Multi-Year Mass-Trapping With Autocidal Gravid Ovitraps has Limited Influence on Insecticide Susceptibility in Aedes aegypti (Diptera: Culicidae) From Puerto Rico.

Mass-trapping has been used to control outbreaks of Aedes aegypti (Linnaeus) (Diptera: Culicidae) in Puerto Rico since 2011. We investigated the effect of multi-year, insecticide-free mass trapping had on the insecticide susceptibility profile of Ae. aegypti. Eggs collected in southern Puerto Rico were used to generate F1 populations that were tested for susceptibility to permethrin, sumethrin, bifenthrin, deltamethrin, and malathion according to CDC bottle bioassays protocols. All populations of Ae. aegypti were resistant to the synthetic pyrethroids and mosquitoes from two locations were partially resistant to malathion. Population genetic analysis, using a double digest restriction sites associated DNA sequencing (ddRADseq) approach, indicated a large amount of migration between study sites effectively homogenizing the mosquito populations. Mass-trapping using noninsecticidal autocidal gravid ovitraps did not restore susceptibility to five active ingredients that are found in commercial insecticides. Migration between communities was high and would have brought outside alleles, including resistant alleles to the treatment communities. Further investigation suggests that household use of commercially available insecticide products may continue to select for resistance in absence of public health space spraying of insecticides.

Validación de Shared Decision Making Questionnaire - physician version (SDM-Q-Doc) en español / Validation of the Shared Decision Making Questionnaire - physician version (SDM-Q-Doc) in Spanish

OBJETIVO: Validar Shared Decision Making Questionnaire - physician version (SDM-Q-Doc) en español. DISEÑO: Estudio transversal, multicéntrico y de validación clinimétrica. EMPLAZAMIENTO: Unidades de Atención Primaria. PARTICIPANTES: En la fase de adaptación transcultural fueron 31 médicos de familia y en la de validación 219, todos activos en la práctica médica a nivel institucional y/o privado. MEDICIONES PRINCIPALES: Adaptación transcultural (traducción directa, síntesis y conciliación de la versión por un comité de expertos, traducción inversa, conciliación de la traducción inversa con autores del cuestionario original, análisis de comprensión en una muestra de pacientes) y aspectos psicométricos (fiabilidad y validez). RESULTADOS: Se realizó la adaptación transcultural, la pregunta guía 2 se homologó al SDM-Q-9. No se observaron valores negativos en la correlación de item corregido - con la correlación total; todos son mayores que 0,80. El Alfa de Cronbach fue de 0,963. El item 1 explicó una varianza del 77,2 %. La prueba de Kaiser-Meyer-Olkin (KMO) fue de 0,924 con una esfericidad de Barlett estadísticamente significativa. La matriz de correlación de Pearson demuestra una correlación positiva; en general la relación inter-item es mayor a 0,606. CONCLUSIONES: Se ha validado un cuestionario útil, corto y accesible para aplicarse en Atención Primaria, para medir la toma de decisiones compartidas desde la perspectiva del médico

OBJECTIVE: To validate the Shared Decision Making Questionnaire - physician version (SDM-Q- Doc) in Spanish. DESIGN: Cross-sectional, multicenter, clinimetric validation study. SETTING: Primary Care Units. PARTICIPANTS: In the cross-cultural adaptation phase there were 31 family doctors, and in the validation phase there were 219, all active medical professionals at the institutional and / or private level. MAIN MEASURES: Cross-cultural adaptation (direct translation, synthesis and reconciliation of the version by an expert committee, reverse translation, reconciliation of the reverse translation with authors of the original questionnaire, comprehension analysis in a sample of patients) and psychometric aspects (reliability and validity). RESULTS: Cross-cultural adaptation was performed, guide question 2 was homologated to SDM-Q-9. No negative values were observed in the corrected item-total correlation- with the total correlation; all are higher than 0.80. Cronbach's Alpha was 0.963. Item 1 explained a variance of 77.2%. The Kaiser-Meyer-Olkin (KMO) test was 0.924 with a statistically significant Barlett Sphericity. Pearson's correlation matrix shows a positive correlation; in general the inter-item relationship is greater than 0.606. CONCLUSIONS: A useful, short and accessible questionnaire to be applied in Primary Care has been validated to measure shared decision-making from the physician's perspective

Entomological Investigation Detects Dengue Virus Type 1 in Aedes (Stegomyia) albopictus (Skuse) during the 2015-16 Outbreak in Hawaii.

