1
Q
What is zoonoses?
A
- Infections that can pass between living animals and humans
- The source of the disease is from the animal
- Infections that are naturally transmitted between vertebrae animals and humans
2
Q
Why are malaria, snail fever, river blindness and lymphatic filariasis not considered zoonoses?
A
Even though transmitted from animals, they depend on the human host for part of their life-cycle
3
Q
What is anthroponosis?
A
‘Reverse zoonoses’ in that humans are infecting animals
4
Q
Give examples of anthoponosis.
A
- Influenza (virus affecting birds, pigs)
- ‘Strep throat’ (bacteria affecting dogs)
- Leishmaniasis (parasite affecting dogs e.g.)
- Chytridiomycosis (fungus affecting amphibians)
5
Q
What can cause zoonoses?
A
- Virus
- Bacteria
- Fungus
- Parasites
6
Q
What strategies have pathogens developed to ensure their own survival/propagation?
A
- Causing a chronic infection to survive
- Have a non-human reservoir
7
Q
Give examples of bacteria zoonoses.
A
- Salmonella
- Campylobacter
- Shigella
- Anthrax
- Brucella
- E-coli (verotoxigenic)
- Leptospirosis
- Plague
- Psittacosis (Ornitosis)
- Q fever
- Tularaemia
8
Q
Give examples of virus zoonoses.
A
- Rabies
- Avian influenza
- Crimean-Congo haemorrhagic fever (CCHF)
- Ebola virus disease
- Lassa Fever
- Rift Valley fever
- West Nile Fever
- Yellow Fever
9
Q
Give examples of parasite zoonoses.
A
- Cysticercosis
- Echinococcosis
- Toxoplasmosis
- Trichinellosis
- Visceral larva migrans (toxocara)
10
Q
Give examples of fungi zoonoses.
A
- Dermatophytoses
- Sporotrichosis
11
Q
Give examples of prion zoonoses
A
BSE/CJDv
12
Q
What are common zoonoses in the UK?
A
- Salmonella
- Campylobacter
- Toxoplasma
- (Psittacosis: Chlamydophila psittaci)
- (Q-fever: Coxiella Burnetti)
- Ringworm/dermatophytosis
13
Q
What zoonoses are now rarely seen in the UK?
A
- Anthrax
- Rabies
- Bubonic plague
- Tularaemia
- Acute brucellosis
14
Q
What is an emerging zoonoses?
A
A zoonosis that is newly recognized or newly evolved, or that has occurred previously but shows an increase in incidence or expansion in geographical, host or vector range
15
Q
Give examples of emerging zoonoses.
A
- Avian influenza
- Nipah virus
- Rabies
- Brucellosis
- Monkeypox
16
Q
What is rabies
A
Viral Infection (lyssavirus) transmitted from the bite of an infected animal
17
Q
What animal can transmit rabies?
A
Wide range of wild animal transmitters:
- Dogs (97%), bats
- Also monkeys, foxes, racoons, skunks, wolves, cats
18
Q
How many people die from rabies per year?
A
App. 55000 people, mainly children, die each year
19
Q
What is the incubation period for rabies?
A
2 weeks to several months
20
Q
What happens once the rabies virus enters the body?
A
It travels to the brain via the peripheral nerves and causes an acute encephalitis
- Malaise, headache & fever
- Progressing to mania, lethargy & coma
- Over production of saliva & tears
- Unable to swallow & ‘hydrophobia’
- Death by respiratory failure
21
Q
How is rabies diagnosed?
A
- Diagnosis is difficult
- PCR of saliva or CSF
- Often confirmed post mortem on brain biopsy
22
Q
How should rabies be treated?
A
It is always fatal if left untreated so immediately after bite give post-exposure prophylaxis:
- Human rabies immunoglobulin (HRIG)
- Infiltrated round the bite (if possible)
- +4 doses of rabies vaccine over 14 days
23
Q
How is brucellosis transmitted?
A
Organisms are excreted in milk, placenta and aborted foetus
24
Q
How are humans infected with brucellosis?
A
- During milking infected animals
- During parturition
- Handling carcasses of infected animals
- Consumption of unpasteurized dairy products
25
What organism is responsible for brucellosis?
Brucella, a small gram negative coccobacilli
26
What are the 3 species of brucella?
- Melitensis
- Suis
- Abortus
27
What are the features of the melitensis species of brucella?
- Most virulent in man
- Goat, sheep and camel host
- Found in the Mediterranean, S. America, China, India and the Middle East
28
What are the features of the suis species of brucella?
- Pig host
| - Found in N. America, S. America and SE Asia
29
What are the features of the abortus species of brucella?
- Least virulent in man
- Cattle and buffalo host
- Found worldwide
30
What is the incubation period for brucellosis?
