Classification of Worms Flashcards

Study Notes

Classification of Worms

Roundworms (Nematoda):
- Include both large (Nematoda) and small (Filariae) species.
- Unsegmented with tougher outer coating.
- Exhibit separate sexes.
Flatworms:
- Possess both male and female reproductive organs.
- Softer outer coating compared to roundworms.

Types of Flatworms

Cestodes (Tapeworms): Characterized by long, flat, segmented bodies.
Trematodes (Flukes): Include organ and blood flukes.

Cestodes - Tapeworms

Types include:
- Taenia species: Beef and pork tapeworms.
- Diphyllobothrium latum: Found in fish.

Trematodes - Flukes

Comprised of organ flukes and three Schistosoma species responsible for blood flukes.

Hosts in Worm Life Cycle

Intermediate Host: Hosts harboring larvae, essential for the worm's developmental stages.
Definitive Host: Hosts that contain the adult worm which reproduces and consumes nutrients.

Effects of Worm Infections

General effects: Decrease host resistance, cause tissue inflammation, malnutrition, and hypersensitivity.
Localized effects: Obstruct fluid/blood flow and damage epithelial tissues.

Pinworm (Enterobius Vermicularis)

Egg Laying: Eggs are laid on the perianum, not in feces; can be dislodged by scratching.
Symptoms: Includes perianal itching, irritability, decreased appetite; one-third of cases are asymptomatic.
Epidemiology: Highly common in children; most prevalent parasitic worm in the U.S.
Diagnosis: Utilizes O&P testing and scotch tape prep.

Whipworm (Trichuris Trichura)

Symptoms: Vary from light to heavy infections; can cause intestinal obstruction and rectal prolapse in children.
Transmission: Ingestion of eggs with further egg production occurring in the intestines.

Ascaris lumbricoides (Large Intestinal Roundworm)

Prevalence: Most common nematode worldwide; prevalent in farm animals and humans.
Transmission: Through feces; eggs embryonate in soil.
Larval Migration: Travels from GI to liver, then to lungs; cough/swallow brings larvae back to GI.
Symptoms: Range from asymptomatic to abdominal discomfort; transient pulmonary issues during migration.
Diagnosis: O&P testing and identifying adult worms in stool, nose, or mouth.

Hookworm

Species: Necatur Americanus and Ancylostoma duodenale.
Infection Method: Larvae penetrate skin from soil; undergo larval migration phase similar to Ascaris.
Symptoms: Includes ground itch, pulmonary issues, and anemia from blood feeding.

Trichinella Spiralis (Trichinosis)

Infection Method: Larvae cysts are ingested in undercooked meat, notably pork or bear.
Symptoms: Migration to muscles, including deltoid and diaphragm, possibly affecting the brain.
Diagnosis: Requires muscle biopsy; no O&P.

Wuchereria Bancrofti (Elephantiasis)

Transmission: Via mosquito bites.
Symptoms: Blockage of lymphatic ducts and immune reactions to dying worms.
Diagnosis: Detection of microfilariae in blood/subcutaneous tissue; parasites are active during host's rest.

Unique Features

Tapeworms: Lack digestive systems, relying on host digestion.
Body Plan:
- Tapeworms have a scolex (suckers) and proglottids containing reproductive structures.
- Flukes exhibit oral and ventral suckers.

Treatment Considerations

Freezing: Effective against flatworms, but does not kill roundworms.
Blood Flukes: Symptoms may include swimmer's itch and bleeding, particularly at entry points.

Description

This quiz offers a comprehensive overview of different types of worms, including roundworms and flatworms, along with their classifications. Learn about the characteristics of nematodes, cestodes, and trematodes through interactive flashcards.