Internal control for real-time polymerase chain reaction based on MS2 bacteriophage for RNA viruses diagnostics.

Background: Real-time reverse transcription polymerase chain reaction (RT-PCR) is routinely used to detect viral infections. In Brazil, it is mandatory the use of nucleic acid tests to detect hepatitis C virus (HCV), hepatitis B virus and human immunodeficiency virus in blood banks because of the immunological window. The use of an internal control (IC) is necessary to differentiate the true negative results from those consequent from a failure in some step of the nucleic acid test.

Dengue virus infections: comparison of methods for diagnosing the acute disease.

Background: The control of dengue depends solely on the control of the insect vector and efficient diagnosis of human cases as no vaccines or specific treatments are currently available. Existing diagnostic methods for suspected clinical cases are complicated by the short duration of viraemia and by serological cross-reactivity with epitopes from other flaviviruses.

Objectives: To evaluate PCR-based tests (nested reverse transcription (RT)-PCR and real-time RT-PCR) for the detection and serotyping of dengue virus and compare the results with those obtained with a widely used immunological test (IgM antibody capture ELISA-MAC-ELISA).