Prediction of malaria cases in the southeastern Iran using climatic variables: An 18-year SARIMA time series analysis

Objective: To predict future trends in the incidence of malaria cases in the southeast of Iran as the most important area of malaria using Seasonal Autoregressive Integrated Moving Average (SARIMA) model, and to check the effect of meteorological variables on the disease incidence. Methods: SARIMA method was applied to fit a model on malaria incidence from April 2001 to March 2018 in Sistan and Baluchistan province in southeastern Iran. Climatic variables such as temperature, rainfall, rainy days, humidity, sunny hours and wind speed were also included in the multivariable model as covariates. Then, the best fitted model was adopted to predict the number of malaria cases for the next 12 months. Results: The best-fitted univariate model for the prediction of malaria in the southeast of Iran was SARIMA (1,0,0)(1,1,1)12 [Akaike Information Criterion (AIC)=307.4, validation root mean square error (RMSE)=0.43]. The occurrence of malaria in a given month was mostly related to the number of cases occurring in the previous 1 (p=1) and 12 (P=1) months. The inverse number of rainy days with 8-month lag ( =0.329 2) and temperature with 3-month lag ( =-0.002 6) were the best predictors that could improve the predictive performance of the univariate model. Finally, SARIMA (1,0,0)(1,1,1)12 including mean temperature with a 3-month lag (validation RMSE=0.414) was selected as the final multivariable model. Conclusions: The number of malaria cases in a given month can be predicted by the number of cases in the prior 1 and 12 months. The number of rainy days with an 8-month lag and temperature with a 3-month lag can improve the predictive power of the model.

Serologic Tests of IgG and IgM Antibodies and IgG Avidity for Diagnosis of Ocular Toxoplasmosis

This prospective study was aimed to detect acute and chronic ocular toxoplasmosis by comparison of anti-Toxoplasma gondii IgM and IgG antibody levels and IgG avidity test. One hundred and seventeen patients with ocular toxoplasmosis (OT) who referred to the Farabi Eye Hospital, Tehran, Iran were included in this study. Of the patients, 77 cases were positive for anti-T. gondii IgG, and 8 cases were positive for anti-T. gondii IgM. IgG avidity test revealed 11, 4, and 102 cases were low, intermediate, and high, respectively, and 6.8% and 9.4% of cases were positive for IgM and IgG avidity tests, respectively (P=0.632). Agreement (Kappa value) between paired tests IgG-IgM, IgG-IgG avidity, and IgM-IgG avidity was 0.080, 0.099, and 0.721, respectively (P < 0.05). This study showed that conventional serologic tests (IgM and IgG levels) and IgG avidity correlate well each other and can be used to differentiate recent infections from old OT. It seems that reactivated old infections rather than recently acquired infections are majority of Iranian OT patients.

Visceral Leishmaniasis in Rural Areas of Alborz Province of Iran and Implication to Health Policy

Visceral leishmaniasis (VL) or kala-azar mainly affects children in endemic areas. This study was conducted to determine the seroprevalence of VL using direct agglutination test (DAT) in children living in rural districts of Alborz Province located 30 km from Tehran capital city of Iran. Multi-stage cluster random sampling was applied. Blood samples were randomly collected from 1,007 children under 10 years of age in the clusters. A total of 37 (3.7%) of the studied population showed anti-Leishmania infantum antibodies with titers of > or =1:800. There was a significant association between positive sera and various parts of the rural areas of Alborz Province (P or =1:3,200 indicated kala-azar clinical features and treated with anti-leishmaniasis drugs in pediatric hospital. The findings of this study indicated that Leishmania infection is prevalent in rural areas of Alborz Province. Therefore, it is necessary to increase the awareness and alertness among physicians and public health managers, particularly in high-risk rural areas of the province in Iran.

