Socioeconomic determinants of global distribution of multiple sclerosis: an ecological investigation based on Global Burden of Disease data.

BACKGROUND: Socioeconomic factors may be involved in risk of multiple sclerosis (MS), either indirectly or as confounding factors. In this study two comprehensive indicators reflecting socioeconomic differences, including the Human Development Index (HDI) and Prosperity Index (PI), were used to assess the impact of these factors on the worldwide distribution of MS. METHODS: The data for this global ecological study were obtained from three comprehensive databases including the Global Burden of Disease (as the source of MS indices), United Nations Development Programme (source for HDI) and the Legatum Institute Database for PI. MS indices (including prevalence, incidence, mortality, and disability-adjusted life years) were all analyzed in the form of age- and sex-standardized. Correlation and regression analyses were used to investigate the relationship between HDI and PI and their subsets with MS indices. RESULTS: All MS indices were correlated with HDI and PI. It was also found that developed countries had significantly higher prevalence and incidence rates of MS than developing countries. Education and governance from the PI, and gross national income and expected years of schooling from the HDI were more associated with MS. Education was significantly related to MS indices (p < 0.01) in both developed and developing countries. CONCLUSION: In general, the difference in income and the socioeconomic development globally have created a landscape for MS that should be studied in more detail in future studies.

PCR detection and sequencing of parasite ITS-rDNA gene from reservoirs host of zoonotic cutaneous leishmaniasis in central Iran.

Leishmania major is the causative agent of zoonotic cutaneous leishmaniasis (ZCL) in which gerbils are the reservoir host. ZCL is of great public health importance in Iran. In the current investigation, nested polymerase chain reaction (PCR) protocols were used to amplify a region of the ribosomal RNA amplicon of Leishmania (ITS1-5.8S rRNA gene). The PCR assays detected L. major in three rodent species: Rhombomis opimus, Meriones lybicus and, for first time, Meriones persicus. L. major parasite was found in Natanz, Isfahan Province in the center of Iran in a focus of rural zoonotic cutaneous leishmaniasis. Four L. major infections were detected in R. opimus species, three in M. Lybicus, and two in M. persicus. All nine rodent infections of L. major were found to be the same haplotype based on the PCR detection and sequencing of parasite ITS-ribosomal DNA gene. In addition, also for the first time, the nested PCR assays detected Leishmania tropica only in one M. persicus. Allied to studies in country, the new findings mean that past conclusions about the reservoir of L. major in Iran must be treated with caution. Finding two Leishmania species in different rodent species as reservoir in Iran, therefore, careful molecular eco-epidemiological investigations will be an essential part of modeling the roles of different gerbil species in maintaining and spreading ZCL foci.