Clinical significance of molecular methods in the diagnosis of imported malaria in returning travelers in Serbia

Abstract

Objectives: The goal of this study was to assess the clinical significance of conventional and PCR-based molecular diagnosis in patients with imported malaria in Serbia.

Methods: Giemsa microscopy, the rapid diagnostic test, and quantitative real-time PCR (qPCR) were used to detect Plasmodium species in 109 whole-blood samples from patients after their return from malaria endemic areas, including those clinically suspected for malaria (n=97) and healthy travelers (n=12) examined as part of epidemiological surveillance.

Results: A total of 45 patients were diagnosed with malaria: 42 (93.3%) by microscopy and three (6.7%) additional ones by qPCR. The agreement between the results of species-specific qPCR and microscopy was 73.3%; it was as high as 90.6% for Plasmodium falciparum infections. Follow-up analysis demonstrated persistence of Plasmodium sp DNA for a mean 6 days after the disappearance of parasitemia on microscopy.

Conclusions: Due to its sensitivity and specificity, qPCR is a helpful method complementary to microscopy, particularly in cases of low parasitemia. In addition, it is superior to microscopy for species identification.

Keywords: Diagnosis; Malaria; Microscopy; Parasitemia; Plasmodium species; Quantitative real-time PCR.