Generic Questions for Module 1

What are the two types of life cycles in parasites?

Direct and Indirect Life Cycles

What are the 5 different types of hosts?

Definitive, Intermediate, Paratenic, Incidental (Dead End) and Reservoir Hosts

What are the 4 routes of infection?

Oral ingestion, Skin penetration (Cutaneous), Air Passages and Prental (Transplacental)

Name the 11 causes of host injury by parasites.

Nutrient competition, Blood loss, Tissue damage, Mechanical obstruction, Opporunity for bacterial invasion, Scar tissue reactions, Toxins, Disease vectors, Stimulate neoplasia, Allergic reactions and Physical annoyance.

What is an example of a mutualistic relationship?

Cowbirds sitting on a cows back and eat bugs.

What’s an example of a commensalistic relationship?

Barnacles attaching to a whale to live with no effect on the whale.

What’s an example of a parasitic relationship?

Hookworms in a dog.

What’s an example of a synnecrotic relationship?

A heavy load of ascarids will kill both them and the host.

What is an example of a Paratenic (Transport) Host?

Toxocara cati (roundworm) in the larval form encapsulated in a mouse’s tissues and released when a cat ingests the mouse.

What’s an example of an Incidental Host?

Cattle with Fascioloides magna encapsulated in the liver which can’t pass egg into the environment.

What’s an example of a Reservoir Host?

Coyotes and wolves pass heartworm to dogs via mosquito.

What’s an example of Oral ingestion as a route of infection?

Horses ingest infective roundworms eggs while grazing in the pasture.

What are the 3 ways of Skin Penetration as a route of infection?

By the parasite itself, via insect bites, and by mechanical means.

What’s an example of a parasite infecting via insect bites?

Mosquito carries heartworm and deposits parasite during blood meal.

What is an example of Nutrient Competition?

Roundworms compete and cause a dry hair coat and potbelly (excessive gas) in the host.

What is an example of Mechanical Obstruction?

Flukes blocking bile ducts

What is an example of Bacterial Invasion from parasite damage?

Black disease in sheep.

What is an example of a Scar Tissue Reaction from parasites?

Flukes migrating through liver causes fibrosis which results in a footprint appearance.

What’s an example of toxins affecting a host from a parasite?

Tick paralysis from a neurotoxin excreted by a tick.