Worms

Chapter 3

Phylum Platyhelminthes

• Characteristics –Flattened, acoelomate, bilaterally

symmetrical –Unsegmented

–Incomplete or absent gut

–Somewhat cephalized, with ganglion and nerve cords

–Protonephridia as excretory/osmoregulatory structures

–Most forms monoecious with complex reproductive systems

Classification

• Domain: Eukarya • Kingdom: Animalia • Phylum: Platyhelminthes • Classes: Turbellaria Monogenea Trematoda Cestoidea

Platyhelmithes Parasites

• Liver Fluke – Class: Trematoda – Description: Dark reddish-brown, mucousy, feed

on blood – Transmission: mammals get it through ingestion

of vegetation with eggs – Effects: abdominal pain, headache, loss of

appetite, anemia, vomitting

• Beef Tapeworm – Class: Cestoda – Size: 3m to 5m in length – Description: long and thin, white, appear

segmented – Transmission: Eating undercooked beef – Effects: Generally no symptoms

• Lung Fluke – Class: Trematoda – Size: 7.5mm to 12mm – Description: looks like a coffee bean – Transmission: consuming raw or undercooked

crustaceans – Effects: coughing

• Pork Tapeworm – Class: Cestoda – Size: 0.5cm to 20cm – Description: – Transmission: eating raw or undercooked pork – Effects: usually no symptoms

• Blood Fluke (Schistosomiasis) – Class: Trematoda – Size: 10 mm long – Description: feed on blood, produce 300 to 3000

eggs a day – Transmission: burrows through the skin when

human is in contaminated water – Effects: stunted growth, brain damage

• Dog Tapeworm – Class: Cestoidia – Size: varies – Description: white, thin, appears segmented – Transmission: eating raw meat or feces – Effects: eggs appear in feces