Zoonoses Flashcards
What is zoonoses
Infections that can pass between living animals and humans
Examples of some diseases that are not zoonoses
Malaria
Schistosomiasis
Oncoceriasis
Elephantiasis
Need human host for their life cycle
Give some examples of reverse zoonoses
Anthroponosis
- influenza
- strep throat
- leishmaniasis
Can be caused by? (4)
virus, bacteria, parasites or fungi
What strategies have Pathogens developed to ensure their own survival/propagation? (2)
- causing a chronic infection to survive
- or have a non-human reservoir
List of zoonoses (partial) - bacteria
Salmonella Campylobacter Shigella Anthrax Brucella E-coli (verotoxigenic) Leptospirosis Plague Psittacosis (Ornitosis) Q fever Tularaemia
List of zoonoses (partial) - viruses
Rabies Avian influenza Crimean-Congo haemorrhagic fever (CCHF) Ebola virus disease Lassa Fever Rift Valley fever West Nile Fever Yellow Fever
List of zoonoses (partial) - parasites
Cysticercosis Echinococcosis Toxoplasmosis Trichinellosis Visceral larva migrans (toxocara)
List of zoonoses (partial) - fungi
Dermatophytoses
Sporotrichosis
Examples of ‘common’ zoonoses in the UK (6)
Salmonella Campylobacter Toxoplasma (Psittacosis – Chlamydophila psittaci) (Q-fever - Coxiella Burnetti) Ringworm/dermatophytosis
UNCOMMON ZOONOSES - rarely seen in UK
Anthrax Rabies Bubonic plague Tularaemia Acute brucellosis
Give some examples of emerging zoonoses (3)
Rabies
Brucellosis
Monkeypox
Describe rabies
Viral Infection (lyssavirus) transmitted from the bite of an infected animal
- Incubation period in humans – 2 weeks to several months
How does the rabies virus travel
to the brain via peripheral nerves
Rabies can go on to cause an? Symptoms
acute encephalitis
- Malaise, headache & fever
- Progressing to mania, lethargy & coma
- Over production of saliva & tears
- Unable to swallow & ‘hydrophobia’
- Death by respiratory failure
Diagnosis of rabies?
DIAGNOSIS is difficult
PCR of saliva or CSF
- Often confirmed post mortem on brain biopsy
What to give immediately after a rabies bite?
give post-exposure prophylaxis
human rabies immunoglobulin (HRIG)
infiltrated round the bite (if possible)
+4 doses of rabies vaccine over 14 days
BRUCELLOSIS - features of? how do humans become affected
Organisms are excreted in milk, placenta and aborted foetus
During milking infected animals
During parturition
Handling carcasses of infected animals
Consumption of unpasteurized dairy products
BRUCELLOSIS - can spread easily in? what is the Brucella organism like?
a lab
- small, gram negative coccobacilli
3 species of Brucellosis
Melitensis
Suis
Abortus
Brucellosis incubation period
5-30 days (up to 6 months)
Symptoms of Brucellosis (4)
Acute (now very rare in Scotland)
Subacute
Chronic
Subclinical (commonest)
Brucellosis - acute presentation (5)
lasts 1 – 3 weeks High ‘undulant’ fever Weakness, headaches Drenching sweats Splenomegaly
Brucellosis - sub acute presentation (2)
lasts over 1 month
Fever and joint pains (knee, hip, back SI joints)
Brucellosis - Chronic (8)
lasts for months or years
Flu-like symptoms. Malaise. Depression. Chronic arthritis
Endocarditis. Epididymo-orchitis. Rarely meningism. Splenomegaly
Most common form of Brucellosis?
subclinical
50% of exposed have positive serology
LEPTOSPIROSIS - symtoms? (2-3) most common cause is cattle
Flu like symptoms – then jaundice, and renal failure
Describe the LEPTOSPIROSIS organism
Thin, highly mobile spirochaetes
- most widespread zoonoses
LEPTOSPIROSIS - symptoms , and symptoms of severe disease/complications
- Undifferented fever; myalgia, headaches & abdominal pain
Severe disease in 5-15%
Weil’s disease (Triad of jaundice, AKI, bleeding)
Pulmonary haemorrhage (PH)
Case fatality 5-40%, >50% in PH
Red yellow bloody jaundiced eyes
LEPTOSPIROSIS - Diagnosis
`Tests? (4)
Fever in a cattle farmer
Exposure to water or rats
The farmer with protracted flu-symptoms is more likely to have leptospirosis than brucellosis
- Microscopic agglutination test (MAT
- ELISA serology - suboptimal
- PCR?
- Culture – take at least one week on special media
LEPTOSPIROSIS - Treatment
- antibiotics most effective during the early phase of the disease
Doxycycline for mild disease, IV penicillin for severe
Steroids do not help - prompt dialysis
- mechanical ventilation
LYME BORRELIOS - Lyme disease - how is it transmitted ?
Spirochaete found in wild deer
Transmitted by tick, Ixodes ricinus
Commonest in summer months
LYME BORRELIOS - what is the vector
Ixodes genus
People with Lyme disease will often present with
Erythema Migrans (EM)
- 3-90 days after the bite
- Single or multiple lesions
Late stage of Lyme disease presentation?
ACRODERMATITIS CHRONICA ATROFICANS (ACA)
Elderly people
Extensor surfaces of distal extremities
Bluish-red discoloration – progresses over months to years to atrophic phase
Peripheral neuropathy common
What can also show with Lyme disease?
LYMPHOCYTOMA
Bluish solitary painless nodule
Earlobe or areola
Children > Adults
Approx 15% of those with Lyme disease will develop?
what symptoms will they have/classical signs
NEUROBORRELIOSIS (NB) - disease if the CNS - systemic infection of lyme
Triad of facial nerve palsy, radicular pain & lymphocytic meningitis
In NEUROBORRELIOSIS what sort of pain will patients have
Radicular pain (70-85%), migratory, worse at night Cranial neuropathy (app 50%) – facial palsy
symptom onset 1-12 weeks after the bite
DIAGNOSIS of LYME
EM a clinical diagnosis – no lab needed
ACA and Lymphocytoma clinical & high serology titres
Arthritis – very high serology titres from synovial fluid. PCR
3 tests used in the diagnosis of Lyme disease?
- Neuro symptoms consistent with LNB & other causes excluded
- CSF pleocytosis (WBC in CSF), often lymphocytic
- Paired blood and CSF serology
If suspicious of lyme and there is no EM rash - what test would you do?
ELISA - if positive follow up with a immunoblot test
Lyme disease – treatment
Oral Doxycycline or Amoxicillin, or IV Ceftriaxone
Most manifestations treat for 21 days (28 in arthritis or ACA)
