Parasite: part 5 Flashcards Preview

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Examples of roundworms (=nematodes)

Ascaris, hookworm, Filaria, Strongyloides


Length of ascaris worm

The adult males are ~15-30cm long and females ~20-35cm


Life cycle of ascariasis

Adult worms in small intestine. Produce 240000 eggs per day Eggs excreted in faeces. Fertile eggs become infective after 18 days-several weeks. Infective eggs swallowed e.g water Larvae hatch, invade intestinal mucosa, portal system to liver, systemic system to lung, penetrate alveolar walls. Asecend bronchial tree, swallowed, and develop into adult worms in small intestine.


How long foes it take from ingestion of infective eggs to adult female. How long do adult worms livee

Between 2 and 3 months are required from ingestion of the infective eggs to oviposition by the adult female. Adult worms can live 1 to 2 years.


Symptoms of ascariasis

Infection with Ascaris lumbricoides often causes no symptoms Large number= abdominal pain/intestinal obstruction Malnourishment (adults feed on content of small intestine) in large infections. Penetration of lung can cause Loeffler's pneumonia. (pools of blood and dead epithelial cells clog air spaces in lungs)


Hook worm example, length (and how they attach) and symptoms

Ancylostoma duodenale -Fe deficiency anaemia -Gastrointestinal and nutritional/metabolic symptoms -respiratory symptoms about 1cm long and curved. They are attached by their buccal capsules to the villi of the small intestine


Lifecycle of hookworm (a nematode)

Larvae are carried through the blood vessels to the heart and then to the lungs. They penetrate into the pulmonary alveoli, ascend the bronchial tree to the pharynx, and are swallowed. The larvae reach the small intestine, where they reside and mature into adults. Adult worms live in the lumen of the small intestine, where they attach to the intestinal wall with resultant blood loss by the host. (much the same as ascariasis)


Treatment for hookworm and diagnosis

albendazole and mebendazole Stool


What is whipworm

Trichuris Trichiura It's a nematode, a type of hookworm which is a type of roundworm


Lifecycle of whipworm (=Trichuris Trichiura )

The eggs hatch in the small intestine, and release larvae that mature and establish themselves as adults in the colon. The adult worms (approximately 4 cm in length) live in the cecum and ascending colon. The adult worms are fixed in that location


Symptoms of whipworm

Small amounts of whipworms might not cause any symptoms. But if there are hundreds of worms, then you might have bloody diarrhea and anemia due to severe vitamin and iron loss. The worms leave open wounds, which cause inflammation of the intestinal wall. In some cases you might also develop rectal prolapse.


Treatment and diagnosis of whipworm

albendazole and mebendazole stool exam


What is lymphatic filariasis

The filarial category of roundoworms can cause lymphatic obstruction leading to elephantiasis lymphatic obstruction (especially in the legs) can progress to elephantiasis – can also occur in arm, breast, scrotum


Example of a filaria

Brugia malayi (one of the tree causative agents of lympatic filariasis) Loasiasis (Loa loa, eyeworm)


Diagnosis and treatment of filarial roundworms

microfilariae are found mainly in the peripheral blood and can be found at peak amounts from 10 p.m. to 4 a.m. During the day, they are present in the deep veins, and during the night, they migrate to the peripheral circulation. Blood smear or antigen detection with a immunochromatic test (card) or ELISA albendazole and ivermectin


Life cycle of loaiasis

Fly takes blood meal from a person, and gives them larvae The adults in subcutaneous tissue produce sheathed microfilariae, found in peripheral blood Fly takes another blood mean and the microfilariae shed sheaths, penetrate fky's midgut and migrate to thoracic muscles Then fly takes another blood meal and the larvae enter into another person's blood