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?

Answer 4

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

Question 5

List some examples of viral zoonoses?

Answer 5

• Rabies
• Avian influenza
• Ebola
• West Nile fever

Question 6

List some examples of parasite zoonoses?

Answer 6

• Toxoplasmosis
• Cysticercosis
• Echinococcosis
• Visceral larva migrans

Question 7

What are fungal and prion zoonoses?

Answer 7

Fungal

• Dermatophytoses
• Sporotrichosis

Prions
-CJD

Question 8

What are examples of more common zoonoses in the UK?

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?

Answer 9

• Anthrax
• Rabies
• Bubonic plague
• Tularaemia
• Acute brucellosis

Question 10

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

Answer 10

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

Question 11

What is rabies and how is it transmitted?

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?

Answer 13

Acute encephalitis

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

Question 14

What is the diagnosis and treatment of Rabies?

Answer 14

Diagnosis

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

Treatment
-Immediately give post exposure prophylaxis: Human rabies immunoglobulin around bite (if possible)

Question 15

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

Answer 15

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

Question 16

Describe the Brucella organisms 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)

Answer 21

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

Question 22

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

Answer 22

• Fever

- Joint pains (knee, hip, back)

Question 23

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

Answer 23

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

Question 24

In subclinical brucellosis, how many have positive serology?

Answer 24

50%

Question 25

What is the treatment for Brucellosis? What would you do 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?

Answer 26

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

Question 27

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

Answer 27

- Flu symptoms - Jaundice - Renal failure

Question 28

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

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?

Answer 29

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

Question 30

How does humans become infected with Leptospirosis?

Answer 30

Penetrated abraded skin or mucous membranes

Question 31

What contact is needed for humans to be infected? What is the incubation period?

Answer 31

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

Question 32

What are the symptoms of Leptospirosis?

Answer 32

- Undifferentiated fever - Myalgia - Headaches - Abd pain

Question 33

Severe Leptospirosis occurs in 5-15% patients. How does it present?

Answer 33

- Weils disease (Triad of jaundice, AKI, bleeding) - Pul. haemorrhage - Fatality 5-40%, >50% in pul. haem.

Question 34

How do you diagnose Leptospirosis?

Answer 34

``` >Microscopic agglutination test >ELISA serology >PCR >Culture >Noticing clues eg fever in cattle farmer, exposed to water or rats ```

Question 35

What is the treatment for Leptospirosis?

Answer 35

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

Question 36

Lyme disease is most common in summer months (active >4 degrees). How is it transmitted?

Answer 36

By tick: - Ixodes ricinus (Europe) - Ixodes scapularis pacificus (N America) - Ixodes persulcatus (Asia)

Question 37

Erythema Migrans preddents in 80-90% of Lyme cases. When does it present after bite?

Answer 37

3-90 days after bite (usually 7-30d). Used as clinical diagnosis

Question 38

Acrodermatitis Chronica Atroficans presents in the elderly sufferers of Lyme disease. How does it present?

Answer 38

>Bluish-red discolouration: progresses over months to years to atrophic phase >Peripheral neuropathy common

Question 39

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

Answer 39

Bluish solitary painless nodule on earlobe/areola

Question 40

Neuroborreliosis presents in around 15% Lyme sufferers. How does it present?

Answer 40

>2-6 weeks after bite usually >Facial nerve palsy >Radicular pain >Cranial nerve palsy - facial palsy, in 50%

Question 41

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

Answer 41

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

Question 42

How do you diagnose Lyme disease?

Answer 42

>Erythema Migrans a clinical diagnosis >ACA and lymphocytoma clinical and high serology titres >Arthritis v high serology titres from synovial fluid. PCR >Exclude other causes of neuro symptoms >CSF pleocytosis, often lymphocytic >Paired blood and CSF serology

Question 43

What is the treatment of Lyme disease?

Answer 43

>Oral doxycycline/Amoxicillin | >IV Ceftriaxone