[Control of Aedes aegypti breeding sites with the program Recicla por tu bienestar in Merida, Mexico]. / Control de criaderos de Aedes aegypti con el programa Recicla por tu bienestar en Mérida, México.

OBJECTIVES: To determine the importance of Ae. aegypti breeding-sites in Merida;to evaluate the impact of Recicla por tu bienestar (RxB, a recycling program) on the reduction of breeding sites and the perception of participants. MATERIALS AND METHODS: The relative importance for pupae production of the different types of breeding-sites was determined. Pre-and post-RxB entomological surveys were performed in participant neighborhoods to evaluate the impact on total containers and positive breeding-sites. A survey on the perception of participating people about dengue prevention and control and RxB was applied. RESULTS: Buckets/pots and "small diverse items" were the most important breeding-sites. RxB had a significant impact in the reduction of total containers (IRR = 0.74), positive containers (IRR = 0.33) and the risk of a house being positive for Ae. aegypti (OR = 0.41). All the interviewed participants referred RxB as needed and most consider it useful. CONCLUSIONS: RxB should be considered as a good practice for the dengue vector control.

CHICKEN COOPS, Triatoma dimidiata INFESTATION AND ITS INFECTION WITH Trypanosoma cruzi IN A RURAL VILLAGE OF YUCATAN, MEXICO.

This study longitudinally investigated the association between Triatoma dimidiata infestation, triatomine infection with Trypanosoma cruzi and household/backyard environmental characteristics in 101 homesteads in Molas and Yucatan, Mexico, between November 2009 (rainy season) and May 2010 (dry season). Logistic regression models tested the associations between insect infestation/infection and potential household-level risk factors. A total of 200 T. dimidiata were collected from 35.6% of the homesteads, mostly (73%) from the peridomicile. Of all the insects collected, 48% were infected with T. cruzi. Infected insects were collected in 31.6% of the homesteads (54.1% and 45.9% intra- and peridomiciliary, respectively). Approximately 30% of all triatomines collected were found in chicken coops. The presence of a chicken coop in the backyard of a homestead was significantly associated with both the odds of finding T. dimidiata (OR = 4.10, CI 95% = 1.61-10.43, p = 0.003) and the presence of triatomines infected with T. cruzi (OR = 3.37, CI 95% = 1.36-8.33, p = 0.006). The results of this study emphasize the relevance of chicken coops as a putative source of T. dimidiata populations and a potential risk for T. cruzi transmission.

Control de criaderos de Aedes aegypti con el programa Recicla por tu bienestar en Mérida, México / Control of Aedes aegypti breeding sites with the program Recicla por tu bienestar in Merida, Mexico

Objetivos. Determinar la importancia de los criaderos de Ae. aegypti en Mérida; evaluar el impacto del programa Recicla por tu bienestar (RxB) sobre la presencia/abundancia de éstos y la percepción de los habitantes. Material y métodos. Se calculó la importancia de los criaderos por su productividad pupal. Se realizaron muestreos pre y post RxB en colonias para cuantificar el total de recipientes/criaderos. Se aplicó una encuesta a participantes sobre la percepción sobre RxB en colonias seleccionadas. Resultados. Los botes, cubetas y diversos objetos chicos fueron los criaderos más importantes. RxB tuvo un impacto significativo en la reducción del número de recipientes (IRR=0.74), en los recipientes positivos (IRR=0.33) y en la positividad de las viviendas para Ae.aegypti (OR=0.41 j.Todos los entrevistados opinaron que RxB es necesario y la gran mayoría piensa que es útil. Conclusiones. RxB debe ser considerada una buena práctica para el control del vector del dengue.

Objectives. To determine the importance of Ae. aegypti breeding-sites in Merida;to evaluate the impact of Recicla por tu bienestar (RxB, a recycling program) on the reduction of breeding sites and the perception of participants. Materials and methods. The relative importance for pupae production of the different types of breeding-sites was determined. Pre-and post-RxB entomological surveys were performed in participant neighborhoods to evaluate the impact on total containers and positive breeding-sites. A survey on the perception of participating people about dengue prevention and control and RxB was applied. Results. Buckets/pots and "small diverse items" were the most important breeding-sites. RxB had a significant impact in the reduction of total containers (IRR = 0.74), positive containers (IRR = 0.33) and the risk of a house being positive for Ae. aegypti (OR = 0.41). All the interviewed participants referred RxB as needed and most consider it useful. Conclusions. RxB should be considered as a good practice for the dengue vector control.

