A patient with a history of travel to a tropical region presents with cyclical fevers and chills.Peripheral blood smear reveals the presence of merozoites and schizonts within erythrocytes. The absence of crescent-shaped gametocytes makes Plasmodium falciparum less likely. The MOST probable species is:

Under the Clinical Laboratory Improvement Amendments (CLIA), participation in an approved external Proficiency Testing (PT) program serves primarily to:

A research laboratory is investigating the mechanism of action of a novel antiviral drug against herpes simplex virus. The drug is found to inhibit the viral DNA polymerase. Which of the following commercially available antiviral agents has a similar mechanism of action?

A microbiology laboratory receives a blood culture from a patient with suspected bacterial endocarditis. After
24 hours of incubation, Gram-positive cocci in clusters are observed on the Gram stain. Catalase test is positive, and coagulase test is negative. Further testing reveals susceptibility to novobiocin. The MOST likely organism is:

A patient returning from a hiking trip in a Lyme disease-endemic area presents with a unilateral facial nerve palsy, headache, and neck stiffness. Serological testing for Borrelia burgdorferi by ELISA is positive, but a Western blot shows only IgM bands. The MOST appropriate interpretation of these results is: