NE507: Mosquitoes, Disease & Public Health
Annual/Termination Reports (SAES-422): [06/13/2008] [01/30/2009]
Date of Annual Report: 06/13/2008
Report Information:
Participants:
Brief Summary of Minutes of Annual Meeting:
URL: Copy of minutes
Accomplishments:
The inaugural meeting of NE-507 was held in March of 2008 in Atlantic City. Five objectives for the project were discussed including: Strengthen basic and applied research on factors that influence mosquito-borne disease emergence. Use knowledge of mosquito, pathogen, vertebrate reservoir, and environment interactions to enhance ability to predict and prevent conditions leading to disease. Develop new strategies to control mosquito disease vectors. Conduct surveillance for mosquitoes and mosquito-borne arboviruses (pathogens). Develop and maintain the national scientific expertise to respond to future health threats by supporting training programs. Members agreed to develop specific aims for each objective. It was agreed to invite extension representatives to join the project. Elections were held.
Impact Statements:
Date of Annual Report: 01/30/2009
Report Information:
Participants:
Brief Summary of Minutes of Annual Meeting:
URL: Copy of minutes
Accomplishments:
NE507 SAES-422: Accomplishments
Objective 1. Strengthen basic and applied research on the pathogen, hosts, and environmental factors that influence mosquito-borne disease emergence A 10-year study was undertaken to identify potential mosquito vectors of Jamestown Canyon virus (JCV) (Bunyaviridae: Orthobunyavirus) in CT, quantify seasonal prevalence rates of infection and define the geographic distribution of JCV in the state as a function of land use and reservoir white-tailed deer populations which have increased substantially. JCV was isolated from 22 mosquito species. Ochlerotatus canadensis, Oc. cantator, Anopheles punctipennis, Coquillettidia perturbans and Oc. abserratus were incriminated as the most likely vectors based on yearly isolation frequencies and the spatial geographic distribution of infected mosquitoes. JCV was isolated from Oc. canadensis more consistently and from a greater range of collection sites than any other species. Frequent virus isolations were also made from Aedes cinereus, Ae. vexans, and Oc. sticticus and new North American isolation records were established for An. walkeri, Culex restuans, Culiseta morsitans, Oc. sticticus, Oc. taeniorhynchus, and Psorophora ferox. Other species included Cs. melanura, Oc. aurifer, Oc. communis, Oc. excrucians, Oc. provocans, Oc. sollicitans, Oc. stimulans, Oc. triseriatus and Oc. trivittatus. Infected mosquitoes were collected from June through September and peak infection rates parallelled mosquito abundance from mid-June through mid-July. Infection rates in mosquitoes were consistent from year to year and overall virus activity was directly related to local mosquito abundance. Infected mosquitoes were equally distributed throughout the state irrespective of land use, and infection rates were not directly associated with the abundance of white-tailed deer possibly due to their saturation throughout the region. (CT)
Epidemics and epizootics of eastern equine encephalitis virus (EEEV) occur sporadically in temperate regions where transmission is seasonal from late summer to early fall. These outbreaks may derive from virus that overwinters locally or perhaps, results from reintroduction of virus from other sites. To evaluate these possibilities, we compared the phylogenetic relationships of EEEV isolates obtained from mosquitoes collected during statewide arbovirus surveillance in CT, in addition to isolates from concurrent outbreaks in southern NH and upstate NY. In CT, viral isolates grouped into temporally discrete clades by year of isolation or over two years of sampling. Two or more clades arose in 2000, 2001, 2003, 2004, and 2006, possibly the result of separate introduction events into the state, whereas viruses from NY and NH segregated into single clades that persisted for two or more years. NH viruses shared recent common ancestry to those isolated in CT suggesting viral dispersal among these regions. These results provide additional evidence for independent episodes of EEEV overwintering in northern foci. (CT) Members of the Culex pipiens complex are the predominant vectors of West Nile virus in the northeastern US. In order to analyze the genetic structure of urban and rural populations of Cx. pipiens f. pipiens and gain insights into behavioral implications, mosquitoes were collected from established WNV transmission foci in CT, examined by using microsatellite markers, and compared to other populations from neighboring states. The mean numbers of alleles per locus for the aboveground Cx. pipiens f. pipiens populations ranged from 11.5 ± 2.34 to 13.17 ± 2.42 and were not significantly different. In contrast, underground populations of Cx. pipiens f. molestus from NY City had greatly reduced allelic diversities with an average of 4.4 ± 1.2 alleles per locus, which was significantly lower than that of any of the Cx. pipiens f. pipiens populations analyzed. We did not detect significant genetic differences between urban and rural populations of Cx. pipiens f. pipiens from CT nor did we observe temporal genetic changes. However, in a comparative analysis with populations of neighboring states, NJ, NY and MA, genetic variations associated with geographic distance were identified. In the analyses of Bayesian clustering and PCA, we identified two clusters separating Cx. pipiens f. molestus from Cx. pipiens f. pipiens populations, indicating that Cx. pipiens f. molestus was genetically distinct from any of the Cx. pipiens f. pipiens populations examined during this study. (CT)
