A mark–release–recapture of Culex pipiens pallens was conducted in an urban area of Japan during June 26–29, 2007. Larvae naturally occurring in rain gutters were collected and reared to adults in a laboratory. A total of 10,183 emerging female Cx. pipiens pallens of 4–8 days old were marked with fluorescent dye and released from one site. Recapture was made on 4 consecutive days using 41 Centers for Disease Control and Prevention traps with 1 kg of dry ice and human landing collection, and 121 marked females were recaptured. The overall recapture rate was 0.01. The mean distance traveled by the recaptured females was estimated as 470, 287, 326, and 517 m on days 1–4, respectively. The maximum flight distance of host-seeking Cx. pipiens pallens was estimated as 1,217 m based on the relationship between distance from the release site to the collection site and the total number of recaptures/traps. The population size of female Cx. pipiens pallens in the study area was estimated as 100,904 ± 8,509. The size of operational area for the control of Cx. pipiens pallens in urban area is discussed.

West Nile virus (WNV) has been present in the Yucatán State, México, since 2002. Culex quinquefasciatus, one of the main vectors of WNV transmission in the United States, is also common in Mexico and may be a key vector of WNV transmission to humans in the Yucatán. The aim of this study was to determine the length of the gonotrophic cycle and the survival rates of Cx. quinquefasciatus from Mérida, Yucatán, during the rainy versus the dry season. Mosquitoes were collected during 25-day periods in October (rainy season) and in April (dry season), and captured females were classified by abdominal appearance (freshly fed, late-stage fed, half gravid, and subgravid). To determine the age structure as nulliparous and parous females and to calculate the gonotrophic cycle through a time series and the mosquito survival, we used Davidson formulae. Also, vitellogenesis analysis to monitor egg maturity was conducted during both seasons. Cross-correlation data suggested a similar length of the gonotrophic cycle (4 days) in both seasons. Oogenic development required a minimum of 72 h in each season. However, survival of the mosquito population collected in the rainy season was significantly higher (0.91) with a mean temperature of 28 ± 1.57°C than was survival in the dry season (0.78) with a mean temperature of 29 ± 1.10°C. Survival, although higher during the rainy season, did not influence the length of the gonotrophic cycle of Cx. quinquefasciatus in Yucatán.

Knowledge of mosquito species diversity, occurrence, and distribution is an essential component of vector ecology and a guiding principle to formulation and implementation of integrated vector management programs. A 12-month entomological survey was conducted to determine the diversity of riceland mosquitoes and factors affecting their occurrence and distribution at 3 sites targeted for malaria vector control in Mwea, Kenya. Adult mosquitoes were sampled indoors by pyrethrum spray catch and outdoors by the Centers for Disease Control and Prevention light traps. Mosquitoes were then morphologically identified to species using taxonomic keys. The characteristics of houses sampled for indoor resting mosquitoes, including number of people sleeping in each house the night preceding collection, presence of bed nets, location of the house, size of eaves, wall type, presence of cattle and distance of the house to the cowshed, and proximity to larval habitats, were recorded. Of the 191,378 mosquitoes collected, 95% were identified morphologically to species and comprised 25 species from 5 genera. Common species included Anopheles arabiensis (53.5%), Culex quinquefasciatus (35.5%), An. pharoensis (4.7%), An. coustani (2.5%), and An. funestus (1.6%). Shannon's species diversity and evenness indices did not differ significantly among the 3 study sites. There was a marked house-to-house variation in the average number of mosquitoes captured. The number of people sleeping in the house the night preceding collection, size of eaves, distance to the cowshed, and the nearest larval habitat were significant predictors of occurrence of either or both An. arabiensis and Cx. quinquefasciatus. The peak abundance of An. arabiensis coincided with land preparation and the first few weeks after transplanting of rice seedlings, and that of Cx. quinquefasciatus coincided with land preparation, late stage of rice development, and short rains. After transplanting of rice seedlings, the populations of Cx. quinquefasciatus were collected more outdoors than indoors, suggesting a shift from endophily to exophily. These results demonstrate that irrigated rice cultivation has a strong impact on mosquito species occurrence, distribution, abundance, and behavior, and that certain house characteristics increase the degree of human–vector contact.