A dengue outbreak occurred on Hawaii Island between September 2015 and March 2016. Entomological investigations were undertaken between December 2015 and February 2016 to determine which Aedes mosquito species were responsible for the outbreak. A total of 3,259 mosquitoes were collected using a combination of CDC autocidal gravid ovitraps, Biogents BG-Sentinel traps, and hand-nets; immature mosquitoes were collected during environmental surveys. The composition of species was Aedes albopictus (58%), Aedes aegypti (25%), Wyeomyia mitchelli (7%), Aedes vexans (5%), Culex quinquefasciatus (4%), and Aedes japonicus (1%). Adult mosquitoes were analyzed by real-time reverse transcription polymerase chain reaction (PCR) for the presence of dengue virus (DENV) RNA. Of the 185 pools of female mosquitoes tested, 15 containing Ae. albopictus were positive for the presence of DENV type 1 RNA. No virus was detected in pools of the remaining species. Phylogenetic analysis showed the virus strain belonged to genotype I and was closely related to strains that were circulating in the Pacific between 2008 and 2014. This is the first report of detection of DENV in Ae. albopictus from Hawaii.

Rapid Screening of Aedes aegypti Mosquitoes for Susceptibility to Insecticides as Part of Zika Emergency Response, Puerto Rico.

In response to the 2016 Zika outbreak, Aedes aegypti mosquitoes from 38 locations across Puerto Rico were screened using Centers for Disease Control and Prevention bottle bioassays for sensitivity to insecticides used for mosquito control. All populations were resistant to pyrethroids. Naled, an organophosphate, was the most effective insecticide, killing all mosquitoes tested.

Impacts of Hurricanes Irma and Maria on Aedes aegypti Populations, Aquatic Habitats, and Mosquito Infections with Dengue, Chikungunya, and Zika Viruses in Puerto Rico.

Puerto Rico was severely impacted by Hurricanes Irma and Maria in September 2017. The island has been endemic for dengue viruses (DENV) and recently suffered epidemics of chikungunya (CHIKV 2014) and Zika (ZIKV 2016) viruses. Although severe storms tend to increase the number of vector and nuisance mosquitoes, we do not know how they influence Aedes aegypti populations and arboviral transmission. We compared the abundance of female Ae. aegypti in autocidal gravid ovitraps (AGO traps), container habitats, and presence of RNA of DENV, CHIKV, and ZIKV in this vector before and after the hurricanes in Caguas city and in four communities in southern Puerto Rico. Two of these communities were under vector control using mass AGO trapping and the other two nearby communities were not. We also investigated mosquito species composition and relative abundance (females/trap) using Biogents traps (BG-2 traps) in 59 sites in metropolitan San Juan city after the hurricanes. Mosquitoes sharply increased 5 weeks after Hurricane Maria. Ensuing abundance of Ae. aegypti was higher in Caguas and in one of the southern communities without vector control. Aedes aegypti did not significantly change in the two areas with vector control. The most abundant mosquitoes among the 26 species identified in San Juan were Culex (Melanoconion) spp., Culex quinquefasciatus, Culex nigripalpus, and Ae. aegypti. No arboviruses were detected in Ae. aegypti following the hurricanes, in contrast with observations from the previous year, so that the potential for Aedes-borne arboviral outbreaks following the storms in 2017 was low.

Citywide Control of Aedes aegypti (Diptera: Culicidae) during the 2016 Zika Epidemic by Integrating Community Awareness, Education, Source Reduction, Larvicides, and Mass Mosquito Trapping.

