RESUMEN

Dengue disease epidemics have increased in time and space due to climatic and non-climatic factors such as urbanization. In the absence of an effective vaccine, preventing dengue outbreak relies on vector control activities. Employing computerized tools to predict outbreaks and respond in advance has great potential for improving dengue disease control. Evidence of integrating or implementing such applications into control programs and their impact are scarce, and endemic countries demand for experience sharing and know-how transfer. Mexico has extensive experience of pre-validated EWARS (Early Warning And Response System), a tool that was developed in 2012 as part of a collaboration with the Special Program for Research and Training in Tropical Diseases Unit (TDR) at the World Health Organization and used at national level. The advancement of EWARS since 2014 and its stepwise integration into the national surveillance system has increased the appreciation of the need for integrated surveillance (including disease, vector and climate surveillance), and for linking inter-institutional and trans-sectoral information for holistic epidemiological intelligence. The integration of the EWARS software into the national surveillance platform in Mexico was a remarkable milestone and a successful experience. This manuscript describes the implementation process of EWARS in Mexico, which started in 2012 and further demonstrates benefits, threats, and opportunities of integrating EWARS into existing national surveillance programs.

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INTRODUCTION: Mexico was the first country in the Americas and the third in the world to eliminate trachoma as a public health problem, as validated by the WHO in 2017. OBJECTIVE: To describe the critical elements that favored the elimination of trachoma as a public health problem in Mexico and the public health impact of this success. METHODOLOGY: A revision and compilation of data and information contained in the dossier presented by the country to PAHO/WHO to obtain the validation of trachoma elimination as a public health problem was conducted by a group of delegates from the national and local trachoma prevention and control program. Data from the national and local surveillance systems and reports of actions conducted after achieving the elimination goal were also included. Critical elements that favored the achievement of the elimination goal from 1896 to 2019 were extracted. RESULTS: Mexico reached the elimination of trachoma in 2016 obtaining the validation in 2017. 264 communities were no longer endemic and 151,744 people were no longer at risk of visual impairment or possible blindness due to trachoma. The key to the success of this elimination process was primarily the local leadership of health authorities with sustained funding for brigades, increased access to potable water and sanitation, and key alliances with indigenous authorities, health authorities, and government institutions that contributed to the achievement of the goal. The SAFE strategy started implementation in Mexico in 2004 as a comprehensive package of interventions. SAFE stands for surgery, antibiotics, facial cleanliness, and improvement of the environmental conditions. These actions impacted drastically on the number of new cases trachmatous trichiasis (TT) and trachomatous inflammation-follicular (TF), which decreased from 1,794 in 2004 to zero in 2016. CONCLUSIONS: The elimination of trachoma as a public health problem in Mexico is a true success story that may serve as a model example for the elimination of other neglected infectious diseases in the Americas.

Asunto(s)

Enfermedades del Recién Nacido , Tracoma , Triquiasis , Prioridades en Salud , Humanos , Lactante , Recién Nacido , México/epidemiología , Prevalencia , Salud Pública , Tracoma/epidemiología , Tracoma/prevención & control , Triquiasis/epidemiología

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BACKGROUND: In the Americas, endemic countries for Aedes-borne diseases such as dengue, chikungunya, and Zika face great challenges particularly since the recent outbreaks of CHIKV and ZIKV, all transmitted by the same insect vectors Aedes aegypti and Ae. albopictus. The Special Program for Research and Training in Tropical Diseases (TDR-WHO) has developed together with partners an Early Warning and Response System (EWARS) for dengue outbreaks based on a variety of alarm signals with a high sensitivity and positive predictive value (PPV). The question is if this tool can also be used for the prediction of Zika and chikungunya outbreaks. METHODOLOGY: We conducted in nine districts of Mexico and one large city in Colombia a retrospective analysis of epidemiological data (for the outbreak definition) and of climate and entomological data (as potential alarm indicators) produced by the national surveillance systems for dengue, chikungunya and Zika outbreak prediction covering the following outbreak years: for dengue 2012-2016, for Zika 2015-2017, for chikungunya 2014-2016. This period was divided into a "run in period" (to establish the "historical" pattern of the disease) and an "analysis period" (to identify sensitivity and PPV of outbreak prediction). RESULTS: In Mexico, the sensitivity of alarm signals for correctly predicting an outbreak was 100% for dengue, and 97% for Zika (chikungunya data could not be obtained in Mexico); the PPV was 83% for dengue and 100% for Zika. The time period between alarm and start of the outbreak (i.e. the time available for early response activities) was for Zika 4-5 weeks. In Colombia the sensitivity of the outbreak prediction was 92% for dengue, 93% for chikungunya and 100% for Zika; the PPV was 68% for dengue, 92% for chikungunya and 54% for Zika; the prediction distance was for dengue 3-5 weeks, for chikungunya 10-13 weeks and for Zika 6-10 weeks. CONCLUSION: EWARS demonstrated promising capability of timely disease outbreak prediction with an operational design likely to improve the coordination among stakeholders. However, the prediction validity varied substantially across different types of diseases and appeared less optimal in low endemic settings.

