Novel Vector Control Approaches: The Future for Prevention of Zika Virus Transmission?

In a Perspective accompanying Abad-Franch and colleagues, Lorenz von Seidlein, Alexander Kekulé, and Daniel Strickman discuss the importance of developing effective strategies to minimize mosquito-borne transmission of human diseases.

Larval mosquito habitat utilization and community dynamics of Aedes albopictus and Aedes japonicus (Diptera: Culicidae).

Aedes albopictus (Skuse) and Ae. japonicus (Theobald) are important container-inhabiting mosquitoes that transmit disease agents, outcompete native species, and continue to expand their range in the United States. Both species deposit eggs in natural and artificial containers and thrive in peridomestic environments. The goal of our study was to examine the types and characteristics of containers that are most productive for these species in the northeastern United States. In total, 306 containers were sampled in urban, suburban, and rural areas of New Jersey. Multiple biotic and abiotic factors were recorded in an attempt to identify variables associated with the productivity of each species. Based on pupal abundance and density of container types, results showed that tires, trash cans, and planter dishes were the most important containers for Ae. albopictus, while planter dishes were the most important containers for Ae. japonicus. Container color (black and gray), material (rubber), and type (tires) were correlated with species presence for Ae. albopictus and Ae. japonicus. These factors may play a role in the selection of oviposition sites by female mosquitoes or in the survival of their progeny. Differences in species composition and abundance were detected between areas classified as urban, suburban, and rural. In urban and suburban areas, Ae. albopictus was more abundant in container habitats than Ae. japonicus; however, Ae. japonicus was more abundant in rural areas, and when water temperatures were below 14 degrees C. Our results suggest many variables can influence the presence of Ae. albopictus and Ae. japonicus in container habitats in northeastern United States.

Willingness-to-pay for an area-wide integrated pest management program to control the Asian tiger mosquito in New Jersey.

Using contingent valuation we estimated the perceived value of an area-wide integrated pest management program for the Asian tiger mosquito, Aedes albopictus, implemented in Monmouth and Mercer counties, NJ. We estimated residents' maximum willingness-to-pay and perceived monetary benefits (willingness-to-pay excluding residents who protested all types of payments) and payment modality through a telephone survey of 51 randomly selected households. The mean (+/- SE) perceived monetary benefits for an enhanced mosquito abatement program was $9.54 +/- 2.90 per capita per year. Most respondents would have been willing to pay through taxes (35%) or charitable donations (6%) starting then, or through one of these approaches in the future (43%), whereas 16% were completely unwilling to pay any additional costs whatsoever. We projected that the perceived monetary benefits to the counties' 1.01 million residents for an enhanced mosquito control program would be $9.61 million annually. Thus, collectively residents perceived monetary benefits of 3.67 times the combined 2008 annual operating costs of the counties' existing mosquito control programs of $2.61 million.

Topically applied AaeIAP1 double-stranded RNA kills female adults of Aedes aegypti.

Aedes aegypti (L.) (Diptera: Culicidae) is the primary vector of both dengue and yellow fever. Use of insecticides is one of the primary ways to control this medically important insect pest. However, few new insecticides have been developed for mosquito control in recent years. As a part of our effort to develop new insecticides to control mosquitoes, an inhibitor of apoptosis protein 1 gene in Aedes aegypti (AaeIAP1) was targeted for the development of molecular pesticides. Herein, for the first time, we report that topically applied AaeIAP1 double-stranded RNA products are able to kill female adults of Ae. aegypti. Our results indicate that critical pathways or genes could be targeted to develop molecular pesticides for the control of medically important diseases vectors.

Longevity of Aedes aegypti (Diptera: Culicidae) compared in cages and field under ambient conditions in rural Thailand.

Aedes aegypti (L.) were exposed to all of the physiological stresses of a natural environment, without mortality from predation or from the defensive behavior of bitten hosts. Each replicate consisted of four cages containing 50 male and 50 female, locally reared Ae. aegypti. The cages were placed in the bedroom and kitchen of a typical Thai house in the village of Hua Samrong, Chachoengsao Province. Replicates were repeated five times between October 1991 and June 1992. Mosquitoes had constant access to sugar and were offered blood meals every day. The number of dead mosquitoes and eggs were recorded daily for 30 days. Indoor maximum temperatures were high throughout the year, ranging from a mean of 32.8 degrees C in October/November to 37.6 degrees C in March-April, with an absolute maximum of 41 degrees C. Survival in cages was related to temperature, with the force of mortality lowest in November-December (0.002) and highest in May-June (0.043). The negative slope of cohort survival was also greatest in the warmest months. Egg laying rate was lower in the cooler months (minimum 16.4 eggs/female/day in November-December), but did not vary greatly in absolute value (maximum 22.7 eggs/female/day in March-April). Statistically, survival of females in cages was much greater than survival calculated from mark-release-recapture studies conducted by other authors in Hua Samrong. The difference in survival for mosquitoes released in the field and those confined to cages suggests that predation or defensive behavior may be important in regulating adult populations of this vector.

Suppression of Aedes albopictus, the Asian tiger mosquito, using a 'hot spot' approach.

BACKGROUND: Recent changes in climate and human behavior have led to dramatic increases in the abundance and geographic expansion of invasive mosquito vectors such as Aedes albopictus. Although source reduction has been shown to be effective in reducing mosquito populations, thousands of backyards need to be inspected during door-to-door campaigns, which is labor intensive and expensive. We identified 'hot spots' as high (five or more female or male Ae. albopictus) adult mosquito populations at very focal locations. We tested whether hot spot source reduction efforts were effective in reducing mosquito populations in the early summer season (June to July). RESULTS: Analysis of historical data from the study sites indicated the proportion of hot spots in the control site relative to the intervention site was much greater in 2011, when hot spot treatments were applied to the intervention site, than in 2012, 2013 and 2014 combined, when no sites were treated [OR (95% CI) = 3.9 (1.8, 8.5), Z = 3.39, P < 0.001). CONCLUSION: Hot spot treatments can be incorporated into existing integrated mosquito management programs to increase effectiveness while reducing the time, cost and effort spent on methods such as door-to-door source reduction. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.

Making Mosquito Taxonomy Useful: A Stable Classification of Tribe Aedini that Balances Utility with Current Knowledge of Evolutionary Relationships.

The tribe Aedini (Family Culicidae) contains approximately one-quarter of the known species of mosquitoes, including vectors of deadly or debilitating disease agents. This tribe contains the genus Aedes, which is one of the three most familiar genera of mosquitoes. During the past decade, Aedini has been the focus of a series of extensive morphology-based phylogenetic studies published by Reinert, Harbach, and Kitching (RH&K). Those authors created 74 new, elevated or resurrected genera from what had been the single genus Aedes, almost tripling the number of genera in the entire family Culicidae. The proposed classification is based on subjective assessments of the "number and nature of the characters that support the branches" subtending particular monophyletic groups in the results of cladistic analyses of a large set of morphological characters of representative species. To gauge the stability of RH&K's generic groupings we reanalyzed their data with unweighted parsimony jackknife and maximum-parsimony analyses, with and without ordering 14 of the characters as in RH&K. We found that their phylogeny was largely weakly supported and their taxonomic rankings failed priority and other useful taxon-naming criteria. Consequently, we propose simplified aedine generic designations that 1) restore a classification system that is useful for the operational community; 2) enhance the ability of taxonomists to accurately place new species into genera; 3) maintain the progress toward a natural classification based on monophyletic groups of species; and 4) correct the current classification system that is subject to instability as new species are described and existing species more thoroughly defined. We do not challenge the phylogenetic hypotheses generated by the above-mentioned series of morphological studies. However, we reduce the ranks of the genera and subgenera of RH&K to subgenera or informal species groups, respectively, to preserve stability as new data become available.

The past and present threat of rickettsial diseases to military medicine and international public health.

Morbidity and mortality caused by rickettsioses have had a major influence on military activities and public health for >2000 years. The threat posed by the rickettsioses is reviewed, focusing on the impact and epidemiology of those that have adversely influenced wartime operations and the current challenges posed by these diseases. With their uneven worldwide distribution, the discovery of drug-refractory strains of Orientia tsutsugamushi, the increased threat of their use in acts of bioterrorism, frequent deployment of troops to regions of endemicity, and exposures due to increased humanitarian missions, these diseases continue to be a threat to military personnel in the field. Effective strategies to reduce the impact of these diseases include development of effective vaccines, enhanced surveillance, and development of new safe, effective, and odorless repellants. The continuation of a proven, highly productive military infectious disease research program is essential for providing solutions to these daunting tasks.

