Parasitology 2 Flashcards
What are helminths?
Helminths are parasitic worms that infect humans and other animals, classified into three main groups: roundworms (nematodes), tapeworms (cestodes), and flukes (trematodes).
How are helminths transmitted?
Transmission occurs through ingestion of contaminated food or water, skin penetration, or via insect vectors.
What are some examples of human helminth infections?
Hookworm (Ancylostoma duodenale), tapeworms (Taenia spp.), liver flukes (Fasciola hepatica), and schistosomiasis (Schistosoma spp.).
What is the main pathogenic mechanism of hookworms?
Hookworms attach to the intestinal wall, feeding on blood, leading to anemia and malnutrition.
How does Taenia saginata differ from Taenia solium?
T. saginata (beef tapeworm) has cows as intermediate hosts, while T. solium (pork tapeworm) uses pigs and can cause neurocysticercosis in humans.
Hookworms can live up to
10 years inside the human intestine.
Tapeworms are hermaphrodites, capable of
self-fertilization.
Schistosoma species require
freshwater snails as intermediate hosts.
Mebendazole and albendazole are commonly used anthelmintics for treating
helminth infections.
Hookworm larvae penetrate the skin, often through
bare feet in contaminated soil.
All helminths infect the human intestine.
False – some infect the liver, lungs, or bloodstream.
Hookworm eggs hatch in the human intestine.
False – they hatch in soil before infecting the host.
Taenia solium infections can lead to cysticercosis in the brain.
True
Schistosomiasis is transmitted through mosquito bites.
False – it is transmitted via contact with contaminated freshwater.
The three main groups of helminths are ______________, ______________, and ______________.
Nematodes, Cestodes, Trematodes
Hookworm larvae penetrate the skin and travel to the ______________ before reaching the intestine.
Lungs
Tapeworms attach to the host’s intestinal wall using a structure called the ______________.
Scolex
The intermediate host of Schistosoma species is a ______________.
Freshwater snail
Which helminth infection is acquired by eating undercooked pork?
a) Ancylostoma duodenale
b) Taenia solium
c) Schistosoma mansoni
d) Ascaris lumbricoides
Answer: (b) Taenia solium
Which helminth is responsible for iron-deficiency anemia due to blood loss?
a) Fasciola hepatica
b) Ancylostoma duodenale
c) Taenia saginata
d) Wuchereria bancrofti
Answer: (b) Ancylostoma duodenale
Which laboratory test is most useful for diagnosing tapeworm infection?
a) Blood smear
b) Fecal microscopy
c) PCR for viral RNA
d) Skin biopsy
Answer: (b) Fecal microscopy
A patient presents with chronic fatigue and iron-deficiency anemia. They recently traveled to a rural area where they walked barefoot. What is the most likely diagnosis?
Hookworm infection (Ancylostoma duodenale or Necator americanus).
A person consumes undercooked beef and later experiences mild abdominal discomfort. What parasite might they have, and what test should be conducted?
Taenia saginata; fecal microscopy to detect eggs or proglottids.
A child from a developing country presents with bloating and signs of malnutrition. Stool examination reveals eggs of a large roundworm. What is the likely infection?
Ascaris lumbricoides infection.
Helminths:
Parasitic worms that infect humans and animals.
Nematodes:
Roundworms, such as hookworms and Ascaris lumbricoides.
Cestodes:
Tapeworms, including Taenia saginata and Taenia solium.
Trematodes:
Flukes, such as Schistosoma and Fasciola hepatica.
Proglottid:
A segment of a tapeworm that contains reproductive organs.
