Detection and genotyping of Toxoplasma gondii isolated from soil in Ahvaz, southwest of Iran

To detection and genotype of Toxoplasma gondii isolated from soil in Ahvaz, southwest of Iran. Between August 2011 and May 2012 at different sites located in the area of the Ahvaz city south west Iran. A total of 200 soil samples were taken from different points of the region. Oocysts were recovered using the flotation method. Then, PCR reactions targeting the GRA6 gene were performed for specific T. gondii detection. The positive samples were studied by RFLP (random amplified fragment length polymorphism) using MseI enzymes to confirm the parasite linage. Toxoplasma DNA was found in 18 samples. Among them, 12 samples were successfully genotyped as GRA6 type III and 6 as GRA6 Type II. This is the first investigation detecting and genotyping T. gondii oocyst in environmental soil samples of Ahvaz, South west of Iran. The results of this study indicated that soil contaminated with T. gondii oocysts especially in public park may play a role in the epidemiology of human toxoplasmosis in southwest of Iran.

An in vitro study on suppressive effects of Leishmania major on IL-2Rα expression on peripheral human T lymphocyte

Leishmania sp. is an intracellular protozoan parasite that causes significant morbidity and mortality in many parts of the world. The parasite can escape from host immune system by several mechanisms. Understanding biological behavior of the parasite can help us to control and treatment leishmaniasis. Therefore current study was conducted to determine suppresive effect of Leishmania major on IL-2Rα expression in the human peripheral T Lymphocytes. Human peripheral T Lymphocyte were co-cultured with standard strain of Leishmania major (MRHO/IR/75/EK) in RPMI1640 medium. Infected cells were stained with FITC-labelled anti-CD25 (IL-2Rα chain MAb) and Picoerithrin-labelled anti-CD4 (CD4 MAb) and analyzed by flow cytometry. The results showed that L. major suppressed IL- 2Rα expression in activated T cells as well as inhibited lymphocyte proliferation 6h after infection and was increased up to 36 hour later. This finding also indicated that suppressed IL- 2R expression was increased when the number of promastigote was added up to 7.5×10(6) cells/ml. Inhibition of IL-2R expression by the parasite might play a critical role for escaping from host immune system. Understanding biological characterization of the Leishmania can be useful for vaccine development and also cytokine therapy.

Diagnosis and identification of Leishmania spp. from Giemsa-stained slides, by real-time PCR and melting curve analysis in south-west of Iran

BACKGROUND

The aim of present study was describing a real-time PCR assay for the diagnosis and direct identification of Leishmania species on Giemsa-stained slides in south-west of Iran.

MATERIALS AND METHODS

Altogether, 102 Giemsa-stained slides were collected from different part of south-west of Iran between 2008 and 2011. All the Giemsa-stained slides were examined under light microscope. After DNA extraction, real-time PCR amplification and detection were conducted with fluorescent SYBR Green I. For identification, PCR products were analysed with melting curve analysis.

RESULTS

One hundred and two archived slides from suspected lesion examined by microscopy and real-time PCR. The sensitivity of the real-time PCR on Giemsa-stained slid was 98% (96/102). The melting curve analysis (T(m)) were 88·3±0·2°C for L. tropica (MHOM/IR/02/Mash10), 86·5±0·2°C for L. major (MHOM/IR/75/ER) and 89·4±0·3°C for L. infantum (MCAN/IR/97/LON 49), respectively.

CONCLUSION

This study is first report in use of real-time PCR for diagnosis and identification of Leishmania spp. in Iran. Up to now, in Iran, the majority of identification of Leishmania species is restriction fragment length polymorphism (PCR-RFLP) of ITS1 and kinetoplast DNA. Our data showed that Giemsa-stained slides that were stored more than 3 years, can be use for Leishmania DNA extraction and amplification by real-time PCR. Compared to conventional PCR-based methods, the real-time PCR is extremely rapid with results and more samples can be processed at one time.

Detection of IgM and IgG anti-Toxoplasma antibodies in renal transplant recipients using ELFA, ELISA and ISAGA methods: comparison of pre- and post-transplantation status

In the transplant recipient patients receive immunosuppressive therapy, the possibility of reactivation of the old infection or acquisition of infection from a donor's tissue increases. In this study, IgM and IgG anti-Toxoplasma immunoglobulins seroconversion in renal transplant recipients (RTRs) have been evaluated before and after transplantation. This is a prospective cohort study on a total of 102 RTRs. Two serum samples were obtained from each patient. The first was taken before administration of any immunosuppressive drugs such as corticosteroids and the second was taken 3 months after transplantation. The IgM and IgG anti-Toxoplasma antibodies were assayed by enzyme-linked flourescence assay (ELFA) and enzyme-linked immunosorbent assay (ELISA) techniques. IgM/immunosorbent agglutination assay (ISAGA) method has also been used. All RTRs were tested for toxoplasmosis before and after transplantation. ELFA identified 65 (63·7%) pre-transplantation samples as IgG+ and did not detect any positive IgM samples. However, IgM was detected in three (2·9%) post-transplantation samples by this method. Forty-nine (48%) pre-transplantation samples were reported IgG+ by ELISA and no IgM positive sample was identified by this method. ELISA has detected two (1·9%) IgM-positive reactions in post-transplantation samples. By IgM/ISAGA method, we have detected no IgM positive reactions in pre-transplantation samples, whereas 3 months later (second sampling) IgM antibody was detected in 3 (2·9%) cases. Secondary toxoplasmosis infection was observed in 30 cases per 1000 RTRs, which indicates that screening for toxoplasmosis infection should be performed in developed countries for these patients. On the other hand, as the risk of re-active toxoplasmosis infection exists in developing nations, they should consider the necessary preventive measures to control this condition.