Zoonoses: Aerosol & Respiratory Transmission Flashcards
(29 cards)
Enzootic bacterial “Category A” Agents
Bacillus anthracis
Yersinia pestis
Francisella tularensis
Francisella tularensis affects
humans
domestic cats
sheep
Francisella tularensis reservoir
rodents and lagomorphs
Francisella tularensis transmission
- tick-born (sheep)
- eating infected rodents (cats)
- tick, direct contact with animal carcasses, aerosol (humans)
Yersinia pestis reservior
rodent-flea-rodent cycle
- host include: squirrels, prairie dogs, mice, wood rats, chipmunks, rats, mice
- 31 species of flea are vectors
Yersinia pestis transmission
- flea bite
- aerosol from pneumonic cases
- directly from infected animal blood or abscesses
Cats foraging outside allow exposure to what?
Yersinia pestis & tularemia
Plague & tularemia clinical signs in cats
- plague many cause necrotic eschar at skin entry site
- fever, lethargy, anorexia, sepsis
- lymphadenopathy often in cervical region
- rapid progression
Plague & tularemia in people
- plague eschars
- high fever & fatality seen in septic/pneumonic cases
Plague & tularemia risk reductions
- lymph node aspirates are highly infectious
- isolation
- PPE, gloves & mask. Mucous membrane protection
Bacillus anthracis transmission
- Vets: aerosol or percutaneous exposure to blood
- herbivores: ingests spores in soil
- carnivores: eat infected herbivores
- all species: inhalation of spores in aerosolized soil or other fomites (wool sorter’s disease)
Process of anthrax
- spores enter host
- spores germinate & cause sepsis
- Exotoxins create massive edema, shock, & death
- death often follows DIC
Hantavirus: where & what reservoir?
- distributed world-wide
- rodents, typically asymptomatic. Usually sylvatic cycle, but pet rodents can be infected too.
Hantavirus transmission
- Primarily aerosol: inhalation of viruses in urine & feces. Can be direct or indirect
- Secondary through bites
Hantavirus clinical signs in humans
-severity depends on species of virus
-New world strains= Hantavirus Pulmonary Syndrome: fever, chills, myalgia, headache—> inc. vascular permeability in lungs.
Fatal up to 40%
-Old world strains= Hemorrhagic Fever with Renal Syndrome: petechial hemorrhage, renal damage, & cardiovascular shock
Fatal up to 15%
Hantavirus risk factors
-Rodent contact
Prevention= reduce exposure- face mask and gloves when appropriate.
Organisms that can cause infections from spores in the environment that become aerosolized and are inhaled
- Blastomyces & Coccidiodes
- Saprophytic soil fungi
Humans & animal exposure via spores
Organisms from fecal excretion/soil contamination from birds & bats
-Histoplasma & Cryptococcus (opportunistic)
spores in soil or bird bedding/feces
Are humans & pets infectious from fungal organisms?
No, body temp is too high for sporulation… post-mortem may be a risk?
Coccidioides immitis
- reservoir is soil
- infects and amplifies in mammals
- signs range from asymptomatic to disseminated
Histoplasmosis
- found in soil or buildings with bird or bat poo
- affects people, dogs, cats
- ~90% asymptomatic
Blastomyses dermatitidis
- soil fungus (also bird/bat poo)
- affects people, dogs, cats, horses, etc.
- in people ~50% are asymptomatic
Influenza transmission
- animal to human transmission only documented for bird & swine flu
- animal-to-human: contaminated surfaces, manure, dust
Influenza control & prevention
- avian flu is reportable
- wear PPE
- test & isolate sick animals
- educate owners of zoonotic risk
- vaccines for pets & at risk workers
