Zoonoses Flashcards
What are zoonoses?
Infection that can pass from living animal and humans
What is the WHO definition of zoonoses?
Infections that are naturally transmitted between vertebrate animals and humans
Why are the like of Malaria, Schistosmoiasis, Onceriasis, Elephantiasis not consider zoonoses?
They depend on the human host for part of their life-cycle
What are anthropnosis?
“Reverse zoonoses” in which humans are infecting animals
What are examples of anthropnosis?
Influenza = Virus affecting birds and pigs
Strep throat = Dogs
Leishmaniasis = Parasite affecting dogs
Chytridiomycosis = Fungus affecting amphibians
Of the 1415 pathogens currently known to affect humans how many are zoonotic?
61%
List of bacterial zoonoses.
Salmonella Campylobacter Shigella Anthrax Brucella E-coli (verotoxigenic) Leptospirosis Plague Psittacosis (Ornitosis) Q fever Tularaemia
List of viral zoonoses.
Rabies Avian influenza Crimean-Congo haemorrhagic fever (CCHF) Ebola virus disease Lassa Fever Rift Valley fever West Nile Fever Yellow Fever
List of parasitic zoonoses.
Cysticercosis Echinococcosis Toxoplasmosis Trichinellosis Visceral larva migrans (toxocara)
List of fungal zoonoses.
Dermatophytoses
Sporotrichosis
List of prion zoonoses.
BSE/CJDV
Common zoonoses in the UK?
Bacterial:
- Salmonella
- Campylobacter
- Q-fever - Coxiella Burnetti
- Psittacosis – Chlamydophila psittaci
Parasitic:
- Toxoplasma
Fungal:
- Ringworm/dermatophytosis
Uncommon zoonoses in the UK?
Anthrax Rabies Bubonic plague Tularaemia Acute brucellosis
Examples of emerging zoonoses?
Avian influenza Nipah virus Rabies Brucellosis Monkeypox
What are emerging zoonoses?
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
What is the virus that causes rabies?
Lyssavirus
How is rabies transmitted?
Through the bite of an infected animal
How many people each year die from rabies?
55,000 mainly children
What is the incubation period of rabies in humans?
2 weeks to several months
How does the rabies virus reach the brain?
Via peripheral nerves
What is the main complication of rabies?
Acute encephalitis
How is rabies diagnosed?
Difficult:
- PCR of saliva or CSF
- Often confirmed post mortem
What is the mortality rate of rabies if left untreated?
100%
If exposed to the rabies virus what needs to be done?
Pose-exposure prophylaxis:
- Human rabies immunoglobulin (HRIG)
- +4 doses of rabies vaccine over 14 days
How is brucellosis transmitted?
1) During milking of infected animals
2) During parturition
3) Handling carcasses of infected animals
4) Consumption of unpasteurised dairy products
Microbiology od brucellosis?
Small, gram negative coccobacilli
What are the there species of Brucella?
1) Melitensis = Goats, sheep and camals
2) Suis = Pigs
3) Abortus = Cattle and buffalo
Which species of Brucella is most virulent in humans?
Brucella melitensis, found in goats, sheep and camels in the Mediterranean
Which species of Brucella is least virulent in humans?
Brucella abortus, found in cattle and buffalo worldwide
What is the incubation period of brucellosis?
5-30days (Up to 6 months)
What are the symptoms of Brucellosis?
Acute (V rare in Scotland)
Subacute
Chronic
Subclincal (Most common)
What are the acute symptoms of Brucellosis?
Acute - Last 1-3 weeks:
- High undulant fever
- Weakness, headaches
- Drenching sweats
- Splenomegaly
What are the subacute symptoms of Brucellosis?
Subacute - Last over a month:
- Fever and joint pains (Knee, hip, back and SI joints)
What are the chronic symptoms of Brucellosis?
Chronic - Lasts for months or years:
- Flu-like symptoms
- Endocarditis
- Epididymo-orchitis
- Rarely meningism
- Splenomegaly
What are the subclinical symptoms of Brucellosis?
Subclinical - Most common form:
- 50% of exposed have positive serology
How do you treat Brucellosis?
