National Program 104       

Veterinary, Medical, and Urban Entomology

National Program Annual Report:  FY 2004 

• Introduction
• Ecology and Epidemiology
• Detection and Surveillance Technology
• Biology, Physiology, and Vector-Pathogen Interaction
• Control Technology

Introduction

ARS has a long and illustrious history of finding ways to prevent the harm that some arthropods - insects and ticks - do to livestock and people.  Indeed, it was ARS scientists who first discovered, in the 1890s, that arthropods could transmit disease, a discovery that led to the eradication of Cattle Fever from the United States.  And it was ARS scientists who first developed the sterile insect technique, which resulted in the eradication of screwworm from both North and Central America, who invented the aerosol can (originally for insecticide application by soldiers), who discovered the repellent properties of DEET, and who pioneered the method of treating bed nets with repellents, a tool that now protects millions of children in the tropics from contracting malaria.  ARS scientists developed imported fire ant bait toxicants that are in wide use today, and are leading the first attempt to successfully implement classical biological control against a pest ant.  ARS scientists pioneered development of insecticide delivery systems for livestock including boluses, microspheres, and ear tags.  Some ARS solutions have tremendous impact “behind the scenes” but are not widely known among the public, such as sterile insect technique—while others have led to products that most everyone relies on to make their lives better. 

Scientists in National Program 104 are building on past successes and pioneering new methods to continue to meet challenges posed by insects, ticks and mites, and the diseases they transmit that affect animal and human well being.  The program enjoyed continued success and high productivity in 2004.  Each Research Unit in the program sought input from stakeholders and presented a 5-year plan to the Office of Scientific Quality Review.  We will begin a new 5-year cycle of high-impact, cutting edge research in 2005, continuing to address the high priorities communicated to us by our customers and stakeholders.

 During 2004, National Program 104 consisted of scientists working on a total of 19 appropriated projects in 8 locations across the United States.  Program increases in 2004 included Agricultural Genomics (livestock, poultry, and babesiosis) (Kerrville, TX), Emerging Animal Diseases (Laramie, WY), Formosan Subterranean Termites (New Orleans, LA), Vector Borne Diseases (Gainesville, FL), and West Nile Virus (Gainesville, FL) bringing total appropriations in the national program to $23.6 million.  Ron Rosenberg served as the National Program Leader with input from the Program Team members Bob Faust, Robert Heckert, and Kevin Hackett.

Several ongoing partnerships with Land Grant Universities and other entities were critical to the success of the national program in 2004.  We recognize the important contributions made by these institutions, which included Virginia Polytechnic Institute and State University, Washington State University, Louisiana State University, Colorado State University, University of Nebraska, National Center for Physical Acoustics (University of Mississippi), Mississippi State University, Alabama A&M University, Tennessee State University, The University of Florida, Texas A&M University, The University of Hawaii, Tulane University, Nicholls State University, Clemson University, and Oklahoma State University, as well as numerous international, national, and state organizations.   

Scientists in the national program maintained a high level of productivity throughout 2004.  A total of 182 publications (102, or 56 % peer-reviewed) were approved by ARS during this time. 

Awards received by NP 104 scientists during 2004 included:

• Drs. Juan Morales and Guadalupe Rojas received the Superior Effort on Technology Transfer Award 2004: For Development and Transfer of Nutritionally-Based Bait Matrices for Control of Invasive Pests such as the Formosan Subterranean Termite and Red Imported Fire Ant. Awarded by USDA-ARS, September, 2004.

• Drs. Juan Morales and Guadalupe Rojas received the 2004 Excellence in Technology Transfer Award: Bait Matrices for Controlling Subterranean Termites and Ants. Awarded by The Federal Laboratory Consortium, October 2004.

Significant acquisitions and cooperative research and development agreements within the national program for 2004 are summarized below:

The University of Nebraska reassigned three rooms to the Midwest Livestock Insect Research Unit for the development of a molecular biology laboratory.  The rooms were remodeled using benchwork and equipment from the dismantled screwworm facility.  The new laboratory provides needed facilities for molecular population genetics and systematics.

