2-Zoonoses from Carnivores: Dogs, Cats and Raccoons Flashcards
Several developmental stages of the Toxoplasma gondii life cycle take place where?
Within cat intestinal cells.
Are cats with Toxoplasma gondii usually infected early or late in life?
Early in life.
What is excreted by the cat that has Toxoplasma gondii?
Oocysts
How long to cats usually excrete Toxoplasma gondii oocysts for?
1-3 weeks
How long does oocyst sporulation of Toxoplasma gondii take place in the soil?
1-5 days
Initial infection of Toxoplasma gondii in intermediate hosts are located where?
What is this life stage called?
- Macrophages
- Tachyzoites
Which part of the life cycle of Toxoplasma gondii undergoes rapid replication, release and systemic spread?
Tachyzoites
As immunity to Toxoplasma gondii kicks in, what develop?
Bradyzoites
Cells infected with which part of the Toxoplasma gondii life cycle typically encyst into muscular tissues or neurologic tissues?
Bradyzoites
What are 2 forms of human exposure to Toxoplasma gondii?
- Oocysts in soil
- Ingestion of tissue bradyzoites in undercooked meat
T/F: Toxoplasma gondii oocysts are very resistant and can survive most disinfectants, freezing and drying.
True
What is a major source of tissue bradyzoites of Toxoplasma gondii?
What are 2 other sources?
- Pork
- Lamb and venison
How can tissue cysts seen with Toxoplasma be rendered non-infectious?
By freezing for >7 days or by cooking.
What should food preparers handling uncooked meat do?
Wash their hands after preparing pork chops, etc. for cooking.
Infections of Toxoplasma are usually asymptomatic in what 2 groups of humans?
- Immunocompetent adults
- Children
If a person has poor immunity, it can lead to what with Toxoplasma?
Tachyzoites out of control.
Toxoplasma can cause severe problems in what 2 groups of people?
- AIDS patients
- Pregnant women
Are there any good control programs for Toxoplasma in cats?
No
What are 4 ways to control Toxoplasma by reducing the risk of human infections?
- Pregnant women can be tested serologically for antibodies.
- Buy cats that are less likely to be shedding.
- Prevent oocyst sporulation.
- Reduce exposure.
What is a term for diseases caused by migrating larvae in paratenic hosts?
Larval migrans
T/F: Parasitic nematodes are almost never migratory during the larval stages.
False - they are almost always migratory.
What are 4 examples of types of larval migrans?
- Visceral
- Cutaneous
- Ocular
- Neurologic
What are 3 roundworms common of pet animals?
- Toxocara canis
- Toxocara cati
- Toxocara vitulorum
T/F: Almost every dog is infected with a roundworm at some point in its life.
True
Human toxacariasis is considered what?
A “neglected tropical disease”
What are 2 risk factors for human toxocariasis?
- Children between the age of 1-4 years
- Pica and geophagia
What type of larval migrans is the most common in human toxocariasis cases?
Visceral larval migrans
Which other 2 types of larval migrans can be seen with human toxocariasis but are more rare?
- Ocular
- Neurologic
Do humans have low or high exposure rate to Toxocara?
High exposure with seroprevalence up to 100% in some places.
What is one way to prevent toxocariasis?
What is an example of how to do this?
- Reduce the reservoir
- Regular antihelminthic treatment of dogs, cats, puppies