In vitro and in vivo potential of RH strain of toxoplasma gondii [type I] in tissue cyst forming

Based on recent studies, there are controversial reports on the capacity of tissue cyst forming of Toxoplasma gondii RH strain. In this study, the capacity was evaluated by in vivo and in vitro experiments. RH strain was subcutaneously inoculated to ten Wistar rats. After one month, their blood, brain, tongue and diaphragm were collected and evaluated by MAT, PCR, pathological and bioassay methods. The parasite was cultivated in the cell monolayer. To change to bradyzoite, the media pH was altered to 6.8. Biological aspect of the bradyzoites was evaluated by incubation in acidic pepsin and it's inoculation in ten BALB/c mice. All rats showed antibodies to Toxoplasma at titers >/= 1:320 but no DNA and tissue cyst were detected in the tissues. Following intraperitoneal inoculation of rats' brain homogenate into BALB/c mice, no infection was established in none of the animals. During presence of cell culture, in acid media for a 3-5 days period, cyst-like structures were noticed when they were stained with PAS. The visible bradyzoites in the cysts that were incubated in acid pepsin medium were not able to kill any mice. This study confirmed that Iranian RH strain has lost the potential of tissue cyst forming in rats and bradyzoites cultivated in cell culture lost their resistance to acidic condition, so this strain can be a candidate for future vaccine researches

Preparation and evaluation of a glycerol-preserved direct agglutination antigen for long-term preservation: a comparative study of the detection of anti-Leishmania infantum antibodies in human and dog

OBJECTIVE@#To prepare and evaluate a glycerol-preserved antigen from an Iranian strain of Leishmania infantum (L. infantum) for use in glycerol-preserved direct agglutination tests (GP-DAT) as an alternative to freeze dried direct agglutination tests (FD-DAT) that use freeze-dried antigen.@*METHODS@#Glycerol-preserved DAT antigen was prepared and stored at different temperatures. We tested antigen stored at 4 °C, 22-37 °C and 50 °C over a period of 365 days. Seven hundred twenty-nine serum samples were collected from different geographical zones of Iran from 2007-2009, and 80 of these samples were pooled to produce sera. Each pooled serum contained 10 sera. All positive and negative pooled sera were separately tested for anti-L. infantum antibodies with GP-DAT, FD-DAT and formaldehyde-fixed direct agglutination test (FF-DAT) antigens; tests were performed on both human and dog sera over a period of 12 months.@*RESULTS@#There was strong agreement between the results obtained using GP-DAT and FD-DAT antigens stored at 22-37 °C for 12 months for both human (100%) and dog (100%) pooled sera. The direct agglutination test results were highly reproducible (weighted kappa: GP=0.833, FD=0.979 and FF=0.917).@*CONCLUSIONS@#Because GP-DAT antigen is highly stable over a range of temperatures and is easy to transport in the field, this type of antigen may be particularly useful in areas with endemic visceral leishmaniasis.

Spatial outline of malaria transmission in Iran

OBJECTIVE@#To conduct for modeling spatial distribution of malaria transmission in Iran.@*METHODS@#Records of all malaria cases from the period 2008-2010 in Iran were retrieved for malaria control department, MOH&ME. Metrological data including annual rainfall, maximum and minimum temperature, relative humidity, altitude, demographic, districts border shapefiles, and NDVI images received from Iranian Climatologic Research Center. Data arranged in ArcGIS.@*RESULTS@#99.65% of malaria transmission cases were focused in southeast part of Iran. These transmissions had statistically correlation with altitude (650 m), maximum (30 °C), minimum (20 °C) and average temperature (25.3 °C). Statistical correlation and overall relationship between NDVI (118.81), relative humidity (⩾45%) and rainfall in southeast area was defined and explained in this study.@*CONCLUSIONS@#According to ecological condition and mentioned cut-off points, predictive map was generated using cokriging method.

Real-Time RT-PCR on SAG1 and BAG1 Gene Expression during Stage Conversion in Immunosuppressed Mice Infected with Toxoplasma gondii Tehran Strain

