Iranian Journal of Parasitology
Volume:2 Issue: 2, Apr-Jun 2007

Toxoplasma gondii is an obligate intracellular parasite and its sexual and asexual cycles, respectively take place in the intestinal epithelial cell of definitive host and tissue of intermediate hosts. Congenital toxoplasmosis is more impor tant when the mother acquired the infection during pregnancy period for the first time. Serological tests are the only meth ods for diagnosis of toxoplasmosis. Among serological tests, ELISA has specific value and availability of parasite spe cific anti gen increases the specificity of test. This study has designed and performed in the aim of availability to specific anti gen of Toxoplasma. A pair of forward and reverse primers was designed based on published sequence of T. gondii SAG1 gene. PCR reac tion was performed and PCR product was cloned in the pQE-30 expression vector. The gene of 30 kDa protein of Toxoplasma tachyzoites was cloned in expression vector successfully. Recombinant plas mid was confirmed and is ready to express recombinant protein for further studies. In this research we cloned P30 gene of T. gondii tachyzoites surface protein successfully and is ready to ex press the recom binant protein.

To evaluate the immunological properties of Leishmania major excreted- secreted (E-S) products on the progress of leishmaniasis in susceptible BALB/c mice. Promastigotes of the Leishmania major were cultured and E-S products were collected during the culture preiod. Groups of BALB/c mice (n= 12) were immunized with E-S products or whole antigen. Animals were challenged with promastigotes of stationary phase culture, then mortality was followed up to 6 months. In another group of animals drainage lymph nods cells were removed and cultured for cytokines assay. Activity of acteylcholinesters (AChE) and acid phosphatase (ACP) incresed time dependently. Using SDS-PAGE two major protein bands of 110 and 75 kDa were seen on the gel. Wound diameter in group receiving 24 h E-S products was significantly lower than the other experimental groups (P< 0.05). During the first 4 months of the follow up no mortality was seen in this group, but mortality was started in the second months of the challenge in other groups. The IL-4 and IL-10 level in whole Ag group were significantly higher than the other groups. In cells from animals receiving 24 h E-S products the IL-2 level was significantly higher than the other experimental groups (P< 0.05). Also the IFN g level was significantly higher both in 24 h E-S and whole Ag groups (P< 0.01). The 24 h E-S group corresponded with small wounds, dominant Th1 cytokines response and low level of mortality.

Hydatidosis is one of the most prevalent zoonotic diseases worldwide. So far no survey was conducted to deter mine the rate of human hydatidosis in Golestan Province, so using IFA and ELISA tests the prevalence of this disease was detected in patients referred to health centers in this province. Totally 1024 serum samples were collected from patients referred to different health centers in 4 cities of Gloestan Province including Gorgan, Gonbad kawoos, Aliabad Katool and Kordkoy. All the sera were examined using IFA and ELISA tests. Twenty four cases (2.34%) were positive for hydatidosis in Golestan Province using IFA, whereas 22 cases (2.15%) showed positivity using ELISA. Gorgan, Gonbadkaoos, Aliabad Katool and Kordkoy demonstrated the rate of positiv ity as 1.41%, 2.40%, 5.36% and 2.30%, respectively, but no significant difference was seen. As to positivity, there was no significant difference between age groups, sex, different cities and rural or urban life, but a significant different was seen according to job and literacy (P< 0.001). According to Job and literacy, housewives and illiterates had the highest rate of infection as 3.67% and 3.72%, respectively. As regards residency, urban life showed no significant difference with rural life (2.47% vs. 2.45%). Age group of 40-49 years old had the highest rate of positivity (3.95%). Females were more infected than males (3.16% vs. 1.93%). The rate of prevalence in this province shows somehow a resemblance with the other cities in Iran. Consider ing the lifestyle in this province a complementary study is suggested in all related cities.

The Mediterranean type of kala-azar is occurred in different parts of Iran and caused by Leishmania infan tum. A rapid and valid test for early detection of visceral leishmaniasis in human would be highly desirable because it could de crease mortality rate of the disease. In this study, we aimed to compare the results of K39sub antigen with an commercial immu nochromatographic dipstick rk39 test (Cypress Diagnostic Company, Belgium) for early detection of L. infantum infec tion in human. K39sub recombinant antigen of L. infantum LON49 was expressed in prokaryotic system and evaluated for the diagno sis of human visceral leishmaniasis. This study evaluated the performance of recombinant K39sub antigen by ELISA and an commercial immunochromatographic dipstick rk39 test for the detection of L. infantum antibodies in 43 clinically in fected patients with direct agglutination test (DAT) at a 1: 3200 cut off titer and higher. Controls included 69 healthy volun teers and 28 patients with other diseases including malaria (n=5), tuberculosis (n= 3), toxoplasmosis (n= 4), cystic hydatido sis (n= 5) and cutaneous leishmaniasis (n= 11). The sensitivity of the K39sub antigen and an immunochromatographic dipstick rk39 test was 90.7%, and 97.7%, respec tively, while the specificity was 95.6% and 97.9%, correspondingly. A good concordance was found between k39sub anti gen and commercial dipstick rk39 strips (k= 96.4%). The accuracy of the K39sub antigen in the detection of L. infantum antibodies in human infec tion is confirmed.