This investigation was initiated to control Aedes aegypti and Zika virus transmission in Caguas City, Puerto Rico, during the 2016 epidemic using Integrated Vector Management (IVM), which included community awareness and education, source reduction, larviciding, and mass-trapping with autocidal gravid ovitraps (AGO). The epidemic peaked in August to October 2016 and waned after April 2017. There was a preintervention period in October/November 2016 and IVM lasted until August 2017. The area under treatment (23.1 km2) had 61,511 inhabitants and 25,363 buildings. The city was divided into eight even clusters and treated following a cluster randomized stepped-wedge design. We analyzed pools of female Ae. aegypti adults for RNA detection of dengue (DENV), chikungunya (CHIKV), and Zika (ZIKV) viruses using 360 surveillance AGO traps every week. Rainfall, temperature, and relative humidity were monitored in each cluster. Mosquito density significantly changed (generalized linear mixed model; F8, 14,588 = 296; P < 0.001) from 8.0 ± 0.1 females per trap per week before the intervention to 2.1 ± 0.04 after the percentage of buildings treated with traps was 60% and to 1.4 ± 0.04 when coverage was above 80%. Out of a total 12,081 mosquito pools, there were 1 DENV-, 7 CHIKV-, and 49 ZIKV-positive pools from October 2016 to March 2017. Afterward, we found only one positive pool of DENV in July 2017. This investigation demonstrated that it was possible to scale up effective Ae. aegypti control to a medium-size city through IVM that included mass trapping of gravid Ae. aegypti females.

Trombólisis exitosa en la enfermedad cerebrovascular: reporte de un caso / Successful thrombolysis in cerebrovascular disease: a case report

Resumen El factor de riesgo más importante para presentar una enfermedad cerebrovascular (EVC) es la edad. El ictus es la causa más frecuente de discapacidad adquirida en la edad adulta. De acuerdo con la Organización Mundial de la Salud, se estima que en el año 2050, casi la mitad de la población mayor de 65 años podría sufrir o haber sufrido un EVC. Debido a la gran incidencia y al impacto negativo que tiene esta enfermedad, presentamos el caso clínico de una trombólisis exitosa en una paciente con ictus isquémico y crisis hipertensiva en el Servicio de Urgencias. Ponemos de manifiesto la adecuada evaluación con las diferentes escalas existentes, clínicas, radiológicas y pronósticas (NIHSS, Dragon Score, ASPECT, HAT score), así como los criterios de inclusión y exclusión, los cuales son indispensables para administrar una terapia de repercusión intravenosa. Conclusiones En México, los casos reportados con trombólisis exitosa son sólo el 5%. En este caso de éxito, la adecuada actuación en el Servicio de Urgencias de primer contacto impactó de manera positiva en el pronóstico de la paciente, ya que el diagnóstico oportuno y la administración de rTPA (activador tisular del plasminógeno) evitó secuelas importantes y consiguió una mejor calidad de vida -la cual se ve disminuida hasta en 70% de los pacientes que sufren un EVC (según estudios realizados en los EUA)-.

Abstract The most important risk factor for presenting a cerebrovascular disease (CVA) is age. Stroke is also the most frequent cause of disability acquired in adulthood. According to the World Health Organization, it is estimated that by the year 2050, almost half of the population over 65 could suffer or have suffered a CVA. Due to the high incidence and negative impact of this disease, we present a clinical case of successful thrombolysis in a patient with ischemic stroke and hypertensive crisis in the emergency department. We emphasize the adequate evaluation with the different existing clinical, radiological and predictive scales (NIHSS, Dragon Score, ASPECT, HAT score), as well as the inclusion and exclusion criteria, which are indispensable to administer an intravenous reperfusion therapy. Conclusions In Mexico, the cases reported with successful thrombolysis are only 5%. In this successful case, the proper performance in the emergency service impacted positively on the prognosis of the patient, since the timely diagnosis and administration of rTPA avoided important sequelae and provided a better quality of Life, which is decreased in up to 70% of patients suffering from a CVA (according to studies conducted in the USA).

