Parasitology Lab # 3- Cestodes 1
Generalcharacters 1- All tape worms consist of long, multi-segmented body. 2- Cuticle of the body is provided with pores through which the worm takes its nutrients (no digestive system). 3- All are hermaphroditic.
The adult worm is divided into 3 distinct parts: head (scolex), neck and strobilla. a- Head or scolex:Usually provided with muscular suckers and crown of hooks (rostellum) to attach to intestinal wall. b- Neck region:Serves as generative organ. c- Strobilla:The long segmented body consists of three types of segments: Immature segments: follow the neck region and contain immature sex organs. Mature segments: containing both sex organs & responsible for reproduction. Gravid segments: filledwith fertilized eggs.
Generalcharacters 5- Eggs: Contain hexacanth embryo (oncosphere). 6- All cestodes have intermediate host except Hymenolepis nana.
Life cycle of Taeniaspp. Infective Stage Final Host Intermediate Host Diagnostic Stage
1. Taeniasaginata(beef tape worm) • Length: up to 10 m
2. Taeniasolium(pork tape worm) Length: 2-8 m
3. Hymenolepisdiminuta(rat tape worm) Infective Stage Final Host Intermediate Host Diagnostic Stage
3. Hymenolepisdiminuta(rat tape worm) Length:20-60 cm
4. Hymenolepis nana (dwarf tape worm) NO Intermediate Host Final Host Infective & Diagnostic Stage
4. Hymenolepis nana (dwarf tape worm) Very small 15-40 mm