José Antonio de Diego

Protective effect of Trypanosoma rangeli against infections with a highly virulent strain of Trypanosoma cruzi

Summary We investigated the protective effect of Trypanosoma rangeli against infection with Trypanosoma cruzi in animal models of various ages and with different doses of inoculum. The age of the mice and the dose of parasites determined the course of the infection. When T. cruzi was inoculated into mice after challenge with T. rangeli, parasitaemia was more controlled, mortality decreased and histopathology showed lower inflammatory infiltration and pseudocysts. This study proposes a new murine model of the protective effect of recombinant proteins of T. rangeli for possible application in the vaccines field.

Natural infection and distribution of triatomines (Hemiptera: Reduviidae) in the state of Querétaro, Mexico

Chagas disease is present in Mexico but data on the presence of its vectors are not known for all the states. We conducted an epidemiological study to ascertain the presence of bedbugs in 23 communities of seven municipalities in the state of Querétaro, Mexico. Sampling was performed within and outside dwellings, using the technique of one person searching per hour per house. Four triatomine species were found: Triatoma mexicana (94%), Tri. dimidiata (3%), Tri. gerstaeckeri (2%) and Tri. pallidipennis (1%). Triatoma mexicana was found in six of the seven municipalities but has previously been found only in the state of Hidalgo, where it is considered the most important vector species of Trypanosoma cruzi. This is the first time that the presence of Tri. gerstaeckeri or Tri. dimidiata has been reported in the state of Querétaro. Tolimán municipality had the highest entomological indices: infestation index 73%; infection index 34.5%; crowding index 9.2%; density index 6.7%; and colonization index 20.6%. Although the prevalence and colonization indices were low, the infestation and infection indices indicate that different Triatoma species are becoming established in Querétaro. This work represents the first entomological study in this Mexican state and suggests that some triatomine vectors are extraordinarily mobile.

Trypanosoma cruzi: seroprevalence detection in suburban population of Santiago de Queretaro (Mexico).

Objectives. To evaluate the potential of iron-oxide dismutase excreted (SODeCRU) by T. cruzi as the antigen fraction in the serodiagnosis of Chagas disease and compile new epidemiological data on the seroprevalence of this disease in the suburban population of the city of Santiago de Querétaro (Mexico). Design and Methods. 258 human sera were analyzed by the techniques of ELISA and Western blot and using the homogenate and the SODeCRU. Results. A total of 31 sera were positive against ELISA/SODeCRU (12.4%), while 30 sera proved positive by WB/SODeCRU (11.6%). The comparison between the technique of ELISA and WB showed a sensitivity of 93%, and a specificity of 99%. The positive predictive value was 93% and the negative predictive value was 99%, with a Kappa (κ) value of 1. Conclusions. These preliminary data reveal the degree of infection of nonrural areas of Mexico and demonstrated that SODeCRU is an antigen useful to diagnose Chagas disease.

Trypanosoma rangeli infected mouse sera reactivity with Trypanosoma cruzi synthetic peptides

In man, differential diagnosis of Trypanosoma cruzi and Trypanosoma rangeli infections represents a serious problem, not only because both parasites present similar geographical distribution, the same hosts and sometimes the same insect vector, but also because they have common antigen determinants. In this work IgM and IgG humoral responses to T. cruzi syntethic peptides in mice infected with T. cruzi and with T. rangeli were analysed. In a immunoradiometric assay ( IRMA ) 6 syntethic peptides were used, denominated as clones 1, 2, SAPA, 13, 30 and 36. The results showed that sera from infected mice with T. rangeli recognized all peptides derived from T. cruzi proteins, at IgM as well as IgG level. Reactivity with peptide SAPA is discussed as previous work indicated that SAPA is not codified in the T. rangeli genome. Our results support the suggestion that crossed reactions are due to the fact that both parasites present common antigens.