Asunto(s)

Aedes , Fiebre Chikungunya , Dengue , Infección por el Virus Zika , Virus Zika , Animales , Fiebre Chikungunya/epidemiología , Dengue/epidemiología , Brotes de Enfermedades , Humanos , Mosquitos Vectores , Estudios Retrospectivos , Infección por el Virus Zika/epidemiología

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Dengue fever is one of the most devastating infectious diseases worldwide. Development of methods for dengue virus (DENV) detection in mosquitoes to assess prevalence as a preliminary screen for entomological surveillance in endemic regions of DENV will certainly contribute to the control of the disease. A monoclonal antibody against the NS1 (nonstructural protein 1) viral protein was generated using recombinant NS1 protein and used to detect and analyze DENV in both excreta and total homogenates from Aedes aegypti mosquitoes. Results demonstrated expression of NS1 in excreta of DENV laboratory-infected mosquitoes and homogenates from field mosquitoes infected with DENV. The immunodetection method reported here represents a first-line strategy for assessing the prevalence of DENV in mosquitoes, for entomological surveillance in endemic regions of dengue. Detection of DENV prevalence in field mosquitoes could have an impact on vector surveillance measures to interrupt dengue transmission.

Asunto(s)

Aedes , Virus del Dengue , Animales , Anticuerpos Monoclonales , Mosquitos Vectores

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BACKGROUND: Effective Aedes aegypti control is limited, in part, by the difficulty in achieving sufficient intervention coverage. To maximise the effect of vector control, areas with persistently high numbers of Aedes-borne disease cases could be identified and prioritised for preventive interventions. We aimed to identify persistent Aedes-borne disease hotspots in cities across southern Mexico. METHODS: In this spatial analysis, geocoded cases of dengue, chikungunya, and Zika from nine endemic Mexican cities were aggregated at the census-tract level. We included cities that were located in southern Mexico (the arbovirus endemic region of Mexico), with a high burden of dengue cases (ie, more than 5000 cases reported during a 10-year period), and listed as high priority for the Mexican dengue control and prevention programme. The Getis-Ord Gi*(d) statistic was applied to yearly slices of the dataset to identify spatial hotspots of each disease in each city. We used Kendall's W coefficient to quantify the agreement in the distribution of each virus. FINDINGS: 128 507 dengue, 4752 chikungunya and 25 755 Zika clinical cases were reported between Jan 1, 2008, and Dec 31, 2016. All cities showed evidence of transmission heterogeneity, with a mean of 17·6% (SD 4·7) of their total area identified as persistent disease hotspots. Hotspots accounted for 25·6% (SD 9·7; range 12·8-43·0) of the population and 32·1% (10·5; 19·6-50·5) of all Aedes-borne disease cases reported. We found an overlap between hotspots of 61·7% for dengue and Zika and 53·3% for dengue and chikungunya. Dengue hotspots in 2008-16 were significantly associated with dengue hotspots detected during 2017-20 in five of the nine cities. Heads of vector control confirmed hotspot areas as problem zones for arbovirus transmission. INTERPRETATION: This study provides evidence of the overlap of Aedes-borne diseases within geographical hotspots and a methodological framework for the stratification of arbovirus transmission risk within urban areas, which can guide the implementation of surveillance and vector control. FUNDING: USAID, the US Centers for Disease Control and Prevention, the Canadian Institutes of Health Research, International Development Research Centre, Fondo Mixto CONACyT (Mexico)-Gobierno del Estado de Yucatan, and the US National Institutes of Health. TRANSLATION: For the Spanish translation of the abstract see Supplementary Materials section.

