Iranian Journal of Parasitology
Volume:3 Issue: 2, Apr-Jun 2008

Leishmaniasis is an endemic disease in 88 countries. Reports on Leishmania drug resistance are growing in number. The mechanism of unresponsiveness against glucantime in Iranian cutaneous leishmaniasis has not yet been characterized. To begin the first step in finding an anti-Leishmania chemotherapy, we prepared recombinant L. major PTR1 enzyme and characterized its activity by enzymatic assay. Leishmania promastigote DNA was extracted and the ptr1 gene amplified using specific primers. The PCR product was cloned in pQE30 expression vector, transformed into E.coli and expressed. The recombinant protein was purified, its enzymatic activity was assayed and anti-PTR1 antibody prepared in rabbit. The PCR product of ptr1 gene was sequenced and deposited in GenBank. The amino acid sequence of Iranian L.major PTR1 was compared with other Leishmania PTR1 and showed some identities and diversities. Purified protein was reacted by anti PTR1 antibody in gel diffusion and western blot assy. Enzyme activity of purified recombinant PTR1 was 38 nmol/min per 0.4 mg of protein and it showed pteridine reduction by PTR1 We cloned and expressed Iranian L. major ptr1 gene and assayed its enzymatic activity. This enzyme will be used for further investigation about Leishmania antifolate therapy that is effective against PTR1

Cystic echinococcosis (CE) is one of the most predominant parasitic zoonosis infections in the world. Due to the high recurrence rate of the disease after surgery, follow up of the patient is necessary. The aim of current research was to evaluate the sensitivity of ELISA method for hydatid antibodies detection in confirmed CE cases before and its pattern after surgery. The sensitivity of ELISA method was assessed for hydatid antibody detection in 143 pathologically confirmed CE cases. The existence of CE antibody in 69 confirmed CE cases were followed up for 6 to 12 months and up to 48 months in some cases. Sensitivity of ELISA was 90.2%. Fifty percent of seronegative cases had lung infection. All of the CE cases who were monitored for antibodies assessment after surgery showed variable levels of decrease in antibody titer. However, this decrease was not constant, regular and occurred at different times after surgery. Increasing antibody levels were occurred in few cases after surgery for up to 6 months. The present study showed that the sensitivity of ELISA for antibody detection against purified antigen B was high. Furthermore, this test is a useful and valuable index for post monitoring of CE patients after surgical treatment.

The worldwide distribution of P. vivax has expanded significantly and the number of reported cases has been on the rise. Approximately 88% of malaria cases in Iran are caused by Plasmodium vivax, and in order to management of the disease, understanding the population genetic structure of the parasite is necessary for designing and applying drugs and vaccines. Among many potential candidates, merozoite surface protein-3α gene (PvMSP-3α) is promising target to develop an effective vaccine. This study was carried out to determine the variation of this gene, as a genetic marker, in Plasmodium vivax isolates in malarious areas of Iran. Diversity in PvMSP-3α gene was assessed in 85 Plasmodium vivax isolated from four southern and east-southern provinces of the country by PCR/RFLP method. Amplification was performed with two primer pair sets in a nested PCR format and the products were digested by the enzyme HhaI in RFLP method. Based on the size of the PCR products, we observed three biotypes A (about 1900bp), B (about 1400bp) and C (about 1100bp) of PvMSP-3α gene. Biotype A was predominant. According to RFLP patterns, 10 allelic groups of the gene were observed, that, 7, 2 and 1 groups correspond to the biotype A, B and C, respectively. Mixed genotype and multiple infections were not seen. RFLP method with HhaI enzyme is a useful method for determining the polymorphism of biotype A of PvMSP-3α gene.

Pneumocystis carinii is one of opportunistic organisms especially in immuno-compromised patients. For years, diagnosis of Pneumocystis pneumonia (PCP) has relied on microscopic visualization of organism in specimens obtained from the lung either by bronchoalveolar lavage (BAL) or by induction of sputum, but failed to provide efficient diagnosis. The aim of this study was to compare of PCR result and Gomori''s methenamine silver (GMS) of invasive and noninvasive specimens in infected rat. Thirteen stimulated rat with methylprednisolone acetate used as test group and 4 non-stimulated rats were used as control group. Oral swabs (OS), BAL and lung homogenate (LH) specimens were collected from weeks 0, 2, 4, 5, 6 and 7. All samples were tested with (GMS) staining method and PCR technique. The results showed the sensitivity of PCR method higher than GMS (69.2% versus 0%) in oral swab samples (P> 0.001). The analysis of the results also proved that PCR test using noninvasive oral swab had comparable results with the GMS staining method on invasive lung biopsy specimens (69.2% versus 61% and 84.6 for BAL and Lung Biopsy). Higher sensitivity of PCR using noninvasive sample can made it a useful method in rapid diagnosis of PCP.

