Exam 2 Zoonoses from Carnivores

Question 1

When are cats usually infected with Toxoplasma gondii?

Answer 1

Early in life, excrete oocycts for 1-3 weeks and then appear to recover

Question 2

Toxoplasma gondii oocyst sporulation take how long in the soil?

Answer 2

1-5 days

Question 3

What cells are affected in initial Toxoplasma gondii infections of intermediate hosts

Answer 3

macrophages

-rapid replication, release, systemic spread

Question 4

Tachyzoites=

Answer 4

fast

Question 5

Bradyzoites=

Answer 5

slow

Question 6

What cells are affected by Toxoplasma gondii as immunity kicks in?

Answer 6

infected cells typically encyst into muscular or neurological tissues
-possibly cats are latently infected?

Question 7

When a mouse gets Toxoplasma gondii it loses its fear of cats (T/F)

Answer 7

True, even once the infection has cleared

Question 8

Two ways of human exposure to Toxoplasma gondii

Answer 8

• Oocysts in soil: wash or cook to remove/kill

- Ingestion of tissue bradyzoites: cook or freeze (primarily from pork)

Question 9

People affected by Toxoplasma gondii

Answer 9

• people with poor immunity–>tachyzoites out of control
• severe problems in AIDS patients
• severe problems in pregnancy

Question 10

Reduce exposure for Toxoplasma gondii

Answer 10

• serologically testing for antibodies
• get older cats
• keep off counters
• wash veggies

Question 11

Areas of larval migration

Answer 11

• visceral
• cutaneous
• ocular
• neurologic

Question 12

Common roundworms of pet animals

Answer 12

• Toxocara canis
• Toxocara cati
• Toxocara vitulorum

Do not reach adult stage in humans

Question 13

Human Toxocariasis

Answer 13

• children between 1 & 4, pica & geophagia
• visceral larval migrans is most common
• ocular or neurologic migration is rare, but can happen

Question 14

Prevention of Toxocariasis

Answer 14

• reduce the reservior: treat puppies & kittens

- cover sand pits, 20-40% may have toxocara eggs

Question 15

Baylisascara procyonis

Answer 15

• raccoon roundworm

- tropism for ocular or neurologic tissue

Question 16

Cestodes: Humans become intermediate host by eating ______.

Symptoms are caused by the _______

Answer 16

larvated eggs.

cysts

Question 17

Clinical signs of cestodes in intermediate hosts

Answer 17

• systemic cysts
• primary organ affected dependent on species of parasite
• sometimes anaphylactic symptoms follow rupture of cyst

Question 18

Echinococcus granulosus

Answer 18

• hydatid cyst disease
• liver most common
• sometimes brain
• slow growing (10-20 years)

Question 19

Echinococcus multilocularis

Answer 19

• alveolar cyst disease
• multilocular, small, solid cysts in tissues
• often liver, can spread into lungs
• cysts grow over 10 years
• metastatic, usually inoperable by discovery

Question 20

Cystic Echinococcosis

Answer 20

• canids are reservoirs
• associated with sheep industry
• sylvatic cycle, between wolves & moose, in large parts of Canada

Question 21

Prevention of Cystic Echinococcosis

Answer 21

• regularly treat dog with praziquantel
• dog control
• condemn infected offal
• educate people

Question 22

Alveolar Echinococcosis

Answer 22

• naturally between foxes & rodents
• rare in humans, but high fatality rate if untreated
• northern hemisphere: very common in China

Question 23

Control of E. multilocularis

Answer 23

• routine antihelminth treatment
• reduce exposure of pets to rodents
• treat foxes
• education
• dog control