Asunto(s)

Fiebre Chikungunya , Dengue , Infección por el Virus Zika , Virus Zika , Canadá , Fiebre Chikungunya/epidemiología , Dengue/epidemiología , Humanos , México/epidemiología , Mosquitos Vectores , Medición de Riesgo , Análisis Espacial , Infección por el Virus Zika/epidemiología

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Zika virus (ZIKV) is a mosquito-borne pathogen discovered in the late 40's in Uganda during a surveillance program for yellow fever. By 2014 the virus reached Eastern Island in the Americas, and two years later, the virus spread to almost all countries and territories of the Americas. The mosquito Aedes aegypti has been identified as the main vector of the disease, and several researchers have also studied the vector competence of Culex quinquefasciatus in virus transmission. The aim of the present study was to evaluate the vector competence of Ae. aegypti and Cx. quinquefasciatus in order to understand their roles in the transmission of ZIKV in Guadalajara, Jalisco, Mexico. In blood feeding laboratry experiments, we found that Ae. aegypti mosquitoes showed to be a competent vector able to transmit ZIKV in this area. On the other hand, we found that F0 Cx. quinquefasciatus mosquitoes are refractory to ZIKV infection, dissemination and transmission.

Asunto(s)

Aedes/virología , Culex/virología , Mosquitos Vectores/virología , Infección por el Virus Zika/transmisión , Virus Zika , Animales , Ciudades , Femenino , Saliva/virología , Carga Viral

RESUMEN

Since past century, vector-borne diseases have been a major public health concern in several states of Mexico. However, Mexico City continues to be free of endemic mosquito-borne viral diseases. The city is the most important politic and economic state of Mexico and one of the most important city of Latin America. Its subtropical highland climate and high elevation (2240 masl) had historically made the occurrence of Aedes species unlikely. However, the presence of other potential disease vectors (Culex spp, Culiseta spp), and the current intermittent introductions of Aedes aegypti, have revealed that control programs must adopt routine vector surveillance in the city. In this study, we provide an updated species list from a five-years of vector surveillance performed in Mexico City. A total of 18,553 mosquito larvae were collected. Twenty-two species from genus Culex, Aedes, Culiseta, Anopheles, Lutzia and Uranotaenia were observed. Nine new mosquito records for the city were found. Ae. albopictus was recorded for the first time in Mexico City. Interestingly, a new record, Ae. epactius was the most frequent species reported. Cx. pipiens quinquefasciatus exhibited the highest number of individuals collected. We detected six areas which harbor the highest mosquito species records in the city. Cemeteries included 68.9% of our collection sites. Temporarily ponds showed the highest species diversity. We detected an increasing presence of Ae. aegypti, which was detected for three consecutive years (2015-2017), predominantly in the warmer microclimates of the city. We found a possible correlation between increasing temperature and Ae. aegypti and Ae. albopictus expanding range. This study provides a starting point for developing strategies related to environmental management for mosquito control. The promotion of mosquito control practices through community participation, mass media and education programmes in schools should be introduced in the city.

Asunto(s)

Distribución Animal , Culicidae/microbiología , Enfermedades Endémicas/prevención & control , Control de Mosquitos , Mosquitos Vectores/microbiología , Animales , Ciudades , Calor , México , Microclima

RESUMEN

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has not been fixed in the paper.

