Non-randomized controlled trial of the long-term efficacy of an Ecohealth intervention against Chagas disease in Yucatan, Mexico.

Non-domiciliated intrusive triatomine vectors are responsible for a low but significant transmission of Trypanosoma cruzi to humans. Their control is a challenge as insecticide spraying is of limited usefulness, and alternative strategies need to be developed for a sustainable control. We performed a non-randomized controlled trial of an Ecohealth intervention based on window insect screens and community participation to reduce house infestation by Triatoma dimidiata in two rural villages in Yucatan, Mexico. Efficacy of the intervention was measured over a three years follow-up period and entomological indicators showed that the proportion of triatomines found inside houses was significantly reduced in houses with insect screens, which effectively kept more bugs on the outside of houses. Using a previously developed model linking entomological data to the prevalence of infection in human, we predicted that the intervention would lead to a 32% reduction in yearly incidence and in the prevalence of T. cruzi infection. The cost for the coverage of all the windows of a house was of comparable magnitude to what families currently spend on various domestic insecticide, and most screens were still in good conditions after three years. In conclusion, the Ecohealth approach proposed here is effective for the long-term and sustainable control of intrusive T. dimidiata vectors in the Yucatan peninsula, Mexico. This strategy may also be easily adapted to other intrusive triatomine species as well as other regions/countries with comparable eco-epidemiological settings, and would be an excellent component of a larger integrated program for the control of a variety of other vector-borne diseases, bringing additional benefits to the communities. Our results should encourage a further scaling-up of our implementation strategy in additional villages in the region.

An innovative ecohealth intervention for Chagas disease vector control in Yucatan, Mexico.

BACKGROUND: Non-domiciliated (intrusive) triatomine vectors remain a challenge for the sustainability of Chagas disease vector control as these triatomines are able to transiently (re-)infest houses. One of the best-characterized examples is Triatoma dimidiata from the Yucatan peninsula, Mexico, where adult insects seasonally infest houses between March and July. METHODS: We focused our study on three rural villages in the state of Yucatan, Mexico, in which we performed a situation analysis as a first step before the implementation of an ecohealth (ecosystem approach to health) vector control intervention. RESULTS: The identification of the key determinants affecting the transient invasion of human dwellings by T. dimidiata was performed by exploring associations between bug presence and qualitative and quantitative variables describing the ecological, biological and social context of the communities. We then used a participatory action research approach for implementation and evaluation of a control strategy based on window insect screens to reduce house infestation by T. dimidiata. CONCLUSIONS: This ecohealth approach may represent a valuable alternative to vertically-organized insecticide spraying. Further evaluation may confirm that it is sustainable and provides effective control (in the sense of limiting infestation of human dwellings and vector/human contacts) of intrusive triatomines in the region.

Analysis of children's perception of triatomine vectors of chagas disease through drawings: opportunities for targeted health education.

BACKGROUND: Chagas disease is a tropical parasitic disease affecting about 10 million people, mostly in the Americas, and transmitted mainly by triatomine bugs. Insect vector control with indoor residual insecticides and the promotion of housing improvement is the main control intervention. The success of such interventions relies on their acceptance and appropriation by communities, which depends on their knowledge and perceptions of both the disease and the vector. In this study, we investigated school-aged children's knowledge and perception on triatomine vectors and Chagas disease to further understand how communities view this vector and the disease in Yucatan, Mexico. METHODOLOGY/PRINCIPAL FINDINGS: We performed an analysis of children's drawings on the theme of triatomines and their house in several rural villages, to explore in an open-ended manner their views, understanding and misconceptions. A total of 261 drawings were collected from children ages 6-12 from four villages. We found that children are very familiar with triatomine vectors, and know very well many aspects of their biology and ecology, and in particular their blood-feeding habits. On the other hand, their drawings suggest that the role of triatomines as vectors of a chronic and severe cardiac disease is less understood, and the main perceived health threat appears limited to the bite itself, as previously observed in adults. CONCLUSIONS/SIGNIFICANCE: These results have important implications for the specific design of future education materials and campaigns, and for the promotion of the inclusion of children in raising Chagas disease awareness in these endemic communities.