Entomological Investigation of Aedes aegypti In Neighborhoods With Confirmed Human Arbovirus Infection In Puerto Rico.

The exotic arboviruses chikungunya (CHIKV) and Zika (ZIKV) recently caused large outbreaks and continue to circulate in Puerto Rico, prompting entomological investigations at 9 locations with confirmed CHIKV- or ZIKV-infected human cases. Adult mosquitoes were collected using the Centers for Disease Control and Prevention autocidal gravid ovitraps over a 14-day period at each site. Mean female Aedes aegypti captured per trap-week ranged from 13.47 per trap-week to 1.27 per trap-week. Arbovirus-positive pools were detected at 7 of the 9 sampling sites. We investigated vertical transmission by collecting Ae. aegypti eggs in a single location where ZIKV was found in adult mosquitoes. We discuss the relationship between vector density and infection rates and its implications for determining mosquito density thresholds of novel invasive arboviruses such as CHIKV and ZIKV.

Impact of Autocidal Gravid Ovitraps on Chikungunya Virus Incidence in Aedes aegypti (Diptera: Culicidae) in Areas With and Without Traps.

Puerto Rico detected the first confirmed case of chikungunya virus (CHIKV) in May 2014 and the virus rapidly spread throughout the island. The invasion of CHIKV allowed us to observe Aedes aegypti (L.) densities, infection rates, and impact of vector control in urban areas using CDC autocidal gravid ovitraps (AGO traps) for mosquito control over several years. Because local mosquitoes can only get the virus from infectious residents, detecting the presence of virus in mosquitoes functions as a proxy for the presence of virus in people. We monitored the incidence of CHIKV in gravid females of Ae. aegypti in four neighborhoods-two with three AGO traps per home in most homes and two nearby neighborhoods without AGO mosquito control traps. Monitoring of mosquito density took place weekly using sentinel AGO traps from June to December 2014. In all, 1,334 pools of female Ae. aegypti (23,329 individuals) were processed by real-time reverse transcription PCR to identify CHIKV and DENV RNA. Density of Ae. aegypti females was 10.5 times lower (91%) in the two areas with AGO control traps during the study. Ten times (90.9%) more CHIKV-positive pools were identified in the nonintervention areas (50/55 pools) than in intervention areas (5/55). We found a significant linear relationship between the number of positive pools and both density of Ae. aegypti and vector index (average number of expected infected mosquitoes per trap per week). Temporal and spatial patterns of positive CHIKV pools suggested limited virus circulation in areas with AGO traps.

Health care utilization of mexican patients with medically unexplained physical symptoms.

