Source: CORNELL UNIVERSITY submitted to
ECOLOGY AND BEHAVIOR OF ARTHROPOD DISEASE VECTORS IN THE NORTHEASTERN UNITED STATES.
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
TERMINATED
Funding Source
Reporting Frequency
Annual
Accession No.
0191099
Grant No.
(N/A)
Project No.
NYC-139432
Proposal No.
(N/A)
Multistate No.
(N/A)
Program Code
(N/A)
Project Start Date
Oct 1, 2001
Project End Date
Sep 30, 2005
Grant Year
(N/A)
Project Director
Harrington, L. C.
Recipient Organization
CORNELL UNIVERSITY
(N/A)
ITHACA,NY 14853
Performing Department
ENTOMOLOGY
Non Technical Summary
There is a tremendous gap in our knowledge of the biology of some of the most important arthropod vectors of public health importance in the United States. The focus of this proposed research will be to investigate the biology, abundance and feeding behavior of some of these disease vectors in New York State and the United States. The outcome of this research program will be a greater understanding of medically important mosquitoes that will elucidate new and effective strategies for regional control and prevention of vector-borne disease.
Animal Health Component
25%
Research Effort Categories
Basic
75%
Applied
25%
Developmental
(N/A)
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
7223110113075%
7223110107025%
Goals / Objectives
This research will focus on three main objectives (1) to identify the most accurate and practical means to determine host blood feeding behavior in mosquito vectors (2) to determine the blood feeding behavior of putative mosquito vectors that may be responsible for human and horse infections in New York State, such as West Nile fever, Eastern equine encephalitis and other arboviral illnesses, (3) to investigate the biology and behavior of recently established exotic mosquito vector species, such as Aedes albopictus and Ochlerotatus japonicus japonicus, and the poorly understood species Culex pipiens molestus, and (4) to determine the insecticide susceptibility of medically important mosquito vectors in New York State so that control strategies can be refined and targeted.
Project Methods
Obj.1. To identify the most accurate and practical means to determine host blood feeding behavior in mosquito vectors. Of the standard bloodmeal identification methods, the precipitin test and ELISA are considered the most accurate. However, ELISA may be more labor-intensive, time consuming and expensive than the precipitin test. No comparison has ever been made with these methods. The precipitin test, antibody-sandwich ELISA and heteroduplex methods will be evaluated to determine the most sensitive, economical and practical approach for large-scale screening of field collected disease vectors. Obj.2. To determine the blood feeding behavior of putative mosquito vectors that may be responsible for human and horse infections in New York State such as West Nile fever, Eastern equine encephalitis and other arboviral illnesses. One of the most important factors related to the transmission of virus by a mosquito is host preference. Two years have passed since West Nile virus was first detected in the United States, yet we still do not know which species are important bridge vectors to humans and horses. I will focus my efforts on seven species of mosquitoes that have been identified as efficient vectors of WNV in the laboratory including several species that were identified in virus positive pools from 1999 and 2000. Obj. 3. To investigate the biology and behavior of recently established exotic mosquito vector species, such as Aedes albopictus and Ochlerotatus japonicus japonicus, and the poorly understood species Culex pipiens molestus. No studies of host feeding patterns of Oc. j. japonicus populations in the US have been published, yet the importance of gaining information about host feeding preference of this mosquito is critical. The biology of another invasive species, Aedes albopictus (known as the Asian tiger mosquito), also has not been studied in appreciable detail in regional populations. This species is an important vector of many different arboviruses and filaria including dog heartworm (Mitchell 1991). The tremendous public health importance of this mosquito in other regions of the world warrants an investigation of its feeding behavior and biology in the Northeast US. Another species that may play a role in disease transmission to humans is Culex pipiens molestus. This mosquito is an urban, subterranean species that breeds in subway tunnels and prefers mammalian blood in contrast to its close relative Cx. pipiens pipiens which is primarily an avian feeder (Byrne and Nichols 1999). Obj. 4. To determine the insecticide susceptibility of medically important mosquito vectors in New York State, so that control strategies can be refined and targeted. There is a critical need for more information about the susceptibility/resistance status of WNV and EEE mosquito vectors particularly in areas of active transmission. It is always a good practice to monitor insecticide susceptibility of target species in a control program. I aim to determine the susceptibility/resistance status of important EEE and WNV mosquito vectors and how this varies among collection site location.

