Flashcards in Zoonoses: Aerosol/Respiratory Deck (59)
What makes a bacterial pathogen fit into the "Category A" agents?
These all have MULTIPLE routes of infection. Their aerosol potential makes them BIOWEAPONS but veterinary risks are more diverse and include necropsy and tx of animals
What bacterial pathogens are category A agents?
What domestic animal are humans most likely to get Tularemia from?
Who are the long term reservoirs of F. tularensis?
Rodents and lagomorphs
What are the routes of transmission of F. tularensis?
Tickborne (common in sheep)
Ingestion (cats ingesting infected rodents)
People - most often get it from ticks or direct contact with animals/carcasses; aerosol exposure is less common
What animals serve as the bridge for Yersina pestis between wildlife and human population ?
Infected domestic animals - often cats
What animals/vectors are involved in the primary cycle of Y. pestis?
(31 species of flea are competent vectors)
How can people be infected with Y. pestis?
aerosol from pneumonic cases
Directly from infected animal blood or abscesses
What clinical signs will you see in cats with either plague or tularemia?
local infection followed by sepsis --> endotoxemia--> pneumonia
Lymphadenopathy of draining LN (often in cervical region), fever, lethargy, anorexia, sepsis
What symptoms will you see in humans with tularemia or plague?
*plague eschars - areas of bacteria entry - necrosis
Both: high fever and high fatality in pneumonia and septic cases
Circulatory collapse with blackened extremities
What cautions should be taken when dealing with a potentially infected cat?
Lymphnode aspirates are highly infections - wear proper PPE
Isolation for the animal
PPE for the vet and staff at during any encounter with the animal: gloves, mask, +/- mucous membrane protection
How long can Bacillus anthracis survive in soil? Why?
it is a spore forming bacterium that can survive in the soil under good conditions for years
How do herbivores and carnivores get anthrax?
Herbivores ingest spores in the soil while grazing
Carnivores eat infected herbivores
*all species: inhalation of spores in aerosolized soil or other contaminated fomites
What are the most common way veterinarians could get anthrax?
Aerosol or percutaneous exposure to blood from infected animals
**most veterinary cases are seen in cattle **
What process do anthrax spores undergo when they enter the bloodstream?
They germinate --> cause sepsis
In cattle infected with anthraz, death will often follow what syndrome? How can you tell?
The carcass will have un-clotted blood seeping from the orifices
Which of the following are PM signs of anthrax in cattle? (more than one may apply)
1. blood not clotted
2. spores in blood on microscopy
4. lack of rigor mortis
5.blood from orifices
ALL OF THEM
Who is the reservoir of Hantavirus?
*typically sylvatic but can also infect some pet rodents
How do rodents shed hantavirus?
saliva, urine, feces
What is the primary mode of transmission of Hantavirus?
*inhalation of viruses in urine or feces
Transmission can be direct or indirect - secondary transmission through bite
What determines the severity of dz due to Hantavirus?
The species of virus
What is the "new world" disease caused by Hantavirus?
Hantavirus Pulmonary Syndrome (HPS)
*USA strains of the virus
Starts as fever, chills, myalagia, headache.. increased vascular permeability in the lungs
*fatal in 40% of human cases
What is the "old world" disease caused by Hantavirus?
Hemorrhagic Fever with Renal syndrome (HFRS)
Petechial hemorrhage, renal damage, and cardiovascular shock
*fatal in up to 15% of cases
What are the risk factors to contracting Hantavirus?
*increased rodent density
*rodents living in barns or buildings
*people who work with rodents or rodent habitats
How do you prevent contracting Hantavirus?
Reduce human exposure. Wear proper PPE when dealing with rodents or their habitats (face mask and gloves)
How are humans exposed to fungal pulmonary infections?
Infections from spores in the environment become aerosolized and are inhaled
What are two saprophytic soil fungi that have the potential to cause fungal pulmonary infections in humans?
Blastomyces and Coddidiodes
*birds and bats can be reservoirs - fecal excretion = soil contamination
What are two opportunistic fungi that can cause fungal pulmonary infections in humans?
Histoplasma and Cryptococcus
Spores in soil or in bird bedding/feces
Are humans and animals with fungal pulmonary infections infectious?
The body temperature is too high for sporulation of these fungi
*could be a risk post mortem potentially