OBJECTIVE: To determine the prevalence of medically unexplained physical symptoms and the characteristics and use of health services in a group of patients with medically unexplained physical symptoms and a group of patients with other illnesses. METHODS: This was a cross-sectional, retrospective and multicenter study. We included 1,043 patients over 18 years of age from 30 primary care units of a government health institution, in 11 states of Mexico, attended by 39 family physicians. The prevalence of medically unexplained physical symptoms was determined and both groups with or without symptoms were compared with regard to drug use, laboratory and other studies, leaves of absence, and referrals in the last six months. The group with medically unexplained physical symptoms was diagnosed using the Patient Health Questionnaire and the diagnostic criteria of Reid et al. Emergency or terminal illnesses were excluded. The chi square test was used with a statistical significance of p < 0.05. RESULTS: Medically unexplained physical symptoms was diagnosed in 73 patients (7.0%). The majority were women (91.8%); their predominant symptom was from the gastrointestinal system in 56 (76.7%). This group had a greater use of clinical studies and referrals to other services (mean 1.1 vs. 0.5; p <0.0001 and 0.6 vs. 0.8; p < 0.01, respectively). CONCLUSIONS: The prevalence of medically unexplained physical symptoms was low, but with a greater impact on some health services. This could represent an overload in medical costs. OBJETIVO: Determinar la prevalencia de Síntomas Físicos Medicamente No Explicables y las características y uso de los servicios de salud entre el grupo de pacientes con Síntomas Físicos Medicamente No Explicables, y el grupo con otras enfermedades. MÉTODOS: Estudio transversal, retroprospectivo y multicéntrico. Se incluyeron a 1,043 pacientes mayores de 18 años, en 30 unidades de atención primaria de una institución gubernamental en salud, en 11 estados de la República Mexicana, atendidos por 39 médicos familiares. Se estimó la prevalencia de Síntomas Físicos Medicamente No Explicables y se compararon los dos grupos con y sin estos síntomas, en cuanto al uso de medicamentos, estudios de laboratorio, de gabinete, incapacidades y referencias en los últimos seis meses. El grupo de Síntomas Físicos Medicamente No Explicables fue diagnosticado por el Patient Health Questionnaire (son los síntomas físicos más comúnmente referidos por estos pacientes en el primer nivel de atención), además de criterios diagnósticos de Reid et al. Se excluyeron urgencias o con enfermedad terminal. Se utilizó prueba Chi cuadrada con p <0.05 para significancia estadística. RESULTADOS: El 7.0% (73) se diagnosticó como Síntomas Físicos Medicamente No Explicables, la mayoría mujeres (91.8%); el síntoma predominante pertenece al sistema gastrointestinal con 76.7% (56). Este grupo demandó mayor uso de estudios de gabinete y referencias a otros servicios (media 1.1 vs. 0.5; p <0.0001 y 0.8 vs 0.6; p <0.01, respectivamente). CONCLUSIONES: La prevalencia de Síntomas Físicos Medicamente No Explicables fue baja, pero con impacto significativo en el uso de algunos servicios de salud. Esto pudiera representar un mayor costo comparado con otro grupo de pacientes.

Operational Aspects of the Centers for Disease Control and Prevention Autocidal Gravid Ovitrap.

Dengue viruses cause hundreds of millions of infections every year in tropical and subtropical countries. Unfortunately, there is not a single universal vector control method capable of suppressing Aedes aegypti (L.) populations. Amongst novel control tools or approaches are various types of traps targeting gravid females or their eggs. Here, we provide details of the operational use of the Centers for Disease Control and Prevention autocidal gravid ovitrap (CDC-AGO trap) for the surveillance and control of Ae. aegypti. Adult mosquitoes were monitored every week in 2 isolated neighborhoods treated with 3 AGO traps per house in 85% of houses and in 2 reference neighborhoods without control traps. Between March 2013 and April 2015 we serviced the AGO traps 14 times in each community (every 2 months). Common trap problems were absent or broken trap tops (1-1.5%), flooded (0.1-0.7%) or dry (0.5-1.3%) traps, and missing (0.3-0.8%) or vandalized (0.5-1.4%) traps. Most traps kept a volume of infusion between 45% and 97% of their original volume (10 liters). Nontarget organisms captured in AGO traps were mostly small flies, and to a lesser extent ants, cockroaches, grasshoppers, butterflies, dragonflies, and lizards. Trap coverage ranged between 83% and 87% of houses in both communities throughout the study. We interpret such high levels of trap retention over time as an expression of acceptance by the community.

Non-human primate antibody response to mosquito salivary proteins: Implications for dengue virus transmission in Puerto Rico.

