Parasites

Question 1

What is a parasite?

Answer 1

An organism that lives on or in another organism and derives a benefit at the expense of the host
Can be acquired as a result of a bite, contaminated water, or contaminated environment

Question 2

What is an exoparasite?

Answer 2

It lives on the host-infestation

Question 3

What is an endoparasite

Answer 3

Lives in the host-infection

Question 4

What are some exoparasites?

Answer 4

Scabies, Body Louse, Head lice, ticks, pubic lice(crabs)

Question 5

What is the direct life cycle?

Answer 5

The entire life cycle is completed in 1 host
You get infected, you get sick, then pass it on
Easy to control
Eggs are often only viable for a short time in the environment

Question 6

What is an indirect life cycle?

Answer 6

The lifecycle is completed in more than one host
You need to control rodents to get reduction in humans
Harder to control
Like Lyme disease and malaria

Question 7

What are some single celled parasites

Answer 7

Protozoa-intestinal and blood/tissue

Question 8

What are some multicellular parasites?

Answer 8

Helminths-cestodes (flat worms), nematodes (round worms), and trematodes (flukes)

Question 9

Give some examples of protozoa

Answer 9

Entamoeba histolytica-associated with poor sanitization
Giardia lamblia-beaver fever
Cyclospora cayetansis-not washed lettuce
Dientamoeba fragilis-person to person
Cryptosporidium parvum-cattle

Question 10

Facts about intestinal protozoa

Answer 10

500 million cases a year
All are direct life cycle
contamination route is typically food, water or soil

Question 11

What is trichomonas vaginalis

Answer 11

STI-blood/tissue protozoa
common STI, vaginal discharge
easily treatable

Question 12

Plasmodium spp

Answer 12

Malaria, transmission via anopheles mosquiotos
Mosquito bites dusk to dawn so mosquito nets work well

Question 13

Toxoplasma gondii

Answer 13

Cats! Mouse becomes unafraid, cat eats mouse, humans get infected
If mother gets infected during pregnancy, it can transmit to baby in utero

Question 14

What are 3 helminths-cestodes

Answer 14

Cestodes (tapeworms)
Diphylobothrium latum-from freshwater fish
Taenea solium-pork (multiple hosts)
Taena saginita-beef (multiple hosts)

Question 15

Helminths (Nematodes)

Answer 15

Round worms-
Strongyloides free larval worms in soil
Ascaris lumbricoides-egg ingestion
Enterobius vermacularis. (pin worms)-itchy butt

Question 16

Strongyloides stercoralaris

Answer 16

1 host
Has 2 phases, free living in the environment, shedding feces, then when in a warm climate and stepping with no slippers it gets inside
Only comes out when immune incompetent (30 years later)

Question 17

Trematodes

Answer 17

Shistosoma-1 host (contaminated water)
Clonorchis-1 host (drink contaminated water or eat contaminated fish)

Question 18

How to detect parasites?

Answer 18

stool specimen in preservatives for intestinal parasites
Antibody detection for tissue and blood parasites