Culex salinarius is considered one of the most likely bridge vectors involved in the human transmission cycle of West Nile virus (WNV) and eastern equine encephalomyelitis virus (EEEV) in the northeastern USA. The larval habitats of this species in the coastal region of New York State are currently poorly known. Between 2005 and 2007, a larval survey was carried out to identify and characterize possible larval habitats in Suffolk County, encompassing natural and man-made freshwater wetlands, artificial containers, and salt marshes. Only relatively undisturbed salt marsh yielded Cx. salinarius larvae in considerable numbers from several sites over a period of 2 years. The immature stages of this species were found associated with Spartina patens and S. alterniflora of the upper marsh at salinities ranging from 4.3 to 18.8 parts per thousand. Both heavily impacted and relatively undisturbed salt marshes produced several hundreds of adult Cx. salinarius per Centers for Disease Control and Prevention (CDC) light trap per night, an order of magnitude higher than CDC light traps deployed at upland sites. The ability of Cx. salinarius to use both heavily impacted and relatively undisturbed salt marshes for reproduction has significant repercussions for marsh restoration and vector control practices.

Forecasting models were developed for predicting Aedes aegypti larval indices in an endemic area for dengue (cities of Tartagal and Orán, northwestern Argentina), based on the Breteau and House indices and environmental variables considered with and without time lags. Descriptive models were first developed for each city and each index by multiple linear regressions, followed by a regional model including both cities together. Finally, two forecasting regional models (FRM) were developed and evaluated. FRM₂ for the Breteau index and House index fit the data significantly better than FRM₁. An evaluation of these models showed a higher correlation FRM₁ than for FRM₂ for the Breteau index (R = 0.83 and 0.62 for 3 months; R = 0.86 and 0.67 for 45 days) and the House index (R = 0.85 and 0.79 for 3 months; R = 0.79 and 0.74 for 45 days). Early warning based on these forecasting models can assist health authorities to improve vector control.

With nuisance mosquito species, the goal of integrated pest management is to keep mosquito density below a tolerance level that is often set by economic, ecological, and political factors. This study compares actual human annoyance, as measured by a phone survey, with several measures of mosquito abundance, in order to determine a threshold that is both relevant and practical. The efficiency of CO₂-baited traps, container index (CI), and oviposition traps for monitoring Aedes albopictus, and CO₂-baited traps for monitoring Aedes caspius, was evaluated. CO₂-baited traps were confirmed to be of low efficiency in Ae. albopictus collection, while correlation matrices showed a good relationship between CI and the number of eggs collected (R = 0.91), and between number of eggs and phone-survey nuisance level estimates (R = 0.88). Correlation between CI and phone-survey nuisance levels was slightly lower (R = 0.78). We found a close relationship between the nuisance level declared by residents and mosquito captures obtained with CO₂-baited traps (Ae. caspius) and ovitraps (Ae. albopictus). An equation is presented to estimate annoyance according to dwelling characteristics and to the presence of children in the family.

This report presents a set of field experiments designed to assess different protocols for the use of ovitrap and MosquiTRAP, a promising new trap for dengue vector monitoring. Percentage of positive houses, calculated either by the use of 2 traps (outside inside) or 1 trap (outside) per house, tended to increase with time of exposure, at similar rates. When the aim was either to obtain a qualitative index (Aedes aegypti–positive site) or to determine percentage of positive houses in a selected neighborhood, the use of 1 ovitrap per house with only 5 days of exposure at the peridomestic area was quite sensitive. Seven days of exposure was too long, as saturation is expected in some places. The number of eggs collected per site increased with the time of exposure in all sites. At the 3-day trap exposure, we were not able to discriminate neighborhoods in terms of egg productivity per house. At the 5-day trap exposure, a rank of 4 sites was achieved. There was no correlation between the number of adults caught in MosquiTRAPs and number of eggs collected in ovitraps, neither per neighborhood nor per house where both traps were simultaneously exposed for 7 days in the peridomestic area.