An important step to incriminate a mosquito as a vector of a disease pathogen is finding evidence of direct contact between the mosquito and humans. Typically, this is accomplished through landing/biting catches, or host blood meal analysis in engorged mosquitoes via immunologic assays. An alternate approach is to identify the presence of specific mosquito anti-saliva protein antibodies in the blood of exposed hosts. Following the discovery of dengue infected, free roaming non-human primates in Puerto Rico, we investigated which mosquito species had bitten these primates using a serologic assay. Serum samples from 20 patas monkeys (Erythrocebus patas) and two rhesus macaques (Macaca mulatta) were used to evaluate mosquito bite exposure to Aedes aegypti, Aedes mediovittatus, Aedes taeniorhynchus, and Culex quinquefasciatus mosquitoes. Of 22 non-human primates examined 20 (90%), 17 (77%), 13 (59%), and 7 (31%) were positive for exposure to Ae. mediovittatus, Cx. quinquefasciatus, Ae. taeniorhynchus, and Ae. aegypti, respectively. Our findings indicated that free-roaming primates in Puerto Rico were exposed to the bites of one proven dengue vector, Ae. aegypti and one potential dengue vector, Ae. mediovittatus.

Health care utilization of mexican patients with medically unexplained physical symptoms / Uso de los servicios de salud de pacientes mexicanos con síntomas físicos medicamente inexplicables

Abstract Objective: To determine the prevalence of medically unexplained physical symptoms and the characteristics and use of health services in a group of patients with medically unexplained physical symptoms and a group of patients with other illnesses. Methods: This was a cross-sectional, retrospective and multicenter study. We included 1,043 patients over 18 years of age from 30 primary care units of a government health institution, in 11 states of Mexico, attended by 39 family physicians. The prevalence of medically unexplained physical symptoms was determined and both groups with or without symptoms were compared with regard to drug use, laboratory and other studies, leaves of absence, and referrals in the last six months. The group with medically unexplained physical symptoms was diagnosed using the Patient Health Questionnaire and the diagnostic criteria of Reid et al. Emergency or terminal illnesses were excluded. The chi square test was used with a statistical significance of p < 0.05. Results: Medically unexplained physical symptoms was diagnosed in 73 patients (7.0%). The majority were women (91.8%); their predominant symptom was from the gastrointestinal system in 56 (76.7%). This group had a greater use of clinical studies and referrals to other services (mean 1.1 vs. 0.5; p <0.0001 and 0.6 vs. 0.8; p < 0.01, respectively). Conclusions: The prevalence of medically unexplained physical symptoms was low, but with a greater impact on some health services. This could represent an overload in medical costs....au

Resumen Objetivo: Determinar la prevalencia de Síntomas Físicos Medicamente No Explicables y las características y uso de los servicios de salud entre el grupo de pacientes con Síntomas Físicos Medicamente No Explicables, y el grupo con otras enfermedades. Métodos: Estudio transversal, retroprospectivo y multicéntrico. Se incluyeron a 1,043 pacientes mayores de 18 años, en 30 unidades de atención primaria de una institución gubernamental en salud, en 11 estados de la República Mexicana, atendidos por 39 médicos familiares. Se estimó la prevalencia de Síntomas Físicos Medicamente No Explicables y se compararon los dos grupos con y sin estos síntomas, en cuanto al uso de medicamentos, estudios de laboratorio, de gabinete, incapacidades y referencias en los últimos seis meses. El grupo de Síntomas Físicos Medicamente No Explicables fue diagnosticado por el Patient Health Questionnaire (son los síntomas físicos más comúnmente referidos por estos pacientes en el primer nivel de atención), además de criterios diagnósticos de Reid et al. Se excluyeron urgencias o con enfermedad terminal. Se utilizó prueba Chi cuadrada con p <0.05 para significancia estadística. Resultados: El 7.0% (73) se diagnosticó como Síntomas Físicos Medicamente No Explicables, la mayoría mujeres (91.8%); el síntoma predominante pertenece al sistema gastrointestinal con 76.7% (56). Este grupo demandó mayor uso de estudios de gabinete y referencias a otros servicios (media 1.1 vs. 0.5; p <0.0001 y 0.8 vs 0.6; p <0.01, respectivamente). Conclusiones: La prevalencia de Síntomas Físicos Medicamente No Explicables fue baja, pero con impacto significativo en el uso de algunos servicios de salud. Esto pudiera representar un mayor costo comparado con otro grupo de pacientes...au

Knockdown Resistance Mutations in Aedes aegypti (Diptera: Culicidae) From Puerto Rico.

