Submicroscopic malaria parasite carriage: how reproducible are polymerase chain reaction-based methods?
Costa, Daniela Camargos
Mem. Inst. Oswaldo Cruz
DATA DE PUBLICAÇÃO
The polymerase chain reaction (PCR)-based methods for the diagnosis of malaria infection are expected to accurately identify submicroscopic parasite carriers. Although a significant number of PCR protocols have been described, few studies have addressed the performance of PCR amplification in cases of field samples with submicroscopic malaria infection. Here, the reproducibility of two well-established PCR protocols (nested-PCR and real-time PCR for the Plasmodium 18 small subunit rRNA gene) were evaluated in a panel of 34 blood field samples from individuals that are potential reservoirs of malaria infection, but were negative for malaria by optical microscopy. Regardless of the PCR protocol, a large variation between the PCR replicates was observed, leading to alternating positive and negative results in 38% (13 out of 34) of the samples. These findings were quite different from those obtained from the microscopy-positive patients or the unexposed individuals; the diagnosis of these individuals could be confirmed based on the high reproducibility and specificity of the PCR-based protocols. The limitation of PCR amplification was restricted to the field samples with very low levels of parasitaemia because titrations of the DNA templates were able to detect < 3 parasites/µL in the blood. In conclusion, conventional PCR protocols require careful interpretation in cases of submicroscopic malaria infection, as inconsistent and false-negative results can occur.
- Rapid, polymerase chain reaction-based identification assays for Candida species.
- Polymerase chain reaction-based strain characterization of noncapsulate Haemophilus influenzae.
- Comparison of three nonradioisotopic polymerase chain reaction-based methods for detection of human immunodeficiency virus type 1.
- Comparison of a Ligase Chain Reaction-Based Assay and Cell Culture for Detection of Pharyngeal Carriage of Chlamydia trachomatis
- Polymerase chain reaction-Based clonality analysis of cutaneous B-cell lymphoproliferative processes