Use of insecticide-treated house screens to reduce infestations of dengue virus vectors, Mexico.

Dengue prevention efforts rely on control of virus vectors. We investigated use of insecticide-treated screens permanently affixed to windows and doors in Mexico and found that the screens significantly reduced infestations of Aedes aegypti mosquitoes in treated houses. Our findings demonstrate the value of this method for dengue virus vector control.

Long-lasting insecticide-treated house screens and targeted treatment of productive breeding-sites for dengue vector control in Acapulco, Mexico.

BACKGROUND: Long-lasting insecticidal net screens (LLIS) fitted to domestic windows and doors in combination with targeted treatment (TT) of the most productive Aedes aegypti breeding sites were evaluated for their impact on dengue vector indices in a cluster-randomised trial in Mexico between 2011 and 2013. METHODS: Sequentially over 2 years, LLIS and TT were deployed in 10 treatment clusters (100 houses/cluster) and followed up over 24 months. Cross-sectional surveys quantified infestations of adult mosquitoes, immature stages at baseline (pre-intervention) and in four post-intervention samples at 6-monthly intervals. Identical surveys were carried out in 10 control clusters that received no treatment. RESULTS: LLIS clusters had significantly lower infestations compared to control clusters at 5 and 12 months after installation, as measured by adult (male and female) and pupal-based vector indices. After addition of TT to the intervention houses in intervention clusters, indices remained significantly lower in the treated clusters until 18 (immature and adult stage indices) and 24 months (adult indices only) post-intervention. CONCLUSIONS: These safe, simple affordable vector control tools were well-accepted by study participants and are potentially suitable in many regions at risk from dengue worldwide.

"You are not fat, you are hermosa": Mexican caregivers share their perceptions about their role supporting their morbidly obese children.

This qualitative study reports the findings from 6 focus groups conducted at a clinic in Southern Mexico with caregivers of morbidly obese children. This study was developed with the purpose of gaining a further understanding of caregivers' perceived role in addressing their children's obesity within the family context and identifying topics that could be considered when providing health care in similar sociocultural environments. We identified that although caregivers acknowledge the role of modifiable factors in obesity prevention and treatment, they held beliefs about determinism in obesity. In addition, diet was the more frequently identified means of reducing the impact of obesity. The importance of role modeling and promoting healthy behaviors in the family context are topics that could be addressed in clinical practice.

Use and acceptance of long lasting insecticidal net screens for dengue prevention in Acapulco, Guerrero, Mexico.

BACKGROUND: Dengue, recognized by the WHO as the most important mosquito-borne viral disease in the world, is a growing problem. Currently, the only effective way of preventing dengue is vector control. Standard methods have shown limited effect, and there have been calls to develop new integrated vector management approaches. One novel tool, protecting houses with long lasting insecticidal screens on doors and windows, is being trialled in a cluster randomised controlled trial by a joint UADY/WHO TDR/IDRC study in various districts of Acapulco, Mexico, with exceptionally high levels of crime and insecurity.This study investigated the community's perspectives of long lasting insecticidal screens on doors and windows in homes and in schools, in order to ascertain their acceptability, to identify challenges to further implementation and opportunities for future improvements. METHODS: This was a sequential mixed-methods study. The quantitative arm contained a satisfaction survey administered to 288 houses that had received the intervention examining their perspectives of both the intervention and dengue prevention in general. The qualitative arm consisted of Focus Group Discussions (FGDs) with those who had accepted the intervention and key informant interviews with: schoolteachers to discuss the use of the screens in schools, program staff, and community members who had refused the intervention. RESULTS: Overall satisfaction and acceptance of the screens was very high, with only some operational and technical complaints relating to screen fragility and the installation process. However, the wider social context of urban violence and insecurity was a major barrier to screen acceptance. Lack of information dissemination and community collaboration were identified as project weaknesses. CONCLUSIONS: The screens are widely accepted by the population, but the project implementation could be improved by reassuring the community of its legitimacy in the context of insecurity. More community engagement and better information sharing structures are needed.The screens could be a major new dengue prevention tool suitable for widespread use, if further research supports their entomological and epidemiological effectiveness and their acceptability in different social and environmental contexts. Further research is needed looking at the impact of insecurity of dengue prevention programmes.

Ecological, biological and social dimensions of dengue vector breeding in five urban settings of Latin America: a multi-country study.