We evaluated the blood-feeding patterns in several mosquito species that may serve as vectors of disease agents in the northeastern US. Blood-fed mosquitoes were collected from 91 different sites throughout CT over a 6-year period 2002 to 2007, and the host feeding patterns of 23 mosquito species representing 6 genera were examined by using a PCR-based assay and sequencing portions of the cytochrome b gene of mitochondrial DNA. With the exception of Cx. territans that acquired blood meals from all 4 classes of vertebrates-birds, reptiles, amphibians, and mammals, all species of Aedes, Anopheles, Coquillettidia, Psorophora, and to a lesser degree, Uranotaenia were found to feed predominately upon mammalian hosts. Fourteen different mammalian species were identified as sources of blood, but the majority of feedings were taken from the white-tailed deer, Odocoileus virginianus. Human-derived blood meals were identified from 13 of the 23 mosquito species. Limited avian-derived blood meals were detected in Ae. canadensis, Ae. cantator, Ae. cinereus, Ae triseriatus, Ae. trivittatus, Cq. perturbans, Cx. territans, Ps. ferox, and Ur. sapphirina. American robin, Turdus migratorius, was the most common source of avian blood, followed by a few other mostly Passeriformes birds. White-tailed deer appear to serve as the main vertebrate host for these mammalophilic mosquitoes in this region of the US. This feeding pattern supports enzootic amplification of arboviruses including Jamestown Canyon, Cache Valley, and Potosi viruses that perpetuate in cervid hosts. Occasional feeding on avian hosts suggests that some of these mosquito species, such as Cq. perturbans, could also facilitate transmission of West Nile and eastern equine encephalitis viruses from viremic birds to mammalian hosts. (CT)
We hypothesized that larval competition would have an effect on the susceptibility of Ae. aegypti and Ae. albopictus to dengue fever virus. We conducted a laboratory experiment that exposed larval mosquitoes from different competitive treatments to dengue fever virus. We found more competitive environments increased the susceptibility of Ae. albopictus mosquitoes to infection. In a companion study, we found a significant effect of adult size on dengue infection and dissemination. (OK)
We tested the hypothesis that Culex territans use amphibian vocalizations as a long distance attractant, to locate either a blood meal or oviposition site. Females were allowed to choose between a treatment (frog call, bird call, live frog, or control) versus no treatment for fifteen minutes. Females exhibited positive phonotaxis to the frog call, but did not orient to the bird call, live frog or control. Twenty five females were allowed to choose between a treatment (spring peeper call, bullfrog call, green frog call, northern gray tree frog call, wood frog call, American toad call, or control) versus no treatment for fifteen minutes. Females exhibited positive phonotaxis to the spring peeper call, northern gray tree frog, American toad, and green frog, but were not attracted to the calls of the bull frog, wood frog, or control. Females were allowed to choose between spring peeper calls versus no spring peeper calls at increasing decibel levels. Mosquitoes oriented to calls in the range of 50 to 75 decibels, indicating that phonotaxis is highest at 15 to 90 meters away from the source. This supports our hypothesis that amphibian vocalizations may be used as a mid to long-range attractant. (NJ)
We examined the susceptibility of Florida Aedes mosquitoes to infection by the emergent strain of chikungunya virus. We found there to be significant differences in the susceptibility of Ae. aegypti and Ae. albopictus, and differences between laboratory colonies and F1 individuals (Reiskind et al. 2008). In order to determine vector competence differences in possible CHIKV vectors, we evaluated the dose-dependent susceptibility of Florida strains of Ae. albopictus and Ae. aegypti for infection with a La Réunion island strain of CHIKV. We also evaluated pledget and water-jacketed membrane feeding systems. We show that both Aedes spp. were susceptible to the highest CHIKV doses, while only A. albopictus developed disseminated infections after exposure to the two lowest doses. Infection rates for both mosquito species were significantly affected by the blood meal delivery method utilized. This information is important in assessing risk of an outbreak of imported CHIKV in the United States, in determining differences in vectorial capacity of these two vector species, and in evaluating arbovirus delivery methods in the laboratory. This work is currently in press at the Journal of Medical Entomology (Pesko et al. 2009). (OK)
