zoonoses Flashcards
WHO definition
Infections that are naturally transmitted between vertebrate animals and humans.
This excludes organisms which depend on the human host for part of their life-cycle (e.g. malaria, schistosomiasis, onchocerciasis, elephantiasis).
common zoonoses in UK
salmonella campylobacter toxoplasma psittacosis Q- fever Emerging: Avian Influenza Nipah virus rabies
Rabies
Lyssavirus
dogs (97%) bats monkeys
animal tend to die quickly
o Incubation period: 2 weeks to several months
o Rabies virus travels to the brain via peripheral nerves
o 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
diagnosis and management
PCR of saliva or CSF o post-exposure prophylaxis o human rabies immunoglobulin (HRIG) o infiltrated round the bite (if possible) \+4 doses of rabies vaccine over 14 days
brucellosis
small gram-ve coccobacilli organism excreted in milk, placenta & aborted foetus risk: milking infected animals dairy products presentation acute: high rising and falling fever sweats splenomegaly o Subacute (lasts over 1 month) Fever and joint pains (knee, hip, back SI joints o Chronic (lasts for months or years) ♣ Flu-like symptoms ♣ Malaise ♣ Depression ♣ Chronic arthritis ♣ Endocarditis
management
long acting doxycycline + rifampicin or +im gentamycin
relapse can occur
add co-trimoxazole for 2 weeks in CNS disease
leptospirosis
(weil’s disease)
L.hardjo-cattle
fever meningism-no jaundice
• Think water exposure
o E.g. planting, hunting, gutting, canoeing, weeding, fishing, bathing, swimming
• Fever in a cattle farmer – more likely to be leptospirosis than brucellosis
• Treatment:
o Penicillin as early as possible.
o L. hardjo usually benign, self-limiting
toxoplasmosis
due to intracellular protozoan parasite
-cats
• • Human acquire infection from oocysts in cat faeces or from trophozoites in undercooked meat (cattle, pigs and horses may be intermediate hosts).
clinical features
o Acute form:
♣ Pneumonia, fever, cough, rash
♣ Acute infection during pregnancy can be transmitted to baby, leading to congenital malformation
o Chronic form:
♣ Lymphadenopathy (occipital), lymphocytosis, atypical mononuclear cells on blood film
o Chorio-retinitis and uveitis
o Congenital form:
♣ Hydrocephalus, microphthalmos, microcephaly, convulsions, calcification in brain on x-ray
treatment
o Most don’t require treatment
o Sulphonamide and pyrimethamine (Fansidar)
o (folate antagonists)
o Occasionally tetracycline
lyme borrelios
to Borrelia burgdorferi
• tick, Ixodes ricinus
o Nymph carries the highest amount of lyme
• Symptoms:
Erythema migrans
-redness spreads and clears in the middle, ring
Acrodermatitis chronica atroficans (ACA)
o Lymphocytoma
o Neuroborreliosis (NB)
♣ Triad of facial nerve palsy, radicular pain & lymphocytic meningitis
diagnosis
o EM a clinical diagnosis
o ACA and lymphocytoma – clinical & high serology titres
o Arthritis – very high serology titres found in synovial fluid
NB – clinical + lab findings
management
doxycycline, amoxicillin or cefuroxime
