Journal of School of Public Health and

Toxoplasmosis is a common disease caused by the protozoal parasite Toxoplasma gondii. Most human cases occur by 1) eating raw or undercooked meat containing T. gondii tissue cysts. 2) ingestion of oocysts from soil and 3) vertical transmission through the placenta. Immunocompetent adults are usually asymptomatic or present with self-limited fever and lymphadenopathy. Infection acquired during pregnancy can be transmitted to the fetus and may cause mental retardation, blindness, epilepsy, and abortion. In this cross-sectional study we determined the prevalence of toxoplasma infection in residents of Meshkin-Shahr in 2001-2002. We applied a cluster sampling method to family health files in local health centers to recruit a total of 909 individuals for this study. All family members were requested to complete the study&aposs questionnaire. For each individual, two separate blood samples were collected and placed in microhematocrite tubes. Titers of anti-toxoplasma antibodies were measured by IFA with levels in excess of 1/20 taken as positive. Questionnaire information and examination results were analyzed by the SPSS software package using chi-square tests. Results of this survey show the overall prevalence of toxoplasma infection to be around 18.3%. Figures for men and women were 19.7% and 17.2%, respectively but the difference was not statistically significant. Prevalence rates show a significant association with age (greater prevalence in higher age groups) and the type of meat consumed (P<0.05). But there were no significant associations with education level, occupation-keeping cats in the house, ingestion of meat and history of previous abortions. The most frequently occurring antibody titer was 1/20 (6.9%). and frequency decreased with higher antibody titers.
This study shows that toxoplasma infection is not as common in Meshkin-Shahr as in some parts of the country, with more than 80% of individuals being seronegative. Because of the low immunity level and the risk of vertical transmission, educating the public in prevention methods could be very important.

Toxoplasmosis is a zoonosis of broad geographic distribution. This disease is caused by infection with the protozoan parasite Toxoplasma gondii. The most important ways to diagnose the disease are the serological techniques such as IFA and ELISA. The aim of this consideration, was comparison between the two methods, IFA and ELISA, in order to determine the incidence of antibody against Toxoplasma in pregnant women. In this descriptive-cross sectional study, from 600 pregnant woman whom have referred to Alzzahra and Izadi maternity hospitals of Qom, during four months (from Sep.2001 to Jan.2002), the specimen of blood have been prepared. After bloodletting and parting of serum, IFA and ELISA have tested its specimens. From 600 specimens of serum, from the tested mothers by IgG-ELISA method, 257 individuals (%42.8) and by IgG-IFA method, 246 individuals (%41) had Specific IgG antibody. Also, The comparison between the two methods, IFA and ELISA, demonstrates that 246 cases (%41) were positive in both methods, and 343 cases (%57.2) were negative in both methods, and only 11 cases (%1.8) were positive in ELISA and negative in IFA technique. In this study, the effect of different factors has been studied, in which deal with the prevalence rate of Toxoplasma infection. Although, these results shows that transmission of Toxoplasma infection in this city, like other parts of world and Iran has been done, but considerable percent of pregnant women (%57.2 by ELISA method and %59 by IFA method) lacking any type of acquired immunity against of this infection. Therefore, considering secure status and accomplishing exclusive experiments before marriage and also training and informing the people of region especially pregnant women with educational programs and supervision in pregnant period is necessary. On the other hand, with regard to the rate of concordance of the two tests (%98.2), The ELISA because of its high sensitivity and specificity, easier technique and lower expense it is preferred in order to screening Toxoplasma infection.

Background and Aim: Case-Control studies provide evidence in the area of health. Validity and accuracy of such studies depend to a large extent on the similarity (similar distributions) of the case and control groups according to confounding variables. Matching is a method for controlling or eliminating the effects of important confounders. Matching using propensity score has recently been introduced to control the effect of confounders, especially when there are many of them in a study.

Materials and Methods: Matching according to propensity score was used in a genetic association study-a case-control study involving 300 subjects-to assess the effect of candidate genes on Alzheimer's disease in the Iranian population. Propensity score was calculated using STATA.8 software age, sex, education level, job and genetic background were included in the model to calculate the score.

Results: A total of 385 blood samples were taken from the participants. We managed to extract DNA in 155 of the 173 case subjects and in 161 of the 212 control subjects. The model for propensity score was statistically significant. Of the total of 316 DNA samples, 302 were matched based on their calculated propensity scores, while the individual matching method could only deliver 28 pairs.

Conclusion: The propensity-score matching method results in selection of a larger number of pairs, as compared with the conventional individual matching method. We propose to use this method, which also ensures a similar distribution of confounders between the case and control groups, particularly when there are limitations in the number of subjects available for matching.

