14 Molecular evidence.pmd

1Malaria Research Group, Biotechnology Department, Pasteur Institute of Iran, Tehran, Islamic Republic of Iran. 2Department of Microbiology, Faculty of Science, University of Tehran, Tehran, Islamic Republic of Iran. 3Centre for Diseases Management and Control, Tehran, Islamic Republic of Iran. 4Public Health Department, Ardebil University of Medical Science, Ardebil, Islamic Republic of Iran. Received: 23/06/03; accepted: 29/09/03 ABSTRACT This study compared basic microscopy with molecular detection of Plasmodium species. According to thick-film microscopy, 100% of 142 malaria cases in Pars-Abad, Ardebil province, were infected with a single species, P. vivax. However, nested polymerase chain reaction (PCR) detected mixed species infections of both P. vivax and P. falciparum in 7.0%. In Mazanderan province, 2/20 blood films were diagnosed with only P. falciparum and 18/20 with only P. vivax. However, nested PCR detected 17/20, 2/20 and 1/20 with P. vivax only, P. falciparum only and mixed species respectively. The unexpected presence of P. falciparum urges prompt investigation and immediate treatment of malaria cases in this region.