Dengue and its vectors in Thailand: introduction to the study and seasonal distribution of Aedes larvae.

A study was conducted from 1989 to 1994 that included surveillance for dengue and its mosquito vectors in 3 villages and 2 schools in Chachoengsao Province, 100 km east of Bangkok, Thailand. The study is introduced, and results of larval surveys for Aedes mosquitoes (predominantly Aedes aegypti (L.)), with 94, 86, and 90% of positive containers infested by this species in the hot, wet, and cool seasons, respectively), are described. These surveys were conducted in 1990-1991 during each of the 3 principal seasons: hot (February-April), rainy (May-October), and cool (November-January). Indoor maximum and minimum temperatures were consistently greater than outdoor temperatures. The differences between maximum and minimum temperatures both indoors and outdoors varied seasonally, with the greatest differences in the cool season and the least differences in the rainy season. The most rain fell in September and October and the least rain in December, January, and February. The number of Aedes larvae in each container was categorized (no larvae, 1-9 larvae, 10-50 larvae, > 50 larvae) by dipping with a fishnet or by visual examination (for drinking water). A larval index was calculated for each house and school by summing the estimations from each container. These indexes showed that one village had more larvae in every season (mean larval index per house = 117) than the other 2 villages (larval indexes of 86 and 70). The larval index of each house was mapped for each season, and the distribution was spatially analyzed by producing kriged estimates of interpolated data. These analyses showed that larvae were significantly concentrated in particular areas of the villages, especially during the wet season. Even when larvae were least abundant, every part of each village had at least some larvae. The results of the study imply that dengue vector control programs in Southeast Asian villages could increase their efficiency by applying their most energetic efforts on schools and areas with the greatest abundance of larvae, as measured by calculation of larval indexes.

Dengue and its vectors in Thailand: calculated transmission risk from total pupal counts of Aedes aegypti and association of wing-length measurements with aspects of the larval habitat.

Working in a village dengue focus in Chachoengsao Province, Thailand, aedine mosquito larvae and pupae were counted in all containers of 10 houses per month. The wings of female Aedes aegypti (L.) emerging from pupae were measured. Number of pupae and size of emerging females increased in containers with qualities that favored availability of larval food sources (e.g., uncovered containers). The small size of most mosquitoes compared with those raised in the laboratory indicated that the larval population as a whole was under nutritional stress. Applying the number of pupae per house and measurement of air and water temperature with an existing model, the risk of dengue transmission was greatest in May and June. The estimated number of female Ae. aegypti per house was well above the threshold for increasing transmission in all months but December through February. A phased approach to sampling immature aedine mosquitoes in Thailand is proposed, which would consist of routine surveillance of larval index and occasional total counts with measurement of wing size. Such a system would combine the benefits of the simple application of larval surveillance with the valuable data gathered from pupal counts and wing measurements.

Occurrence of Orientia tsutsugamushi in small mammals from Thailand.

Extensive sampling of small mammals was conducted in eight provinces of Thailand between September 9, 1992 and April 29, 2001. A total of 3,498 specimens representing 22 species were collected. Eighty-eight percent (3,089 of 3,498) of the animals were collected from a region in Chiangrai Province, which is commonly recognized as endemic for human scrub typhus. Blood and tissue samples from each animal were tested for the presence of Orientia tsutsugamushi, the etiologic agent of scrub typhus. The predominant species collected were Rattus rattus (53%, n = 1,863), R. losea (18%, n = 638), Bandicota indica (16%, n = 564), and R. exulans (4%, n = 146). Orientia tsutsugamushi was detected in 10 of the 22 species of mammals that included R. bukit (25% infected, 1 of 4), R. rattus (23%, 419 of 1,855), R. argentiventer (22%, 5 of 23), R. berdmorei (22%, 2 of 9), R. losea (13%, 82 of 638), B. indica (9%, 52 of 564), R. koratensis (8%, 1 of 12), B. savilei (3%, 1 of 30), R. exulans (1%, 2 of 146), and Tupaia glis (2%, 1 of 49). Infected animals were found in Chiangrai (18% infected, 563 of 3,084), Bangkok (11%, 1 of 9), Sukothai (3%, 1 of 30), and Nonthaburi (1%, 1 of 69) Provinces. The implications towards scrub typhus maintenance and transmission are discussed.

