INTRODUCTION TO HELMINTHS

Question 1

Classification by Infection Mode: What are the different modes of infection for helminths?

Answer 1

①By ingestion
②By penetration of skin
③By blood sucking insects
④By inhalation of dust containing eggs

Question 2

Which helminths are associated with ingestion of eggs?

Answer 2

①Enterobius
②Ascaris
③Trichuris
(EAT)

Question 3

Which helminths are associated with ingestion of Larvae within intermediate host?

Answer 3

Dracunculus

Question 4

Which helminths are associated with ingestion of Encysted larvae in the muscle?

Answer 4

Trichinella

Question 5

Which helminths are transmitted by penetration of skin？

Answer 5

①Ancylostoma
②Necator
③Strongyloides

Question 6

Which helminths are transmitted by blood sucking insects？

Answer 6

Filariae

Question 7

Which helminths are transmitted by inhalation of dust containing eggs?

Answer 7

①Ascaris
②Enterobius

Question 8

Egg Laying/Larvae Types: Can you describe the differences between oviparous, viviparous, and ovoviviparous helminths?

Answer 8

①Oviparous: Egg laying nematodes
②Viviparous: Producing larvae
③Ovoviviparous: Laying eggs containing fully formed larvae which hatch out immediately

Question 9

Oviparous: Egg laying nematodes

Answer 9

①Unsegmented eggs: Ascaris & Trichuris
②Segmented eggs: Ancylostoma & Necator

Question 10

Viviparous: Producing larvae:

Answer 10

①Trichinella
②Wuchereria
③Brugia
④Dracunculus

Question 11

Ovoviviparous: Laying eggs containing fully formed larvae which hatch out immediately:

Answer 11

Strongyloides

Question 12

Helminth Groups: What are the two main groups of helminths and what distinguishes them?

Answer 12

①Nemahelminths
Nematodes – Roundworms

②Platyhelminths ( Flatworms)
- Trematodes - flukes
- Cestodes - tapeworms

Question 13

Nematode Habitats: How are nematodes classified based on their habitat？

Answer 13

①Intestinal nematodes
②Blood and tissue nematodes

Question 14

Intestinal nematodes；

Answer 14

①Soil transmitted helminths (STH)
②Others Non – soil transmitted helminths ( Non- STH)

Question 15

Blood and tissue nematodes

Answer 15

Filaria and drucunculus

Question 16

INTESTINAL NEMATODES

Answer 16

Small intestine: ①Ascaris
②Ancylostoma
③Necator
④Strongyloides
⑤Trichinella
Large intestine: ①Enterobius
②Trichuris

Question 17

TISSUE NEMATODES (Somatic nematodes)

Answer 17

①Lymphatic: Wuchereria, Brugia
②Sub-cutaneous: Loa loa, Onchocerca, Dracunculus
③Mesentry: Mansonella spp.
④Conjunctiva: Loa loa
⑤Zoonotic filariasis: Dirofilaria spp.

Question 18

Soil transmitted helminths；

• These require period of development and maturation during their life cycle in the soil

Answer 18

①Ascaris lumbricoides
②Trichuris trichiura
③Hookworm ( Necator americanus and Ancylostoma duodenale)
④Strongyloides stercolaris

Question 19

Non – soil transmitted helminths；

Answer 19

①Enterobius vermicularis
②Trichinella spiralis

Question 20

Filaria and drucunculus

Answer 20

①Wuchereria bancrofti
②Brugia malayi
③Brugia timori
④Onchocerca vovulus
⑤Drucunculus medinensis

Question 21

HUMAN FILARIAL WORMS

Answer 21

thread-like worms transmitted by blood sucking arthropods

they are zoonotic
Cause FILARIARIS

Question 22

Morphology of filarial worms

Answer 22

①Adult worm
②Microfilariae(embryo)；
Sheathed microfilarie or
unsheathed microfilariae

Question 23

How many species of filarial worms infect humans ?

Answer 23

eight

Question 24

Definite hosts of filarial worms

Answer 24

Humans

Question 25

Classification of human filarial worms

Answer 25

①Lymphatic filariasis ②Subcutaneous filariasis ③Serous cavity filariasis

Question 26

Lymphatic filariasis agents

Answer 26

①Wuchereria bancrofti (bancroftian filariasis) ②Brugia Malaya (Malayan filariasis) ③Brugia timori

Question 27

Subcutaneous filariasis

Answer 27

①Loa loa(calabar/fugitive swelling) ②Oncocerca volvulus（river blindness, dermatitis) ③Mansonella streptocerca(skin diseases)

Question 28

Serous cavity filariasis

Answer 28

①Mansonella ozzardi（asymptomatic) ②Mansonella perstans（asymptomatic)

Question 29

Tapelike and segmented helminths

Answer 29

Cestodes

Question 30

Leaflike and unsegmented helminths

Answer 30

Trematodes

Question 31

Elongated, cylindrical and unsegmented helminths

Answer 31

Nematodes

Question 32

Sexes not separate , monoecious, hermaphrodite

Answer 32

Cestodes

Question 33

Sexes not separate , monoecious, except for schistosoma

Answer 33

Trematodes

Question 34

Sexes separate , diecious

Answer 34

Nematodes

Question 35

Head end has suckers, often with hooks.

Answer 35

Cestodes

Question 36

Head end has suckers, no hooks.

Answer 36

Trematodes

Question 37

Head end has no suckers, with no hooks, well developed

Answer 37

Nematodes

Question 38

No alimentary canal

Answer 38

Cestodes

Question 39

Incomplete alimentary canal with no anus

Answer 39

Trematodes

Question 40

Alimentary canal present

Answer 40

Nematodes

Question 41

No body cavity

Answer 41

Cestodes and Trematodes

Question 42

Body cavity present

Answer 42

Nematodes

Question 43

。。。do not multiply in man or host

Answer 43

Nematodes