1) Long acting Doxyclycline for 2-3 months; +
2) Rifampicin for the first week; or
3) Intramuscular gentamicin for the first week
4) For CNS disease add Cotrimoxazole for 2 weeks
If there is CNS disease in Brucellosis what drug should be added to the treatment?
Cotrimoxazole for 2 weeks
What caused leptospirosis in fisherman in NE Scotland?
L icterohaemorrhagica
What are the symptoms of Leptospirosis (icterohaemorrhagica)?
1) Flu-like symptoms
2) Jaundice
3) Renal failure
What are the symptoms of Leptospirosis (hardjo)?
1) Fever
2) Meningism, myalgia, headaches
3) Abdominal pain
No jaundice
What is the most common from of leptospirosis in modern day?
L hardjo - Found in cattle
What is leptospirosis?
A thin, highly mobile spirochaetes
How long can leptospirosis survive in the environment?
Weeks to months
How does leptospirosis enter a host?
Penetration of abraded skin or mucous membrane
Can either be from direct contact with the animal or contact with contaminated water (Urine)
What has caused emerging leptospirosis in Bornea, 2000?
Recreational, Borneo Eco Challenge
What has caused emerging leptospirosis in Thailand, 1990s?
Unexplained emergence
What has caused emerging leptospirosis in Philippines, 2009?
Typhoons
What has caused emerging leptospirosis in Costa Rica, 2017?
Hurricane
What complication can occur in severe leptospirosis?
1) Weil’s disease (Triad of jaundice, AKI, bleeding)
2) Pulmonary haemorrhage
3) Fatality 5-40%, >50 in PH
How can you diagnose Leptospirosis?
1) History - Fever in cattle farmers; exposure to water or rats etc
2) MAT, Microscopic agglutination test
3) ELISA
4) PCR
5) Culture - take at least one week on special media
How do you treat Leptospirosis?
1) Early treatment:
- Mild disease = Doxycycline
- Severe = IV Penicillin
2) Prompt dialysis
3) Mechanical ventilation
What is Lyme borrelios transmitted from and by?
Spirochaete found in wild deer and transmitted by ticks (lodes ricinus)
When is Lyme borrelios most commonly transmitted?
In the summer months
What is the vector of Lyme Borrelios?
Lxoden genus (Ticks):
- Europe = L. ricinus
- USA = L. scapularis, L pacificus
- Asia = L. persulcatus
How does someone present with Lyme Borrelios?
With Erythema migrans:
- 3-90 days after the bite
- Single or multiple lesions
Complications of Lyme Borrelios?
1) Acrodermatitis chronica atroficans (ACA):
- Elderly patient
- Extensor surfaces
- Bluish-red discolouration
- Peripheral neuropathy
2) Lymphocytoma:
- Bluish solitary painless nodule
- Earlobe or areola
- Children > Adults
3) Neuroborreliosis
4) Carditis
5) Chronic arthritis
6) Encephalopathies
What is Neuroborreliosis?
> About 15% of people with Lyme Borrelios develop NB
> Triad of facial palsy, radicular pain and lymphocytic meningitis:
- Radicular Pain (70-85%), migratory, worse at night
- Cranial neuropathy (50%)
- -> Facial palsy
> Onset of symptoms 2-6 weeks after bite
A key Lyme pie to the FACE…
FACE: F - Facial nerve palsy A - Arthritis C - Cardiac Block E - Erythema migrans
Stages of Lyme disease?
Stage 1 - Early localised:
- Erythema migrans (Typical bulls-eye configuration)
- Flu-like symptoms
Stage 2- Early disseminated:
- Secondary lesions
- Carditis
- AV heart block
- Facial palsy
- Myalgias
- Transient arthritis
Stage 3 - Late disseminated:
- Encephalopathies
- Chronic arthritis
What does erythema migrans look like?
Typical Bulls-eye configuration
How can we diagnose Lyme disease?
1) Erythema migrans - No lab needed
2) No Erythema migrans - ELISA –> Immunoblot test
3) Arthritis - Very high serology from synovial fluid, PCR
4) Clinical + Labs (CSF and bloods)
How is Lyme disease treated?
1st line = Oral doxycycline
2nd line = Oral amoxicillin or IV Ceftriaxone
Children + pregnant women = Cefuroxime
Treat for 21 days (28 for arthritis or ACA)