Progress 10/01/01 to 09/30/05

Outputs
Objective 1. ELISAs were the most sensitive and useful methods for blood meal identification. Antisera for blood meal analysis against 20 hosts and anti-mammal, wild bird and reptile/amphibian screens, was developed by testing indicated they were not sensitive enough to provide reliable results when compared with ELISA. Accurate detection of hosts in mosquito blood meals with ELISA was achieved after 48 hrs of digestion at 25C (9.9 degree days) in time series studies. Of the 1210 blood meals tested in ELISA, the greatest percentage of human blood feeding was detected in Oc. triseriatus, Oc. aurifer, Oc. stimulans/fitchii and Cx. restuans. Data were analyzed over seasons and a manuscript on vector feeding patterns was written. Objective 2. Resting collections were conducted for three summers from May to September 2004. Collections yielded a much greater diversity of species than the standard surveillance method (CDC miniature light trapping). The greatest numbers of species and individual blood meals were collected during the 2003 season and frozen for ELISAs. 2004 collections were reserved for future analysis if funds become available. A total of 31 different mosquito species with a total of 10,564 female specimens and 3,250 blood meals were collected. Species abundance varied significantly by habitat within a small geographic region, highlighting the importance of conducting surveillance in a variety of areas with human activity. Throughout the collection sites Cx. restuans, Culex pipiens, Oc. stimulans/fitchii, Cx. territans and Oc. triseriatus were the most abundant mosquito species. We found no differences in host preferences at canopy or ground locations, but significantly greater collections at the canopy level. Our results indicate that surveillance should be conducted in the canopy and that significant site variation occurs. Objective 3. Considerable collection effort was made at various locations around the state. Three Ae. albopictus were collected from Central Park in 2002. No Ae. albopictus were collected in 2003-2004 throughout New York State, suggesting that this species has not established itself in the state yet but the potential is great. Considerable numbers of the invasive species Oc. japonicus were collected from several areas of New York State as the species continues range expansion across the NY. Objective 4. Strains of Cx. pipiens were collected from urban centers in NY (Albany and Syracuse) and tested for susceptibility to B. sphaericus, B. thuringiensis israliensis (Bti) and methoprene. Less than 10-fold resistance to all insecticides was detected at both sites, except for Bti where 34-fold resistance was detected in one site. This is the first report of Bti resistance in mosquitoes in NYS. A For each of these objectives, we were also able to gather data and develop three important new fact sheets which are posted on our Extension Medical Entomology Website (http://www.entomology.cornell.edu/MedEnt/index.html). Additional manuscripts will be submitted in the coming year reporting additional results from our studies.

Impacts
We now have a wealth of new information (published, in press, and available to the public on our website) on the mosquito vectors of human disease in New York State including mosquito feeding behavior and host preferences, ways to refine/improve our surveillance, and knowledge about the efficacy of vector/public health control. Public health programs/advisories ultimately will be strengthened by application of this new knowledge.

Publications

  • Darbro, J.M. and L.C. Harrington. 2006 In press. Bird-baited Traps for Surveillance of West Nile Mosquito Vectors: Effect of Bird Species, Trap Height and Mosquito Escape Rates. Journal of Medical Entomology.
  • Paul, A., Harrington, L.C., Zhang, L. and Scott, J.G. 2005. Insecticide resistance in Culex pipiens from New York. J. Am. Mosq. Contr. Assoc. 2005 21(3): 305-309.
  • Spencer, C., Pendergast, T.H. and L.C. Harrington. 2005. Plant sugar feeding patterns of the dengue vector, Aedes aegypti, during high and low transmission seasons in the Mae Sot region of Thailand. Journal of the American Mosquito Control Association. 21(2): 177-181.
  • Kaufman, P.E., Harrington, L.C., Waldron, J.K., and D.A.Rutz. 2005. The Importance of Agricultural Tire Habitats for Mosquitoes of Public Health Importance in New York State. Journal of the American Mosquito Control Association. 21(2): 171-176.
  • Anderson, R.R. and L.C. Harrington. 2004. West Nile Virus. http://www.entomology.cornell.edu/MedEnt/index.html
  • Anderson, R.R. and L.C. Harrington. 2004. Mosquito Biology for the Homeowner. http://www.entomology.cornell.edu/MedEnt/index.html
  • Anderson, R.R. and L.C. Harrington. 2004. Tick Biology for the Homeowner. http://www.entomology.cornell.edu/MedEnt/index.html


