? [3] 2 Types

Answer 26

>Leptospira icterohaemorrhagica (fish) >Leptospira hardjo (cattle) is commonest form now Cattle, fish, rats

Question 27

What are the leptospirosis symptoms when infected with L. icterohaemorrhagica? [3]

Answer 27

- Flu symptoms - Jaundice - Renal failure

Question 28

What are the leptospirosis symptoms when infected with L. hardjo? [3]

Answer 28

- Fever - Meningism - No jaundice

Question 29

Leptospirosis organisms (spirochaetes) exist in contaminated water, mud and soil. What activities associated with these pose as risk factors? [7]

Answer 29

- Planting - Hunting - Gutting - Canoeing - Weeding - Fishing - Swimming

Question 30

What contact is needed for humans to be infected? [3] | What is the incubation period?

Answer 30

>direct contact with animal (cattle/fish/rats) >Contact with environment > contaminated with urine Incubation period 2-30 days (usually 10-14d)

Question 31

What are the symptoms of Leptospirosis? [4]

Answer 31

- Undifferentiated fever - Myalgia - Headaches - Abd pain

Question 32

What is the treatment for Leptospirosis? [3]

Answer 32

- Doxycycline for mild disesase, IV penicillin for severe - Prompt dialysis - Mechanical ventilation

Question 33

Lyme disease - most common pathogen in Europe | What is the causative organism?

Answer 33

By tick: -Ixodes ricinus (Europe) Causative organism: Borrelia burgdorferi

Question 34

Erythema Migrans presents in 80-90% of Lyme cases. When does it present after bite? Describe erythema migrans visible appearance

Answer 34

7-30 days after bite | Redness spreads and clears in middle forming a ring

Question 35

``` Acrodermatitis Chronica Atroficans presents in the late stage of Lyme disease. How does it present? Visible appearance Duration, progression Associated sx [1] Sites ```

Answer 35

>Bluish-red discolouration: progresses over months to years to atrophic phase >Peripheral neuropathy common > Extensor surfaces of distal extremities

Question 36

Lymphocytoma is more common in children than adults in Lyme sufferers. How does it present?

Answer 36

Bluish solitary painless nodule on earlobe or areola

Question 37

Neuroborreliosis presents in around 15% Lyme sufferers. How does it present? [3] When does it present

Answer 37

>2-6 weeks after bite >Facial nerve palsy >Radicular pain >Lymphocytic meningitis

Question 38

In America, what symptoms present more often in Lyme borreliosis?

Answer 38

Cardiac disorders (8-10%): Carditis, heart block Arthritis (large joints, often knees)

Question 39

How do you diagnose Lyme disease? [3]

Answer 39

>Erythema Migrans a clinical diagnosis >ACA plus lymphocytoma clinical and high serology titres >Arthritis v high serology titres from synovial fluid. PCR

Question 40

What is the treatment of Lyme disease? EM - 2 options, duration of course ACA - 3 options, dose and timing LNB - Lyme Neuroborrealiosis Disseminated infection

Answer 40

EM >Oral doxycycline/Amoxicillin 2 weeks ACA > PcV 2g TDS or amoxicillin > or Doxy 200mg OD 3/52 LNB > Doxy 200 mg OD 10-14 days > OR IV Ceftriaxone Disseminated infection: ceftriaxone

Question 41

``` Toxoplasmosis Pathogen What type of organism is it? Source How is it acquired by humans - 2 ways ```

Answer 41

Toxoplasma gondii Protozoan parasite Cats are the main source Humans acquire infection from oocysts in cat feces or from trophozoites in undercooked meat e.g. cattle, pigs, horses

Question 42

Clinical features of toxoplasmosis 3 features of acute form What is one feature of the acute form which necessitates prompt treatment in pregnant women? 3 clinical signs of chronic form 1 feature in both chronic and acute form [2]

Answer 42

Clinical features: - Acute form - pneumonia, fever, cough, rash - Acute infection during pregnancy can be transmitted to baby > congenital malformation - Chronic form - occipital lymphadenopathy, lymphocytosis, atypical mononuclear cells on blood film - chorioretinitis, uveitis

Question 43

Describe congenital form of toxoplasmosis [5]

Answer 43

``` Hydrocephalus Microphtalmos Microcephaly Convulsions Calcification in brain on x-ray ```

Question 44

Toxoplasmosis Ix [2] What is a positive result and what does it indicate Which test indicates acute infection

Answer 44

- Sabin Feldman dye test If positive within 1 month of infection, positive for life - IgM Abs indicate acute infection

Question 45

Toxoplasmosis Treatment (although most don't require treatment) 2 mainstays 2 modes of tx depending on case

Answer 45

sulfonamide + pyrimethamine folate antagonist