Toxoplasmic encephalitis is caused by reactivation of bradyzoites to rapidly dividing tachyzoites of the apicomplexan parasite Toxoplasma gondii in immunocompromised hosts. Diagnosis of this life-threatening disease is problematic, because it is difficult to discriminate between these 2 stages. Toxoplasma PCR assays using gDNA as a template have been unable to discriminate between an increase or decrease in SAG1 and BAG1 expression between the active tachyzoite stage and the latent bradyzoite stage. In the present study, real-time RT-PCR assay was used to detect the expression of bradyzoite (BAG1)- and tachyzoite-specific genes (SAG1) during bradyzoite/tachyzoite stage conversion in mice infected with T. gondii Tehran strain after dexamethasone sodium phosphate (DXM) administration. The conversion reaction was observed in the lungs and brain tissues of experimental mice, indicated by SAG1 expression at day 6 after DXM administration, and continued until day 14. Bradyzoites were also detected in both organs throughout the study; however, it decreased at day 14 significantly. It is suggested that during the reactivation period, bradyzoites not only escape from the cysts and reinvade neighboring cells as tachyzoites, but also converted to new bradyzoites. In summary, the real-time RT-PCR assay provided a reliable, fast, and quantitative way of detecting T. gondii reactivation in an animal model. Thus, this method may be useful for diagnosing stage conversion in clinical specimens of immunocompromised patients (HIV or transplant patients) for early identification of tachyzoite-bradyzoite stage conversion.

Production and Evaluation of Toxoplasma gondii Recombinant GRA7 for Serodiagnosis of Human Infections

The precise diagnosis of the acute toxoplasmosis in pregnant women and immunocompromsied patients has critical importance. Most of the commercially available assays use the whole Toxoplasma soluble extract as the antigen. However, the assays currently available for the detection of specific anti-Toxoplasma antibodies may vary in their abilities to detect serum immunoglobulins, due to the lack of a purified standardized antigen. The aim of this study was production and evaluation of the usefulness of the recombinant Toxoplasma gondii GRA7 antigen for the serodiagnosis of Toxoplasma gondii IgM and IgG by ELISA. A total of 70 T. gondii IgM positive sera, 74 T. gondii IgG positive sera, and 60 sera from subjects who were not infected with T. gondii were examined. These sera were shown different absorbance values in ELISA test. To control the specificity of the rGRA7 other parasitic diseases, for example, echinococcosis, malaria, leishmaniasis, fascioliasis, and strongyloidiasis were tested of which none showed positive results. Sensitivity and specificity of the generated recombinant IgG ELISA in comparison with commercial ELISA (com ELISA) were 89% and 90%, and the sensitivity and specificity of the generated recombinant IgM ELISA were 96% and 90%, respectively. The results obtained here show that this antigen is useful for diagnostic purposes.

[Phenotyping of peripheral memory T cell subsets in cutaneous leishmaniasis]

The heterogenous population of memory T lymphocytes is distinguished based on surface markers and effector functions such as cytokine secretion. Recently, two subsets of memory T cells are defined by expression of chemokine receptor CCR7 and CD45RA designating as "central memory" T cells [TCM] and "effector memory" T cells [TEM]. The objective of this study was to evaluate the phenotype and function of these lymphocytes in healed cases of cutaneous leishmaniasis. The phenotype of lymphocytes were determined in blood samples of 13 volunteers with history of self healing cutaneous leishmaniasis [HCL] and in 6 healthy controls. No significant difference was found in memory T cell subsets between HCL volunteers and healthy controls using flow cytometry. However, following sorting of different memory subsets, a significantly higher proliferation was seen in cells of HCL volunteers comparing to the control group. A significantly higher IFN-gamma response in TEM and a significantly higher IL-2 response in TCM were observed in cell culture of HCL volunteers comparing controls. The responses were elicited when the cells were stimulate with SLA in vitro, it is concluded Leishunania-specific TEM and Leishmania-specific TEM subsets exist in HCL volunteers and since the volunteers with history of CL presumed to be protected against reinfection, it seems that both TCM and TEM play role in the protection against Leishmania infection in these individuals

Genetic diversity in merozoite surface protein (MSP)-1 and MSP-2 genes of Plasmodium falciparum in a major endemic region of Iran

Merozoite surface protein-1 (MSP-1) and merozoite surface protein-2 (MSP-2) were used to develop vaccines and to investigate the genetic diversity in Plasmodium falciparum malaria in Iran. Nested polymerase chain reaction amplification was used to determine polymorphisms of block 2 of the MSP-1 and the central domain of MSP-2 genes. A total of 67 microscopically positive P. falciparum infected individuals from a major endemic region, southeast Iran, were included in this trial. Nine alleles of MSP-1 and 11 alleles of MSP-2 were identified. The results showed that amplified product from these surface antigen genes varied in size and there was specific pattern for each isolate. Besides, regarding this pattern, 23 multiple infections with at least 2 alleles were observed. While the endemic regions of malaria in Iran is classified in low to moderate group, but extensive polymorphism was observed for each marker and the MSP-2 central repeat was the most diverse that could be considered in designing malaria vaccine.