Progress 01/01/04 to 12/31/04

Outputs
The main objectives (1) to identify the most accurate and practical means to identify host blood meals in mosquito vectors (2) to determine the blood feeding behavior of mosquito vectors of human and horse pathogens in New York State, (3) to investigate the biology of recently established exotic mosquito species, and (4) to determine the insecticide susceptibility of medically important mosquito vectors in New York State, so that control strategies can be refined and targeted. Summary of progress: Objective 1. ELISAs were the most sensitive and useful methods for blood meal identification. Antisera for blood meal analysis against 20 hosts and anti-mammal, wild bird and reptile/amphibian screens, was developed by testing indicated they were not sensitive enough to provide reliable results when compared with ELISA. Accurate detection of hosts in mosquito blood meals with ELISA was achieved after 48 hrs of digestion at 25C (9.9 degree days) in time series studies. Of the 1210 blood meals tested in ELISA, the greatest percentage of human blood feeding was detected in Oc. triseriatus, Oc. aurifer, Oc. stimulans/fitchii and Cx. restuans. Data were analyzed over seasons and a manuscript on vector feeding patterns was written. Objective 2. Resting collections were conducted for three summers from May to September 2004. Collections yielded a much greater diversity of species than the standard surveillance method (CDC miniature light trapping). The greatest numbers of species and individual blood meals were collected during the 2003 season and frozen for ELISAs. 2004 collections were reserved for future analysis if funds become available. A total of 31 different mosquito species with a total of 10,564 female specimens and 3,250 blood meals were collected. Species abundance varied significantly by habitat within a small geographic region, highlighting the importance of conducting surveillance in a variety of areas with human activity. Throughout the collection sites Cx. restuans, Culex pipiens, Oc. stimulans/fitchii, Cx. territans and Oc. triseriatus were the most abundant mosquito species. Population abundance and dynamics data were analyzed and a manuscript was written. Objective 3. Considerable collection effort was made at various locations around the state. Three Ae. albopictus were collected from Central Park in 2002. No Ae. albopictus were collected in 2003-2004 throughout New York State, suggesting that this species has not established itself in the state yet but the potential is great. Considerable numbers of the invasive species Oc. japonicus were collected from several areas of New York State as the species continues range expansion across the NY. Objective 4. Strains of Cx. pipiens were collected from urban centers in NY (Albany and Syracuse) and tested for susceptibility to B. sphaericus, B. thuringiensis israliensis (Bti) and methoprene. Less than 10-fold resistance to all insecticides was detected at both sites, except for Bti where 34-fold resistance was detected in one site. This is the first report of Bti resistance in mosquitoes in NYS. A manuscript was submitted to the JAMCA and is currently in review.

Impacts
The results of this project will contribute significantly to our knowledge of mosquito borne diseases in New York State and the northeast region and will facilitate the development of improved surveillance and control strategies.