I completed a lab study examining the effects of infection with chikungunya virus, an emerging pathogen from east Africa, on the adult longevity of A. albopictus and A. aegypti. I hypothesized that the emergent strain of chikungunya has a more severe impact on the longevity of A. albopictus than A. aegypti. I tested this in a laboratory experiment with both species, exposed and not exposed to virus. Using Kaplan-Meier survival analysis, I found a small but significant decrease in longevity between infected A. albopictus and all other groups (log-rank Ç2 = 3.6347, p=0.028, one-tailed). I also found a significant, negative correlation between days to death and body titer in A. albopictus mosquitoes (r = 0.7871, p < 0.0001). (OK)
The effects of competition on larval growth have been well examined, but the effects of competition at the larval stage on adult longevity have been less well explored. We examined how larval competition affected longevity under starvation conditions for A. aegypti and A. albopictus at two humidity regimes (85% RH and 50%RH). We found significant differences between the two species, and significant effects of competition on A. aegypti. (OK)
Few previous studies on mosquito larval biology have examined the importance of different leaf resources, and none have examined the effects of leaf resource diversity. We conducted a study to address this question, using A. albopictus and Aedes triseriatus, and four leaf species found in coastal hammocks in Florida. We found significant variation in larval response of A. albopictus to leaves from different species. We found larvae to grow best on leaves from live oak (Quercus virginiana), had moderate growth on fern leaves (Nephrolepsis exalta), and had poor growth on grape (Vitis aestivalis) and wild coffee (Psychotria nervosa) leaves. A congener, A. triseriatus had similar responses. Aedes albopictus did not respond to mixtures of these leaves in an additive manner, suggesting some degree of synergy of mixed species resources. Oviposition studies demonstrated that both of these species avoid laying eggs in grape leaf infusion, and prefer oak leaf infusion. This work has important implications for both how larvae respond to variation in the aquatic environment and how females make oviposition choices. (OK)
I have continued to examine the effects of different leaf resources on larval growth and survival with a study examining the response of A. albopictus to invasive and native species identified from our on-going field survey. I found that diversity of plant inputs increases with distance from the coast and decreased urbanization in Palm Beach County, FL. I also found significantly more A. albopictus in sites that had the invasive Brazilian pepper present than in sites that had no Brazilian pepper (log-transformed A. albopictus abundance, t-test, d.f.=28, t=-3.36, P=0.0023), a pattern that was not found for the other plant species examined. We then examined the response of A. albopictus larvae at a variety of densities to two common invasive plants in south Florida (Brazilian pepper, Schinus terebinthifolious, and Australian pine, Causarina equisetifolia), and live oak (Quercus virginiana) in a laboratory experiment at Oklahoma State University. I found significantly better estimates of population performance (») of A. albopictus on Brazilian pepper leaves then on live oak or Australian pine leaves at medium and high larval densities (randomization ANOVA: leaf effect: d.f.=2, F=7.21, P=0.0034; leaf x density effect: d.f.=4, F=3.28, p=0.024). Results suggest invasive plants may contribute to the spread of A. albopictus. (OK)
Objective 2. Use knowledge of mosquito, pathogen, vertebrate reservoir, and environment interactions to enhance ability to predict and prevent conditions leading to disease.
Heterogeneity in urban landscapes can influence the effectiveness of mosquito-borne disease control. Remotely sensed vegetation indices were used to discriminate among mosquito habitats within a densely populated urban environment in New Haven, CT. ASTER derived vegetation indices were identified for 16 sites where adult mosquitoes were trapped over the summer. Canonical correlation analysis showed a significant relationship between the environmental variables (normalized difference vegetation index, disease/water stress index and distance to water) and four local West Nile virus (WNV) competent vectors (Cx. pipiens, Cx. restuans, Cx. salinarius, and Ae. vexans) (0.93, P = 0.03) explaining 86% of the variance in the environmental and mosquito measures. Sites were clustered based on these remotely sensed environmental variables. Three clusters were identified which provide insight into the distribution of WNV vectors in an urban area. Identification of habitat differences of mosquitoes within the urban landscape has important implications for understanding WNV transmission and for control of vector-competent mosquito species (CT).