5-30 days (up to 6 months)
31
What is the acute presentation of brucellosis?
Lasts 1-3 weeks
- High ‘undulant’ fever
- Weakness, headaches
- Drenching sweats
- Splenomegaly
32
What is the subacute presentation of brucellosis?
Lasts over 1 month
| -Fever and joint pain (knee, hip, back SI joints)
33
What is the chronic presentation of brucellosis?
Lasts for months or years
- Flu-like symptoms
- Malaise
- Depression
- Chronic arthritis
- Endocarditis
- Epidiymo-orchitis
- Rarely meningism
- Splenomegaly
34
What is the subclinical presentation of brucellosis?
Most common form
| -50% of exposed have positive serology
35
What is the treatment for brucellosis?
- Long acting Doxycycline for 2-3 months + Rifampicin, or + intramuscular gentamycin for first week(s)
- Relapses occur due to intracellular organism (5-10%)
- Chronic form – difficult to treat
- Add Cotrimoxazole for 2 weeks in CNS disease
36
What organism causes leptospirosis?
- L. icterohaemorrhagica from rats
| - L. hardjo from cattle
37
What is another name for leptospirosis?
Rat fever
38
How does L.hardjo infection present?
- Fever
- Meningism
- NO JAUNDICE
39
How does L. icterohaemorrhagica infection present?
Flu-like symptoms then jaundice and renal failure
40
What are the featres of leptospira?
```
Thin, highly mobile spirochaetes
-One of the most widespread
Zoonosis
-Many reservoir host
-Survive in the environment
for weeks to months
-Penetrate abraded skin or
mucous membranes and
cause systemic illness-
```
41
How is the epidemiology of leptospirosis changing?
- Used to be an occupation disease
| - Now outbreaks associated with recreational challenges. unexplained emergences and disaster associated outbreaks
42
How do humans contact leptospirosis?
- Humans are incidental hosts
- Direct contact with the animal
- Contact with environment (water) contaminated with their urine
43
What is the incubation period for leptospirosis?
2-30 days (10-14)
44
What are the symptoms of leptospirosis infection?
- Undifferented fever
- Myalgia
- Headaches
- Abdominal pain
45
What symptoms can occur in severe leptospirosis?
- Weil’s disease (Triad of jaundice, AKI, bleeding)
- Pulmonary haemorrhage (PH)
- Case fatality 5-40%, >50% in PH
46
How is leptospirosis diagnosed?
- Microscopic agglutination test (MAT) requires paired sera – not useful in clinical context
- ELISA serology - suboptimal
- PCR?
- Culture – take at least one week on special media
-Think of the diagnosis in contect of the patient's history
47
What is the treatment for leptospirosis?
Early treatment
- Doxycline for mild disease
- IV penicillin for severe disease
- Prompt dialysis
- Mechanical ventilation
48
How is Lyme borrelios transmitted?
Tick (Ixodes ricinus in Europe)
49
When is Lyme disease most common?
Summer months ( ticks active >4C and in humid conditions)
50
What organism is responsible for Lyme disease in Europe?
Borrelia burgdoferi
51
What is erythema migrans?
- A rash associated which can provide the clinical diagnosis of Lyme disease
- Single or multiple lesions
- Occur in 80-90% of cases
- Appears 3-90 days after the bite (7-30)
52
What is acrodermatitis chronic atroficans?
- A late manifestation of Lyme disease
- Occurs in elderly people
- Bluish-red discolouration of the extensor surfaces of distal extremities which progresses over monthe to years to atrophic phase
- Peripheral neuropathy is common
53
What is lymphocytoma?
- A bluish solitary painless nodule that usually occurs on the earlobes or areola
- More common in children
- Can occur in Lyme disease
54
What is neuroborreliosis?
- A triad of facial nerve palsy, radicular pain (migratory and worse at night) and lymphocytic meningitis
- Onset 2-6 (1-2) weeks after tick bite (Lyme's)
- Often preceded by EM
55
What symptoms of Lyme disease are more common in the USA?
Cardiac disorders
- Carditis (peri-myocarditis)
- Heart block
Arthritis
-Large joints, often knees
56
How is Lyme disease diagnosed?
- EM by clinical observation
- ACA and lymphocytoma: high serology titres
- Arthritis: very high serology titres of synovial fluid and PCR
- Neuro symptoms consistent with LNB & other causes excluded
- CSF pleocytosis (WBC in CSF), often lymphocytic
- Paired blood and CSF serolgoy
57
What is the treatment for Lyme disease?
- Oral Doxycycline or Amoxicillin, or IV Ceftriaxone
| - Most manifestations treat for 21 days (28 in arthritis or ACA)
Systems: Infection AB
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