Comparative resistance of Anopheles albimanus and Aedes aegypti to N,N-diethyl-3-methylbenzamide (Deet) and 2-methylpiperidinyl-3-cyclohexen-1-carboxamide (AI3-37220) in laboratory human-volunteer repellent assays.

The insect repellents N,N-diethyl-3-methylbenzamide (Deet) and the racemate and 1S,2'S stereoisomer of 2-methylpiperidinyl-3-cyclohexene-1-carboxamide (AI3-37220) were tested against Anopheles albimanus Wiedemann and Aedes aegypti (L.) in laboratory human-volunteer assays. Estimated skin doses of Deet or racemic AI3-37220 required to reduce biting by 95% in Ae. aegypti were 2.3 and 3.5 x 10(-2) micromol/cm2 skin, respectively, whereas estimated doses for 95% bite reduction of An. albimanus in an approximately 40-yr-old laboratory colony established from El Salvador were 5 times higher at 12 x 10(-2) micromol Deet/cm2 skin and >20 x 10(-2) micromol/cm2 skin for AI3-37220. In tests with the 1S,2'S stereoisomer of AI3-37220, a newly established colony of An. albimanus from Belize bit less aggressively than El Salvador An. albimanus. However, the Belize-derived mosquitoes were as resistant as the old El Salvador colony to repellent effects of 1S,2'S stereoisomer of 2-methylpiperidinyl-3-cyclohexene-1-carboxamide. Earlier workers surmised that usual skin doses of Deet would offer only limited protection against An. albimanus in the field. Our findings support this speculation, but they also indicate that doses of Deet higher than those needed for protection against Ae. aegypti might offer reasonable protection against An. albimanus. Results indicate that neither racemate nor 1S,2'S stereoisomer of 2-methylpiperidinyl-3-cyclohexene-1-carboxamide offer as much protection as Deet against An. Albimanus, despite being highly effective against Ae. aegypti.

The genus and subgenus categories within Culicidae and placement of Ochlerotatus as a subgenus of Aedes.

Many species of Culicidae are of major medical, veterinary, and economic importance. To facilitate discussion among taxonomists, medical entomologists, ecologists, and vector control specialists, it is essential that culicidologists be able to readily recognize individual genera. Adult female mosquitoes, the stage most often encountered in surveys, should be identifiable to genus without dissection with the aid of a good-quality dissecting microscope. Female adult specimens of Ochlerotatus and Aedes as defined by Reinert cannot be identified morphologically without dissection, and no distinct differences in biology, behavior, and ecology distinguish these 2 taxa as currently defined. Use of these names as genera complicates mosquito identification and interferes with information retrieval and communication among taxonomists, medical entomologists, and vector control specialists. Therefore, it is our opinion that Ochlerotatus Lynch Arribalzaga should be placed as a subgenus of Aedes Meigen, Aedes (Ochlerotatus). We believe that the usage of the genus Aedes and the subgenus Ae. (Ochlerotatus) should be restored to the traditional usage during the interval 1906-2000.

Differences in male-female ratios of Aedes albopictus (Diptera: Culicidae) following ultra-low volume adulticide applications.

Suppression of Aedes albopictus populations is a substantial challenge for mosquito control programs globally because juveniles of this species are found in numerous kinds of domestic artificial containers that are difficult to detect, access, and eliminate. We conducted a multi-year assessment of the effect of different interventions to control Ae. albopictus near the northernmost geographic boundary of the species in temperate North America and deployed an array of BG-Sentinel traps for adult surveillance. Here we present the results of a comparative examination of adult sex ratios in urban and suburban areas, shifts in sex ratios after control interventions, and a discussion of the critical drivers of population dynamics of Ae. albopictus in our area. We collected significantly more male mosquitoes in urban as compared to suburban areas in June through September, but not in May (p<0.001). The higher number of male mosquitoes in urban areas could be attributed to a higher number of larval habitats within a closer proximity of the surveillance traps and the lower flight dispersal of males. Following application of adulticides in urban areas, Ae. albopictus male populations were reduced by 88% on average, which was higher than the 69% reduction in female populations. The higher reduction of male mosquitoes could be attributed to the smaller body mass of the males and their higher susceptibility to adulticides. The results of this study are directly relevant to the development of suitable control strategies that depend on manipulation of males, such as the sterile insect technique. The results could also be used to refine mosquito abatement by providing more accurate methods to determine the need and timing of vector control.

