Ascaris lumbricoides Flashcards
(32 cards)
What is the scientific name of the Giant Intestinal Round Worm?
Ascaris lumbricoides
What is the common name for Ascaris lumbricoides?
Giant Intestinal Round Worm
What type of organism is Ascaris lumbricoides?
It is the most common intestinal nematode of man and a soil-transmitted helminth (STH).
What is the infective stage of Ascaris lumbricoides?
Embryonated Egg
What is the diagnostic stage of Ascaris lumbricoides?
Egg in stool
How is Ascaris lumbricoides transmitted?
Ingestion of Embryonated Egg
What are the vectors for Ascaris lumbricoides?
Flies and Cockroaches
What happens after ingestion of infective eggs?
Infection begins following ingestion of infective eggs that contain viable larvae.
What occurs after larvae emerge from eggs in the small intestine?
Larvae complete a liver-lung migration via the bloodstream.
Where do larvae migrate after entering the lungs?
They burrow inside alveoli, then migrate to bronchioles.
What are the symptoms of pulmonary involvement in patients?
Patients with pulmonary symptoms have cough, eosinophilia, and/or pneumonia.
What is 7töffler syndrome?
7töffler syndrome is characterized by eosinophils accumulation in the lung as a response to a parasitic infection.
What can the larvae of the parasite cause in the host?
The larvae may cause host sensitization resulting in allergic manifestations such as lung infiltration, asthmatic attacks, and edema of the lips.
How are larvae transferred back to the intestine?
Larvae are transferred through coughing into the pharynx, where they are swallowed and return to the intestine.
What are moderate infections associated with?
Moderate infections can lead to lactose intolerance and vitamin A malabsorption.
What is the specimen of choice for laboratory diagnosis?
The specimen of choice is stool (DFS, Kato-Katz, Kato thick, FECT).
What happens if the diagnosis is negative?
Maturation of larvae occurs, resulting in adult worms that take up residence in the small intestine.
What are the characteristics of adult worms?
Adults are whitish or pinkish worms with a terminal mouth with three lips and sensory papillae, and they do not attach to the mucosa of the small intestines.
How many undeveloped eggs can adult worms pass daily?
Adults can pass as many as 250,000 undeveloped eggs per day, which decreases with increasing worm load.
What are the stages of infection?
- No infection 2. Early infection (no eggs laid yet) 3. All male worm infection.
What factors affect the embryonation of eggs?
The soil contains the necessary environment for eggs to embryonate (2-3 weeks/2-6 weeks).
How long can infective eggs survive in the environment?
Infective eggs may remain in the outside environment for years (months to 2 years) and can even survive 10% formalin fixative.
What are the organs involved in the lifecycle of the parasite?
- Small intestine 2. Gallbladder 3. Liver 4. Appendix.
What is the most common intestinal helminth infection in the world?
Ascaris lumbricoides infection affects 1 billion people worldwide, with 70% from Asia.
