Intro to Zoonoses Flashcards
What is a zoonotic disease?
Diseases and infections which are naturally transmitted from vertebrates to humans and vice-versa.
What agents can cause zoonoses?
Parasites Prions Bacteria Viruses Fungi
What is a sapronosis?
Disease resulting from an agent present in a natural source ie: soil and water
An example of a saprozoonosis
Cryptosporidium
Can food bourne illness be a zoonosis?
Sometimes. Anthrax and Coxiella burnetii are zoonoses and can be transmitted through food.
What is an example of a disease that used to be considered zoonotic, but due to viral mutation is no longer transmitted between species?
HIV (SIV). Original zoonotic strain has changed, and HIV is now only transmitted between humans.
Definition of emerging zoonosis
Either a new zoonosis, or a zoonosis that has occurred previously and is showing an increase in incidence, or expansion in geographical, host or vector range.
Examples of current emerging zoonoses
Ebola Dog rabies MERS (respiratory) BSE (bovine spongiform enceph) Echinococcosis/hydatidosis Avian influenza Cysticercosis/taeniasis Brucellosis Nipah virus
Percent of all human pathogens that are zoonoses
61%
Percent of all emerging pathogens during the past decade that are zoonoses
75%
How many diseases can be transmitted between humans and animals?
Over 800
Worldwide deaths per year caused by Rabies
55,000
Worldwide cases per year of Leishmaniasis
2 million
Worldwide cases per year of Leptospirosis
10 million
Yearly cases of Salmonellosis in the US
1-2 million
Yearly cases of Lyme disease in the US
300,000
Which areas of the world are most affected by emerging zoonotic events?
Developed countries/areas (US, Europe)
2 factors of cost of zoonotic diseases
Human health
Economic cost
Role of the veterinarian in public health
Surveillance Diagnose and control zoonotic disease Inform pet owners Protect consumer health - maintain herd health Occupational safety
How severe is rabies infection?
Almost always deadly
Zoonosis that makes humans sick but shows no signs in animals)
Chlamydia psittaci
Zoonosis that makes both humans and animals sick, but in a different manner
Anthrax
Zoonosis that makes both humans and animals sick in the same way
Rabies
Zoonosis that doesn’t show signs in humans but does in animals
TB (spreading in cattle)
What would make a disease reportable?
Zoonotic
Economically important (anthrax, brucellosis, coxiella burnetii
Category A biologic weapons
Highest risk:
Easily transmitted/disseminated
High mortality rates
Potential for public panic
Require special action
Category B biologic weapons
Moderately easy to disseminate
Moderate morbidity / low mortality
Specific enhancements for diagnosis
Enhanced surveillance
Category C biologic weapons
Emerging pathogens
Could be engineered for mass dissemination in future
Changes in small animal ownership, status of animals, exotic animal ownership, and food animal production are all…
Social changes that affect zoonoses
Trend in number of household pets and food animal populations on farms
Increasing.
63% of US households have at least one pet.
Increase in number of animals per farm
Travel, exotic animal trade, and climate change are all…
Global trends that affect zoonoses
What type of viruses are responsible for more current and emerging zoonises?
RNA viruses - greater genetic variation (mutation) due to lack of proofreading mechanism. Extends host range.
*DNA uses polymerase to proofread, resulting in greater genetic stability while restricting the host range.
Transmission of bacterial zoonoses
All routes. Bites, scratches, inhalation, food, vectors, soil, water.
Risks with bacterial zoonoses
Antimicrobial resistance
Bite risk for veterinarian (Pasteurella, Streptococcus, staphylococcus)
Parasitic zoonotic agents
Helminths
Protozoa
Acanthocephala
What does “various cycle” mean in regards to parasitic zoonotic agents?
Various life cycle. Humans can be final, intermediate, or paratenic host.
What is a prion?
Infectious protein
Characteristics of prion infections
Long incubation (years) Always fatal: neurodegeneration
Examples of animal prion diseases
BSE (mad cow)
Scrapie (goats/sheep)
Chronic wasting disease (deer/elk) (maybe zoonotic)
Transmissible mink encephalopathy
Examples of human prion diseases
Creutzfeld-Jakob
Kuru
New variant CJD (like BSE, no link with original CJD)
Dermatophytosis by keratinophilic fungi (agent)
Ringworm (Microsporum and Trichophyton)
Occupational saprozoonoses:
Blastymyces dermatitidis
Histoplasma capsulatum
Coccidioides immitis and posadasii
Case Study: Lyme disease
NYC Aug 2017
Woman with spinal meningitis
Hylan Blvd near Wolfe’s Pond Park
Transmitted by Ixodes tick. Rodent reservoir.
Case study: Brucellosis
Paraguay Veterinary Oct 2017
15 patients, 1 death
Lost international certification
Brucella melitensis
Direct/indirect/vector transmission (mechanical)
Unpasteurized milk (bovine reservoir)
Biggest problem for humans
Case study: Sin Nombre
NM March 2018 9 y/o boy Flu-like symptoms, coma Hantavirus Direct transmission human-human Rodent reservoir: feces, urine Category C reportability