Background and Aim: Experience at the national and international levels shows that internal evaluation, especially at the level of academic departments, can play a critical role in warranting having a university with high standards. The objectives of the present research project were to determine (a). the quality of the structural elements of the Epidemiology and Biostatistics Department (EBD) School of Public Health,  Tehran University of Medical Sciences,  and (b). The strengths, weaknesses, opportunities and threats, on the basis of which action could be taken to improve the quality of activities in the Department.

Materials and Methods: The study was conducted with the collaboration of the head and faculty members, all of the students (residents, Ph.D. and M.S. students), and the graduates, of the EBD. Nine variables were studied, namely, 1). Aims and objectives 2). Organizational and management structure 3). Faculty members 4). Students 5). Teaching and learning process 6). Courses and curricula 7). Graduates 8). Research and educational facilities and equipment and 9). Research activities of the faculty members. First the initial weight of the 9 variables were  determined by opinion poll carried out among all the faculty members of EBD. Then unrelated data were identified through proper tests and omitted and the final weights extracted. The tools used to collect the data included interview, observation, and 7 self-prepared questionnaires and 2 check lists.

Results: The mean score for the 9 factors studied was 59.8%, the range being between 37.0% (for objectives and mission) and 72.0% (for graduates).

Conclusion: The graduate domain is one of the key areas in internal evaluation of the Department of Epidemiology and Biostatistics. On the other hand, the lower score for objective and aims domain implicates the need for future intervention in this domain.

Data missing, which occurs for different reasons, is an unavoidable problem in epidemiological studies. It is quite widespread and, therefore, it is considered as a challenge in research design and data analysis by many methodologists. Complete case analysis is often used in studies with missing data however, this approach may result in inaccurate estimates and inferences due to bias associated with missing data. It is possible to obtain more accurate results through data repairing methods. Ordinary, simple strategies, such as single imputation methods, have drawbacks and limitations in practice. It has, however, been demonstrated that using modern imputation techniques can, despite their complexity, reduce bias dramatically in many situations, if used appropriately and properly. In this review, application of multiple imputations, as a novel technique for handling missing data in health and epidemiological research, is briefly discussed

Background and Aim: Malaria threatens more than half of the world's population in about 100 countries. During the period 1921-1951 malaria was one of the most important public health issues in Iran, no other disease causing as much financial loss and mortality as malaria did. The objective of this study was to investigate malaria epidemiology in Iran during the period 1940- 2006 (65 years), in the hope that the infotmation and experience will be used in the future.

Materials and Methods: This study included a review of the available literature on the suject, as well as a study of health systems, existing records, and analysis of data and information on malaria in Iran. Data were colected from three main sources: national or international electronic sources (26 sources) non-electronic sources, including theses, journal articles, and various documents and reports, as well as data obtained from the national malaria surveillance system (a total of 180) and interviews with five informed and expert individuals. In addition, national documents prepared by the Center for Disease Control, Ministry of Health and Medical Education, during the previuos 6 months were made available to, and used by, the research team.

Results: The findings show that, despite several annual fluctuations, the trend of incidence of the disease during the 65-year period, from 1940 to 2006, was a downward trend. The incidence declined from 250-333 per 1000 people in the early 1940's to 0.22 per 1000 people in 2006.

Conclusion: The changes in incidence of malaria show that elimination of malaria is a possible and feasible goal. The experiences achieved in controlling this disease can be utilized for controlling other diseases as well.

Background and Aim: Malaria is still one of the major health problems in comparison with any other parasitic disease in Iran with considerable economic and mortality consequences. Sistan-and-Baluchestan, Hormozgan and Kerman are the most affected provinces in the country approximately 96% of the cases are reported from these three provinces. The aim of this study was to determine the frequency, distribution and rate of parasitaemia of human Plasmodium (P.) species in patients infected with malaria parasites in Kerman province.

Materials and Methods: A total of 92,798 peripheral blood smears were collected from suspected malaria patients during the period 2009-10. Thin and thick blood smears were prepared according to the World Health Organization (WHO) standard procedure. Percentage of parasitaemia was determined based on the number of parasites in the positive slides. The Chi-square test was used for data analysis.

Results: A total of 571 samples were found to contain human Plasmodium species, including 523, 44, and 4 cases of P. vivax, P. falciparum and mixed infection, respectively. The results also showed that, as compared with the previous year, the total number of P. vivax cases

decreased in 2010 by 33.96%. The highest level of parasitaemia was observed in one of the patients infected with P. falciparum, with 77240 parasites/µl of blood, and the lowest in a patient infected with P. vivax, with 48 parasites/µl of blood. There were no differences between the positive and negative cases as regards parameters such as nationality, habitat or gender (Chi-square, p<0.05).  Furthermore, based on the Mann-Whitney test, there was no significant difference between the mean counts of P. falciparum and P. vivax (p-value = 0.464).

Conclusion: Considering that Iran is in the elimination stage of malaria, patient finding and rapid, timely diagnosis of the disease are very important, particularly cases coming from Pakistan and Afghanistan, helping sustainability of the elimination program.