NewLec25-12-62บทนำทั่วไปของหนอนพยาธิตัวตืด

Common genital pore Testes and Vitelleria Uterine pore Uterus with eggs Ovary

Life cycle of Pseudophyllidean  An unembryonated egg with operculum as trematode

Life cycle of Pseudophyllidean  A coracidium  an onchosphere (1st stage larva) still enclosed in a ciliated embryophore



Life cycle of Pseudophyllidean  A procercoid is an elongated onchosphere bearing the six hooks on a posterior disc-like portion of the body

Life cycle of Pseudophyllidean  A plerocercoid (sparganum) is an elongate, solid-bodied, worm-like larva bearing the young scolex at one end (infective stage)

Life cycle of Pseudophyllidean Unembryonated egg free swimming coracidium (Onchosphere) Adult Plerocercoid Procercoid (Infective stage)

Pseudophyllidean cycle Plerocercoid (Sparganum) 6 hooks Ciliated embryophore Procercoid Unembryonated Egg Coracidium Onchosphere

Cyclophyllidean group  Family Taeniidae  Family Hymenolepididae  Family Anoplocephalidae  Family Davaineidae  Family Mesocestoididae  Family Dipylididae

Cyclophyllidean group The body consists of  Head or Scolex  usually provided with suckers and hooks  Strobila  consists of a number of segments or proglottids

Cyclophyllidean group  Between the scolex and the strobila there may be a short unsegmented portion(stem cells) that is often called the neck  Vary in size from a few millimetres to several metres in length

Cyclophyllidean group  The scolex is usually more or less globular and bears four suckers with muscular walls which may be armed with hooks  Anteriorly the scolex may be armed with a protrusible part, the rostellum, which may bear one, two or several rows of hooks

Cyclophyllidean group  These hooks vary much in shape, but generally they may consist of 3 parts  Handle or Base  Guard  Blade  The hooks are sometimes lost, especially when they are small





Cyclophyllidean group  The strobila may consist of a few (Echinococcus spp.) or numerous proglottids (Taenia spp.)  These vary considerably in shape and size in different species

Cyclophyllidean group  The anterior ones are the youngest, and they increase in size and development of their internal parts progresses (strobilation)  The structure of the body is somewhat similar to that of the trematodes

Cyclophyllidean group  The body is covered by a tegument.  Beneath the tegument the body is filled with a parenchyma similar to that of the trematodes  In this lie more centrally, strong bundles of longitudinal muscle fibres

Cyclophyllidean group  Internal to these there is a thinner layer of transverse muscles which divide the body into outer cortical and inner medullary portions  The medulla contains the excretory, nervous and reproductive organs

Cyclophyllidean group  The excretory system consists of  Flame-cells and efferent canals as in the trematodes  There are usually, on either side, two longitudinal canals, a larger central and a smaller dorsal



Cyclophyllidean group  Nervous system  The central part of the nervous system is situated in the scolex and consists of several ganglia and commissures, from which two large and several smaller nerve trunks run through the strobilia  The main trunks are lateral to the large excretory canals

Cyclophyllidean group  Reproductive system  The male genital organs are the first to develop in the young proglottids or immature segments  Segments in which the reproductive organs have become mature and functional are called mature segments or proglottids

Cyclophyllidean group  Vitelline gland compact and unpaired, near the ovary  The genital pore is marginal  Each proglottid usually contains one or two sets of male and female reproductive organs





Cyclophyllidean group  Life cycle  Heteroxenous (Indirect), requiring one or more intermediate hosts except H. nana and H.diminuta

Life cycle of the Cyclophyllidean Tapeworms

Life cycle of Cyclophyllidean  Egg ---> Onchosphere ---> Cysticercoid ---> Adult  Egg ---> Onchosphere ---> Cysticercus ---> Adult  Egg ---> Onchosphere ---> Coenurus ---> Adult  Egg ---> Onchosphere ---> Hydatid cyst ---> Adult





Life cycle of Cyclophyllidean  Cysticercoid  a small larva containing a scolex withdrawn into a fold of the body  Cysticercus  a bladder into which is invaginated a single scolex

Life cycle of Cyclophyllidean  Coenurus  similar to the cysticercus but with many scolices  Hydatid cyst  a large cyst containing free individual scolices, brood capsules from which these are generated, and daughter cysts.

Life cycle of Cyclophyllidean  A hydatid cyst contains not only numerous scolices but also brood capsules bearing scolices and daughter cysts bearing other cysts or scolices  Asexual reproduction resulting in colonies occurs in the coenurus and hydatid cyst





Cysticercus bovis





ac 2 mm bd 0.5 mm

a b 0.5 mm 200 mm c 50 mm

ab c 1 mm

ab 2 mm 1 mm

a 1 mm bc 50 mm 100 mm

b cd a 100 mm 1 mm 100 mm 100 mm

ab c de 200 mm 200 mm 200 mm 2 mm 200 mm

20 mm 50 mm

20 mm 50 mm

50 mm