[Single-tube Single-run Multiplex PCR Detects Mixed Samples with Four Species of Plasmodium].

OBJECTIVE: To establish a single-tube single-run multiplex PCR technique that can detect single or mixed samples with four species of Plasmodium. METHODS: Folding primers were designed based on the fast nested PCR. The reaction component concentrations were optimized and the primers were selected based on the annealing temperature. The established single-tube single-run folding-primer multiplex PCR (FP-PCR) was tested for its sensitivity and specificity to detect single-species and mixed samples with P. vivax, P. falciparum, P. ovale (including P. ovale wallikeri) and/or P. malariae. RESULTS: In all the seven experimental repeats, FP-PCR successfully detected single-species infection for all the four species, with the detection limit reaching or close to 1 parasite/µl blood. For mixed infections with 2-4 species at different densities with the highest being 100 times of the lowest, FP-PCR identified all the species in each combination in 57 out of 84 tests. Further, in 10 dried blood samples on filter paper from healthy subjects, no FP-PCR amplification was found, except weak formation of dimers. CONCLUSION: FP-PCR is a simple and sensitive method for detecting both single-species and mixed infections with human Plasmodium, and can be applied for malaria diagnosis, screening and monitoring.

[Comparison of Malaria Diagnosis between County and Provincial Laboratories in Guizhou Province].

Malaria cases reported by county laboratories were further tested in the provincial laboratory in Guizhou province by using PCR test and microscopy. The consistency between PCR and microscopic results in the provincial laboratory was set as the basis for evaluation of microscopic results in county laboratories. In 89 samples, 24 were identified by PCR to be positive for malaria, among which 15 were infected with P. falciparum, 7 with P. vivax, and 2 with P. ovale; all were imported cases. And 21 samples had consistent identifications by PCR test and microscopic examination in the provincial laboratory. The total coincidence rate between county and provincial laboratories was 79.8%(67/84), and the undetected and error rates in county laboratories were 9.5%(2/21) and 23.8% (15/63), respectively. The Kappa value between county and provicial diagnosis was 0.6, being at the medium-to-high level of consistency.