ABSTRACT The antigenic potential of seven immunogenic peptides of the dengue virus was evaluated in the sera of patients with dengue confirmed by IgM/IgG serology. Antibodies IgM and IgG against dengue virus peptides were analyzed by ELISA in 31 dengue sero-positive and 20 sero-negative patients. The P5 peptide showed significant IgG immunoreactivity mostly in the sera of patients with dengue without warning signs in comparison with patients with dengue with warning signs, correlating with mild disease. This finding suggests that the low antibody response against P5 epitope could be a risk factor for higher susceptibility to dengue virus infection with warning signs, and that P5 could be a potential antigen for vaccine development.

Chagas disease prevention remains mostly based on triatomine vector control to reduce or eliminate house infestation with these bugs. The level of adaptation of triatomines to human housing is a key part of vector competence and needs to be precisely evaluated to allow for the design of effective vector control strategies. In this review, we examine how the domiciliation/intrusion level of different triatomine species/populations has been defined and measured and discuss how these concepts may be improved for a better understanding of their ecology and evolution, as well as for the design of more effective control strategies against a large variety of triatomine species. We suggest that a major limitation of current criteria for classifying triatomines into sylvatic, intrusive, domiciliary and domestic species is that these are essentially qualitative and do not rely on quantitative variables measuring population sustainability and fitness in their different habitats. However, such assessments may be derived from further analysis and modelling of field data. Such approaches can shed new light on the domiciliation process of triatomines and may represent a key tool for decision-making and the design of vector control interventions.

The neglected tropical diseases (NTDs) represent a group of chronic parasitic and related infections that promote poverty because of their impact on child development, pregnancy, and worker productivity. The estimated 20 million Mexicans who live below the poverty line suffer disproportionately from a high prevalence of neglected tropical diseases such as amebiasis, Chagas disease, dengue, leishmaniasis, soil-transmitted helminth infections, trachoma, and vivax malaria. However, because the NTDs occur predominantly among the poor, new industrial and financial models are required to establish innovative technologies to address these conditions in Mexico and elsewhere in Latin America. In response, the Slim Initiative for Antipoverty Vaccine Development was established to foster a public/private partnership between key academic, government, and industrial institutions in the U.S. and Mexico. Initial emphasis will be placed on developing new vaccines for Chagas disease and leishmaniasis, two of the highest burden NTDs in Mexico and Mesoamerica.

In most countries, Chagas disease transmission control remains based on domestic insecticide application. We thus evaluated the efficacy of intra-domicile cyfluthrin spraying for the control of Triatoma dimidiata, the only Chagas disease vector in the Yucatán peninsula, Mexico, and monitored potential re-infestation every 15 days for up to 9 months. We found that there was a re-infestation of houses by adult bugs starting 4 months after insecticide application, possibly from sylvatic/peridomicile areas. This points out the need to take into account the potential dispersal of sylvatic/peridomestic adult bugs into the domiciles as well as continuity action for an effective vector control.

Chagas' disease, caused by the protozoan parasite Trypanosoma cruzi, represents a major public health problem in most of the American continent. As transmission of the parasite is being interrupted in most of South America, the disease remains endemic in various areas of Mexico. We review here some of the information gathered in recent years. Seroprevalence of T. cruzi infection in humans remains relatively high in some areas, and there has been a general increase in the number of chronic cases reported to health authorities in recent years. In fact, chronic chagasic cardiomyopathy appears to be affecting a large number of patients with heart disease, but many cases may be misreported because of the unspecific nature of the clinical symptoms. Epidemiological monitoring of vector and reservoir populations, as well as of human cases is helping focus on endemic areas, but a better coordination and development of these efforts is still needed. Recent studies of parasite biology are in agreement with previous work showing the great diversity of parasite characteristics, and support the need for a regional approach to this zoonosis. Strong and continuing support from health and academic authorities is thus still needed to further improve our understanding of Chagas' disease in Mexico and implement efficient control programs.

La enfermedad de Chagas, causada por el parásito protozoario Trypanosoma cruzi, constituye un importante problema de salud pública en el continente americano. La transmisión del parásito se ha ido interrumpiendo en la mayor parte de América del Sur, pero la enfermedad sigue siendo endémica en varias regiones de México. En este artículo se revisa la información más reciente sobre dicha enfermedad. La seroprevalencia de la infección por T. cruzi se ha mantenido a niveles relativamente altos en algunas regiones, y se observa un aumento general en el número de casos reportados a las autoridades de salud en los últimos años. La cardiomiopatía chagásica crónica parece afectar a muchos pacientes con enfermedad cardiaca, pero aparentemente muchos casos no se reportan debido a la ausencia de especificidad del cuadro clínico. El monitoreo epidemiológico de las poblaciones de vectores y reservorios, así como de los casos humanos, contribuye a enfocar estudios en las zonas endémicas, pero se requiere de un mayor avance y coordinación de estos esfuerzos. Estudios sobre la biología del parásito coinciden con trabajos previos que demuestran la gran diversidad de las características del parásito, y apoyan la necesidad de estudios regionales de esta zoonosis. Es necesario un fuerte apoyo continuo por parte de las autoridades de salud y académicos para enriquecer nuestro conocimiento sobre la enfermedad de Chagas en México y desarrollar programas eficaces de control.