Nokea
A farmer developed a black, painless carbuncle with peripheral vesicular rash. Microscopy of pus revealed non-motile Gram-positive rods with a capsule. What microorganism caused the condition?
- A. Bacillus anthracis
- B. Staphylococcus aureus
- C. Clostridium perfringens
- D. Bacillus subtilis
Correct Answer: A
Rationale: The correct answer is A: Bacillus anthracis. The black, painless carbuncle with peripheral vesicular rash is characteristic of cutaneous anthrax. Microscopy showing non-motile Gram-positive rods with a capsule aligns with Bacillus anthracis. The other choices can be eliminated: B: Staphylococcus aureus does not typically form a black lesion or have a capsule. C: Clostridium perfringens causes gas gangrene, not the described lesion. D: Bacillus subtilis is not associated with the specific clinical presentation mentioned.
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Lytic cycle of the bacteriophages differs from the lysogenic one by
- A. lysogenetic phages destroy the host cell when leaving the cell
- B. lytic phages do not destroy the host cell
- C. do not differ
- D. none of them
Correct Answer: A
Rationale: The correct answer is A because in the lytic cycle, the bacteriophage destroys the host cell upon release, whereas in the lysogenic cycle, the phage integrates its DNA into the host genome without killing the host immediately. This integration may lead to the destruction of the host cell at a later stage. Choice B is incorrect as lytic phages do destroy the host cell. Choice C is incorrect as the two cycles have distinct mechanisms. Choice D is incorrect as there are clear differences between the lytic and lysogenic cycles.
Parents with ill child came to the infectionist. They worked in one of the Asian countries for a long time. Child has eathy colored skin, loss of appetite, laxity, enlarged liver, spleen, peripheral glands. What protozoan illness can this child have?
- A. Amebiasis
- B. Balantidiasis
- C. Visceral leishmaniasis
- D. Lambliasis
Correct Answer: C
Rationale: The correct answer is C: Visceral leishmaniasis. This disease is caused by the protozoan parasite Leishmania, which is transmitted by sandfly bites. The symptoms described in the question, such as enlarged liver and spleen, peripheral gland enlargement, and eathy colored skin, are characteristic of visceral leishmaniasis. Amebiasis (choice A) typically presents with gastrointestinal symptoms, Balantidiasis (choice B) is caused by a different parasite and presents with dysentery, and Lambliasis (choice D) is caused by Giardia lamblia and presents with diarrhea.
Which bacteria are responsible for causing the disease known as 'whooping cough'?
- A. Bordetella pertussis
- B. Haemophilus influenzae
- C. Streptococcus pneumoniae
- D. Mycobacterium tuberculosis
Correct Answer: A
Rationale: The correct answer is A: Bordetella pertussis. Bordetella pertussis is the bacterium responsible for causing whooping cough, also known as pertussis. It produces toxins that damage the respiratory tract, leading to severe coughing fits. Haemophilus influenzae, Streptococcus pneumoniae, and Mycobacterium tuberculosis are not associated with whooping cough. Haemophilus influenzae can cause respiratory infections but not whooping cough. Streptococcus pneumoniae is known for causing pneumonia, and Mycobacterium tuberculosis causes tuberculosis, both different from whooping cough. Therefore, the correct answer is A as it is the specific bacterium linked to the disease in question.
A 16-year-old boy from the rural area entered the technical school. During a regular Mantoux test, it turned out that this boy had a negative reaction. What tactics should the doctor choose as the most rational in this case?
- A. Repeat the test in a month
- B. Serodiagnosis of tuberculosis
- C. Urgent isolation of the boy from his groupmates
- D. BCG vaccination
Correct Answer: D
Rationale: The correct answer is D: BCG vaccination. BCG vaccination is recommended for individuals with a negative Mantoux test result, especially in countries where tuberculosis is prevalent. This vaccination can help provide protection against tuberculosis.
Choice A is incorrect because repeating the Mantoux test in a month is unnecessary since the boy already had a negative reaction.
Choice B is incorrect as serodiagnosis of tuberculosis is not the first-line approach for diagnosis, especially in this scenario.
Choice C is incorrect because urgent isolation is not necessary based solely on the Mantoux test result. Isolation is typically reserved for individuals with active tuberculosis.
Sanitary assessment of a pond, where the children from a recreation summer camp take their swims, detected there oval cysts 50-60 micron in diameter, with 2 nuclei visible in their cytoplasm (macronucleus and micronucleus). What protozoa do these cysts belong to?
- A. Toxoplasma
- B. Amoeba
- C. Balantidium
- D. Lamblia
Correct Answer: D
Rationale: The correct answer is D: Lamblia. The cysts described match the characteristics of Giardia lamblia, a protozoan parasite. Giardia cysts are oval-shaped, 50-60 microns in diameter, and contain 2 nuclei (macronucleus and micronucleus). Giardia is commonly found in contaminated water sources and can cause gastrointestinal illness in humans.
Incorrect choices:
A: Toxoplasma - Toxoplasma gondii is a parasite that causes toxoplasmosis, transmitted through ingestion of contaminated food or water, but its cysts do not match the description given in the question.
B: Amoeba - Amoebas are single-celled organisms, but they do not typically form cysts with visible nuclei as described.
C: Balantidium - Balantidium coli is a ciliated protozoan that can cause dysentery in humans, but its cysts do not