Economic evaluation of an area-wide integrated pest management program to control the Asian tiger mosquito in New Jersey.

Aedes albopictus is the most invasive mosquito in the world, an important disease vector, and a biting nuisance that limits outdoor activities. Area-wide integrated pest management (AW-IPM) is the recommended control strategy. We conducted an economic evaluation of the AW-IPM project in Mercer and Monmouth Counties, New Jersey with a controlled design (AW-IPM vs. control) from 2009 through 2011. The study analyzed financial documents and staff time for AW-IPM and surveyed an average of 415 randomly chosen households in AW-IPM and control areas each fall from 2008 through 2011. Hours lost from yard and porch activities were calculated as differences between actual and potential hours of these activities in an average summer week if there had been no mosquito concerns. Net estimated benefits of AW-IPM were based on cross-over and difference-in-difference analyses. Reductions in hours lost were valued based on respondents' willingness to pay for a hypothetical extra hour free of mosquitoes spent on yard or porch activities and literature on valuation of a quality adjusted life year (QALY). The incremental cost of AW-IPM per adult was $41.18 per year. Number of hours lost due to mosquitoes in AW-IPM areas between the base year (2008) and the intervention years (2009-2011) declined by 3.30 hours per summer week in AW-IPM areas compared to control areas. Survey respondents valued this improvement at $27.37 per adult per summer week. Over the 13-week summer, an average adult resident gained 42.96 hours of yard and porch time, worth $355.82. The net benefit over the summer was $314.63. With an average of 0.0027 QALYs gained per adult per year, AW-IPM was cost effective at $15,300 per QALY gained. The benefit-cost ratio from hours gained was 8.64, indicating that each $1 spent on AW-IPM gave adults additional porch and yard time worth over $8.

Quantifying the impact of mosquitoes on quality of life and enjoyment of yard and porch activities in New Jersey.

The recent expansion of Aedes albopictus, a day-biting mosquito, to densely inhabited areas in the northeastern Atlantic states of the USA has dramatically increased the problem that mosquitoes create for urban and suburban residents. We quantified the impact of mosquitoes on residents' quality of life within the context of a comprehensive area-wide integrated pest management program to control Ae. albopictus in two counties (Mercer and Monmouth) in New Jersey. We interviewed residents of 121 randomly selected households in both counties between October and November 2010. We asked residents about their experience with mosquitoes in their neighborhood and the importance of the ability to relax outdoors without mosquitoes compared to other neighborhood characteristics (1 = not important, 5 = extremely important). We rated residents' utility based on paired comparisons to known states from the EuroQol health description system. The majority (54.6%) of respondents considered mosquitoes to be a problem. Respondents reported an average of 7.1 mosquito bites in a typical week during that summer. Mosquitoes prevented 59.5% of residents from enjoying their outdoor activities at least to some extent. Residents rated the mosquito acceptability (mean ± standard deviation) during that summer on a scale of 0 (mosquito invasion) to 100 (no mosquitoes) at 56.7±28.7, and their overall utility at 0.87±0.03. This is comparable to living with up to two risk factors for diabetes (i.e., abdominal obesity, body mass index of 28 or more, reported cholesterol problems, diagnosis of hypertension, or history of cardiovascular disease) or women experiencing menstrual disorders. Respondents rated the importance of enjoying outdoor activities without mosquitoes (4.69±0.80) comparable to that of neighborhood safety (4.74±0.80) and higher than that of a clean neighborhood (4.59±0.94). In conclusion, New Jersey residents reported that mosquitoes decreased their utility by 0.13, comparable to the loss from worrisome health risk factors, underscoring the importance of controlling this problem.

Crouching tiger, hidden trouble: urban sources of Aedes albopictus (Diptera: Culicidae) refractory to source-reduction.