RESUMEN

Response to Zika virus (ZIKV) invasion in Brazil lagged a year from its estimated February 2014 introduction, and was triggered by the occurrence of severe congenital malformations. Dengue (DENV) and chikungunya (CHIKV) invasions tend to show similar response lags. We analyzed geo-coded symptomatic case reports from the city of Merida, Mexico, with the goal of assessing the utility of historical DENV data to infer CHIKV and ZIKV introduction and propagation. About 42% of the 40,028 DENV cases reported during 2008-2015 clustered in 27% of the city, and these clustering areas were where the first CHIKV and ZIKV cases were reported in 2015 and 2016, respectively. Furthermore, the three viruses had significant agreement in their spatio-temporal distribution (Kendall W>0.63; p<0.01). Longitudinal DENV data generated patterns indicative of the resulting introduction and transmission patterns of CHIKV and ZIKV, leading to important insights for the surveillance and targeted control to emerging Aedes-borne viruses.

Asunto(s)

Fiebre Chikungunya/epidemiología , Dengue/epidemiología , Brotes de Enfermedades , Infección por el Virus Zika/epidemiología , Aedes/virología , Animales , Fiebre Chikungunya/transmisión , Fiebre Chikungunya/virología , Virus Chikungunya/aislamiento & purificación , Virus Chikungunya/fisiología , Dengue/transmisión , Dengue/virología , Virus del Dengue/aislamiento & purificación , Virus del Dengue/fisiología , Mapeo Geográfico , Humanos , México/epidemiología , Control de Mosquitos , Mosquitos Vectores/virología , Análisis Espacio-Temporal , Virus Zika/aislamiento & purificación , Virus Zika/fisiología , Infección por el Virus Zika/transmisión , Infección por el Virus Zika/virología

RESUMEN

Zika virus (ZIKV) is a mosquito-borne pathogen, and Aedes aegypti has been identified as the main vector of the disease. Other mosquito species in the Aedes and Culex genera have been suggested to have the potential for being competent vectors based on experimental exposition of mosquitoes to an infectious blood meal containing ZIKV. Here, we report the isolation in cell culture of ZIKV obtained from different body parts of wild-caught female mosquitoes (Ae. aegypti, Ae. vexans, Cx. quinquefasciatus, Cx. coronator, and Cx. tarsalis) and whole male mosquitoes (Ae. aegypti and Cx. quinquefasciatus) in Mexico. Importantly, this is the first report that shows the presence of the virus in the salivary glands of the wild-caught female mosquitoes species, Cx. coronator, Cx. tarsalis, and Ae. vexans. Our findings strongly suggest that all the species reported herein are potential vectors for ZIKV.

Asunto(s)

Aedes/virología , Culex/virología , Mosquitos Vectores/virología , Virus Zika/aislamiento & purificación , Animales , Femenino , Masculino , México , Glándulas Salivales/virología , Cultivo de Virus

RESUMEN

Background: We report on the results of an entomovirological surveillance system of Aedes populations performed by the Ministry of Health of the central state of San Luis Potosí, Mexico. Methods: Indoor adult Aedes aegypti and Aedes albopictus pools collected at San Martín, Tamazunchale, Ciudad Valles, Metlapa, Ebano, Tamuin and Axtla during the dry season of 2016 were examined for the presence of dengue (DENV), chikungunya (CHIKV) and Zika (ZIKV) viruses using real-time PCR. Results: Both Ae. aegypti and Ae. albopictus were found to be infected with ZIKV in the absence of confirmed symptomatic human cases. Conclusions: The entomovirological surveillance system analysed here identified both Ae. aegypti and Ae. albopictus infected with ZIKV which triggered an immediate aggressive vector control campaign.

Asunto(s)

Aedes/virología , Insectos Vectores/virología , Estaciones del Año , Infección por el Virus Zika/virología , Virus Zika , Animales , Virus Chikungunya , Virus del Dengue , Humanos , México , Control de Mosquitos , Reacción en Cadena en Tiempo Real de la Polimerasa , Virus Zika/genética , Virus Zika/crecimiento & desarrollo

RESUMEN

Prior to the current public health emergency following the emergence of chikungunya and Zika Virus Disease in the Americas during 2014 and 2015, multi-country research investigated between 2011 and 2013 the efficacy of novel Aedes aegypti intervention packages through cluster randomised controlled trials in four Latin-American cities: Fortaleza (Brazil); Girardot (Colombia), Acapulco (Mexico) and Salto (Uruguay). Results from the trials led to a scaling up effort of the interventions at city levels. Scaling up refers to deliberate efforts to increase the impact of successfully tested health interventions to benefit more people and foster policy and program development in a sustainable way. The different scenarios represent examples for  a 'vertical approach' and a 'horizontal approach'. This paper presents the analysis of a preliminary process evaluation of the scaling up efforts in the mentioned cites, with a focus on challenges and enabling factors encountered by the research teams, analysing the main social, political, administrative, financial and acceptance factors.

