III - B. Helminthology | 28. Characterisation of the helminths, anthelminthic drugs Flashcards
I. General helminthology
1. What are the features of helminths?
- multicellular organisms
- vary in size from 200 um to 15 m!
- reproduction by eggs ( microscopy!)
- may have intermediate and definitive host
- majority are GI parasites => may infect other organs as well!
I. General helminthology
2. What is the route of transmission of helminths?
- per os
- through intact skin
- via vectors
- transplacentary
- autoinfection
I. General helminthology
3. What is general pathomechanism of helminthic diseases?
- mechanical obstruction
- malnutritio due to competition for metabolites
- production of toxic metabolites or toxins
I. General helminthology
4. Give the taxonomic classification of helminths?
- Platyhelminthes (flatworms)
- Trematodes (flukes)
- Cestodes (tape worms) - Nemathelminthes (roundworms)
- Nematodes (thread worm)
I. General helminthology - Platyhelminthes (flatworms)
5. What are the features of Flukes (trematodes)?
- Short, flat, leaf shaped, hermaphrodites
- equipped with two muscular suckers
- Water snail is the most common intermediate host of the flukes
- incomplete digestive system
I. General helminthology - Platyhelminthes (flatworms)
6. What’s the life cycle of Flukes (trematodes)?
egg
➞ larva with flagells (miracidium)
➞ sack-like larva (in intermediate host)
➞ redia (larva with developed GI tract)
➞ cercaria (infectious
larva form)
➞ mature larva (in definite host)
I. General helminthology - Platyhelminthes (flatworms)
7. What are example species of Flukes (trematodes)?
- Fasciola hepatica
- Schistosoma spp.
- Paragonimus westermani
I. General helminthology - Platyhelminthes (flatworms)
8. What are the features of Cestodes (tape worms)?
- flat and ribbon-like, segmented body plan => segments are called proglottids
- do not have GI tract => absorbs nutrients on the entire body surface
- heads (scolex) are equipped with structures off attachment => cup-shaped suckers & crown of hooklets
I. General helminthology - Platyhelminthes (flatworms)
9. What is the life cycle of Tapeworms (cestodes)?
Relatively simple life cycle
1. proglottids mature as they move distally
2. mature proglottids are filled with eggs
- proglottids released into feces
- eggs infect intermediate host
I. General helminthology - Platyhelminthes (flatworms)
10. What are example species of Tapeworms (cestodes)?
- Taenia solium
- Taenia saginata
- Diphyllobotrium latum
- Hymenolepsis nana
- Echinococcus granulosus
- Echinococcus multilocularis
I. General helminthology- Roundworms (nematodes)
1. What are the features of Roundworms (nematodes)?
- cylindrical, unsegmented body
- usually larger size
- well-developed GI and genital tracts
I. General helminthology- Roundworms (nematodes)
2. How do we classify Roundworms (nematodes)?
can classify them based on reproduction srategy
* lays non-segmented egg (oviparous)
* lays segmented egg (ovoviviparous)
* lays larvas (viviparous)
I. General helminthology- Roundworms (nematodes)
3. What are example species ?
I. General helminthology- Nematodes (thread worm)
1. What are examples of Nematodes (thread worm)?
II. DIAGNOSTICS OF HELMINTHS
1. How do we diagnose Helminths?
- sample: stool (except for Enterobius)
- examina8on method: detec8on of egg via direct op8cal microscopy
II. DIAGNOSTICS OF HELMINTHS
1. How do we diagnose Helminths?
- sample: stool (except for Enterobius)
- examination method: detection of egg via direct op8cal microscopy
III. Antihelminthic drugs
1. What are the Antihelminthic drugs?
- Benzimidazoles
- Bithionol
- Niclosamide
- Praziquantel
- Levamisole
III. Antihelminthic drugs
2. What are the features of Benzimidazoles?
III. Antihelminthic drugs
3. What are the features of Bithionol?
III. Antihelminthic drugs
4. What are the features of NICLOSAMIDE?
III. Antihelminthic drugs
5. What are the features of PRAZIQUANTEL?
III. Antihelminthic drugs
6. What are the features of LEVAMISOLE?
What are the helminths that cause GI infections?