Our ultimate objective is to design cost-effective control strategies for Aedes albopictus, the Asian tiger mosquito, an important urban nuisance and disease vector that expanded worldwide during the last 40 years. We conducted mosquito larval surveys from May through October 2009 in the City of Trenton, New Jersey, USA, while performing intensive monthly source-reduction campaigns that involved removing, emptying, or treating all accessible containers with larvicides and pupicides. We examined patterns of occurrence of Ae. albopictus and Culex pipiens, another urban mosquito, among different container types by comparing observed and expected number of positive containers of each type. Expected use was based on the relative frequency of each container type in the environment. Aedes albopictus larvae and pupae were found significantly more often than expected in medium volumes of water in buckets and plant saucers but were rarely collected in small volumes of water found in trash items such as discarded cups and cans. They were also absent from large volumes of water such as in abandoned swimming pools and catch basins, although we consistently collected Cx. pipiens from those habitats. The frequency of Ae. albopictus in tires indicated rapid and extensive use of these ubiquitous urban containers. Standard larval-based indices did not correlate with adult catches in BG-Sentinel traps, but when based only on Ae. albopictus key containers (buckets, plant saucers, equipment with pockets of water, and tires) they did. Although we found that only 1.2% of the 20,039 water-holding containers examined contained immature Ae. albopictus (5.3% if only key containers were counted), adult populations were still above nuisance action thresholds six times during the 2009 mosquito season. We conclude that in urban New Jersey, effective source reduction for Ae. albopictus control will require scrupulous and repeated cleaning or treatment of everyday use containers and extensive homeowner collaboration.

Area-wide management of Aedes albopictus. Part 2: gauging the efficacy of traditional integrated pest control measures against urban container mosquitoes.

BACKGROUND: Aedes (Stegomyia) albopictus (Skuse) is an important disease vector and biting nuisance. During the 2009 active season, six ∼1000-parcel sites were studied, three in urban and three in suburban areas of New Jersey, United States, to examine the efficacy of standard integrated urban mosquito control strategies applied area wide. Active source reduction, larviciding, adulticiding and public education (source reduction through education) were implemented in one site in each county, an education-only approach was developed in a second site and a third site was used as an untreated experimental control. Populations were surveyed weekly with BG-Sentinel traps and ovitraps. RESULTS: A substantial reduction in Ae. albopictus populations was achieved in urban sites, but only modest reductions in suburban sites. Education alone achieved significant reductions in urban adult Ae. albopictus. Egg catches echoed adult catches only in suburban sites. CONCLUSIONS: There are significant socioeconomic and climatic differences between urban and suburban sites that impact upon Ae. albopictus populations and the efficacy of the control methods tested. An integrated pest management approach can affect abundances, but labor-intensive, costly source reduction was not enough to maintain Ae. albopictus counts below a nuisance threshold. Nighttime adult population suppression using truck-mounted adulticides can be effective. Area-wide cost-effective strategies are necessary.

Autogeny in Culex pipiens complex mosquitoes from the San Francisco Bay Area.

We surveyed the genetic ancestry and recorded the occurrence of autogeny, the developmental times, and survival rates in families of Culex pipiens in Santa Clara County, CA, at 37°N latitude. Females in 95% of the families produced fertile egg rafts without access to blood (= autogeny) after mating in stenogamous conditions. Developmental time, survival, and egg raft production were closely correlated to temperature. Male DV/D ratios overwhelmingly matched Cx. pipiens but a microsatellite analysis revealed these were Cx. pipiens form molestus hybridized with Culex quinquefasciatus and to a lesser extent to Cx. pipiens form pipiens, a genetic mix heretofore not recorded elsewhere. Greater DV/D ratios and larger proportions of genetic ancestry from Cx. quinquefasciatus were negatively correlated to autogeny. The combination of multiple overwintering strategies and widespread autogeny in females arising from aboveground larval sites supports the hypothesis that some North American populations of Cx. pipiens complex mosquitoes express unusual phenologies.

Source reduction behavior as an independent measurement of the impact of a public health education campaign in an integrated vector management program for the Asian tiger mosquito.

The goal of this study was to evaluate the effectiveness of a public health educational campaign to reduce backyard mosquito-larval habitats. Three communities each, within two New Jersey counties, were randomly selected to receive: (1) both education and mosquito control, (2) education only, and (3) no education or mosquito control. Four separate educational events included a 5-day elementary school curriculum in the spring, and three door to door distributions of educational brochures. Before and after each educational event, the numbers of mosquito-larval container habitats were counted in 50 randomly selected homes per study area. Container surveys allowed us to measure source reduction behavior. Although we saw reductions in container habitats in sites receiving education, they were not significantly different from the control. Our results suggest that traditional passive means of public education, which were often considered the gold standard for mosquito control programs, are not sufficient to motivate residents to reduce backyard mosquito-larval habitats.