Permethrin resistance is widespread in Aedes aegypti (L.), the main dengue, zika, and chikungunya virus vector in Latin America and the Caribbean. A common mechanism of resistance to pyrethroids-knockdown resistance (kdr)-is conferred through mutations in the insect's voltage-dependent sodium channel. In this mosquito, around 10 replacement substitutions in the voltage-gated sodium channel gene (vgsc) have been reported in pyrethroid-resistant strains. Two of these mutations, named Ile1,016 and Cys1,534, are widespread in mosquito populations from Latin America and the Caribbean. This study assessed the levels of permethrin resistance and the frequency of two kdr mutations in eight Ae. aegypti populations collected in Puerto Rico in 2013. Permethrin resistance factors ranged from 33-214-fold relative to the New Orleans reference strain. The frequency of kdr mutation Ile1,016 ranged from 0.65 to fixation (1.0), and for Cys1,534 frequencies varied from 0.8 to fixation. Alarmingly, two populations-Carolina and Caguas-reached fixation at both loci. Our results suggest that permethrin effectiveness for Ae. aegypti control is compromised in these collections from Puerto Rico.

Susceptibility to Temephos and Spinosad in Aedes aegypti (Diptera: Culicidae) From Puerto Rico.

We examined the susceptibility to temephos and spinosad (Natular EC) of eight Aedes aegypti (L.) populations from Puerto Rico, following WHO method (WHO 2005). Enzyme activity was measured for alpha- and beta-esterases, multiple function oxidases, glutathione-s-transferases, and insensitive acetylcholinesterase and was tested for correlation with the susceptibility level. The results showed that larval populations from Puerto Rico obtained during 2014 were found to be susceptible to both larvicides, with low (resistance factor) RRLC50 values (<5 fold) and altered and incipiently altered enzyme expression for all populations, except the insensitive acetylcholinesterase enzyme, where only the population of Ponce showed overexpression (53.3%) above the threshold established with the New Orleans susceptible strain. We recommend the use of both larvicides for mosquito control in the study area and encourage further susceptibility monitoring.

Evaluation of Household Bleach as an Ovicide for the Control of Aedes aegypti.

Accumulations of dormant eggs in container habitats allow Aedes aegypti populations to survive harsh environmental conditions and may frustrate control interventions directed at larval and adult life stages. While sodium hypochlorite solutions (NaOCl) have long been recognized as ovicides for use against dengue vectors, the susceptibility of eggs to spray applications has not been robustly evaluated on substrate materials representative of the most frequently utilized artificial container habitats. Experiments were performed under controlled and natural conditions by applying dilutions of household bleach (52.5 ppt NaOCl) as a spray to eggs on plastic, rubber, and concrete surfaces, with and without a smectite clay thickener. Laboratory assays identified the minimum NaOCl concentrations required to eliminate eggs on plastic (10 ppt), rubber (20 ppt) and concrete (20 ppt) surfaces. Addition of smectite clay reduced the minimum effective concentration to 10 ppt NaOCl for all 3 substrates. A minimum exposure period of 24 h was required to completely eliminate egg viability on concrete surfaces, even at the highest NaOCl concentration (52.5 ppt). Field experiments verified that spray application of a 1∶3 dilution of household bleach mixed with smectite clay can reduce egg hatching by ≥ 99% in shaded and sun-exposed plastic containers. Similarly, 4∶1 dilution of household bleach (with or without smectite clay) eliminated ≥ 98% of eggs from concrete surfaces in outdoor, water-filled drums. In this study, we propose a practical, effective and safe strategy for using household bleach to eliminate Ae. aegypti eggs in a range of artificial container habitats.

Comparison of vector competence of Aedes mediovittatus and Aedes aegypti for dengue virus: implications for dengue control in the Caribbean.