Genetic diversity in merozoite surface protein (MSP)-1 and MSP-2 genes of Plasmodium falciparum in a major endemic region of Iran

Merozoite surface protein-1 (MSP-1) and merozoite surface protein-2 (MSP-2) were used to develop vaccines and to investigate the genetic diversity in Plasmodium falciparum malaria in Iran. Nested polymerase chain reaction amplification was used to determine polymorphisms of block 2 of the MSP-1 and the central domain of MSP-2 genes. A total of 67 microscopically positive P. falciparum infected individuals from a major endemic region, southeast Iran, were included in this trial. Nine alleles of MSP-1 and 11 alleles of MSP-2 were identified. The results showed that amplified product from these surface antigen genes varied in size and there was specific pattern for each isolate. Besides, regarding this pattern, 23 multiple infections with at least 2 alleles were observed. While the endemic regions of malaria in Iran is classified in low to moderate group, but extensive polymorphism was observed for each marker and the MSP-2 central repeat was the most diverse that could be considered in designing malaria vaccine.

Evaluation of protectivity and immunogenicity of alum precipitated autoclaved Leishmania major vaccine mixed with Mycobacterium vaccae in the murine model of leishmaniasis

Leishmaniases represent a group of diseases caused by protozoan parasite of the genus Leishmania. Control strategies are not always effective, it seems that the sole control measure is to search for an effective vaccine. The objective of this study was evaluation of the rate of protection and immune response induction in Balb/c mice immunized with alum precipitated autoclaved Leishmania major [Alum-ALM] vaccine mixed with M. vaccae. Eleven groups of female 8-10 week old Balb/c mice were immunized subcutaneously [SC] three times, 21 days apart, with different doses of Alum-ALM mixed with different doses of either M. vaccae or BCG. The immunized animals and control group were challenged with 1 x 10 [6] L. major. Development and progression of leishmania infection were assessed by footpad swelling measurement at the site of challenge and parasite burden in lymph nodes. The immune responses of vaccinated animals were evaluated in vivo by leishmanin skin test [LST] and in vitro by measurement of cytokine [IFN-lamda and IL-4] levels in mononuclear cell culture] supernatants and titration of serum anti-leishmania antibodies [IgG and its sub-classes]. Footpad thickness measurment after challenge with live L. major showed no significant difference between immunized groups and control group. However, there were some prominent exceptional cases in the parasite burden titration in groups 1, 4, 6, and 8. Immunization with low dose of Alum-ALM mixed with M. vaccae or BCG induced IFN-lamda production, and diminished IL-4 level [in vitro], and caused a stronger LST response in a group that received BCG as an adjuvant. Mice that were immunized with high doses of Alum-ALM mixed with high doses of M. vaccae showed an increase in footpad thickness at the site of challenge and higher levels of IL-4 and IgGl. It seems that immunization of mice with a low dose of Alum-ALM mixed with M. vaccae as an adjuvant might induce a Thl type response. M.vaccae mixed with low dose of Alum-ALM has an inhibitory influence on the parasite burden in the infected tissues of mice. Also, BCG mixed with different doses of Alum-ALM induces a Thl immune response in Balb/c mice. Apparently, there is no significant difference in adjuvancity of BCG and M. vaccae. High dose of Alum-ALM mixed with high dose of M. vaccae induces a Th2 response

prevalence of intestinal parasites in afghan refugees in Kerman City, Iran

Single stool specimens were obtained from the subjects at the referral center for refugees in Kerman city during spring and fall seasons of 1993. Specimens were processed within 1-2 hours of receipt by the formalin-ether concentration method. The overall prevalence of infection was 23.7% for one or more species of intestinal parasites. The common parasites were Giardia lamblia, 15.2%; Hymenolepis nana, 5.2%, Entamoeba histolytica, 2.5%, and Ascoris lumbricoides, 0.8 perecnt. In general the difference in the distribution of parasites between females and males was not significant