What would be the conclusion?
- A. The water is safe for consumption
- B. The water quality is doubtful
- C. The water quality is extremely doubtful
- D. The water is polluted
Correct Answer: B
Rationale: Step-by-step rationale for choice B being correct:
1. The conclusion should be based on evidence or observations.
2. "Doubtful" suggests uncertainty, indicating lack of definitive safety.
3. Choice A is too absolute without considering potential risks.
4. Choice C uses extreme language without proper evidence.
5. Choice D is overly definitive without considering varying levels of contamination. Therefore, choice B is the most reasonable conclusion.
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The causative agent of the disease gas gangrene Clostridium perfringens is:
- A. Gram-negative rod-shaped bacteria, fixed with capsule
- B. Gram-negative rod-shaped bacterium, motile, peritrichous without capsule
- C. Gram-positive rod-shaped bacterium, motile, peritrichous without capsule
- D. Gram-positive rod-shaped bacterium non-motile, with capsule
Correct Answer: C
Rationale: The correct answer is C because Clostridium perfringens is a Gram-positive rod-shaped bacterium, which matches the description provided. It is motile and peritrichous (having flagella all over the surface) without a capsule. This bacterium is known to cause gas gangrene due to its ability to produce toxins that destroy tissue.
Choice A is incorrect because Clostridium perfringens is Gram-positive, not Gram-negative, and it does not have a capsule. Choice B is incorrect because Clostridium perfringens is not motile and does not have flagella all over its surface. Choice D is incorrect because Clostridium perfringens is Gram-positive, not Gram-negative, and it is motile without a capsule.
Which of the following is a primary function of bacterial capsules?
- A. Energy production
- B. Protection from desiccation
- C. Adhesion and immune evasion
- D. DNA replication
Correct Answer: C
Rationale: The correct answer is C: Adhesion and immune evasion. Bacterial capsules serve as a protective layer that aids in adhesion to surfaces and host cells, allowing bacteria to colonize and evade the immune system. This function is crucial for bacterial survival and pathogenicity. Choices A and D are incorrect because energy production and DNA replication are not primary functions of bacterial capsules. Choice B is incorrect because while bacterial capsules do provide some protection from desiccation, their primary function lies in adhesion and immune evasion.
Typhoid fever is caused by the bacterium:
- A. Escherichia coli
- B. Salmonella enterica
- C. Shigella flexneri
- D. Staphylococcus aureus
Correct Answer: B
Rationale: The correct answer is B: Salmonella enterica. Typhoid fever is caused by the bacterium Salmonella enterica serotype Typhi. This specific strain of Salmonella is responsible for typhoid fever, a serious illness characterized by high fever, abdominal pain, and diarrhea. Escherichia coli (choice A) is not the causative agent of typhoid fever. Shigella flexneri (choice C) causes bacillary dysentery, not typhoid fever. Staphylococcus aureus (choice D) can cause food poisoning but is not associated with typhoid fever.
The virus most commonly transmitted during pregnancy is:
- A. cytomegalovirus
- B. HIV
- C. herpes simplex virus
- D. Epstein-Barr virus
Correct Answer: A
Rationale: The correct answer is A: cytomegalovirus. CMV is the most common virus transmitted during pregnancy, leading to potential serious complications for the fetus. It can cause birth defects, hearing loss, and developmental delays. CMV is commonly spread through bodily fluids. HIV (B) can also be transmitted during pregnancy but is less common. Herpes simplex virus (C) can be transmitted but typically results in localized infection. Epstein-Barr virus (D) is not commonly transmitted during pregnancy.
A 34-year-old male visited Tajikistan. After return, he complains of fever up to 40oC which occurs every second day and is accompanied by chills, sweating. Hepatosplenomegaly is present. Blood test results: RBC- 3x1012/l, b- 80 g/l, WBC- 4x109/l, eosinophils - 1%, stab neutrophils - 5%, segmented neutrophils - 60%, lymphocytes - 24%, monocytes - 10%, ESR - 25 mm/h. What is the provisional diagnosis?
- A. Malaria
- B. Infectious mononucleosis
- C. Sepsis
- D. Typhoid fever
Correct Answer: A
Rationale: The correct answer is A: Malaria. The patient's travel history to an endemic area like Tajikistan, along with symptoms of fever with chills, sweating, and hepatosplenomegaly, are classic for malaria. The blood test results show anemia (low RBC and hemoglobin levels), which can occur in malaria due to hemolysis. The presence of eosinophils and lymphocytes are not typical for malaria, but the overall clinical picture fits. Infectious mononucleosis (choice B) typically presents with sore throat, lymphadenopathy, and atypical lymphocytosis, which are not seen in this case. Sepsis (choice C) is characterized by systemic inflammatory response syndrome and organ dysfunction due to infection, which does not align with the symptoms and findings in the case. Typhoid fever (choice D) usually presents with gradual onset of sustained fever, abdominal pain, headache, and constipation, which are not present in this patient