Viral Infection (lyssavirus) transmitted from the bite of an infected animal - Incubation period in humans – 2 weeks to several months

Zoonoses Flashcards by Sophie C

What is zoonoses

Infections that can pass between living animals and humans

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Examples of some diseases that are not zoonoses

Malaria
Schistosomiasis
Oncoceriasis
Elephantiasis

Need human host for their life cycle

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Give some examples of reverse zoonoses

Anthroponosis

influenza
strep throat
leishmaniasis

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Can be caused by? (4)

virus, bacteria, parasites or fungi

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What strategies have Pathogens developed to ensure their own survival/propagation? (2)

causing a chronic infection to survive

- or have a non-human reservoir

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List of zoonoses (partial) - bacteria

Salmonella
Campylobacter
Shigella
Anthrax
Brucella
E-coli (verotoxigenic)
Leptospirosis
Plague
Psittacosis (Ornitosis)
Q fever
Tularaemia

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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

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List of zoonoses (partial) - parasites

Cysticercosis
Echinococcosis
Toxoplasmosis
Trichinellosis
Visceral larva migrans (toxocara)

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List of zoonoses (partial) - fungi

Dermatophytoses

Sporotrichosis

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Examples of ‘common’ zoonoses in the UK (6)

Salmonella
Campylobacter
Toxoplasma
(Psittacosis – Chlamydophila psittaci)
(Q-fever - Coxiella Burnetti)
Ringworm/dermatophytosis

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UNCOMMON ZOONOSES - rarely seen in UK

Anthrax
Rabies
Bubonic plague
Tularaemia
Acute brucellosis

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Give some examples of emerging zoonoses (3)

Rabies
Brucellosis
Monkeypox

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Describe rabies

Viral Infection (lyssavirus) transmitted from the bite of an infected animal

Incubation period in humans – 2 weeks to several months

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How does the rabies virus travel

to the brain via peripheral nerves

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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

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Diagnosis of rabies?

DIAGNOSIS is difficult

PCR of saliva or CSF
- Often confirmed post mortem on brain biopsy

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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)