BACKGROUND: Dengue is an increasingly important public health problem in most Latin American countries and more cost-effective ways of reducing dengue vector densities to prevent transmission are in demand by vector control programs. This multi-centre study attempted to identify key factors associated with vector breeding and development as a basis for improving targeted intervention strategies. METHODS: In each of 5 participant cities in Mexico, Colombia, Ecuador, Brazil and Uruguay, 20 clusters were randomly selected by grid sampling to incorporate 100 contiguous households, non-residential private buildings (businesses) and public spaces. Standardized household surveys, cluster background surveys and entomological surveys specifically targeted to obtain pupal indices for Aedes aegypti, were conducted in the dry and wet seasons. RESULTS: The study clusters included mainly urban low-middle class populations with satisfactory infrastructure and -except for Uruguay- favourable climatic conditions for dengue vector development. Household knowledge about dengue and "dengue mosquitoes" was widespread, mainly through mass media, but there was less awareness around interventions to reduce vector densities. Vector production (measured through pupal indices) was favoured when water containers were outdoor, uncovered, unused (even in Colombia and Ecuador where the large tanks used for household water storage and washing were predominantly productive) and -particularly during the dry season- rainwater filled. Larval infestation did not reflect productive container types. All productive container types, including those important in the dry season, were identified by pupal surveys executed during the rainy season. CONCLUSIONS: A number of findings are relevant for improving vector control: 1) there is a need for complementing larval surveys with occasional pupal surveys (to be conducted during the wet season) for identifying and subsequently targeting productive container types; 2) the need to raise public awareness about useful and effective interventions in productive container types specific to their area; and 3) the motivation for control services that-according to this and similar studies in Asia- dedicated, targeted vector management can make a difference in terms of reducing vector abundance.

The risk of Aedes aegypti breeding and premises condition in South Mexico.

A recent innovation instrumented for the Dengue Prevention and Control program in Mexico is the use of the premises condition index (PCI) as an indicator of risk for the vector Aedes aegypti infestation in dengue-endemic localities of Mexico. This paper addresses whether further improvements for the dengue control program could be made if the prevalence and productivity of Ae. aegypti populations could be reliably predicted using PCI at the household level, as well as medium-sized neighborhoods. We evaluated the use of PCI to predict the infestation with Aedes aegypti (breeding sites and immature productivity) in Merida, Mexico. The study consisted of a cross-sectional survey based on a cluster-randomized sampling design. We analyzed the statistical association between Aedes infestation and PCI, the extent to which the 3 components of PCI (house maintenance, and tidiness and shading of the patio) contributed to the association between PCI and infestation and whether infestation in a given premises was also affected by the PCI of the surrounding ones. Premises with the lowest PCI had significantly lower Aedes infestation and productivity; and as PCI scores increased infestation levels also tended to increase. Household PCI was significantly associated with Ae. aegypti breeding, largely due to the effect of patio untidiness and patio shade. The mean PCI within the surroundings premises also had a significant and independent explanatory power to predict the risk for infestation, in addition to individual PCI. This is the 1st study in Mexico showing evidence that premises condition as measured by the PCI is related to Ae. aegypti breeding sites and immature productivity. Results suggest that PCI could be used to streamline surveys to inform control efforts at least where Ae. aegypti breeds outdoors, as in Merida. The effect of individual premises, neighborhood condition, and the risk of Aedes infestation imply that the risk for dengue vector infestation can only be minimized by the mass effect at the community level.

Lagochilascaris minor Leiper, 1909 (Nematoda: Ascarididae) in Mexico: three clinical cases from the Peninsula of Yucatan / Lagochilascaris minor Leiper, 1909 (Nematoda: Ascarididae) en México: tres casos clínicos de la Península de Yucatán

Human lagochilascariasis (HL) is a parasite produced by Lagochilascaris minor Leiper 1909 that also can be found in cats and dogs. HL is considered an emerging zoonosis in the Americas, spreading from Mexico to Argentina, and the Caribbean Islands. The present paper describes three HL cases from the Peninsula of Yucatan, Mexico, recorded in the last decade. It describes the characteristics of the lesions and discusses the route of transmission in humans and particularly in the observed patients.

La Lagochilascariasis humana (HL) es producida por Lagochilascaris minor Leiper, 1909; el cual es un parásito que puede ser encontrado también en gatos y perros. HL es considerada una zoonosis emergente en América distribuida desde México hasta Argentina y las islas del Caribe. El presente artículo describe tres casos de HL en la Península de Yucatán, México registrados en la última década. Se describen las características de las lesiones y se discute la ruta de transmisión en humanos y particularmente en los pacientes observados.

