The humoral immunity is related to:

Correct Answer: B

Rationale: The correct answer is B because humoral immunity involves the formation of specific antibodies by B cells. B cells differentiate into plasma cells that produce antibodies to target specific antigens. T cells are involved in cell-mediated immunity, not humoral immunity. Choice A is incorrect because T cells do not produce antibodies. Choice C is incorrect as only B cells are responsible for antibody production in humoral immunity. Choice D is incorrect as B cells play a crucial role in the humoral immune response.

Correct Answer: C

Rationale: Step 1: Define sexually transmitted infections (STIs) as infections primarily spread through sexual contact. Step 2: Understand that STIs can also be transmitted through non-sexual means like blood transfusions. Step 3: Recognize that choice C is incorrect as it limits STIs to only sexually transmitted infections. Step 4: Therefore, the correct answer is C as it does not encompass all possible modes of transmission for STIs. Summary: Choices A, B, and D are incorrect as they all accurately describe the characteristics of sexually transmitted infections, while choice C is incorrect as it excludes other potential modes of transmission for STIs.

Correct Answer: D

Rationale: The correct answer is D: Chlamydia trachomatis. Lymphogranuloma venereum (LGV) is caused by Chlamydia trachomatis serovars L1, L2, and L3. These serovars infect the lymphatic system leading to swelling and inflammation. Choice A, Chlamydia pneumoniae, is associated with respiratory infections, not LGV. Choice B, Chlamydia psittaci, causes psittacosis in birds and humans. Choice C, Mycoplasma genitalium, is a separate STI but is not the causative agent for LGV. The key to the correct answer is understanding the specific pathogen responsible for LGV based on its clinical presentation and mode of transmission.

Correct Answer: D

Rationale: The correct answer is D because all of these symptoms are early signs of rabies. A short period of depression, nausea, and restlessness are common initial symptoms of rabies infection. These symptoms may be followed by more severe manifestations, such as aggression, confusion, and difficulty swallowing. Therefore, option D is the correct choice as it encompasses all the early symptoms of rabies. Options A, B, and C are incorrect as they focus on individual symptoms, whereas rabies typically presents with a combination of these early signs.

Correct Answer: B

Rationale: The correct answer is B: Sporadic disease. When an infection occurs in several persons without any epidemiological link, it is considered sporadic. This term is used to describe isolated cases that do not form a specific pattern or cluster. It indicates random occurrences and lack of connection between the affected individuals. A: Epidemic refers to a sudden increase in the number of cases of a disease within a specific population or region, usually linked by a common source or exposure. C: Endemic signifies the constant presence of a disease within a specific population or region, with cases occurring at a relatively stable rate. D: Pandemic indicates a global outbreak of a disease affecting a large number of people across multiple countries or continents.