Ligulae intestinalis is a parasitic cestode, which has the economic-health importance in fishery industries. The aim of this study was to determine the prevalence of this parasite in Mazandaran. The effects of habitat temperature and kind of pool (sandy-cement) were considered as well. In this study, 103 fish samples were obtained in all stages; the samples (male and female) were divided into 3 groups based on length of fish, temperature, origin of cultured fish, kind of pool, height from sea and sex. Macroscopic and microscopic observations were carried out in all stages of the parasite (procercoid, plerocercoid and adult). Chi-square and Pearson''s double square tests (P<0.05) were conducted in order to evaluate the prevalence and determination of reliability in six sampling areas, respectively Total rate of the parasites were 9.7% in all groups. There was significant difference between parasitism rate and height of sea level, kind of pool (maximum in sandy pools) and high temperature. The multi analyses regarding to above-mentioned three criteria also indicated meaningful difference between these criteria and parasitism rate. Seasonal conditions enhance the prevalence of ligulae intestinalis. Flexibility in parasite''s life cycle and choosing different hosts makes it challenging case in fishery industry; moreover its prevalence could be predicted according to environmental conditions so choosing the minimal at risk place for salmonids farming. Further studies are recommended for evaluating the problems in fish fertility and probable risk for infected fish consumers.

The aim of the present study was to evaluate the effects of metronidazole and albendazole against clinical isolates of Giardia lamblia in vitro. From all human samples of containing cysts, 10 isolates were successfully excysted in vitro. Trophozites viability was assessed by eosine 0.1% and cultured axenically in TYI-S-33 modified medium supplemented with heat inactivated bovine serum 10%. All cultures were incubated in 37°C for 24-48 h. After this time trophozoites were exposed to different concentration (0.05, 0.1, 2, 10, 50 µg/ml) of drugs at 37º for 4 h. The IC50 estimated between 0.1 and 10µg/ml for metronidazole and 0.062 and 0.1 µg/ml for albendazole. Eight isolates were found susceptible to the metronidazole while all isolates were found susceptible to the albendazole. Statistical results indicated that there was significant difference (P<0.05) in the sensitivity to metronidazole and albendazole in all isolates.

This study investigated the association between pfcrt, T76 allele and chloroquine resistance in patients with falciparum malaria. Molecular assays for point mutations on drugs resistance-related genes are applied tools for monitoring emerging resistance and surveillance malaria control strategies in endemic areas. The mutant genotype at codon 76 of Plasmodium falciparum chloroquine resistance transporter gene (pfcrt) has been proposed as a molecular marker for the faster detection of chloroquine resistance in field. In 64 samples from patients with uncomplicated falciparum malaria from Sarbaz district in southeast of Iran, the clinical response to chloroquine and the prevalence of K76T mutations in pfcrt gene were investigated by in vivo and nested-PCR followed restriction enzyme digestion methods. The occurrence of the K76T mutation was very high (60 of 64, i.e. 93.75%) among these filed isolates. Only 4 of 64 isolates harbored wild type K76 codon and no case was a mixed of K76 and 76T codons. All of the 22 (100%) chloroquine-resistant and 16.7% of sensitive isolates were found to harbor the 76T mutation and none was found to contain the wild type (K76) allele. The frequency of chloroquine resistance associated point mutation K76T, in pfcrt gene in this region suggest that detection of this mutation can be applied for predicting chloroquine resistance in epidemiologic settings with sufficiently high sensitivity to make it an attractive alternative to time and labor-consuming in vivo trials.

Infection resulting from Plasmodium vivax is the commonest type found in India as well as other tropical regions. The clini­cal picture is variable depending on the nature, immunity of the child, and lives in an endemic area or not. Here, we report a child, who presented with cerebellar dysfunction with intact sensorium and Plasmodium vivax was positive on peripheral smear