Zoonoses: Aerosol & Respiratory Transmission Flashcards
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
Q-fever transmission
- windborne in dust
- parturient cats
- shed in birth products (esp. sheep) and milk
- tick borne (animal to animal)
Q-fever control
- seek medical attention if suspected
- segregate parturient animals & burn placentas
- proper bio-safety
- vaccinate livestock
Chlamydophylia
mostly in psittacine birds: parrots, cackatiels, etc. Also in domestic poultry
Chlamydophylia transmission
Birds: fecal-oral route
Humans: direct handling of infected bird
Chamydophylia control
- educate owners on signs of illness
- consider as cause in any ill bird
- biosafety measures in handling infected birds
