[Field application of multiplex PCR to distinguish Plasmodium vivax and Plasmodium falciparum]

Abstract

Objective: To explore the application value of multiplex PCR in the diagnosis of malaria in field.

Methods: The plasmodium genus-specific primer, Plasmodium vivax, P. falciparum species-specific primers were synthesis based on the specific target segments of small subunit of 18 S rRNA ribosomal. The multiplex PCR system was optimized, and a PCR diagnostic method of malaria was established based on the genomic specific DNA fragment of P. vivax, and P. falciparum was amplified in the same PCR reaction system. The sensitivity, specificity, and the value of field application of the multiplex PCR were investigated.

Results: The sizes of amplification products of multiplex PCR amplifying genomic DNA of P. vivax and P. falciparum were 833 bp and 1 451 bp, respectively, and the amplification did not take place with the samples DNA of P. berghei, P. cynomolgus and healthy human blood. The sensitivities of multiplex PCR to detect P. vivax and P.falciparum were 1.1 x 10(-6) and 5.6 x 10(-7) parasitemia, respectively. Compared with the microscopic examination, the positive rate of multiplex PCR to detect 119 cases of field samples was 54%, missed diagnosis rate was 0.8%, and the misdiagnosis rate was naught, while the positive rate of the microscopic examination was 53%, its misdiagnosis rate and missed diagnosis rate were 1.7% and 3.4%, respectively. The compliance rate between the multiplex PCR and microscopic examination was 94%.

Conclusion: The multiplex PCR for detecting malaria is simple, rapid, specific, sensitive, etc., which is suitable for the differential diagnosis of suspected cases, and molecular epidemiology investigation.