Comparison of microscopical examination and semi-nested multiplex polymerase chain reaction in diagnosis of Plasmodium Falciparm and P. vivax

We compared light microscopy examination and a semi-nested multiplex PCR [SnM-PCR] assay in endemic areas of the Islamic Republic of Iran. A total of 68 individuals with malaria-positive and suspected malaria symptoms were included in the study. Giemsa-stained thick blood films were examined under a light microscope for malaria parasites in 100 and 200 fields. DNA was extracted from blood samples and SnM-PCR based on the amplification of the small subunit ribosomal RNA [ssrRNA] gene sequences was applied. Microscopical examination showed that 48.5% [33.8% P. vivax and 14.7% P.falciparum] and 50% [35.3% P. vivax and 14.7% P.falciparum] of the samples were positive in 100 and 200 fields respectively. SnM-PCR showed the same results as the 200 field microscopy

Molecular monitoring of plasmodium vivax infection after radical treatment in southeastern Iran

The aim was to evaluate the relapse risk of vivax malaria in patients who received radical treatment in Hormozgan Province, a malarious area located on southeast of Iran. A total of 95 symptomatic vivax malaria infected patients were enrolled in urban health centers of Bandar-Abbas, Minab, Bandar-Jask and Bashagard districts of Hormozgan Province, southeast of Iran from January 2008 to March 2009 for consideration as a case-series study. DNA was extracted from parasite infected whole blood samples. A polymorphic region of Plasmodium vivax merozoite surface protein 1 [pvMSP1] was selected and a PCR method was employed for all the samples to amplify the specific variable gene fragment. The obtained fragments in primary and secondary samples were sequenced. Both nucleotide and amino acid sequences of the samples were investigated for returned patients. 3.2% of the patients experienced a second attack between 83-199 days after the initial episode of infection. Alignment of nucleotide and their deduced amino acid sequences between pair sequences of primary and secondary isolates revealed 8 and 6 dissimilarities respectively for the first case, and 9 and 7 dissimilarities for the second case. Although microscopical examination of recurrent thick blood smear of the third patient confirmed new P. vivax infection, the venous blood sample was accidentally missed. Sequencing results of primary and returned isolates 1P, 1S, 2P, 2S and 3P in this study showed an identity with BP13, T117, BP13, TC28 and Chesson genotypes respectively. The returned [secondary] isolates may account to be for the sake of reinfection

[Comparison between serology and PCR methods for the diagnosis of visceral Leishmaniasis]

Canine visceral leishmaniasis [CVL] caused by Leishmania Infantum is endemic in most Mediterranean basin and its seroprevalence ranges from 10 to 37%. Diagnosis of Infection is very important especially in asymptomatic dogs for control of human leishmaniasis for control of human visceral leishmaniasis. This study was aimed to compare three methods for detection of canine visceral leishmaniasis. In this research process study, 71 dogs were selected from 4 endemic villages in Meshkin-Shahr district. Peripheral blood samples were tested by serologic [DAT and Dipstick rK39] and molecular [PCR] methods. Skin samples were tested by molecular [PCR] methods. Twelve samples of PCR products were sequenced that all of them were identified as Leishmania infantum and 2 nucleotide sequence data submitted to the GenBank database. From 71 dogs that were studied, 21.1% were symptomatic and others were asymptomatic[78.9%]. 17 dogs [23.9%] had >/= 1:320 titer of antibody by direct agglutination test [DAT]. Twenty two dogs[31%] were positive by Dipstick rK39 test, 21 dogs [29.6%] were positive by PCR on skin samples, 31 dogs [43.7%] were positive in blood PCR and 38 dogs [53.5%] were positive by skin/blood PCR. The highest correlation was between DAT and Dipstick test [76%].According to the results of this study, we can diagnose infection in symptomatic and asymptomatic dogs by DAT as a suitable method and PCR is suitable to follow parasite DNA in skin and other tissues of dogs