A Nematodes are among the most common and important parasites of man and animal. DNA of a single worm can be used for several purposes, such as identification to the species, subspecies, strain and antihelmenthic resistance. DNA extraction from a single small worm using traditional methods such as phenol extraction technique faces serious prob lems. DNA from 20 single Haemonchus contortus was isolated using DNA isolation kit newly designed in Iran by the Re search Unit of Molecular Biological System Transfer (MBST) based on the specific binding of DNA to the carrier. The ge nomic DNA was amplified using specific primers derived from β-tubulin isotype 1 in PCR. The specificity of the PCR prod ucts was determined using semi-nested PCR technique. Specific PCR-product from β-tubulin gene could be amplified with 1 ng, 100 pg and 10 pg DNA. The used DNA extraction method was safe, with high quality and quantity, fast, easy to handle and not costly for ge netic analysis of even a single small worm. The Iran produced DNA extraction Kit is grounded on a selective binding of nucleic acids to a silica-based mem brane and is recommended for the isolation of DNA from even small amount of biological materials.

Ticks are obligate blood feeders that parasitize a wide variety of animals. Hyalomma aegyptium, parasitize tortoises and other small wild life and livestock. This study was carried out to determine spur-thighed tortoise (Testudo graeca) infestation to H. ageyptium in Urmia region West Azerbaijan of Iran. The study was carried out over a 16 month period from the spring of 2004 to the fall of 2005. A total of 32 tor toises were sampled. The results indicated that 14 tortoises infected with ticks. A total of 117 ticks were collected from infested animals, the minimum and maximum tick infestation was 1-60. Ticks were attached to the axilla of fore and hind legs of tortoises. All ticks were determined to be H. aegyptium. H. aegyptium was the most common tick species in the study area. Due to tendency of some people to keeping tortoise as pet animal, more attention must be done to tortoise’s tick infestation. Due to existence of H. aegyptium on tor toises in this region more study will need to evaluate presence of this tick on other animal species and its role on transmis sion of diseases.

Differential diagnosis of two protozoan parasites Entamoeba histolytica and E. dispar is of great clinical and epide miologi cal importance, but except in the case of haematophagous trophozoites in acute dysentery, it is not possible to differ entiate them by microscopy. The present study was carried out from February 2005 to July 2006 in order to determine the preva lence of E. histolytica and E. dispar in Gonbad City, by using a PCR method. Five hundred and sixty four fecal samples were collected from primary health care centers of Gonbad both urban and rural ar eas. The stool specimens were examined by light microscopy (Direct slide smear, Iodine wet mount, Formal-ether concentra tion and Trichrome staining) to distinguish E. histolytica/E. dispar complex and differentiate them from other non-patho genic intestinal amoebae. The microscopy results of stool exams showed a frequency rate of 23 positive samples (4.07%) for cyst of E. histo lytica/E. dis par complex. All the microscopy positive isolates appeared to be infected with cyst of E. histolytica/E. dispar com plex were cultivated and maintained successfully in HSr + s medium for DNA extraction and identification by the PCR method. The PCR study showed that 16 isolates (69.56 %) of the Entamoeba samples were E. dispar while 7 samples (30.43%) of those microscopy positive samples were not amplified and none of them showed E. histolytica pattern. High frequency rate of E. dispar in this study were in high agreement with the estimation rate of these entamoe bas worldwide.

Studies concerning ticks were of interest to evaluate the distribution and composition of species affecting live stock, thus it was a main step in our knowledge of the pathogens that they may transmit by tick. A collection of 21 adult female and 15 male hard ticks, all is representing a single species of tick collected under the tail of wild goat. The specimens preserved in 70 % alcohol in glass vial and brought to laboratory for identification. In or der to distinguish species relationships between wild and domestic animals, tick sampling has been achieved in 7 different places located around Kolah Qazi national park in Isfahan Province. Important descriptions of ticks isolated from wild goat strongly supported that the tick species in this collection was only Rhipicephalus (Boophilus) kohlsi. It seems that this is the first report of Rh. (Boophilus) kohlsi in Iran. Wild sheep and goats live throughout Iran ex cept in forest and other tall vegetation areas. Although, both animals has pastured occasionally in same open rangeland but we could not find any tick of Rh. (Boophilus) kohlsi in domestic animals.