Asunto(s)

Transmisión de Enfermedad Infecciosa/prevención & control , Control de Mosquitos/métodos , Control de Mosquitos/organización & administración , Población Urbana , Aedes/crecimiento & desarrollo , Animales , Fiebre Chikungunya/epidemiología , Fiebre Chikungunya/prevención & control , Ciudades/epidemiología , Humanos , América Latina/epidemiología , Infección por el Virus Zika/epidemiología , Infección por el Virus Zika/prevención & control

RESUMEN

In Mexico, the use of repellents to prevent insects from landing and biting is a common practice. However, variation in the efficiency of natural and synthetic repellents has been observed. In this study, we evaluated the repellency and protection time of 16 synthetic and 13 natural-based commercial products against Aedes aegypti (L.) from an endemic dengue area (Jojutla, Morelos) in Central Mexico. The "arm exposure" cage test was used to assess the efficacy of the repellents. Tests were conducted by three adult volunteers. Results showed that DEET (N, N-Diethyl-3-methylbenzamide) repellents provided the highest protection and duration times against Ae. aegypti. However, low repellency and short-time protection was observed (when compared with the manufacturers' protection times). Natural-based products did not repel (either landing or biting) mosquitoes for >30 min. These results show that most of the repellent products did not provide satisfactory levels of personal protection against mosquito bites. Frequent reapplication of repellents (synthetic and natural-based) may compensate for their short duration of action. Repellent efficacy data must be integrated into the decision-making process for an optimal response to the local (or specific region) situation.

Asunto(s)

Aedes , Mordeduras y Picaduras de Insectos/prevención & control , Repelentes de Insectos , Mosquitos Vectores , Animales , Femenino , México

RESUMEN

Objective. To study cutaneous leishmaniasis (CL), in the Calakmul municipality of the Campeche State, during two years. Materials and methods. Individuals with skin lesions were evaluated. Aspirates taken from the lesions were cultured, PCR was performed to diagnose the Leishmania species. Results. The culture detected 42% of the samples. PCR diagnosed CL in 76% of the samples; of those 38% were from children and 62% from adults. 89% of the patients were infected with L. mexicana; 14.4% with Mexican strains of L. mexicana; 7% with L. braziliensis; 3.6% with L. mexicana and L. braziliensis. The most affected villages with CL were Dos Lagunas Sur with 12.3%, La Mancolona with 6.5% and La Guadalupe with 2.2% of prevalence, respectively. After the treatment with Glucantime, 96% of the patients were healed. Conclusion. CL is an important public health concern in Calakmul, and the parasite causing it belongs to Leishmania mexicana and Leishmania braziliensis complexes.

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Objetivo. Estudiar la leishmaniasis cutánea en Calakmul, Campeche, México, durante dos años. Material y métodos. Se estudiaron individuos con lesiones cutáneas, se tomaron aspirados y se inocularon medios de cultivo; se realizó la técnica de PCR para identificar la especie de Leishmania. Resultados. Los cultivos detectaron 42% de las muestras. Con la PCR se amplificaron 76% de las muestras, 38% fueron tomadas de niños y 62% de adultos. En 89% de las muestras positivas se identificó Leishmania mexicana, en 14.4% cepas mexicanas de L. mexicana, en 7% L. braziliensis y en 3.6% L. mexicana y L. braziliensis. En Dos Lagunas Sur se encontró una prevalencia de 12.3%, en La Mancolona 6.5% y en La Virgen 2.2%. Del total de los pacientes, 96% se curó con Glucantime. Conclusion. La leishmaniasis cutánea es un problema de salud pública en Calakmul y las especies causantes pertenecen a los complejos Leishmania mexicana y Leishmania braziliensis.

