2-Zoonoses: Aerosol & Respiratory Transmission Flashcards
Do enzootic bacterial “category A” agents have one route of infection or multiple routes of infection?
What makes them potential bioweapons?
- Multiple routes of infection.
- Their aerosol potential makes them “bioweapons”.
What are 3 examples of enzootic bacterial “category A” agents?
- Bacillus anthracis
- Yersinia pestis
- Francisella tularensis
What is a cosmopolitan intracellular bacterium that affects humans and animals?
Francisella tularensis
What are 3 species that can be affected by Francisella tularensis?
- Humans
- Domestic cats
- Sheep
What is the primary, long-term reservoir of Francisella tularensis?
Rodents and lagomorphs (“rabbit fever”)
How is Francisella tularensis transmitted in sheep?
Usually tick-borne
How is Francisella tularensis transmitted in cats?
Usually from eating infected rodents.
How is Francisella tularensis transmitted in people?
Most often tick or direct contact with animals/carcasses, aerosol exposure less often.
Are urban human cases of Yersinia pestis rare or common?
Rare so long as there is aggressive rodent control.
Infected domestic animals can serve as a “bridge” between what?
Wildlife and human populations.
What is the primary cycle of the plague?
Rodent-flea-rodent
What are 6 examples of potential hosts for the plague?
- Squirrels
- Prairie dogs
- Mice
- Wood rats
- Chipmunks
- Rats
How many different species of flea are competent vectors for the plague?
31
What is the most common flea vector of the plague?
Xenopsylla cheopis (oriental rat flea)
Which species is susceptible to the plague and can infect people?
Cats
When are cats usually exposed to the plague?
While hunting/eating rodents.
What are 2 examples of predators that can be infected by the plague?
- Cougars
- Birds of prey
With the plague, coyotes and dogs seroconvert but are rarely what?
ill
What are 3 ways people can be infected by the plague?
- Flea bite
- Aerosol from pneumonic cases of plague
- Directly from infected animal blood or abscesses?
What is the most common way people can be infected by the plague?
Directly from infected animal blood or abscesses.
Cats that are allowed to do what can be exposed to the plague and tularemia?
Forage outside
The bacteria that cause both plague and tularemia can cause localized infection followed by what 3 things?
- Sepsis
- Endotoxemia
- Pneumonia
What might the plague cause at the site of skin entry?
A necrotic eschar
Which can cause lymphadenopathy of draining lymph nodes, the plague, tularemia or both?
Both
Pulmonary involvement in the plague and tularemia can lead to what?
Aerosol spread
What are 5 clinical signs associated with the plague and tularemia that can be seen in cats?
- Fever
- Lethargy
- Anorexia
- Sepsis
- Lymphadenopathy often located in the cervical region
Do the plague and tularemia progress slowly or rapidly?
Rapidly
What are 2 clinical signs that can be seen with the plague and tularemia that are considered to be poor prognostic indicators?
- Pneumonia
- Septic shock
Are the clinical signs and progression seen with the plague and tularemia in people similar or different from those seen in cats?
Similar
Are plague eschars easier or harder to see on people?
Easier, no fur.
High fever and high case fatality rate are seen in what kind of plague or tularemia cases?
What else can be seen with these cases?
- Septic/pneumonic cases
- Circulatory collapse with blackened extremities
T/F: Lymph node aspirates are highly infectious in the plague and tularemia.
True
Is isolation a good idea when dealing with the plague and tularemia?
Yes
What does PPE stand for in epidemiology?
What are 2 examples of PPE?
- Personal protective equipment
- gloves and masks
What is the spore-forming bacterium that causes anthrax?
Bacillus anthracis
How long can Bacillus anthracis survive in the soil?
Under good conditons for years.
What species can be affected by anthrax?
Most mammal species
How is anthrax transmitted to herbivores?
Ingest spores in soil while grazing.
How is anthrax transmitted to carnivores?
Eat infected herbivores.
What are two forms of transmission that can affect all species?
- Inhalation of spores in aerosolized soil
- Contaminated fomites
“Wool sorter’s disease” is associated with which bacterium?
Bacillus anthracis
What are 2 ways veterinarians can contract anthrax?
- Aerosol
- Percutaneous exposure to blood from infected animals
Most veterinary cases of anthrax are seen in what species?
Cattle
What are 2 things that can be caused by Bacillus anthracis spores as they enter the host?
- A necrotic eschar at skin entry point.
- Causes atypical pneumonia if inhaled.
Once the spores “germinate” they can cause what?
Sepsis
What are 3 things that the exotoxins of Bacillus anthracis can cause?
- Massive edema
- Shock
- Death
With anthrax, death often follows what?
DIC
What are 5 examples of postmortem signs of anthrax in cattle?
- Blood not clotted
- Spores in blood on microscopy
- Rapid bloating
- Lack of rigor mortis
- Blood from orifices
What is an enveloped ssRNA virus seen in the family Bunyaviridae?
Hantavirus
Is Hantavirus seen world-wide?
Yes
Individual species are typically limited to a specific reservoir host and geographic region with what virus?
Hantavirus
What is the reservoir for Hantavirus?
Rodents
Are rodents carrying Hantavirus symptomatic?
No, usually asymptomatic
What are 3 ways rodents shed hantavirus?
- Saliva
- Urine
- Feces
What is the primary mode of transmission of hantavirus?
Aerosol: inhalation of virus in urine or feces
How long can hantavirus survive in most bedding under cool conditions?
Weeks