Tipificación del virus del papiloma humano en mujeres con lesión escamosa intraepitelial de bajo grado / Human Papillomavirus DNA in women having low-grade squamous intraepithelial lesion

El embarazo ectópico bilateral espontáneo es una condición clínica infrecuente que ocurre en 1 de cada 1.580 embarazos ectópicos. En los últimos 25 años se han reportado 72 casos de embarazo ectópico bilateral, 31 de los cuales han sido espontáneos y en ninguno de ellos se ha logrObjetivo: determinar la prevalencia y los genotipos de los papillomavirus humanos (PVH) en mujeres con lesiones escamosas intraepiteliales de bajo grado (LEIBG). Métodos: noventa y seis mujeres de la clínica e colposcopia fueron incluidas. La presencia de los PVH en las biopsias fue determinada por ensayo de reacción en cadena de la polimerasa (RCP) con oligonucleótidos para el gen L1. Las muestras fueron coamplificadas con MY09/MY11/HMB01 e iniciadores para betaglobina GH20/PC04. Para tipificar se utilizó hibridación reversa en línea. Resultados: el ADN de PVH fue detectado en 28/96 (29,1 por ciento) pacientes, de las cuales 21/28 (75 por ciento) tuvieron infección con un sólo tipo y 7/28 (25 por ciento); infección múltiple. En 29/39 (74,3 por ciento) fueron de alto riesgo y 10/39 (25,7 por ciento) de bajo riesgo. Encontramos 13 diferentes tipos 9/13 (69,2 por ciento) de ellos de alto riesgo. PVH 58 fue el tipo más frecuente. Conclusiones: la prevalencia de VPH en mujeres con diagnóstico citológico de LEIBG fue menor que la esperada; este resultado sugiere una clasificación inadecuada de los diagnósticos.

Clinical manifestations of the rotavirus infection and his relation with the electropherotypes and serotypes detected during 1998 and 1999 in Merida, Yucatan, Mexico.

BACKGROUND: Group A rotavirus (RV) is associated with acute infectious diarrhea (AID) in children and adults. The clinical manifestations of RV infection are classified as slight, moderate and severe and could be the results of differing rotaviral serotypes. Attempts have been made to correlate the severity of the infection with specific RV groups, subgroups (SG) serotypes and electropherotypes, but the results have been inconclusive. OBJECTIVE: To correlate the severity of the RV infection with the strains of RV isolated from the patients. STUDY DESIGN: 142 feces were collected from patients with AID caused by RV. The samples were subjected to polyacrylamide gel electrophoresis (PAGE) to determine the electrophoretic pattern and immunoenzymatic assays with monoclonal antibodies specific for serotype, SG and group. The Program EPIINFO 6.0 was used to analyze the correlation. RESULTS: The 142 RV strains isolated were from group A and long electrophoretic pattern. Respect to the symptoms were classified, 43 (30%) as slight; the RV isolates corresponding to these patients were 35 of serotype G1P1A SG II; 4 G1P1A SG I and II; 1 G1P1A SG Non I Non I; 1 G3 SG II; 1 G3 SG Non I and Non II and 1 G3 SG I and II. 89 (53%) of patients showed moderate clinical symptoms. 58 isolates of RV were G1P1A SG II; 11 G1P1A SG Non I Non II; 9 G1P1A SG I and II; 1 G1P1B SG II; 1 G4P1A SG II; 1G1 and G4 SG I and II; 6 G3 SG Non I Non II; 2 G3 SG II. The severe RV infection occurred in only 10 (7%). 8 were serotype G1P1A SG II and 2 were G1P1A SG I and II. CONCLUSION: This study demonstrated that the severity of AID has no significant statistical relationship to the specific RV strains isolated from the patients.

[Rotavirus infections in Yucatan, Mexico, in 2000]. / Infecciones por rotavirus en Yucatán, México, durante el 2000.

OBJECTIVE: To describe the cases of rotavirus infection occurred in Yucatan, Mexico, in the year 2000. MATERIAL AND METHODS: From January to May 2000, were studied 668 patients with acute infectious diarrhea and their fecal samples. A questionnaire was applied and the samples were analyzed by polyacrylamide gel electrophoresis with silver stained. Incidence rates and the frequency of clinical manifestations were calculated. RESULTS: The cases of rotavirus occurred from January to April 2000. Three hundred-thirty seven (50.45%) samples were positives. The higher incidence rate of 0.70% was observed in infants 6 to 8 months of age. Vomit, nausea and hyperthermia were the more frequent clinical manifestations. Abdominal pain and dehydration occurred in 45.9% and 41.8% of the cases respectively. CONCLUSIONS: Presentation of the cases was similar to the reported by the countries with tempered climate. The risk of becoming ill by rotavirus was greater in the children under 1 year of age. Abdominal pain requires be carefully explored. Surveillance of the cases must be carried out throughout the year.