This multistate project was conceptualized and initiated for funding in 2007 and entered its second year beginning in September 2008. Thus this report encompasses approximately 1.5 years of research since inception of the project. Research has focused on the dynamics of West Nile virus transmission relative to diversity of bird hosts available and the tendency of the primary mosquito vector, Culex pipiens, to select a limited range of bird species for blood within a larger set of potential species available. A landmark study on host selection by Culex pipiens at an urban focus of transmission shows that Cx. pipiens overselects certain bird species and underselects others on the basis of estimated bird host availability; and that this process has profound consequences for the role of those bird species in annual virus amplification. Very few bird species contribute to most of the estimated amplification fraction based on an ecological index estimator, namely, American robin, house finch, and blue jay. Blood meal analyses using PCR based host identification with the cytochrome B gene and four different primer pairs identified a large array of bird species that were fed upon, with a generous sample size. It further revealed that Cx. pipiens also fed at a higher than anticipated frequency on mammals, in particular humans. (MI)
To examine the underlying mechanisms of host selection in Culex pipiens, the genetic background of Cx. pipiens was investigated to determine if the relative ancestry of three different species forms of this supraspecies-like taxon contributed to host selection. Those forms are Cx. pipiens pipiens, the known ornithophilic form of more northern latitudes; Cx. pipiens quinquefasciatus, the more flexible feeding form of more southern latitudes; and Cx. pipiens molestus, an unusual form with apparently an entirely human feeding pattern and of very patchy and urban distribution in North America. The analysis was conducted using a microsatellite allele frequency analysis in collaboration with Dr. Andreadis and Dr. Huang at the Connecticut AES (affiliated with this multistate project). Results showed convincingly that the genetic ancestry of individual Culex pipiens when containing a higher molestus heritage significantly contributed to the tendency to feed on mammals versus birds. There was, by contrast, no contribution of heritage of quinquefasciatus genetic background to host selection although genetic signatures of this species form were present throughout the samples from the northern, Chicago study site. Overall, this study is the first of which we are aware that predicts a genetic basis for host selection. It also showed that pipiens is truly a genetic pastiche in the Chicago study area, where West Nile virus remains stably enzootic with annual epizootic and epidemic resurgences. (MI) As indicated above, bird host availability was a contributor to patterns of host selection. Additionally, results of field studies indicated that shifts in bird population age structure affected host selection by Cx. pipiens and also promoted West Nile virus amplification. In particular, as fledglings appeared in the bird populations, virus transmission rapidly intensified. However, a parallel study showed that bird nestlings were not contributing to this intensification, thus young birds that have left the nest, but are not yet free to fly and forage independently, must be by inference the age group causing the observed intensification in virus transmission. Further investigations examine the diversity-dilution hypothesis which predicts that as vertebrate diversity increases, transmission of a vector-borne agent will lessen and dilute owing to the wastage of infective bites on reservoir-incompetent hosts. An exhaustive study in the Chicago study area showed no correlation between avian community diversity and rate of infection with West Nile virus in Cx. pipiens, thus providing no support for the hypothesis. (MI)
In collaboration with Dr. Tony Goldberg at University of Wisconsin, studies on molecular genetic diversity of West Nile virus showed that most of the nucleotide sequence variation observed was generated at highly local scales and within single amplification episodes. Such variation equaled that observed at regional and continental scales, suggesting that viral evolution is dictated by local transmission processes. (MI)
Methodology was developed for the laboratory colonization of Aedes japonicus japonicus, an exotic mosquito species native to eastern Asia and first collected in New Jersey as larvae in 1999. We created a free mating colony in 2000 that readily bloodfeeds on restrained bobwhite quail (Colinus virginianus). A larval diet of finely ground Purina Lab Diet© dissolved in dechlorinated water has proven acceptable. (NJ)
Data examining the landscape patterns of A. albopictus and A. aegypti in Palm Beach County, FL were collected at thirty sites on six east-west transects from the urban coast to suburban/rural fringe of development in Palm Beach County. Climate data (temperature and humidity) were collected daily at between 9-14 sites (climate recording devices were occasionally lost in the field). This data set is being analyzed for spatio-temporal patterns of species occurrence, climate correlations of species presence and abundance, and associations of species abundance and occurrence with other biotic factors. Strong spatial patterns were detected in association with biotic and abiotic factors and some temporal patterns. (OK)