Lagochilascaris minor Leiper, 1909 (Nematoda: Ascarididae) in Mexico: three clinical cases from the Peninsula of Yucatan.

Human lagochilascariasis (HL) is a parasite produced by Lagochilascaris minor Leiper 1909 that also can be found in cats and dogs. HL is considered an emerging zoonosis in the Americas, spreading from Mexico to Argentina, and the Caribbean Islands. The present paper describes three HL cases from the Peninsula of Yucatan, Mexico, recorded in the last decade. It describes the characteristics of the lesions and discusses the route of transmission in humans and particularly in the observed patients.

Storm sewers as larval habitats for Aedes aegypti and Culex spp. in a neighborhood of Merida, Mexico.

We report the collection of Aedes aegypti, Culex quinquefasciatus, Cx. interrogator, Cx. thriambus, Cx. coronator, and Cx. salinarius larvae from storm sewers within an endemic area for dengue transmission in Merida, Mexico, during the rainy season of 2011. This is the first record of the dengue vector Ae. aegypti breeding in storm sewers in the southeast of Mexico.

An iron-superoxide dismutase antigen-based serological screening of dogs indicates their potential role in the transmission of cutaneous leishmaniasis and trypanosomiasis in Yucatan, Mexico.

An increasing number of studies have reported high infection rates for American cutaneous leishmaniasis in dogs, which have thus been proposed as the reservoir host. Canine leishmaniasis is widespread in different states in Mexico, where a number of Leishmania species have been isolated from dogs. In the present study, the detection of different Leishmania species is described in stray dogs from two localities, namely Tulum and Celestún on the Yucatan Peninsula (Mexico). The use of iron-superoxide dismutase excreted by the parasites as the antigen fraction and enzyme-linked immunosorbent assay and western blot tests allowed us to confirm the presence of at least three species of Leishmania (Le. mexicana, Le. braziliensis, and Le. panamensis), some of which are reported for the first time in this species. In addition to a high prevalence of Le. mexicana and Le. braziliensis, and to a lesser degree, Le. panamensis, there is a significant prevalence of Trypanosoma cruzi, suggesting that the dog may be a source of transmission of trypanosomiasis. However, a more thorough epidemiological study on the dog population, both wild as well as urban, of the Yucatan Peninsula will be required to design a control strategy for these diseases, paying particular attention to the population affected and even broadening the study to other Mexican states as well as neighboring countries. These results again confirm that iron-superoxide dismutase excreted by the different trypanosomatid species constitutes a good source of antigen for serodiagnosis in epidemiological studies.

Cytotoxicity of three new triazolo-pyrimidine derivatives against the plant trypanosomatid: Phytomonas sp. isolated from Euphorbia characias.

There is no effective chemotherapy against diseases caused by Phytomonas sp., a plant trypanosomatid responsible for economic losses in major crops. We tested three triazolo-pyrimidine complexes [two with Pt(II), and another with Ru(III)] against promastigotes of Phytomonas sp. isolated from Euphorbia characias. The incorporation of radiolabelled precursors, ultrastructural alterations and changes in the pattern of metabolite excretion were examined. Different degrees of toxicity were found for each complex: the platinum compound showed an inhibition effect on nucleic acid synthesis, provoking alterations on the levels of mitochondria, nucleus and glycosomes. These results, together with others reported previously in our laboratory about the activity of pyrimidine derivatives, reflect the potential of these compounds as agents in the treatment of Phytomonas sp.

Cytotoxicity of three new triazolo-pyrimidine derivatives against the plant trypanosomatid: Phytomonas sp. isolated from Euphorbia characias

There is no effective chemotherapy against diseases caused by Phytomonas sp., a plant trypanosomatid responsible for economic losses in major crops. We tested three triazolo-pyrimidine complexes [two with Pt(II), and another with Ru(III)] against promastigotes of Phytomonas sp. isolated from Euphorbia characias. The incorporation of radiolabelled precursors, ultrastructural alterations and changes in the pattern of metabolite excretion were examined. Different degrees of toxicity were found for each complex: the platinun compound showed an inhibition effect on nucleic acid synthesis, provoking alterations on the levels of mitochondria, nucleus and glycosomes. These results, together with others reported previously in our laboratory about the activity of pyrimidine derivatives, reflect the potential of these compounds as agents in the treatment of Phytomonas sp.

Re-infestation of houses by Triatoma dimidiata after intra-domicile insecticide application in the Yucatán peninsula, Mexico.

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.

Re-infestation of houses by Triatoma dimidiata after intra-domicile insecticide application in the Yucatán peninsula, Mexico

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.