Two types of mosquito trap were tested near Smith Lake in Portland, Multnomah County, OR: 2 Biogents Sentinel (BGS) traps baited with carbon dioxide (CO₂) and an octenol sachet or a BG Lure®, and an encephalitis virus surveillance (EVS) trap with CO₂ but without an odor sachet. After 6 trap-nights, the 2 BGS traps caught significantly more mosquitoes than the EVS trap. More Culex tarsalis and an overall greater number of species were caught in the BGS traps. A BGS trap and an EVS trap, both baited with CO₂ alone, were compared to investigate whether the difference was due to the attractants or the difference in trap type. The BGS trap caught more mosquitoes but the difference was not significant. The BGS trap, when baited with CO₂ and other lures, can be an effective mosquito sampling tool, but further research is needed to understand the importance of the attractants.

The efficacy of technical pyriproxyfen and diflubenzuron was evaluated at the laboratory level against Aedes aegypti, where we achieved adult emergence inhibition (EI₅₀) values of 0.048 and 1.59 ppb (µg/liter), respectively. We compared these data with values obtained for temephos. We prepared emulsifiable concentrate formulations of pyriproxyfen and diflubenzuron in the laboratory and obtained EI₅₀ values of 0.01 and 0.02 ppb, respectively. We also obtained 100% adult emergence inhibition with 0.1% slow-release sand formulations of pyriproxyfen and diflubenzuron. In a simulated field study, the granular sand formulations of pyriproxyfen, diflubenzuron, and temephos remained active for over 4 mo. In a field study, a 0.2% granular formulation of diflubenzuron and 1% temephos showed a similar performance.

Metofluthrin is a newly synthesized pyrethroid possessing high knockdown and lethal activity against mosquitoes. Studies of metofluthrin-impregnated plastic strips have been performed with dengue vectors. This study reports the efficacy of the new prototypes of metofluthrin-impregnated plastic strips against malaria vectors, Anopheles gambiae complex, in the Kongo villages of Bagamoyo district in coastal Tanzania. The study, using 20 houses, half intervention, half control, was conducted for a 124-day period. Pyrethrum spray sheets and Centers for Disease Control and Prevention light traps were used to sample mosquito population indices. The mosquito density indices of the intervention houses were observed to be significantly lower than those of the control houses when pyrethrum spray sheet collection was used (F = 4.61, 1 df, P = 0.038; 98.7% reduction of total mosquito collection compared with that for the controls). These low indices were observed despite the large openings found in Bagamoyo houses, which were predicted to have a considerable negative effect on the spatial repellency of metofluthrin. Based on the present results, the pyrethrum spray sheet collection was the better of the 2 collection methods.

A previously untested strain of Bacillus thuringiensis israelensis (Bti) serotype H14 (ID No. VCRC B17) has been evaluated under field conditions in an urban area of Rourkela city, India for its impact on the larval density of different mosquito species in a variety of habitats. The persistence of the biolarvicide used in an aqueous solution varied in different habitats. The lowest field application rate of 0.5 ml/m² remained effective for about 10–12 days and provided 80–100% reduction in larval abundance of anopheline species, including Anopheles culicifacies breeding in unpolluted water bodies. However, in stagnant polluted waters in drains and cesspools supporting culicine breeding, the biocide at the same rate persists for 5–6 days only. An application rate of 1 ml/m² to stagnant drains and cesspools, resulted in 84–100% reduction in the larval population of Culex quinquefasciatus over a period of 2 wk. Based on the field observations, an operational dose of 0.5 ml/m² at fortnightly intervals is suggested for clean water sources supporting anopheline breeding. However, to control breeding of culicine mosquitoes in stagnant and polluted waters, an operational dose of 1 ml/m² at fortnightly intervals is required. The study showed that Bti serotype H14 (VCRC B17) is a suitable biolarvicide that can be used against different mosquitoes in different types of urban habitats.

