Intro to Zoonoses/Zoonoses from Carnivores Flashcards
What are arthroponoses?
Diseases that people get from other people
*the reservoir is human
What are zoonoses?
Infectious diseases that people get from animals, either directly or indirectly
animals are the ultimate reservoir for dz
T/F: Poisoning/envenomation by animals is a form of zoonoses
FALSE
What are some of the most common zoonoses in the USA?
Salmonellosis lyme dz giardia shiga-toxin E. coli WNV Rocky mountain spotted fever
What are some examples of zoonoses that are reportable in animals?
Yersina pestis rabies bacillus anthracis mycobacterium bovis brucella abortus Venezuelan equine enchephalomyelitis
What are some costs of zoonotic diseases?
Cost in human health: lost of productivity, loss of life - disease/suicide
Economic costs: treatment and prophylaxis, import and export restrictions, lost trade and tourism
How do people acquire zoonotic dz?
pets, farms, state fairs, petting zoos, pet stores, nature parks, wooded and brushy areas, child car facilities
Who ca get zoonotic dz?
Anyone!!
Farmers and vets have a high occupational risk
Children, elderly, pregnant woman, and immuno-compromised are of the biggest concern
What social changes have affected zoonoses?
Changes in small animal ownership Changes in the "status" of animals Changes in exotic animal ownership Changes in food animal production Changes in global trade and travel
What has been the changes noted in food animal populations over the years?
Large increases in the population of production animals per farm
What are the roles of veterinarians regarding zoonoes?
Surveillance
Prevention and control
Occupational safety (protecting yourself and staff from daily exposure)
T/F: Some zoonotic dzs can be perpetuated in nature by a single vertebrate species
TRUE
Ex: rabies, brucella
T/F: All vector transmitted infections require a combination of vertebrate and invertebrate hosts
TRUE
What are some examples of viral zoonoses?
Colorado tick fever Ebola Influenza Rabies Nipah Monkeypox WNV etc etc etc
What are some examples of bacterial zoonoses?
Anthraz brucellosis campylobacteriosis plague psittacosis Q fever etc etc etc
What are some examples of protozoal zoonoses?
Trypanosomiasis babesiosis cryptosporidiosis Giardiasis toxoplasmosis etc etc
What are some examples of helminthic zoonoses?
Baylisascariasis cysticercosis echinococcosis schistosome dermatitis larval migrans etc etc etc
How does a human get infected with Toxoplasma gondii?
infected feces in the litter box
Eating unwashed vegetables with infected feces
Eating raw infected meat (pig/sheep)
How long do cats typically shed immature toxoplasma gondii oocysts?
1-3 weeks; then they recover
How long does it take T. gondii oocysts to sporulate and become infectious?
1-5 days in the soil
What form of the protozoa (T. gondii) replicates within macrophages, and what phase will encyst in the muscle?
Tachyzoites - in intermediate host macrophages
Bradyzoites - encyst into muscular tissue or neurological tissues
By what methods are bradyzoites within muscle tissue rendered non-infectious?
Freezing for 7 days or by fully cooking
T/F: Oocysts of T. gondii are very resistant and can survive freezing
TRUE
can survive most disinfectants, freezing, drying
In who does T. gondii infections cause severe problems?
Immuno-compromised and pregnant women
infections are usually asymptomatic in immunocompetent adults and children
What is the control program for T. gondii in cats?
There is none - no good one
Control is by reducing risk of him infections
How can the risk of human infections of T. gondii be reduced?
Pregnant women can be tested serologically for antibodies
Buy cats that are less likely to be shedding
Prevent oocyst sporulation
reduce exposure
If you have a pregnant client with a cat, and no one else to scoop the litter box, what should you recommend she do?
She should scoop the litter box daily (decreasing the chance of sporulation to occur) it would be preferred to wear a protective mask while doing so
What is the term for diseases caused by migrating larvae in paratenic hosts?
Larval migrans
*remember that parasitic nematodes are almost always migratory during the larval stages
Almost every dog is infected at some time with what parasite?
Roundworms: Toxocara spp - canis, cati, vitulorum
What occurs in human toxocariasis? Who are most at risk?
Children between the ages of 1-4 (pica and geophagia increase risk)
Visceral larval migrans is most common but asymptomatic in most cases
**Ocular or neurologic migrans is rare
What are some methods of prevention of Toxocariasis?
Reduce the reservior: regular antihelminthic treatment of dogs, cats, and puppies
Reduce contact with sand boxes/pits - or keep them covered in the back yard
The reservoir for Baylisascaris procyonis is _________ and it is transmitted via _________
Raccoons
Fecal-oral route
Dogs can function as what kind of host(s) when infected with Baylisascaris procyonis?
alternative definitive hosts or intermediate hosts
What occurs when humans are infected with Baylisascaris procyonis?
Larval migrans - usually ocular or neurological
What kind of host are humans for: beef and pork tapeworms (T. saginata and T. solium), fish tapeworm (diphyllobothrium), and the dog tapeworm (dipylidium caninum - rare)?
Definitive host
**Humans are infested by eating intermediate host tissue
What kind of host are humans for Echinococcus spp, and cysticercosis?
Intermediate
E. granulosus
E. multilocularis
Cysticercosis - T. solium
**humans are infested by eating larvated eggs - symptoms depend based on where cyst develops
Where do cestode larvae tend to form cysts in intermediate hosts?
liver, lungs, kidneys, brain, and muscle
Different species of parasite will tend to go to specific places
What is the reservoir for all Echinococcus spps?
Canids (dogs, wolves etc)
Intermediate hosts are typically their natural prey (sheep, moose, etc), but humans can also serve as an aberrant intermediate host if exposed
Where are the most common places hydatid cysts will occur in humans when exposed to E. granulosus?
Often liver and brain
individual, large, fluid-filled cysts
Where do cysts form in humans when exposed to E. multilocularis?
Aveolar cyst disease - form multiocular, small, solid cysts
often starts in liver and spreads secondarily to the lungs
T/F: Human infection of E. granulosus occurs from ingesting infected meat with cysts
FALSE
ingestion of eggs (often on the fur of infected dogs etc)
Where is the sylvatic cycle of E. granulosus most active in North America?
Active between wolves and moose in many parts of Canada
What can be done to control cystic echinococcosis?
Preventing infestation in dogs: regular tx with praziquantal (q 6wks)
Condemnation/disposal of infected offal - prevent farm dogs from eating infected carcasses
Preventing transmission to people via education and hygiene
The natural cycle of E. multilocularis (Alveolar Echinococcosis) is between _______ and __________
Foxes and rodents
domestic dogs and cats can also be hosts - when hunting infected rodents
T/F: Alveolar Echinococcosis is generally a rare disease, but has a high fatality
TRUE
Sporadic dz in Europe/Russia
Endemic in wildlife of North America - no human transmission
*Very common in parts of China
What methods are used to control E. multilocularis?
Routine tx of dogs (twice annually) Reduce exposure of domestic pets to rats Treatment of foxes: baiting (monthly in urband foxes and q3months in rural foxes) Education Stray dog control
