من سلايد 47-51 Flashcards
Which of the following statements about free-living amoebae is TRUE?
a) They are all harmless to humans.
b) They are only found in freshwater environments.
c) They can become parasites under certain conditions.
d) They are always present in the cyst stage.
C
- What is the infective stage of Naegleria fowleri?
a) Cyst
b) Trophozoite
c) Flagellate
d) All of the above
B
Which of the following is NOT a symptom of primary amebic meningoencephalitis (PAM)?
a) Fever
b) Headache
c) Stiff neck
d) Diarrhea
D
- Which of the following is a common mode of transmission for Acanthamoeba infections?
a) Mosquito bites
b) Contaminated contact lens solutions
c) Food poisoning
d) Animal bites
b
- What is the most serious complication of Acanthamoeba keratitis?
a) Blindness
b) Meningitis
c) Pneumonia
d) Skin rash
A
Naegleria fowleri is the causative agent of:
a) Granulomatous amebic encephalitis (GAE)
b) Amebic keratitis
c) Primary amebic meningoencephalitis (PAM)
d) Disseminated granulomatous amebic disease
C
Naegleria fowleri is the causative agent of:
a) Granulomatous amebic encephalitis (GAE)
b) Amebic keratitis
c) Primary amebic meningoencephalitis (PAM)
d) Disseminated granulomatous amebic disease
C
Acanthamoeba spp. are known to cause:
a) Only keratitis
b) Only granulomatous amebic encephalitis
c) Only disseminated granulomatous amebic disease
d) All of the above
D
Babesiosis is a parasitic infection transmitted by:
a) Mosquitoes
b) Ticks
c) Fleas
d) Snails
B
The gold standard for diagnosing Babesiosis is:
a) Blood culture
b) PCR
c) Microscopy
d) Serology
C
Which of the following is a common symptom of Babesiosis?
a) Rash
b) Fever
c) Joint pain
d) All of the above
B
Trypanosoma brucei is the causative agent of:
a) African Sleeping Sickness
b) Chagas disease
c) Leishmaniasis
d) Malaria
A
- The definitive host for Trypanosoma brucei is:
a) Tsetse fly
b) Human
c) Cattle
d) All of the above
B
Which of the following is TRUE about Trypanosoma brucei gambiense?
a) It causes an acute form of African Sleeping Sickness.
b) It rarely invades the central nervous system.
c) It is found primarily in central and east central Africa.
d) It is transmitted by the bite of an infected tsetse fly.
D
Which of the following is the definitive host for Trypanosoma cruzi?
a) Reduviid bugs
b) Humans
c) Armadillos
d) All of the above
D
What is the mode of transmission for Chagas disease?
a) Ingestion of contaminated food
b) Contact with infected animals
c) Bite from an infected Reduviid bug
d) Inhalation of contaminated air
C
What is the name of the stage of Trypanosomac cruzi that develops in the hindgut of the insect vector?
a) Epimastigote
b) Trypomastigote
c) Amastigote
d) Metacyclic trypomastigote
D
Which of the following is a symptom of chronic Chagas disease?
a) Megacolon
b) Megaesophagus
c) Heart failure
d) All of the above
D
What is the primary method used to diagnose Chagas disease when parasite numbers are low?
a) Blood culture
b) Serological tests
c) Xenodiagnosis
d) Biopsy
C
Choose the correct sentence about Trypanosoma cruzi?
a. Chagas disease is primarily found in North America
b. The kissing bug is the intermediatechoese the correct ahost for Trypanosoma cruzi.
c. Treatment for chronic Chagas disease is highly effective
d. The symptoms of Chagas disease are always severe and easily recognizable
Answer:B
A ➡️ It’s primarily found in Central and South America
C➡️ Treatment is difficult and not always effective, especially in the chronic stage
D➡️ Many people are asymptomatic, and symptoms can be subtle or develop slowly)
Describe the life cycle of Trypanosoma cruzi.
Answer: The life cycle of Trypanosoma cruzi involves both a mammalian host (definitive host) and an insect vector (intermediate host).
* The parasite enters the mammalian host through the bite of an infected Reduviid bug, which defecates near the bite wound.
* The parasite transforms into amastigotes and multiplies inside the host’s cells.
* Trypomastigotes are released from the host cells and circulate in the blood.
* An uninfected bug ingests trypomastigotes while feeding on an infected host.
* The parasite transforms into epimastigotes in the insect’s midgut and then into metacyclic trypomastigotes in the hindgut.
* The metacyclic trypomastigotes are excreted in the bug’s feces and can infect a new host.
Explain the mechanism by which Trypanosoma cruzi causes damage to the heart and digestive system.
- Heart: The parasite can invade and multiply in heart muscle cells, causing inflammation and damage. This can lead to heart enlargement (cardiomegaly), heart failure, and arrhythmias.
- Digestive System: Trypanosoma cruzi can also invade and damage the smooth muscle cells of the esophagus and colon, leading to megaesophagus (difficulty swallowing) and megacolon (constipation and bowel obstruction).
- Discuss the challenges associated with treating Chagas disease.
Limited treatment options: Current treatments, Nifurtimox and Benznidazole, are effective in the acute stage but have severe side effects and are less effective in the chronic stage.
Chronic stage: Chronic Chagas disease is difficult to treat due to the parasite’s ability to persist in the host for many years.
* Lack of access to treatment: Many people in endemic areas lack access to proper diagnosis and treatment.
What are some strategies for preventing Chagas disease?
Vector control: Reducing the population of kissing bugs through insecticide spraying, improved housing conditions, and screening windows.
* Blood screening: Screening blood donations for the parasite to prevent transmission through blood transfusions.
* Early diagnosis and treatment: Prompt diagnosis and treatment with antiparasitic drugs can prevent the development of chronic disease.
