PARASITOLOGY

• What are the general characteristics of nematodes?

  Nematodes are unembryonated and have separate sexes.
• Describe the physical structure of an adult nematode.

  An adult nematode is an elongated, cylindrical worm that is primarily bilaterally symmetrical.
• What features are found at the anterior end of a nematode?

  The anterior end is equipped with hooks, teeth, plates, and papillae for abrasion, attachment, and sensory response.
• What are the three reproductive strategies of nematodes?

  Nematodes can be oviparous, ovoviviparous, or larviparous.
• What are the supporting structures of the nematode body wall?

  • Outer, hyaline, noncellular cuticle
  • Subcuticular epithelium
  • Layer of muscle cells
• Describe the alimentary tract of nematodes.

  The alimentary tract is a simple tube extending from the mouth to the anus.
• What is the function of the mouth in nematodes?

  The mouth is used for attachment and abrasion and is located at the anterior end.
• What is the buccal cavity in nematodes used for?

  The buccal cavity is for sucking and is tubular or funnel-shaped.
• What is the role of the esophagus in nematodes?

  The esophagus is a muscular tube that pumps food posteriorly into the intestine.
• Do nematodes have a circulatory system?

  No, nematodes do not have a circulatory system.
• What are chemoreceptors in nematodes?

  Chemoreceptors are sensory organs that respond to chemical stimuli.
• What are the three basic morphologic forms of nematodes?

  The three forms are eggs, larvae, and adults.
• How are nematodes classified based on the presence of caudal chemoreceptor organs?

  • Class Enoplea: without caudal chemoreceptor organ (aphasmids)
  • Class Rhabditea: mostly with caudal chemoreceptor organ (phasmids)
• Name an example of a nematode from Class Enoplea.

  Trichuris trichiura
• How is the adult nematode described in terms of shape and symmetry?

  The adult nematode is elongated, cylindrical, and primarily bilaterally symmetrical.
• What structures are found at the anterior end of a nematode?

  The anterior end is equipped with hooks, teeth, plates, and papillae for abrasion, attachment, and sensory response.
• Describe the alimentary tract of nematodes.

  The alimentary tract is a simple tube extending from mouth to anus.
• What are the components of the digestive system in nematodes?

  1. Mouth: for attachment and abrasion
  2. Buccal Cavity: for sucking, tubular or funnel-shaped
  3. Esophagus: muscular tube that pumps food into the intestine
• What type of circulatory system do nematodes have?

  Nematodes do not have a circulatory system; they rely on diffusion.
• What are the types of chemoreceptors found in nematodes?

  The types of chemoreceptors are amphid (cephalic), phasmid (caudal), and aphasmid.
• What are the three basic morphologic forms of nematodes?

  • Eggs: vary in size and shape
  • Larvae: typically long and slender
  • Adults: complete digestive and reproductive systems
• How are nematodes classified based on the presence of caudal chemoreceptor organs?

  1. ) Class Enoplea: without caudal chemoreceptor organ (aphasmids)

  II.) Class Rhabditea: mostly with caudal chemoreceptor organ (phasmids)
• Name one example of a nematode from Class Enoplea.

  Trichuris trichiura
• Name one example of a nematode from Class Rhabditea.

  Ascaris lumbricoides
• What are the classifications of nematodes according to habitat?

  • Intestinal nematodes: e.g., Enterobius vermicularis, Ascaris lumbricoides
  • Extraintestinal nematodes: e.g., Trichinella spiralis, Dracunculus medinensis
• What is the most common helminth infection in the world?

  Ascaris lumbricoides
• What is the mode of transmission (MOT) for Ascaris lumbricoides?

  The mode of transmission is ingestion of fully embryonated eggs.
• What are the symptoms and pathology associated with Ascaris lumbricoides infection?

  1. Pneumonia, cough, fever, eosinophilia during larval migration
  2. Vomiting and abdominal pain
  3. Possible intestinal perforation
• Describe the morphology of Ascaris lumbricoides eggs.

  • Egg shell consists of 3 layers:
  • Inner: Vitelline membrane
  • Middle: Glycogen layer
  • Outermost: Albuminous/mammillary coat
• What is the difference between corticated and decorticated eggs?

  Corticated eggs have all 3 layers present, while decorticated eggs have the outermost layer replaced by chitin.
• What are the characteristics of adult Ascaris lumbricoides?

  • Terminal mouth with trilobate lips
  • Small triangular buccal cavity
  • Cuticle with a faint longitudinal white lateral line
• What symptoms can arise from an adult Ascaris lumbricoides infection?

  Complications include abdominal pain, vomiting, diarrhea, malnutrition, and intestinal obstruction.
• What is the specimen of choice for laboratory diagnosis of Ascaris lumbricoides?

  The specimen of choice is stool.
• What is the treatment for Ascaris lumbricoides infection?

  Treatment includes albendazole and mebendazole.
• What are the prevention and control measures for Ascaris lumbricoides?

  • Avoid using feces as fertilizer
  • Proper sanitation
  • Personal hygienic practices
• What is the common name for Enterobius vermicularis?

  Pinworm
• What is the mode of transmission (MOT) for Enterobius vermicularis?

  The mode of transmission is ingestion and inhalation of fully embryonated eggs.
• What are the symptoms and pathology associated with Enterobius vermicularis infection?

  • Symptoms include itching around the anus, irritability, and insomnia.
  • Pathology may involve secondary bacterial infections due to scratching.
• lays unembryonated egg

  Oviparous
• lays embryonated egg, ready for hatching

  Ovoviviparous