Zoonoses Flashcards
What is Brucellosis?
The most common zoonosis worldwide.
It’s a gram -ve intracellular coccobacillus infection of cattle, swine, goats, sheep and dogs.
Human infection via ingestion of infected meat/unpasteurised cheese or milk.
Can also transmit via mucosal contact with animal body fluids.
It’s an occupational disease in farmers, slaughterhuose workers, meat packers and hunters.
Presentation of Brucellosis.
Acute ( < 1 month )
Subacute ( 1 - 6 months )
Chronic ( > 6 months )
Non specific symptoms such as fever, anorexia, sweats, weights loss and malaise.
Localised infection of septic arthritis, spondylitis, meningitis, endocarditis, orchitis and abscess.
Diagnosis of Brucellosis.
Culture with prolonged incubation due to slow doubling time.
Serology
Treatment of brucellosis.
Doxycycline
Rifampicin
Aminoglycoside
Ceftriaxoe
Co-trimoxazole
Needs prolonged course are intracellular with slow doubling time.
What is Q fever?
An illness caused by Coxiella burnetii.
Sheep, goats, cattle are main sources of infection and occupational causes such as farm and abattoir workers.
Transmission to humans occur via contact, inhalation of dust or consumption of raw milk products.
Explain Coxiella burnetii.
A gram -ve intracellular bacterium that forms spores.
It is an obligate intracellular organism but can still survive due to its spores for a very long time.
The infective dose is very small so only minimal animal contact is required to contract infection.
Clinical presentation of Q fever.
Incubation of 3d-30d.
50% are asymptomatic but there can be non-specific symptoms such as fever, nausea, fatigue and headache.
Pneumonia can occur
Splenomegaly, granulomatous hepatitis, aseptic meningitis, encephalitis, osteomyelitis.
Endocarditis is the most common form of chronic disease.
Diagnosis of Q fever.
Coxiella burnetii cannot be cultured like normal using routine lab because it’s an obligate intracellular organism.
PCR is rapid
Serology can take 2-6 weeks to become positive.
Serology on paired sera 2-4 weeks apart provides best diagnostic evidence.
Treatment of Q fever.
Doxycycline.
Rifampicin, chloramphenicol, fluoroquinolone, macrolide or hydroxychloroquine.
Doxycycline is often combined with rifampicin or hydroxychloroquine in chronic infection.
What is leptospirosis?
Pathogenic leptospire spirochaetes belonging to the subgroup Leptospira interrogans.
The carrier are chronic renal infected animals such as rodents, cattle and pigs.
It used to be an occupational infection but is more and more commonly associated with recreational activities that bring people closer to rodents.
Outbreaks of leptospirosis have been associated with floods.
How is leptospirosis spread?
Spread by water/soil/food contaminated by infected animal urine.
Presentation of leptospirosis.
Incubation is around 7 days ( 2 - 30d)
There are two phases:
Acute septicaemic phase with fever, non-specific flu-like symptoms. It is however mild or subclinical in over 90% of cases.
There is then a recovery or 2nd immune/leptospiruric phase - Conjunctival suffusion, myalgia, jaundice, meningitis, uveitis, AKI and pulmonary haemorrhage may occur as well as ARDS, myo/pericarditis.
Diagnosis of leptospirosis.
Via National Leptospirosis Service
Culture of blood/CSF in first phase
Serology
PCR
Treatment of leptospirosis.
Doxycycline
Penicillin
This is however reserved for severe disease