Asunto(s)

Humanos , Animales , Masculino , Femenino , Niño , Adulto , Leishmaniasis Cutánea/epidemiología , Compuestos Organometálicos/uso terapéutico , Roedores/parasitología , Leishmania braziliensis/aislamiento & purificación , Inducción de Remisión , Leishmania mexicana/aislamiento & purificación , Reservorios de Enfermedades , Prevalencia , ADN Protozoario/análisis , Leishmaniasis Cutánea/parasitología , Geografía Médica , Antimoniato de Meglumina , Meglumina/uso terapéutico , México/epidemiología , Antiprotozoarios/uso terapéutico

RESUMEN

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.

Asunto(s)

Aedes/crecimiento & desarrollo , Servicios de Salud Comunitaria/organización & administración , Virus del Dengue/patogenicidad , Dengue/prevención & control , Mosquiteros Tratados con Insecticida , Insecticidas/farmacología , Control de Mosquitos/organización & administración , Animales , Análisis por Conglomerados , Virus del Dengue/aislamiento & purificación , Reservorios de Enfermedades/parasitología , Conocimientos, Actitudes y Práctica en Salud , Humanos , México/epidemiología , Aceptación de la Atención de Salud , Estaciones del Año , Vigilancia de Guardia , Salud Urbana , Abastecimiento de Agua

RESUMEN

OBJECTIVE: To study cutaneous leishmaniasis (CL), in the Calakmul municipality of the Campeche State, during two years. MATERIALS AND METHODS: Individuals with skin lesions were evaluated. Aspirates taken from the lesions were cultured, PCR was performed to diagnose the Leishmania species. RESULTS: The culture detected 42% of the samples. PCR diagnosed CL in 76% of the samples; of those 38% were from children and 62% from adults. 89% of the patients were infected with L. mexicana; 14.4% with Mexican strains of L. mexicana; 7% with L. braziliensis; 3.6% with L. mexicana and L. braziliensis. The most affected villages with CL were Dos Lagunas Sur with 12.3%, La Mancolona with 6.5% and La Guadalupe with 2.2% of prevalence, respectively. After the treatment with Glucantime, 96% of the patients were healed. CONCLUSION: CL is an important public health concern in Calakmul, and the parasite causing it belongs to Leishmania mexicana and Leishmania braziliensis complexes.

Asunto(s)

Leishmaniasis Cutánea/epidemiología , Adulto , Animales , Antiprotozoarios/uso terapéutico , Niño , ADN Protozoario/análisis , Reservorios de Enfermedades , Femenino , Geografía Médica , Humanos , Leishmania braziliensis/aislamiento & purificación , Leishmania mexicana/aislamiento & purificación , Leishmaniasis Cutánea/parasitología , Masculino , Meglumina/uso terapéutico , Antimoniato de Meglumina , México/epidemiología , Compuestos Organometálicos/uso terapéutico , Prevalencia , Inducción de Remisión , Roedores/parasitología

RESUMEN

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.

Asunto(s)

Aedes , Vivienda/estadística & datos numéricos , Insectos Vectores , Animales , Cruzamiento , Dengue/transmisión , México , Control de Mosquitos

RESUMEN

DNA from Onchocerca volvulus from Oaxaca and Chiapas, Mexico were used as templates to amplify members of the O-150 Onchocerca specific repeat sequence family. The resulting PCR amplicons all hybridized with OVS2, an oligonucleotide that has been previously shown to recognize amplicons derived from O. volvulus with 100% sensitivity. However, when PCR products amplified from the O. volvulus specific plasmid pOVS134 were used as a probe, most samples did not hybridize. Similarly, when PCR products amplified from DNA isolated from adult O. volvulus from Oaxaca were used as a probe, amplicons from adult worms from both Oaxaca and Chiapas were recognized, but PCR products from infected black flies from Chiapas were not recognized. Amplicons derived from an adult worm from Chiapas hybridized with PCR products produced from adult parasites from both Oaxaca and Chiapas and to PCR products derived from the DNA of infected black flies from Chiapas. These data, when taken together, suggest that differences exist among the repeat sequence populations of parasites from Oaxaca and Chiapas in Mexico, suggesting that the O-150 repeat sequence family may be a useful tool for biogeographic studies of O. volvulus in the Americas.

