A patient with probable liver abscess was delivered to a surgical department. The patient for a long time had been on an assignment in an African country and had recurrent cases of gastrointestinal disturbance. What protozoan disease can it be?

Correct Answer: D

Rationale: The correct answer is D: Amebiasis. The patient's symptoms of gastrointestinal disturbance and liver abscess are indicative of an infection with Entamoeba histolytica, the protozoan parasite responsible for amebiasis. The patient's travel history to an African country also increases the likelihood of contracting this disease, as it is more prevalent in tropical regions. Toxoplasmosis (A) is primarily associated with exposure to cat feces, Leishmaniasis (B) is transmitted through sandfly bites, and Malaria (C) is caused by Plasmodium parasites transmitted through mosquito bites. Therefore, these options are incorrect given the patient's presentation and travel history.

Correct Answer: C

Rationale: The correct answer is C: Tuberculosis. Granulomas with lymphocytes and macrophages containing Virchow's cells (large cells with fat inclusions containing microorganisms) are classic findings in tuberculosis. Leprosy (A) typically presents with granulomas but with different histopathological features. Syphilis (B) does not usually form granulomas in the skin. Rhinoscleroma (D) is a chronic bacterial infection characterized by nodular lesions but does not typically involve Virchow's cells as seen in tuberculosis.

Correct Answer: A

Rationale: The correct answer is A: Immobilization. This technique is called the Treponema pallidum immobilization (TPI) test, used to diagnose syphilis. The rationale is as follows: 1. TPI test detects antibodies that prevent the movement of treponemas, causing their death. 2. By immobilizing the treponemas, it indicates the presence of specific antibodies against syphilis. 3. This test is highly specific for syphilis diagnosis as it directly targets the causative agent. Other choices are incorrect: B: Complement binding - Not specific to syphilis, more commonly used for other diseases. C: Agglutination - Detects clumping of particles, not specific to treponemas or syphilis. D: Precipitation - Involves the formation of a solid, not directly related to treponema movement or death.

Correct Answer: D

Rationale: The correct answer is D, "All of the above." Neisseria meningitidis, Haemophilus influenzae, and Streptococcus pneumoniae are all bacteria known to cause meningitis. Neisseria meningitidis is a common cause of bacterial meningitis in young adults, Haemophilus influenzae type b is a common cause in children, and Streptococcus pneumoniae is a leading cause in adults and the elderly. Therefore, all three bacteria can potentially cause meningitis depending on the age group and other factors. The other choices are incorrect because each of the bacteria listed can cause meningitis, so selecting only one of them would be incorrect.

Correct Answer: A

Rationale: The correct answer is A: Streptococcus pneumoniae. This bacterium is a Gram-positive cocci that often appear in pairs and can have a capsule. It is a common cause of sore throat and fever, known as streptococcal pharyngitis. Staphylococcus aureus (B) is a Gram-positive cocci but does not typically form pairs. Neisseria meningitidis (C) is a Gram-negative diplococcus and is more associated with meningitis. Klebsiella pneumoniae (D) is a Gram-negative rod and not typically associated with sore throat and fever.

Correct Answer: C

Rationale: The correct answer is C because the case specifically mentions "enteropathogenic bacteria and viruses," indicating a focus on these specific microorganisms. Choice A is too broad and includes all bacteria, which is not specified in the case. Choice B mentions opportunistic pathogenic bacteria, which are not necessarily relevant to the case. Choice D specifies colibacilli, which may or may not be relevant to the case, but it is not as specific as choice C which clearly matches the information provided in the case.

Correct Answer: A

Rationale: The correct answer is A: Commensalism. In this relationship, the skin microflora benefits from the host without causing harm or benefitting it. This is evident in the mutualistic interaction where the microflora receive nutrients and a place to live, while the host remains unaffected. Choice B, Infection, is incorrect because it implies harm to the host. Choice C, Parasitism, is also incorrect as it involves one organism benefiting at the expense of the other. Choice D, No correct answer, is not applicable here as Commensalism accurately describes the relationship between the macroorganism and skin microflora.

Correct Answer: C

Rationale: The correct answer is C: Protection against harsh conditions. Bacterial endospores are dormant structures produced by certain bacteria as a survival strategy under unfavorable conditions. They protect the bacterial DNA and other essential components from damage caused by heat, chemicals, desiccation, and radiation. Endospores do not directly participate in energy production (A), DNA replication (B), or protein synthesis (D). These functions are carried out by the active, vegetative form of the bacterial cell.

Correct Answer: A

Rationale: The correct answer is A: Lassa virus. The rationale is as follows: 1. Lassa virus is a member of the Arenaviridae family, known for causing Lassa fever. 2. Arenaviridae family includes viruses with a segmented genome and are transmitted through rodents. 3. Crimean-Congo hemorrhagic fever virus (Choice B) belongs to the Bunyaviridae family, not Arenaviridae. 4. Rabies virus (Choice C) belongs to the Rhabdoviridae family, not Arenaviridae. 5. Epstein-Barr virus (Choice D) belongs to the Herpesviridae family, not Arenaviridae. In summary, Lassa virus is the correct choice as it aligns with the characteristics of the Arenaviridae family, while the other choices belong to different virus families.