The Biological Control of Pests Research Unit is partnering with Automated Decisions, LLC, a company providing advanced solutions in sensor exploitation, under Cooperative Research and Development Agreement to develop new user tools for analysis and automated detection of imported fire ant mounds in remotely sensed data.  These tools will have broader application for remote sensing of small, temporally variable targets.  Project Director Bradley Wallet of Automated Decisions submitted a Small Business Innovative Research proposal, entitled "Detection and Monitoring of Imported Fire Ants using Remotely Sensed Imagery."  The proposal was recently ranked 3rd among submissions and recommended for full Phase I funding.

A CRADA between Oxitec Limited, Oxford, UK and the Midwest Livestock Insect Research Unit from 1 Feb 2004 to 31 July 2004 was completed and results are being prepared for publication.  The title of the project was "Development of male-only, genetically sterile strains of the New World Screwworm."

The following sections of the report summarize selected high impact research results addressing the four broad objectives in the current national program action plan.

Ecology and Epidemiology

Molecular biology and pathogenesis of arboviruses.  Bluetongue virus is an important concern to the U. S. and Canadian cattle industries with the potential to affect movement of cattle between the countries.  ARS scientists in the Arthropod-Borne Animal Diseases Research Laboratory in Laramie, WY made progress on three fronts in the effort to fully elucidate Culicoides-Bluetongue Virus interactions.  They demonstrated that the virus overwinters in close association with its arthropod vector Culicoides, developed and characterized a new cell line from Culicoides biting midges that will provide a new epidemiological tool, and developed new assays to detect and quantify the virus in host cells.

Ecology, behavior, and control of mosquito vectors of West Nile virus.  Everybody is familiar with the threat of West Nile virus, but critical, basic information on which control and surveillance strategies can be based is lacking.  Scientists in the Mosquito and Fly Research Unit in Gainesville, FL, in collaboration with the Connecticut Agricultural Field Station, demonstrated that tree-dwelling mosquitoes have a much higher likelihood of being infected with West Nile virus than ground-dwelling mosquitoes.  This important finding has implications for pesticide placement to maximize control of the mosquito vectors of West Nile virus.

Detection and Surveillance

Acoustics detection of pests in crops, structures, trees and soils.  The Formosan subterranean termite is a tremendous threat to historical structures and even living trees in the southern U. S.  Difficulties in detecting these pests can make it difficult to apply insecticidal or biologically-based treatments in time to save trees or structures.  A field-portable acoustic probe was co-developed by research engineers at the National Center for Physical Acoustics (NCPA) and research entomologists at the USDA-ARS, Southern Regional Research Center (SRRC), for the purpose of inspecting trees non-invasively for hidden termite infestations.  A total of five probes were fabricated, tested and delivered to entomologists at the USDA-ARS-SRRC in New Orleans, Louisiana, as of March 2004, with training provided by NCPA personnel.  The devices have had a significant impact in the early detection and subsequent monitoring of concealed Formosan and native subterranean termites in trees.  The acoustic probes are also being used for inspection of trees in New Orleans' French Quarter to guide termite treatment programs in an ongoing area-wide termite management program.  Additionally, the probes are being used by personnel of the New Orleans Mosquito and Termite Control Board (NOMTCB), and Louisiana Department of Forestry and Agriculture (LDAF) to detect termites in urban trees.

Tools for disease surveillance in vectors.  Rapid and accurate detection of animal diseases in insect vectors is necessary for efficient certification of livestock and monitoring of disease outbreaks.  The Arthropod-Borne Animal Diseases Research Laboratory has developed a rapid and sensitive PCR method utilizing infrared tags for detection of bluetongue virus in single insects (Culicoides).  The screening method is coupled with a high throughput method for sample homogenization and RNA isolation.  Ninety-six individual Culicoides (or pools of 50) can be processed and assayed in less than 6 hours.

Ecology, behavior, and control of mosquito vectors of West Nile virus.  Scientists in the Mosquito and Fly Research Unit in Gainesville, FL determined that a new mosquito trap, called the counterflow geometry (CFG) trap, may be superior to the trap commonly used for surveillance of viruses carried by mosquitoes.  The CFG trap is expected to allow for more timely and accurate detection of WN virus in mosquitoes than is now possible.

