An 18-year-old female plans to take a mission trip to Ghana for 2 weeks during the summer following her senior year of high school. Her doctor recommends starting a regimen of mefloquine before her trip for malaria prophylaxis rather than the traditional chloroquine because of widespread resistance to chloroquine. What is the mechanism of chloroquine resistance?

An 18-year-old female plans to take a mission trip to Ghana for 2 weeks during the summer following her senior year of high school. Her doctor recommends starting a regimen of mefloquine before her trip for malaria prophylaxis rather than the traditional chloroquine because of widespread resistance to chloroquine. What is the mechanism of chloroquine resistance?

A 19-year-old college student man presents to the student health service with a 2-week history of headache, malaise, sore throat, and dry cough, which has become productive over the last 4 days. He states that several of his dorm mates have complained of similar problems in the last few weeks. Pulmonary auscultation reveals scattered coarse rhonchi bilaterally. What is the best treatment for this patient?

A 12-year-old male complains of red plaques covered by silver scales on his elbows and knees. He has one older sister with similar lesions. In each case, the lesions are worse in the winter months. His pediatrician prescribes acitretin. Which of the following may this boy experience as a result of this treatment?

An 18-year-old male college student presents to the emergency room with a fever of 103°F and stiff neck for the past 3 h. After a lumbar puncture and Gram stain, the diagnosis of meningococcal meningitis is established. Unfortunately, his college did not require students to have the meningococcal vaccine. What prophylaxis should be given to his close contacts in the dorm?

A 35-year-old man with HIV disease presents to the emergency department with a severe headache and fever for the past 6 h. His fever was measured to be 103°F. He also has chills, stiff neck, and nausea. He is diagnosed with Cryptococcus neoformans meningitis and started on amphotericin B. What is the mechanism of action of amphotericin B?