The effectiveness of boric acid (1%) and fipronil (0.1%) bait stations in reducing the number of laboratory-reared female Aedes aegypti and Ochlerotatus taeniorhynchus mosquitoes released in outdoor screened cages was evaluated. Both toxicants significantly reduced landing rates of the 2 mosquito species on a human subject. However, no significant reduction in the number of adult mosquitoes caught by counterflow geometry (CFG) traps baited with CO₂ was observed in the boric acid– and fipronil-treated cages compared with control cage. The 2 bait stations were further evaluated against natural populations of adult mosquitoes in 3 residential yards (each ca. 0.8 ha) in St. Johns County, FL. Both bait stations failed to significantly reduce counts of female mosquitoes landing on a human subject; and the capture rates of adult mosquitoes by CFG traps baited with dry ice in bait-treated and control experimental yards were not significantly different. Further field research is needed on the density and placement of bait stations in order to determine their utility in adult mosquito control programs.

Bioassay cages are commonly used to assess efficacy of insecticides against adult mosquitoes in the field. To correlate adult mortality readings to insecticidal efficacy and/or spray application parameters properly, it is important to know how the cage used in the bioassay interacts with the spray cloud containing the applied insecticide. This study compared the size of droplets, wind speed, and amount of spray material penetrating cages and outside of cages in a wind tunnel at different wind speeds. Two bioassay cages, Center for Medical, Agricultural and Veterinary Entomology (CMAVE) and Circle, were evaluated. The screen materials used on these cages reduced the size of droplets, wind speed, and amount of spray material inside the cages as compared to the spray cloud and wind velocity outside of the cages. When the wind speed in the dispersion tunnel was set at 0.6 m/sec (1.3 mph), the mean wind speed inside of the CMAVE Bioassay Cage and Circle Cage was 0.045 m/sec (0.10 mph) and 0.075 m/sec (0.17 mph), respectively. At air velocities of 2.2 m/sec (4.9 mph) in the dispersion tunnel, the mean wind speed inside of the CMAVE Bioassay Cage and Circle Cage was 0.83 m/sec (1.86 mph) and 0.71 m/sec (1.59 mph), respectively. Consequently, there was a consistent 50–70% reduction of spray material penetrating the cages compared to the spray cloud that approached the cages. These results provide a better understanding of the impact of wind speed, cage design, and construction on ultra-low-volume spray droplets.

This study compares mosquito control within similar environments between 26 and 30 degrees of latitude on the east central coasts of Florida and of Australia. It describes and compares the relevant mosquito-producing environments, the development of mosquito control, legislative framework, funding arrangements, and organizational differences between the areas, including the international interactions that have facilitated good practices. The article identifies some strengths and weaknesses of the programs in each area. Significant strengths include some aspects of funding and administration; collaborations with other organizations; the roles of national and state organizations, including research agencies; and commitment of individuals. Potential weaknesses in programs that are part of larger organizations include their relatively low position in the organizational hierarchy and the need to compete for resources. Programs that are independent districts may lack opportunity to interact with other land management units. Other weaknesses include the relatively high turnover of staff in state environmental resource agencies and the potential loss of institutional memory when long-term mosquito control staff members leave. The case comparison highlights similarities in product use at the individual program level (Indian River Mosquito Control District and Gold Coast Pest Management Unit) and differences in practices including aerial adulticiding being used in Florida but not in Australia.

Specimens of Isomermis wisconsinensis, Gastromermis viridis, Mesomermis flumenalis, and Mesomermis camdenensis have been found in 14 out of 28 studied sites. Their hosts were the following blackfly species: Cnephia dacotensis, Cnephia mutata, Prosimulium sp., Simulium decorum, Simulium tuberosum, Simulium venustum/verecundum complex, and Simulium vittatum. Superparasitism was observed in several simuliid larvae and, occasionally, with 2 different mermithid species. The prevalence of different mermithid species varies according to seasons: Mesomermis genus is more abundant during winter, whereas Isomermis and Gastromermis are found in higher number during summer. The study of environmental parameters related to mermithid presence or absence shows that only stream depth makes a difference.