Geographic distribution of Triatoma dimidiata and transmission dynamics of Trypanosoma cruzi in the Yucatan peninsula of Mexico.

Chagas disease represents a major public health concern in most of Latin America, and its control is currently based on vector control and blood bank screening. We investigated the geographic distribution and seasonal variations in triatomine populations in the Yucatan peninsula of Mexico to obtain entomologic data for the optimization of potential control programs. We collected domiciliated and peri-domiciliated Triatoma dimidiata from 115 houses in 23 villages distributed throughout most of the peninsula. A high abundance of bugs was observed in the northern part of the peninsula, indicating a prioritary area for vector control. Part of this distribution could be attributed to the type of vegetation. We also documented strong seasonal variations in T. dimidiata populations, with a higher abundance during the hot and dry season in April-June. These variations, associated with reduced year-round colonization of houses and the analysis of developmental stage structure, suggest that flying adults seasonally invading houses may play a larger role than domiciliated bugs in transmission of Trypanosoma cruzi to humans. The importance of this transmission dynamics may not be limited to the Yucatan peninsula, but may be a general mechanism contributing to natural transmission that should be taken into account in other regions for the design and optimization of control strategies.

Biological behavior of three strains of trypanosoma cruzi from Yucatán, México / Comportamiento biológico de tres cepas de Trypanosoma cruzi de Yucatán, México

Introducción. El protozoario Trypanosoma cruzi, infecta gran variedad de huéspedes, y produce una alta variabilidad en las manifestaciones clínicas en el humano. Las diferencias en la patogenicidad, están directamente relacionadas con la heterogenicadad genética de los parásitos, lo cual implica que cepas de diferentes áreas deben ser caracterizadas para entender el comportamiento epidemiológico y clínico de la infección. En este trabajo se reporta el comportamiento en vivo de tres cepas de Yucatán, México ( H4, H5, y H10). Material y Métodos. Las cepas H4 y H5, fueron aisladas de pacientes con patología severa, y la H10, de un paciente asintomático. Se infectaron ratones NIH, con las diferentes cepas de Trypanosoma cruzi . Resultados. La infección experimental de ratones NIH con la cepa H4, resultó con alta parasitemia (1.04 x 107 parásitos circulantes/mL e invasión tisular, con 50 por ciento de sobrevivencia. Las cepas H5 y 10 produjeron baja parasitemia (6.10 x 106 and 1.29 x 106 parásitos circulantes/mL) y muy limitada invasión tisular y 92 por ciento de los ratones infectados sobrevivieron. Discusión. Nosotros concluimos que estas cepas, tienen una virulencia comparable con cepas de otras regiones, pero que su comportamiento biológico falta relacionarlo directamente con sus marcadores genéticos.

Leptospirosis anictérica en un brote epidémico de dengue en la Península de Yucatán / Anicteric leptospirosis in a dengue epidemic in Yucatan, Mexico

Introducción. La leptospirosis es una zoonosis de amplia distribución mundial. Posee un amplio polimorfismo clínico, pero en general se presenta en tres formas distintas: subclínica, anictérica (benigna) y grave (enfermedad de Weil). En México la información que se tiene sobre leptospirosis humana de 1970 a la fecha es escasa y en su gran mayoría proviene de estudios de corte seroepidemiológico, por lo que poco se sabe sobre sus otras formas clínicas, y tal vez por ellos sólo se relacione con la forma grave. Objetivo. Demostrar que la leptospirosis no es rara en la región y que puede estarse confundiendo clínicamente con otras entidades febriles, entre ellas el dengue. Método. Se analizaron para la búsqueda de casos de leptospirosis, sueros y expedientes clínicos de 50 pacientes que fueron diagnosticados clínicamente como dengue y que resultaron negativos en las pruebas de confirmación etiológica. Se utilizó como prueba diagnóstica la de microaglutinación (MA), utilizando como antígeno Leptospira interrogans vivas de ocho serovares diferentes. Resultados. Se encontraron siete pacientes positivos a leptospirosis (14 por ciento). La sintomatología que presentaron correspondió a la descrita para la forma anictérica. Tres fueron de Yucatán y cuatro de Campeche. En el primer Estado predominó el serovar canícola y en el segundo el serovar pomona. Conclusiones. La leptospirosis es una enfermedad infecciosa presente al igual que el dengue en los estados de Yucatán y Campeche, por lo que se le debe tomar en cuenta en el diagnóstico diferencial, sobre todo en zonas geográficas en donde los dos padecimientos son endémicos