Objective 3. Develop new strategies to control mosquito disease vectors. Gene silencing using RNAi technology is being investigated in our laboratory as a method to knock down critical proteins in mosquitoes with possible applications for control. As part of this effort to develop novel insecticides for mosquitoes, an inhibitor of apoptosis protein 1 gene in Aedes aegypti (AaeIAP1) was chosen as a target for the development of molecular pesticides. We have developed and refined constructs of AaeIAP1 that when topically applied were shown to cause mortality in adult Aedes aegypti. Other potential targets and new constructs are being evaluated. (ARS-Gainesville, FL)
An area-wide management project aimed at the Asian tiger mosquito, Aedes albopictus has identified six large (1000 home) test and control plots. Operational control efforts will include environmental management and novel methods to reduce larvae and adults. Standard surveillance traps in North America for adult Aedes albopictus, an invasive mosquito with public health implications, are currently ineffective. We found the BGS with or without lures collected more Ae. albopictus compared to other trap configurations and was more specific for Ae. albopictus. In Camden County, the BGS with lures collected three times more Ae. albopictus than the CDC (with carbon dioxide only) and five times more than the GT. In Mercer County, BGS with lures collected the most mosquitoes, with three times more Ae. albopictus than the CDC with all lures and fifty times more than the GT. The BGS collected more male Ae. albopictus than other traps. (NJ)
Control of Ae. albopictus immatures was assessed using two products already available but used in tandem, one with a quick kill and another with a long residual. Specifically, we evaluated a monomolecular film (Agnique) and (S)-methoprene (Altosid) in the laboratory and under field conditions. In the laboratory, combinations of the two products performed better than controls and products on their own for the first 40 d, indicating synergistic or additive effects of the combined products. Agnique alone killed over 95% of larvae in 24 h and over 80% in 20 d in the laboratory, while Altosid/Agnique-containing treatments provided over 95% control for greater than 100 d in the laboratory. Field trials on natural populations of Ae. albopictus, using a single combination of products, provided 100% control for greater than 30 d and significantly more kill than controls for an additional 30 d. Agnique and Altosid, when used together in difficult-to-treat locations, provide long-term control of Ae. albopictus immatures and reduce the number of treatments needed by mosquito control operators. (NJ)
Objective 4. Conduct surveillance for mosquitoes and mosquito-borne pathogens. Statewide mosquito trapping and testing for mosquito-borne arboviruses was conducted from June 2 through October 23 at 92 fixed collection sites with CO2 -baited CDC miniature light traps and gravid mosquito traps baited with an albumin-hay infusion. A total of 211,657 mosquitoes (15,108 pools) representing 38 species were trapped and tested. 191 isolations of West Nile virus were made from 9 species: Culex pipiens = 124, Culex restuans = 48, Culex salinarius =10, Culiseta melanura = 4, Aedes cinereus = 1, Culex territans = 1, Ochlerotatus japonicus = 1, Ochlerotatus stimulans =1, and Ochlerotatus trivittatus =1 collected at 33 sites in 25 towns in 5 counties (Fairfield, Hartford, Middlesex, New Haven, and New London). The first positive mosquitoes were collected on June 11 representing the earliest date virus has been detected in mosquitoes in the state, and the last on October 7. Gravid trap collections accounted for 84% of all WN virus isolates (n=160). The majority of WN virus activity was detected in densely populated urban and suburban regions in southwestern (Fairfield and New Haven counties) and central (Hartford county) Connecticut. Six locally acquired and one imported human cases of WN virus were reported to the State Department of Public Health with no fatalities (age range = 12 to 87 yrs., median age = 49 yrs.). Dates of onset of symptoms ranged from June 21 to September 12. The June 21 date of onset represented the earliest locally acquired WN virus case in the state. Human cases were correlated both temporally and spatially with the detection of WNV-infected mosquitoes. Other mosquito-borne viruses isolated included: Potosi (158), Jamestown Canyon (19), Cache Valley (11), Highlands J (8), Trivittatus (8), and Flanders (3). (CT)
