Zoonoses Flashcards
(28 cards)
What are zoonoses?
Infections that can pass between living animals and humans
Which infections are not considered zoonoses because they depend on the human host for part of their life-cycle?
- Malaria
- Schistosomiasis
- Oncoceriasis (River blindness)
- Elephantiasis
What are anthroponosis, give examples?
- “Reverse zoonoses”: humans infecting animals
- E.g. influenza, strep throat, leishmaniasis and chytridiomycosis
Give examples of common zoonoses in the UK
Salmonella, campylobacter, toxoplasma, psittacosis (chlamydophila psittaci), Q fever (coxiella burnetti) and ringworm
Give examples of uncommon zoonoses in the UK
Anthrax, rabies, bubonic plague, tularaemia and acute brucellosis
What is Rabies and how is it transmitted?
- Viral infection caused by the lyssavirus
- Transmitted by infected animal bites (dogs, bats, monkeys etc.)
How long does Rabies take to incubate?
2wks - several months
What is the effect of rabies on humans
- Causes acute encephalitis
- Malaise, headache and fever
- Progression to mania, lethargy and coma
- Over production of saliva and tears
- Unable to swallow and hydrophobia
- Death by respiratory failure
How can rabies be diagnosed?
- Difficult
- PCR of saliva or CSF
- Often confirmed post mortem on brain biopsy
How can rabies be treated?
Post exposure prophylaxis:
- Human rabies immunoglobulin
- 4 doses of rabies vaccine over 14 days
How can humans be infected with Brucellosis?
- Excreted in milk, placenta and aborted foetuses of animals
- During milking infected animals
- During parturition
- Handling carcasses of infected animals
- Consumption of unpasteurised dairy products
What is Brucellosis?
A small, gram negative coccobacili
List the species of brucellosis from most virulent to least virulent
Melitensis
Suis
Abortus
What are the clinical features of acute Brucellosis?
- High undulant fever
- Weakness, headaches
- Drenching sweats
- Splenomegaly
What are the clinical features of subacute Brucellosis?
Fever and joint pains
What are the clinical features of chronic Brucellosis?
- Flu like symptoms
- Malaise, depression
- Endocarditis
- Chronic arthritis
- Epididymo-orchitis
- Meningism (rarely)
- Splenomegaly
How can Brucellosis be treated?
- Doxycycline for 2-3 months + Rifampicin or IM gentamycin for first weeks
- Add Cotrimoxazole for 2 weeks in CNS disease
What is the commonest form of leptospirosis and how does it present?
- L. hardio (cattle)
- Fever and meningism (no jaundice)
- Most have no history of illness
What is leptospirosis and how is it transmitted?
- Thin, highly mobile spirochaetes
- Penetrates abraded skin or mucous membranes (causes systemic illness)
What are the features of Weil’s disease?
Jaundice, AKI and bleeding
What is the presentation of leptospirosis?
Fever, myalgia, headaches and abdo pain
How can leptospirosis be diagnosed?
- Microscopic agglutination test
- ELISA (not the best)
- PCR
- Culture
How can leptospirosis be managed?
- Doxycycline for mild disease and IV penicilin for severe cases
- Prompt dialysis
- Mechanical ventilation
What is Lyme borrelios and how is it transmitted?
- Spirochaete found in wild deer
- Transmitted by tick (Ixodes ricinus)
