Zoonosis 2

Question 1

List examples of parasitic, viral, bacterial, and vector borne zoonotic disease

Answer 1

zoonotic diseases

Parasitic

• tenia solium- pigs to humans and back
• giardiasis- water to animals to humans

viral

• rabies- animals to humans
• hantavirus-rodents to humans

bacterial

• anthrax- soil to cow to human
• brucellosis- animals to human

vector borne

• boreliosis- rodent to tick to human
• west nile- bird to mosquito to human

Question 2

Tenia Solium (3)

discuss reservoirs, transmission and prevention

Answer 2

Ternia Solium= parasite transmitted by pigs

Reservoirs:

• people- primary host
• pigs- intermediate host

Pigs get it from eating human feces (eggs).

• porcine cysticercosis
  
  • pigs eat eggs (feces) = get cycts in muscle
  • prevent by human sewage managment

Humans get it through a few different routes

• human taeniasis- eat undercooked meat
  
  • human eats cysts in pork = get worms in gut
  • prevent by meat inspection and cooking well
• human cysticercosis (neurocysticercosis)- self infection (feces)
  
  • humans eat eggs = cysts in brain
  • prevent by hygine, sewage managment, treatment of reservoir (humans with tapeworms)

Question 3

Giardiasis

discuss reservoirs, transmission and prevention

Answer 3

Giardiasis= protozoal parasite transmitted through water

Reservoir: many animals transmit the disease

Transmission:consume cysts

• mainly water
• surface contamination of food

Prevention: filter water

Question 4

Rabies

discuss reservoirs, transmission and prevention

Answer 4

Rabies= viral zoonotic disease

the virus is an acute, progressive encephyalomyelitis

Reservoir: most mammals

• “all reservoirs are vectors but not all vectors are reservoirs”

Transmission: bite infects human and virus replicates and travels to CNS where it causes encephalitis

Prevention:

• VACCINATION is our major line of defense
  
  • reduce animal reservoir and human risk through vaccination and control of population/exposure

NOTE: major significance of rabies virus

• highest case fatality of any infections disease
• leading viral zoonosis
• lots of deaths per year (majority in developing countrys)
• some islands are free of the virus

Question 5

Hantavirus

discuss reservoirs, transmission and prevention

Answer 5

Hantavirus= virus transmitted by rodents

Reservoir: rodents (are asymptomatic)

Transmission:

• aerosol- direct or indirect
  
  • inhalation from urine, saliva or feces
• bite- direct

Prevention: reduce human exposure

• rodent population control
• proper protective gear when humans work with/near rodents

Note: human symptoms

• hantavirus pulmonary syndrome (HPS): fever and chills
  
  • new world strain
• hemorrhagic fever with renal syndrome (HFRS): hemorage
  
  • old world strain

Question 6

Anthrax

discuss reservoirs, transmission and prevention

Answer 6

Anthrax= bacterial zoonotic disease

Reservoir: soil

Transmission: affects most mamalian species

• herbivores- ingest spores in soil
• carnivores- ingest infected herbivores
• all species- inhalation of spores or contact with fomites
• veterinarians- aerosol or exposure to bloof of infected animals

Prevention:

• Vets
  
  • no necropsy of suspected cases and burn body
  • vaccinate animals
  • communicate with health officials
• Public health
  
  • monitor exposed individuals/ possible exposures
  • communicate with vet professionals

NOTE: Cattle anthrax is common! symptoms are…

• bleeding from all orifices
• swelling
• sudden death

Question 7

Brucellosis

discuss reservoirs, transmission and prevention

Answer 7

Brucellosis= bacterial zoonitic disease

Reservoir: lots of species

Transmission: ingestion, mucous membrane exposure or through skin

• most common exposure is unpasteurized milk

Prevention:

• eliminate animal reservoirs
• pasteurize milk and milk products

NOTE: different strains and reservoirs

• brucella melitensis: most pathogenic for people
  
  • goats!
  • mostly in mediteranean / other goaty regions
• brucella abortus *
  
  • cattle
  • everywhere/ lots of animals but most common is cattle and unpasteurized milk

Question 8

Borreliosis

discuss reservoirs, transmission and prevention

Answer 8

Borreliosis= vector borne disease. spirochetes transmitted by tick

Reservoir: rodents (NOT DEER)

Transmission: ticks are the vector. bite rodents and then transmit to humans

• lyme disease= hard ticks
• relapsing fever= soft ticks

Prevention:

• avoid direct contact with ticks
• remove ticks from body pets and clothes
• tick medicine

* bulls eye rash is key diagnostic feature

Question 9

West Nile

discuss reservoirs, transmission and prevention

Answer 9

West Nile= not a virus! vector borne disease

Reservoir: birds

Transmission: mosquitos bite humans

• transmitted by mosquito bird mosquito life cycle
• bite humans. often doesnt develope into symptomatic infection

Prevention:

• reservoir control (birds)
• vector control (mosquitos)
• prevent exposure (repellent and nets)