Nokea
The degree or extent of disease-evoking power that a microorganism has is referred to as:
- A. virulence
- B. strength
- C. resistance
- D. competence
Correct Answer: A
Rationale: The correct answer is A: virulence. Virulence refers to the degree or extent of disease-evoking power that a microorganism possesses. This term specifically describes the ability of a microorganism to cause disease in a host. It is a crucial factor in understanding the pathogenicity of different microorganisms.
Choice B: strength is incorrect because it does not specifically relate to the disease-causing potential of a microorganism. Choice C: resistance refers to the ability of an organism to withstand the effects of a particular agent, such as a drug or environmental factor. Choice D: competence is not directly related to the disease-causing ability of a microorganism, but rather refers to the ability of an organism to perform a specific function effectively.
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Toxicity of disinfectant against microbial cells:
- A. Is very weak
- B. Is very selective
- C. Is not selective
- D. Is temporary and more often reversible
Correct Answer: C
Rationale: The correct answer is C because disinfectants are non-selective and can harm a wide range of microbial cells. Disinfectants work by disrupting cell membranes, proteins, and nucleic acids, affecting both harmful and beneficial microorganisms. Choices A and B are incorrect because disinfectants are designed to be potent and non-selective. Choice D is incorrect because the effects of disinfectants are often permanent and irreversible on microbial cells.
In the sixteenth century a father-and-son team, by the name of __________, produced a compound microscope consisting of a simple tube with lenses at each end.
- A. van Leeuwenhoek
- B. Semmelweis
- C. Janssen
- D. Hooke
Correct Answer: C
Rationale: The correct answer is C: Janssen. In the 16th century, Zacharias Janssen and his father Hans Janssen are credited with inventing the compound microscope. They constructed a simple tube with lenses at each end, allowing for magnification of small objects. This innovation laid the foundation for the development of modern microscopes. Van Leeuwenhoek is known for his contributions to microbiology but did not invent the compound microscope. Semmelweis is known for his work in handwashing and preventing infections. Hooke made significant contributions to microscopy but did not invent the compound microscope.
Infectious mononucleosis most often occurs in:
- A. infants
- B. adolescents
- C. young adults
- D. the elderly
Correct Answer: B
Rationale: The correct answer is B: adolescents. Infectious mononucleosis is commonly caused by the Epstein-Barr virus, which is transmitted through saliva. Adolescents are more likely to engage in activities like kissing and sharing drinks, increasing the chances of virus transmission. Infants have maternal antibodies for protection, young adults may have developed immunity, and the elderly have had more exposure to the virus and may have built immunity over time.
A 28 y.o. patient without permanent residence was admitted to the hospital with the preliminary diagnosis influenza. On the fith day of illness he got a maculopapular petechial rash on his body and internal surfaces of extremities. Body temperature is 410 C, euphoria, face hyperemia, sclera reddening, tongue tremor, tachycardia, splenomegaly, excitement. What is the most probable diagnosis?
- A. Epidemic typhus
- B. Delirium alcoholicum
- C. Leptospirosis
- D. Measles
Correct Answer: A
Rationale: Step 1: Initial diagnosis of influenza suggests a viral illness.
Step 2: Presence of maculopapular petechial rash and high fever indicates a systemic infection.
Step 3: Symptoms like euphoria, hyperemia, tachycardia, splenomegaly, and excitement are characteristic of epidemic typhus.
Step 4: Face hyperemia, sclera reddening, and tongue tremor are specific to epidemic typhus.
Step 5: Epidemic typhus is transmitted by body lice, which fits the scenario of a patient without permanent residence.
Summary:
- Delirium alcoholicum is unlikely due to the specific symptoms and lack of history of alcohol abuse.
- Leptospirosis typically presents with jaundice and renal symptoms, not seen in this case.
- Measles rash is different from the maculopapular petechial rash described.
A child entering the school for the first time was given Mantoux test in order to determine if there was a need for revaccination. The reaction was negative. What is the meaning of this test result?
- A. No cell-mediated immunity to tuberculosis
- B. Availability of cell-mediated immunity to tuberculosis
- C. No antibodies to the tuberculosis bacteria
- D. No anti-toxic immunity to tuberculosis
Correct Answer: B
Rationale: The correct answer is B: Availability of cell-mediated immunity to tuberculosis. A negative Mantoux test indicates the presence of an immune response to the TB bacteria, as the test measures the body's delayed hypersensitivity reaction to TB antigens. This means the child has been exposed to TB in the past or has been vaccinated, resulting in the development of cell-mediated immunity against TB.
Incorrect choices:
A: No cell-mediated immunity to tuberculosis - This is incorrect as a negative Mantoux test actually indicates the presence of cell-mediated immunity.
C: No antibodies to the tuberculosis bacteria - Mantoux test measures cell-mediated immunity, not antibody response.
D: No anti-toxic immunity to tuberculosis - Mantoux test does not assess anti-toxic immunity, it specifically measures cell-mediated immunity.