Asunto(s)

ADN de Helmintos/metabolismo , Onchocerca volvulus/genética , Onchocerca volvulus/aislamiento & purificación , Animales , Southern Blotting , Sondas de ADN , ADN de Helmintos/química , Amplificación de Genes , Genes de Helminto , Variación Genética , Geografía , Insectos Vectores/genética , Insectos Vectores/parasitología , Larva/genética , México , Hibridación de Ácido Nucleico , Onchocerca volvulus/crecimiento & desarrollo , Plásmidos/genética , Reacción en Cadena de la Polimerasa , Secuencias Repetitivas de Ácidos Nucleicos , Simuliidae/genética , Simuliidae/parasitología , Moldes Genéticos

RESUMEN

Leishmaniasis in Mexico is a public health problem because all the clinical forms have been recorded in most Mexican states. We studied patients showing clinical symptoms of any form of leishmaniasis, from several endemic areas. Bone marrow samples, aspirates or skin biopsies were taken and deoxyribonucleic acid (DNA) was extracted and amplified by the polymerase chain reaction (PCR) with universal primers AJS1 and DeB8, specific for the Leishmania subgenus Leishmania. The PCR products were then hybridized by dot- or Southern blotting and probed with probe 9.2, specific for the L. mexicana complex. If hybridization did not occur, the DNA was amplified with primers D1 and D2, specific for members of the L. donovani complex, and PCR products were hybridized with probe B4Rsa, also specific for the L. donovani complex. DNA was also amplified with primers B1 and B2, specific for the subgenus Viannia, and the PCR products were hybridized with probe B18, specific for the L. braziliensis complex. It was found that in Tabasco and Veracruz, Mexico, localized cutaneous leishmaniasis (LCL) is caused by infection with members of the L. mexicana complex, whereas in the states of Nayarit and Campeche it was due to infection with the L. mexicana and/or L. braziliensis complexes. Visceral leishmaniasis was caused by L. (L.) chagasi, mainly in the states of Chiapas and Guerrero, and by L. (L.) mexicana in one immunocompromised patient from Tabasco.

Asunto(s)

ADN Protozoario/análisis , Leishmania/clasificación , Leishmaniasis/parasitología , Reacción en Cadena de la Polimerasa/métodos , Animales , Humanos , Leishmania/genética , Leishmania braziliensis/clasificación , Leishmania donovani/clasificación , Leishmania mexicana/clasificación , México , Parasitología/métodos

RESUMEN

An epidemiological study was carried out in the northern Mexican state, Nayarit. Fourteen patients with possible cutaneous leishmaniasis skin lesions gave positive Montenegro skin tests. Biopsies were taken from the skin ulcer and analyzed by polymerase chain reaction (PCR) with specific primers for the Leishmania mexicana complex; however all biopsies were not amplified. PCR carried out with specific primers for the L. braziliensis complex resulted in the amplification of all patient DNA. DNA from 12 out of 14 biopsies gave positive amplification with primers species specific for L. (Viannia) braziliensis and hybridized with a species specific L. (V.) braziliensis probe. These results demonstrate the presence in Nayarit of at least two members of the L. braziliensis complex. Most of the cutaneous lesions were caused by L. (V.) braziliensis and two by another species belonging to the L. braziliensis complex. As far as we are aware, this is the first report of L. (V.) braziliensis in Nayarit. The main risk factor associated with the contraction of this disease in Nayarit is attributed to working on coffee plantations

Asunto(s)

Bovinos , Humanos , Animales , Masculino , Femenino , Leishmania braziliensis , Leishmaniasis Cutánea/parasitología , ADN/aislamiento & purificación , Leishmaniasis Cutánea/epidemiología , Leishmaniasis Cutánea/patología , México/epidemiología , Reacción en Cadena de la Polimerasa , Sensibilidad y Especificidad , Pruebas Cutáneas