We have reviewed some of the recent research findings, as well as obtaining recent unpublished data on various trapping methods and pathogen detection methods. In the last several years, there have been a number of traps developed to collect specific species that were heretofore poorly collected by commonly used traps. For Culex group mosquitoes, recent studies by Bhalala and Arias show that the Zumba trap (including lure and CO2) was superior to the standard CDC trap with CO2, the Omni-directional Fay Prince trap with CO2) and the BG Sentinel Trap with lure and CO2. It was also highly superior to the gravid trap in detecting WNV-infected mosquitoes, presumably because it was detecting older, host-seeking mosquitoes. On the other hand, the BG-sentinel has been more effective than any other trap in collecting day-biting Aedes mosquitoes, including Ae. aegypti, Ae. albopictus, and Ae. polynesiensis, all of which are important vectors. We have tested animal-baited CDC traps (a modification we developed), and although they are better than CO2-baited traps, they are not better than gravid traps in collecting Culex group mosquitoes. They can be useful in also looking at what hosts are attractive to various groups of mosquitoes in the field. (DE)
In terms of pathogen surveillance, this can be looked at in more than one way. For known indigenous pathogens, ease of surveillance may be the right goal. As an example, using the RAMP test for WNV, although it is not as precise and as sensitive as RT-PCR, is more affordable and can be done at the local level. This makes it a possible early warning procedure useful for operational mosquito control. However, in looking for exotic pathogens, and considering the wide spectra of pathogens possible, a surveillance procedure to provide early warning of a new pathogen introduction would be very significant. Early warning in this situation could possibly allow actual eradication of the pathogen before it became established. One of the most promising procedures is the use of microarray technology, especially for arboviruses. This allows a relatively small sample or samples to be tested for an entire spectrum of virus families, or even genera. These tests have been developed for novel respiratory viruses, bacteria, and food pathogens over the past 5 years, and are now being used at USAMRIID, and soon to be introduced at the CDC for other agents, and possibly arboviruses. These tests are backed up by sophisticated algorithm methodology for determining novel agents. What is now needed is to decide how and where to establish them, and determine protocols for their implementation. (DE)
The efficacy and sensitivity of the Rapid Analyte Measurement Platform (RAMP) was compared against reverse transcriptase polymerase chain reaction (RT-PCR) from 2005 to 2007. Results from RAMP-tested pools were verified using RT-PCR. Seventy-two pools (N = 334) were WNV positive with RAMP and RT-PCR. An additional 17 pools were WNV negative with RAMP but WNV positive using RT-PCR. The RAMP assay was 95% efficacious in identifying WNV positive pools when compared to RT-PCR, with no false positives. (NJ)
Mosquito populations were monitored for the presence of West Nile virus in three locations in Pittsburg, Payne, and Ardmore counties. In 2008, there were fewer mosquitoes than in the previous four years, and the infection rates of mosquitoes were also lower. (OK)
Objective 5) Develop and maintain the national scientific expertise to respond to future health threats by supporting training programs. No specific reports submitted; however, training of students and postdocs is an integral component of most of the above reports.
Impact Statements:
- Work carried out in 2008 as part of the Northeast Regional Research Project, NE-507, provided valuable theoretical and applied knowledge to help control mosquito-borne disease. For example, studies showing the dominant role of the mosquito Culex pipiens as both the epizootic vector of West Nile virus amongst bird hosts; and the sole epidemic bridge vector of this virus to humans discounts the need for vector control agencies to implement control measures against other mosquito species to suppress virus transmission, allowing scarce operational resources to be more focused.
- First report of female mosquitoes showing positive phonotaxis towards a specific vertebrate host. These results will be valuable to researchers assessing how blood-feeding mosquitoes make host decisions.
- Local mosquito control programs using RAMP to assess local arbovirus activity will benefit from studies on the sensitivity of this test when compared to RT-PCR. Used in tandem with standard methods, RAMP enhances existing mosquito control and West Nile virus surveillance by providing rapid results leading to quicker mosquito management decisions.
- Statewide mosquito and arbovirus surveillance programs provide an early warning for mosquito intervention activities.
- New mosquito trap designs were evaluated, providing new tools for mosquito research and surveillance programs.
- Significant progress was made in building data sets to develop models for predicting mosquito abundance.
- In many geographic regions, West Nile virus appears annually in summer bird populations but does not bridge extensively to humans; the reason may very well be that the genetic ancestry of the molestus form is simply lacking in the Culex pipiens populations in those areas. This would be a prediction worth continued research where risk of human infection is low despite high prevalence in mosquitoes and birds.
- Research led to a deeper understanding of host-mosquito interactions across an array of ecosystems. Unraveling these ecological relationships is essential to developing economical and effective integrated pest management programs for mosquitoes.