Helminths

Question 1

Monoecious

Answer 1

Parasitic helminth that has both male and female reproductive parts

Question 2

Dioecious

Answer 2

Parasitic helminth that is either male or female NOT both

Question 3

Platyhelminthes

Answer 3

Flatworms
Class : Trematodes (flukes)
Class: Cestodrs (tapeworms)

Question 4

Nematodes

Answer 4

Roundworms

Question 5

Cestodes (tapeworm)
Characteristics

Answer 5

-Head is called Scolex
-Lack a digestive system
-Body consists of segments called proglottids, each being filled with eggs
-Anaerobes

Question 6

Cestodes (tapeworms)
Humans as definitive hosts

Answer 6

-Taenia solium (pork)
-Taenia saginata (beef)
*T. saginata can live in the intestine for about 25 years reaching 6 meters in length

Question 7

Humans as definitive hosts
(Life cycle)

Answer 7

-Lives in intestines of human host
-Produces eggs that are excreted in feces
-Eggs are ingested by animals where the egg hatches into larval form called cysticercus and attaches to muscle
-Humans are infected by consuming undercooked meat (pork or beef)
-Cysticerci develop into adult tapeworm and attach to the intestinal wall

Question 8

Cestodes (tapeworms)
Humans as intermediate hosts

Answer 8

Echinococcus granulosus
creates hydatid cysts
-humans are intermediate hosts
-dogs/wolves are definitive hosts

Question 9

Humans as intermediate hosts
(Life cycle)

Answer 9

1. Adult tapeworm releases eggs, excreted by definitive host
2. Intermediate host ingests eggs
3. Egg hatches and larvae migrate to liver or lungs
4. Larvae develop into hydatid cysts
5. Definitive host eats intermediate host ingesting cysts
6. Scoleces from cysts attach to intestine and grow into adults

Question 10

Nematodes (roundworm)
Characteristics

Answer 10

-Cylindrical and tapered at east end
-Have a complete digestive system
-Most species are dioecious
-Males are smaller than female with curved tail
-Some roundworm some their whole life cycle in a single host
-Egg and Larvae are both infectious to humans

Question 11

Enterobius vermicularis

Answer 11

Pinworms
-Eggs are infectious
-females remain in the cecum, travel up the ascending colon meet with males in traverse colon, continue down the descending colon and deposits eggs in perianal skin
-Diagnosed using Graham sticky tape method

Question 12

Trichuris trichiura

Answer 12

Whipworm
-Eggs are infectious
-Infects large intestine and causes trichuriasis
-Ova are football shaped with bipolar plugs
-Infection occurs through ingestion of eggs (usually found in various grains, beans and rice)
-Whipworm infestation is detected by examination of stool for eggs

Question 13

Ascarius lumbricoides

Answer 13

-Eggs are infectious, 200,000 produced/day and remains in soil for 10 years
-Causes ascariasis
-Over 1billion infected worldwide
-Hatches in the intestines, travels to lungs, gets coughed up and reswallowed and travels back to intestines
-Diagnosis is made when adult worm is excreted through feces, mouth or nose

Question 14

Nematodes: Hookworms

Answer 14

Larvae is infectious
*Nector americanus & Ancylostoma duodenal
-live in intestines and feeds on blood and tissues causing anemia
*Trichinella spiralis
-Causes trichinellosis
-Acquired by eating undercooked pork

Question 15

Antihelminths (medications)

Answer 15

*Mebendazole
*Piperazine
*Niclosamide (specific for tapeworms, NOT pinworms or roundworms)
*Pyrantel