Helminths and Arthropods

Q: What is a helminth?

A: A parasitic worm, typically visible to the naked eye in adult form.

Q: Name the three major groups of helminths.

A: Nematodes (roundworms), Trematodes (flukes), and Cestodes (tapeworms).

Q: What type of body do nematodes have?

A: Cylindrical, unsegmented bodies.

Q: How do nematodes reproduce?

A: They are usually dioecious (separate sexes).

Q: What are trematodes also known as?

A: Flukes.

Q: What type of body do trematodes have?

A: Leaf-shaped, unsegmented, and often hermaphroditic.

Q: What are cestodes also called?

A: Tapeworms.

Q: What are the body parts of a cestode?

A: Scolex (head with suckers/hooks), neck, and proglottids (segments).

Q: How are helminth infections usually transmitted?

A: Through ingestion of eggs or larvae, or skin penetration.

Q: What is the definitive host?

A: The host in which the parasite reaches sexual maturity.

Q: What is the intermediate host?

A: The host that harbors the larval or asexual stage.

Q: What is the purpose of an ova and parasite (O&P) test?

A: To detect parasite eggs or organisms in a stool sample.

Q: What are arthropods?

A: Invertebrate animals with exoskeletons and jointed appendages.

Q: Name three classes of arthropods relevant to microbiology.

A: Insects, arachnids, and crustaceans.

Q: How do arthropods cause disease?

A: As vectors (transmitting pathogens), parasites, or by causing allergic reactions.

Q: Give an example of an insect vector.

A: Mosquito (transmits malaria, dengue, etc.)

Q: Give an example of an arachnid vector.

A: Tick (transmits Lyme disease, Rocky Mountain spotted fever)

Q: What is the difference between mechanical and biological transmission?

A: Mechanical: pathogen is carried on the body surface; Biological: pathogen multiplies or develops in the vector.

Q: What diseases are caused by trematodes?

A: Schistosomiasis, liver fluke disease.

Q: What diseases are caused by cestodes?

A: Taeniasis, cysticercosis.

Q: What diseases are caused by nematodes?

A: Ascariasis, hookworm, pinworm infections.