Publications

  • No publications reported this period


Progress 01/01/03 to 12/31/03

Outputs
The main objectives of this research project are (1) to identify the most accurate and practical means to identify host blood meals in mosquito vectors (2) to determine the blood feeding behavior of mosquito vectors of human and horse pathogens in New York State, (3) to investigate the biology of recently established exotic mosquito species, and (4) to determine the insecticide susceptibility of medically important mosquito vectors in New York State, so that control strategies can be refined and targeted. Progress toward objectives during year 2: Objective 1. Capillary precipitin and antibody sandwich ELISAs were found to be the most sensitive and useful methods for blood meal identification. Over the past year we developed antisera for blood meal analysis against 20 potential host species of mosquito host animals. Anti-mammal, wild bird and reptile/amphibian screening antisera was also produced. Optimization of antibody sandwich ELISA is currently underway. Once ELISA optimization is complete, side-by-side comparisons of precipitin and ELISA results will be conducted. Compatibility assessments of precipitin and ELISA methods are complete. Objective 2. Resting collections were conducted for a second season from May to September 2003. Collections once again yielded a much greater diversity of species than the standard surveillance method (CDC miniature light trapping). The greatest numbers of species and individual blood meals were collected during the 2003 season and frozen for blood-meal identification. Mosquitoes from a total of 15 different locations were collected, identified to species and frozen for further analysis. A total of 31 different mosquito species with a total of 10,564 female specimens and 3,250 blood meals were collected in 2003. Objective 3. Considerable collection effort was made at various locations around the state. No Ae. albopictus were collected in larval or adult collections in 2003 throughout New York State, suggesting that this species has not established itself in the state. Considerable numbers of the invasive species Oc. japonicus were collected from areas of New York State. This species continues to expand its range across the state. Work began on identifying polymorphic markers to distinguish Culex p. molestus from the enzootic West Nile virus vector Cx. p. pipiens. Objective 4. In 2003 strains of Cx. pipiens were collected from urban centers in New York State (Albany, Binghamton and Syracuse). Colonies were established and bioassays of susceptibility to Bacillus sphaericus, Bacillus thuringiensis israliensis and methoprene are underway.

Impacts
The results of this project will contribute significantly to our knowledge of mosquito borne diseases in New York State and the northeast region and will facilitate the development of improved surveillance and control strategies.

Publications

  • No publications reported this period


Progress 01/01/02 to 12/31/02

Outputs
The main objectives of this research project are (1) to identify the most accurate and practical means to identify host blood meals in mosquito vectors (2) to determine the blood feeding behavior of mosquito vectors of human and horse pathogens in New York State, (3) to investigate the biology of recently established exotic mosquito species, and (4) to determine the insecticide susceptibility of medically important mosquito vectors in New York State, so that control strategies can be refined and targeted. Progress toward objectives during year 1: Objective 1. We have developed antisera for blood meal analysis against the 9 host species of mosquitoes (swine, cat, dog, rat, human, rabbit, horse, cow, raccoon), and are currently developing antisera against 11 more species. Anti-mammal, wild bird and reptile/amphibian screening antisera is also underway. To date most antisera produced is sensitive to homologous serum at titers up to 1:32000. Initial experiments were conducted to optimize age of animals and timing of injections. A protocol was developed using Freund's adjuvant to produce the most reactive antisera possible. Once antisera development is complete, side-by-side comparisons of precipitin and ELISA results will be conducted. The heteroduplex method does not appear to be practical for identification of mosquito blood meals. Development of cytochrome B and 12s ribosomal markers for identification of mosquito blood meals is planned for later years of the project. Objective 2. High-powered aspirators for collecting mosquitoes resting in vegetation were built and tested. Resting collections yielded a much greater diversity of species than the standard surveillance method (CDC miniature light trapping). Resting collections of mosquitoes around New York State began on June 4, 2002 and were conducted until September 30, 2002. Mosquitoes from a total of 26 different locations were collected, identified to species and frozen for further analysis. A total of 26 different mosquito species with a total of 3,868 female specimens and 1,130 blood meals were collected in 2002. Objective 3. No Ae. albopictus were collected in larval or adult collections in 2002 throughout New York State, suggesting that this species has not established itself in the state. Considerable numbers of the invasive species Oc. japonicus were collected from Downstate areas (New York City and Dutchess County) with moderate numbers from the Finger Lakes region and none from Northern New York State. It appears that this species is in the process of expanding its range across the state. A colony of Culex p. molestus was established and will be used future studies. Objective 4. Baseline bioassays of phenothrin on a susceptible S-LAB strain of Culex were completed this year. The LC50 values are 7.8 PPB (95 percent CI=6.4-9.5) and 70.6 ng/cm2 (95 percent CI= 34.4-360) for the larvae and adults, respectively. Preliminary results on field collected Cx. pipiens and Cx. restuans from New York indicate no cross-resistance to phenothrin among different populations. More detailed bioassays will be conducted in the coming years of the project.

Impacts
The results of this project will contribute significantly to our knowledge of mosquito borne diseases in New York State and the northeast region and will facilitate the development of improved surveillance and control strategies.

Publications

  • No publications reported this period