Estimación del impacto económico de la equinococosis quística en Chile y análisis de las posibles causas que han dificultado su erradicación / Estimation of costs caused by cystic echinococcosis

Background: Hydatid disease or cystic echinococcosis, caused by the parasite Echinococcus granulosus, has a worldwide distribution, affecting people of working age and can cause high levels of morbidity and even death. Aim: To estimate the economic impact at the human and animal level caused by the disease in Chile. Material and Methods: We analyzed information about the disease obtained from reports and publications emanated from the Chilean Ministry of Health, United Nations Food and Agriculture Organization, the U.S. National Institute of Statistics and the National Agricultural Service. Animal derived costs were estimated evaluating the expenses for pharmacological treatment of infected dogs and animal production losses derived from confiscations and reductions in meat production. Results: The total number of patients who underwent surgery to remove a hydatid cyst in Chile during 2012, was estimated as 767 individuals. The annual costs derived only from surgical treatment, were estimated in USD 2.46 million. Summing the costs of sick leaves and loss of productivity, the costs at the human level ascended to USD 3.13 million. Considering human and animal costs, the annual economic burden of the disease was estimated in USD 14.35 million. Conclusions: The Analysis of the regional distribution of human and animal hydatidosis, suggests a significant environmental contamination with parasite eggs in high incidence regions such as Aysén, Araucanía, BioBío and Coquimbo. The efficiency of control programs for the disease would be greatly improved if the causes for these regional contaminations are elucidated.

Inmunofenotipificación de linfocitos en sangre periférica de pacientes chagásicos crónicos chilenos mediante citometría de flujo / Immnunophenotyping by flow cytometry of peripheral blood lymphocytes from Chilean chronic chagasic patients

Background: Cellular immune mechanisms of the resistance to infection by T cruzi as well as the pathogenesis of Chagas disease are still controversial. Aim: To quantify and analyse the peripheral blood immune cells from chagasic and non chagasic patients by flow cytometry. Patients and methods: Peripheral blood samples were taken from 21 individuals seropositive for Chagas disease, under no specific treatment. Control samples from 21 healthy blood donors were also obtained. To quantify immune cells populations by flow cytometry, antibodies against CD3, CD4, CD8, CD16/56, CD45/14, CD19 and HLA-DR markers were used. Results: The percentage of CD8+ cells was low and the CD4+/CD8+ ratio was high in chagasic patients, compared to their non infected counterparts. No statistically significant differences in the number of CD4+, NK, B, CD4+HLADR+ and CD8+HLADR+ cells, were observed within the two groups. Conclusions: These results show that Chilean chronic chagasic patients have lower percentage of CD8+ cells and higher CD4+/CD8+ ratio than non infected individuals

Studies on parasitemia courses and mortality in mice infected with genetically distant Trypanosoma cruzi clonets

The biological characterization of bloodstream forms of eleven Trypanosoma cruzi cloned stocks, corresponding to two genetically similar clonets (19 and 20) and one distant clonet (39), according to multilocus enzyme electrophoresis analysis, showed dissimilar parasitemia in an experimental isogenic mouse model. While clonet 39 stocks gave low parasitemias, clonets 19 or 20 stocks gave high parasitemias, independently of the inocula (102 and 104 bloodstream forms) used. High parasitemia did not always associate with greater mortality. Statistical studies on mortality using a low inocula showed significantly higher mortality with clonet 39 stocks when compared to clonets 19 or 20 stocks. Finally, in order to confirm the identity of each stock studied, typing by molecular karyotype was performed before inoculating mice.

Characterization of Trypanosoma cruzi populations by several molecular markers supports a clonal mode of reproduction

Chilean T. cruzi populations from different endemic areas and transmission cycles were characterized at several biochemical levels, to mention: hybridization with kinetoplast DNA probes, molecular karyotype, isoenzyme studies and kinetoplast DNA restriction fragment length polymorphism. Furthermore, an immunological approach with immune sera from Balb/c infected mice with different T. cruzi populations was used to differentiate among parasite types by the in vitro complement-mediated lysis assay. Parasite grouping by the above described methods allows to classify T. cruzi populations on a very defined number, suggesting that they have a clonal structure