Search for malaria parasites by PCR and southern blot in patients with imported malaria in Italy

The present study evaluates the sensitivity, specificity and usefulness of a PCR method with Southern blot hybridization to detect malaria parasites i n blood samples from subjects with a suspect clinical diagnosis of malaria imported to Italy. Plasmodia were detected by PCR using a genus-specific primer-set correspond ing to the sequences common to P. falciparum, P. vivax, P. malariae and P. ovale, as described by Arai (Arai ct al., Nucleosides Nucleotides, 1994, 13 , 1363-1364) and Kimura (Kimura et al., Journal of Clinical Microbiology, 1 995, 33, 2342-2346). In addition, four distinct tandemly repetitive species -specific probes, described by Kawai (Kawai et at, Analitical Biochemestry, 1993, 209, 63-69), were synthetised to specifically detect the four malari a parasites species by Southern blot hybridization. Fifteen blood samples from 12 patients (7 with malaria) were tested and the genus-specific PCR method showed a sensitivity of 100% and a specificity o f 100%, when compared to microscopy, in detecting malaria parasites in the tested blood samples. Fourteen samples (nine were positive and five negativ e by PCR) were confirmed by Southern blot, whereas only one P. vivax positi ve sample was not hybridized with the species-specific probes. We conclude that this PCR method with Southern blot hybridization may be us eful in detecting malaria parasites in patients with malaria imported to It aly.