Phlebotomine sand flies are vectors of bacteria, parasites, and viruses. Lutzomyia apache, a North American sand fly, was incriminated as a vector of vesicular stomatitis viruses (VSV) due to overlapping ranges of the sand fly and recent outbreaks of VSV. We report on the discovery of 2 populations of L. apache in Wyoming from Albany and Fremont counties. We attempted to isolate VSV and phleboviruses from sand flies from Albany County and screened select flies by polymerase chain reaction for Bartonella and blood meals. We did not isolate viruses or detect DNA from vertebrate hosts or Bartonella. Flies were also tested for insect pathogens and other microbes. We detected a Rickettsia sp. in all flies that were examined and a parasitic protozoon, Ascogregarina sp., from the midgut of a larva. Eustigmaeus lirella, a stigmaeid mite, parasitized 2 field-caught females.

We report the first collection of Anopheles pictipennis from northern Chile, particularly sectors of Totoral, Perales, Puerto Viejo, and Salinas in the Atacama region. Adults were captured using human bait, while larvae and pupae were collected from various habitats including ponds, puddles left by overflowing river water, edges along river banks, wells, irrigation ditches, and permanent and semipermanent ground water. Associated species were Culex (Culex) quinquefasciatus and Ochlerotatus albifasciatus. The internal transcribed spacer 2 of the ribosomal DNA of An. pictipennis was sequenced.

The checklist of the mosquito species reported to occur in the state of Indiana is updated to include a number of new records and new classifications. Specimens of the cryptic species complex Anopheles quadrimaculatus s.l. are identified as An. quadrimaculatus s.s., and specimens of An. punctipennis are identified as the Eastern form of the species.

Records of mosquito species occurring in Lubbock County, TX, have not been reported since 1970. An updated mosquito survey was conducted as part of the West Nile virus surveillance program conducted throughout Lubbock County, TX from July 2002 through December 2004. A large number of species not previously recorded occurring in this area were collected, whereas several species historically occurring in the area were not collected during this survey. Based upon the data from this study, dominant species in Lubbock County include Aedes sollicitans, Aedes vexans, and Culex tarsalis.

We conducted larval surveys in habitats located in urban Malindi, Kenya, in 2005 and 2006 with the goal of determining the productivity of unused swimming pools in relation to other habitats. Of the 250 habitats sampled, 66 were unused swimming pools, 93 were wells, 60 were drainage troughs, and 31 were miscellaneous areas, such as septic tanks, swamps, concrete tanks, fish ponds, car-track depressions, and drainage ponds. Anopheles gambiae s.l. was the only anophelines species found in the habitats, whereas Culex quinquefasciatus made up >95% of all culicine immature stages found. Of the 110 habitats found to be positive for mosquitoes, unused swimming pools represented 42.7%. One hundred and forty-eight anopheline pupae were found in 8 of the 66 unused swimming pools, but none was found in the other habitats. Using a nonparametric test, Kruskal–Wallis H test, there was no significant difference in the abundance of culicine pupae found in the 4 habitat types (χ² = 7.350, df = 3, p = 0.062). Unused swimming pools in Malindi provide ideal habitats that should be targeted for mosquito control.

Methods used to rear Aedes aegypti larvae were modified to maximize production under limited space requirements. Traditionally, 150 larvae were reared in 25 × 42 × 5-cm pans containing 1 liter of water. It was noticed, however, that the larvae congregated during development and did not utilize the entire rearing environment. Two new rearing methods were investigated to partition larval populations within the rearing space and thus increase rearing efficiency. The 2 methods separated groups of 50 larvae into each of either six 500-ml cylindrical cups or twelve 400-ml rectangular bins, each containing approximately 450 or 400 ml of water, respectively, and occupying approximately the same amount of shelf space as the 25 × 42 cm pans. The cup and bin protocols multiplied rearing potential by 2 and 4, respectively, under the same space constraints. A preliminary experiment was conducted to compare larval development and adult body size (using wing length as a surrogate) of mosquitoes reared in partitioned containers with those reared in the traditional open pan method. Results indicated that the pan and bin partition methods produced adults that were significantly larger than pan-reared adults, yet develop to 4th stage at a significantly slower and less synchronized rate.

A multiunit CO₂ delivery and anesthetizing system that supports expanded cage testing of mosquitoes is described. This system has proven more efficient than pipetting for conducting multiple tests and has facilitated the tripling of cage testing capabilities.