BACKGROUND: Aedes mediovittatus mosquitoes are found throughout the Greater Antilles in the Caribbean and often share the same larval habitats with Ae. Aegypti, the primary vector for dengue virus (DENV). Implementation of vector control measures to control dengue that specifically target Ae. Aegypti may not control DENV transmission in Puerto Rico (PR). Even if Ae. Aegypti is eliminated or DENV refractory mosquitoes are released, DENV transmission may not cease when other competent mosquito species like Ae. Mediovittatus are present. To compare vector competence of Ae. Mediovittatus and Ae. Aegypti mosquitoes, we studied relative infection and transmission rates for all four DENV serotypes. METHODS: To compare the vector competence of Ae. Mediovittatus and Ae. Aegypti, mosquitoes were exposed to DENV 1-4 per os at viral titers of 5-6 logs plaque-forming unit (pfu) equivalents. At 14 days post infectious bloodmeal, viral RNA was extracted and tested by qRT-PCR to determine infection and transmission rates. Infection and transmission rates were analyzed with a generalized linear model assuming a binomial distribution. RESULTS: Ae. Aegypti had significantly higher DENV-4 infection and transmission rates than Ae. mediovittatus. CONCLUSIONS: This study determined that Ae. Mediovittatus is a competent DENV vector. Therefore dengue prevention programs in PR and the Caribbean should consider both Ae. Mediovittatus and Ae. Aegypti mosquitoes in their vector control programs.

Sustained, area-wide control of Aedes aegypti using CDC autocidal gravid ovitraps.

We have shown that the Centers for Disease Control and Prevention (CDC) autocidal gravid ovitraps (AGO trap) reduced the Aedes aegypti population and prevented mosquito outbreaks in southern Puerto Rico. After showing treatment efficacy for 1 year, we deployed three traps per home in an area that formerly did not have traps and in a site that served as the intervention area. Two new areas were selected as reference sites to compare the density of Ae. aegypti without traps. We monitored mosquitoes and weather every week in all four sites. The hypotheses were the density of Ae. aegypti in the former reference area converges to the low levels observed in the intervention area, and mosquito density in both areas having control traps is lower than in the new reference areas. Mosquito density in the former reference area decreased 79% and mosquito density in the new reference areas was 88% greater than in the intervention areas.

Use of the CDC autocidal gravid ovitrap to control and prevent outbreaks of Aedes aegypti (Diptera: Culicidae).

Populations ofAedes aegypti (L.) can be managed through reductions in adult mosquito survival, number of offspring produced, or both. Direct adult mortality can be caused by the use of space sprays or residual insecticides to mosquito resting sites, and with a variety of residual insecticide-impregnated surfaces that are being tested, such as curtains, covers for water-storage vessels, bednets, and ovitraps. The fertility ofAe. aegypti populations can be reduced by the use of autocidal oviposition cups that prevent the development of mosquitoes inside the trap by mechanical means or larvicides, as well as by releasing sterile, transgenic, and para-transgenic mosquitoes. Survival and fertility can be simultaneously reduced by capturing gravid female Ae. aegypti with sticky gravid traps. We tested the effectiveness of the novel Centers for Disease Control and Prevention autocidal gravid ovitrap (CDC-AGO trap) to control natural populations ofAe. aegypti under field conditions in two isolated urban areas (reference vs. intervention areas) in southern Puerto Rico for 1 yr. There were significant reductions in the captures of female Ae. aegypti (53-70%) in the intervention area The presence of three to four AGO control traps per home in 81% of the houses prevented outbreaks of Ae. aegypti, which would be expected after rains. Mosquito captures in BG-Sentinel and AGO traps were significantly and positively correlated, showing that AGO traps are useful and inexpensive mosquito surveillance devices. The use of AGO traps to manage Ae. aegypti populations is compatible with other control means such as source reduction, larviciding, adulticiding, sterile insect techniques, induced cytoplasmic incompatibility, and dominant lethal gene systems.