Medical Parasitology Lecture 2 - Life Cycle of Nematodes (Flashcards)

Fill-in-the-blank flashcards based on the provided lecture notes on medical parasitology, focusing on nematodes and their life cycles.

__ are unsegmented, bilaterally symmetrical roundworms.

Nematodes

Human nematode infections are grouped into two categories: __.

Intestinal and blood and tissue

Male nematodes often have a curved or coiled posterior end with __.

copulatory spicules

The anterior region of nematodes may have attachment structures such as __ in the buccal cavity.

hooks, teeth, or cutting plates

Nematodes possess well-developed internal organs, such as a __.

complete digestive system

__ may serve as intermediate hosts and/or vectors for nematodes.

Arthropods

Nematode eggs may require a developmental period in the environment to be infective, developing into the __ stage.

filariform

__ are the 3rd or infective stage of nematodes, characterized by their long, thread-like form suitable for penetration.

Filariform larvae

__ are nematode larvae with a muscular esophagus and bulbular pharynx.

Rhabditiform larvae

Except for __ in which there is skin penetration by the filariform, humans ingest infective eggs.

Hookworm and Strongyloides stercoralis

With Ascaris lumbricoides, hookworms, and Strongyloides stercoralis larvae penetrate the intestinal mucosa and initiate a __ cycle.

heart - lung

Diagnostic stages, eggs or larvae, exit the host in its __.

faeces

Larvae develop within the egg in __, except for Strongyloides stercoralis.

Warm, moist soil

Nematode infections are often __ until worm burden becomes large.

asymptomatic

__ is also known as whipworm.

Trichuris trichiura

Trichuris trichiura infection is a __ disease, commonly seen along with Ascaris lumbricoides.

filth-associated

Adult Trichuris trichiura worms live mainly in the human __.

caecum/colorectum

Female Trichuris trichiura worms lay approximately __ eggs daily.

1000-7000

Trichuris trichiura eggs are typically __ with two polar plugs.

Barrel-shaped

Trichuris trichiura eggs contain an __ when passed in the faeces.

unsegmented ovum

Trichuris trichiura larvae hatch in the __.

small intestine

Trichuris trichiura eggs develop into an infective, third-stage larva in __ in warm, moist soil.

3-5 weeks

A severe infection with whipworm can cause __.

Trichuris colitis

Diagnosis of Trichuris trichiura infection is by microscopic identification of __ in stool.

barrel-shaped ovum

__ is a common medication used for treatment of Trichuris trichiura infection.

Albendazole

__ is the largest human nematode.

Ascaris lumbricoides

Ascaris lumbricoides has a complex life cycle involving a __ cycle.

heart-lung

The female Ascaris lumbricoides is a prodigious egg producer, depositing about __ eggs daily.

200,000

Ascaris lumbricoides eggs have __ layers in the shell.

three

Adult Ascaris lumbricoides worms inhabit the lumen of the __.

Small intestine

The outer __of the fertilized Ascaris lumbricoides egg is golden brown due to bile pigment adsorbed from faeces.

Albuminous coat

After __ in moist soil at optimal temperatures, the Ascaris lumbricoides embryo molts and develops into an infective second-stage larva.

2-4 weeks

After being ingested by a human, Ascaris lumbricoides eggs containing infective larvae hatch in the __.

Duodenum

Ascaris lumbricoides larvae are carried via the portal circulation to the liver, through the right side of the heart, and to the lungs by the __.

Pulmonary artery

The interval from the ingestion of infective Ascaris lumbricoides eggs to the appearance of sexually mature worms is about __.

60-75 days

__ is associated with migration of Ascaris lumbricoides larvae in the lungs.

Pneumonia

__ is a medication used to treat Ascaris lumbricoides infections.

Albendazole

Pinworm is also known as __.

Enterobius vermicularis

__ are the only known host for Enterobius vermicularis.

Humans

Transmission of Enterobius vermicularis is by __ via fertilized egg ingestion.

Person-to-person

Gravid female Enterobius vermicularis migrate to the __ at night to lay eggs.

Perianal area

Enterobius vermicularis eggs develop to infective stage within __.

4-6 hours

Diagnosis of Enterobius vermicularis relies on the __ from the perianal region.

Cellophane tape preparation

A common symptom of Enterobius vermicularis infection is __.

Perianal itching

The vector for Wuchereria bancrofti is the __ mosquito.

Culex

Onchocerca volvulus is transmitted by __.

Simulium flies

Onchocerca volvulus causes __.

River blindness

Loa loa is transmitted by __.

Chrysops flies

Loa loa adults live in the __ tissue.

Subcutaneous

__ is a condition characterized by swollen lymph nodes.

Lymphadenopathy