Types of Hosts and Parasites Quiz

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Questions and Answers

What type of host harbors the adult stage of a parasite?

Intermediate host

Vector

Definitive host (correct)

Reservoir host

What is the term for a parasite that can live both as a parasite and free-living?

Specific parasite

Facultative parasite (correct)

Obligatory parasite

Temporary parasite

What color is the hydatid cyst's inner cellular germinal layer?

Greenish

Transparent

Brownish

Yellowish brown (correct)

Which hosts are definitive hosts for Echinococcus granulosus?

Dogs, foxes, and wolves Signup and view all the answers

Which animal commonly serves as the definitive host for Fasciola?

Herbivorous animals Signup and view all the answers

How does an individual become infected with Fasciola?

By consuming contaminated vegetation Signup and view all the answers

What is the typical size range of a hydatid cyst?

1-10 cm Signup and view all the answers

Which of the following is NOT a clinical symptom of Hymenolepiasis diminuta?

Weight gain Signup and view all the answers

What phase of Fascioliasis may present symptoms such as jaundice and biliary colic?

Chronic phase Signup and view all the answers

How do humans typically become infected with Echinococcus granulosus?

Ingestion of contaminated food and drinks Signup and view all the answers

What is the initial diagnostic phase for Fascioliasis involving stool examination?

Confirmatory detection of parasitic eggs Signup and view all the answers

Which characteristic describes an ectoparasite?

Inhabits the surface of the host's body Signup and view all the answers

Which diagnostic method can be used to identify the presence of hydatid cysts?

Ultrasound Signup and view all the answers

What does the term 'pathological condition' refer to in the context of hydatid disease?

The presence of a hydatid cyst in human tissues Signup and view all the answers

What size are Fasciola eggs, and what is their primary diagnostic feature?

150 x 90 um, thin and operculated Signup and view all the answers

What complications may arise from spontaneous rupture of hydatid cysts?

Severe allergic reactions Signup and view all the answers

What is the infective stage of Schistosoma species?

Cercariae Signup and view all the answers

What symptoms are associated with Schistosoma haematobium infection?

Burning sensation during micturition Signup and view all the answers

Which laboratory method is direct for diagnosing Schistosoma mansoni?

Rectal biopsy Signup and view all the answers

What is the characteristic shape of Ascaris lumbricoides eggs?

Broad oval Signup and view all the answers

What is the drug of choice for treating schistosomiasis?

Praziquantel Signup and view all the answers

Which of the following is a primary method for prevention of schistosomiasis?

Sanitary water supply Signup and view all the answers

Which stage of Ascaris lumbricoides is considered infective?

Egg containing the second stage rhabditiform larva Signup and view all the answers

What is a common complication associated with intestinal ascariasis?

Intestinal obstruction Signup and view all the answers

How does the cercariae of Schistosoma penetrate the host?

Via skin penetration Signup and view all the answers

What structure is used by the cercariae for skin penetration?

Forked tail Signup and view all the answers

What is the primary habitat of Trichuris trichiura?

Large intestine Signup and view all the answers

Which diagnostic method is NOT direct for Schistosoma species?

Eosinophilia test Signup and view all the answers

Which of the following is a method for the direct laboratory diagnosis of intestinal parasites?

Stool examination for eggs Signup and view all the answers

What is the size of Trichuris trichiura eggs?

50 x 25 μm Signup and view all the answers

Which treatment is NOT typically used for helminth infections like ascariasis?

Antibiotics Signup and view all the answers

How can contamination of food with Ascaris lumbricoides eggs be prevented?

By washing hands regularly Signup and view all the answers

Which condition may result from a heavy infection of Trichuris in children?

Rectal prolapse Signup and view all the answers

What is the primary mode of infection for Ancylostoma duodenale?

Active penetration of skin by larvae Signup and view all the answers

Which of the following treatments is effective for both Ancylostoma duodenale and Trichuris?

Albendazole Signup and view all the answers

What laboratory finding is common in infections caused by Trichuris?

Eosinophilia Signup and view all the answers

What is the appearance of the eggs of Ancylostoma duodenale?

Oval and thin-shelled Signup and view all the answers

Which symptom is associated with the pulmonary stage of Ancylostomiasis?

Verminus pneumonia Signup and view all the answers

What preventive measure can reduce the risk of Ancylostomiasis?

Wearing gloves Signup and view all the answers

What is a common complication of Ancylostomiasis?

Hypoproteinemia Signup and view all the answers

What is the size of the diagnostic egg of Heterophyes heterophyes?

30 μm × 15 μm Signup and view all the answers

Which of the following treatment options is used for Heterophyes heterophyes?

Triclabendazole Signup and view all the answers

What is the definitive host for Heterophyes heterophyes?

Fish-eating animals and man Signup and view all the answers

What is the mode of infection for humans by Heterophyes heterophyes?

Eating undercooked fish containing encysted metacercariae Signup and view all the answers

Which intermediate host is the first for Heterophyes heterophyes?

Pirenella conica snail Signup and view all the answers

What type of microscopy is primarily used for the laboratory diagnosis of Heterophyes heterophyes?

Direct microscopic examination Signup and view all the answers

Which prevention measure is recommended for Heterophyes heterophyes infection?

Proper cooking of fish Signup and view all the answers

Study Notes

Types of Hosts

Definitive host: The host that harbors the adult (mature) stage of the parasite.
Intermediate host: The host that harbors the immature larval stage of the parasite.
Reservoir host: An animal that harbors the mature stage of the parasite.
Vector: An arthropod that carries the parasite from one host to another host.

Types of Parasites

Ectoparasite: Inhabits the surface of the host's body without penetrating the tissues. Infection is called infestation.
Endoparasite: Lives within the host's body. Infection is called invasion.
Temporary parasite: Visits the host to take a blood meal.
Permanent parasite: Lives in or on the host for its entire life.
Facultative parasite: Lives as a parasite or freely.
Obligatory parasite: Cannot live without a host.
Specific parasite: Affects only one particular host.
Nonspecific parasite: Normally inhabits and completes its life cycle in one animal host but can also inhabit humans without completing its life cycle.
Opportunistic parasite: Only causes disease in immunocompromised individuals, while displaying no symptoms in healthy individuals.

Fasciola

Disease: Fascioliasis.
Habitat: Bile ducts of the liver and gall bladder.
Definitive host: Herbivorous animals, most commonly sheep, cattle, and goats.

Egg in Stool (Diagnostic Stage)

Size: 150 x 90 μm.
Shape: Ovoid.
Shell: Thin, operculated.
Color: Bile stained (yellowish brown).
Content: Embryonic cells (immature).

Encysted Metacercaria (Infective Stage)

Size: 0.25 mm diameter.
Shape: Spherical with a thick white cyst wall.
Mode of infection: Ingesting contaminated vegetation or water containing metacercaria.

Clinical Picture (Acute Phase)

Symptoms: Prolonged fever, anorexia, and right upper quadrant abdominal pain.

Clinical Picture (Chronic Phase)

Symptoms: Biliary obstruction (biliary colic, epigastric pain, jaundice), anemia.

Laboratory Diagnosis

Stool examination: Detecting parasitic eggs is confirmatory.
Serological tests: For antibody/antigen detection during the migratory stage of the worms or ectopic infection.
Eosinophilia: Elevated eosinophil count.
Ultrasound/CT: Imaging techniques for diagnosis.
Molecular diagnosis: Nested-PCR for detecting parasitic DNA in human stool and urine samples.

Treatment

Triclabendazole
Biothionol

Prevention and Control

Mass drug administration
Health education
Snail control

Heterophyes heterophyes

Habitat: Small intestine.
Definitive Host: Man and fish-eating animals (dogs and cats).
Intermediate Host: 1st, Pirenella conica snail; 2nd, boury and bolty fish.
Diagnostic Stage: Egg in stool.
Infective Stage: Encysted metacercaria.
Diagnostic Stage (Egg):
- Size: 30 µm ×15 µm.
- Shell: Thick double walled with operculum & posterior knob.
- Colour: Brownish yellow.
- Content: Miracidium (mature).
Mode of Infection: Man and fish-eating animals are infected by eating raw, undercooked, or under-salted fish within 10 days of containing infected metacercaria.

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Description

Test your knowledge on the various types of hosts and parasites! This quiz covers the definitions and characteristics of definitive hosts, intermediate hosts, and different types of parasites including ecto and endoparasites. Challenge yourself and see how well you understand these important biological concepts.