Optimization of a propane-powered mosquito trap.  Researchers at the Mosquito and Fly Research Unit in Gainesville, FL improved a commercial mosquito trap by changing from a passive (sticky paper) to an active (suction based) collecting device.  This required the use of a fan, which resulted in a more even distribution of trap-generated attractants (carbon dioxide, water vapor, heat and octenol). This technology advance will benefit all end users and provide better surveillance and protection from mosquitoes.

Regional integrated management of imported fire ant.  Detecting and delineating fire ant infestations on the ground is time consuming and expensive.  Scientists with the Biological Control of Pests Research Unit made progress in development of remote sensing technologies for detecting imported fire ant mounds.  Basic methods for detecting mounds using airborne multispectral imagery were expanded with the development of image enhancement algorithms designed to maximize contrast between mounds and their surroundings.  This technology will increase detection accuracy and support research and control efforts that rely on quantifying fire ant populations.

Control Technology

Manipulation of arthropod behavior for protection of livestock and humans.  The introduction of West Nile virus into the U. S. and the continuing need to provide the best protection possible for U. S. Military personnel is making development of new, more effective insect repellents a research priority for ARS.  In an effort to speed up development and testing of new, more effective insect repellents, scientists with the Chemicals Affecting Insect Behavior Laboratory in Beltsville, MD developed a new in vitro bioassay system to quantify repellent effects of deet and SS220 against the biting responses of the yellow fever mosquito, Aedes aegpti, and the malaria mosquito, Anopheles stephensi.   Estimated dose response curves and estimated proportions of repelled mosquito in vitro were compared to estimates obtained earlier using in vivo (human volunteer) assays.  Data show that the in vitro results correlate with in vivo bioassays.  Because the in vitro system yields repellent test results that closely agree with results obtained with humans, it will be used to speed up the process of screening large numbers of chemicals to identify novel repellent compounds for human use.

Rationally designed insect NP agonists and antagonists.  Development of innovative, environmentally-friendly insect control methods will decrease reliance on chemical insecticides and help overcome pesticide resistance.  ARS researchers with the Southern Plains Agricultural Research Center, Areawide Pest Management Research Unit have significantly added to the scientific foundation necessary for ultimate development of effective and practical neuropeptide-based insect control agents that will act within living insects to disrupt critical life processes, with minimal or no adverse environmental effects.  Their most recent accomplishments involve development of new neuropeptide mimics capable of disrupting the natural transformation process from immature to adult stage in a pest fly.

Biology and control of the Formosan subterranean termite.  ARS scientists with the Southern Regional Research Center, New Orleans, LA, in collaboration with Louisiana State University, continued to expand the treated area within the French Quarter of New Orleans as part of an areawide management program for reducing population densities of the highly destructive Formosan subterranean termite.  Researchers demonstrated that alates trapped in the course of monitoring were coming from untreated colonies within the French Quarter, or colonies outside of the treated area.  Monitoring of alate swarms indicated a significant drop in the number of termites within the treated areas, indicating that the areawide program has been successful in reducing termite populations. 

Development of biological control agents for management of subterranean termites.
Scientists with the Formosan Subterranean Termite Research Unit demonstrated that a new isolate of a fungus, Metarhizium, is a highly effective pathogen of adult termites and that small-scale field application results in significant mortality to termites that enter the treated area.  Work is continuing on ways to improve delivery techniques and formulations for this and other termite pathogens. 

Classical biological control of imported fire ants using phorid flies (multiple projects).  Self-sustaining biological control agents effective against imported fire ants have the potential to greatly reduce reliance on chemical insecticides and improve the quality of life for millions of people in the U. S.  ARS scientists with the Imported Fire Ant and Household Insects Research Unit in Gainesville, FL, and the Biological Control of Pests Research Unit in Stoneville, MS, along with cooperators in several states, have demonstrated establishment, overwintering, and expansion of multiple exotic phorid fly species.  This important success lays the groundwork for determining the impact of the flies, which kill fire ants and hamper their competitive abilities.  If successful this will be the first effective classical biological control program targeting a social insect.   

Laboratory study of the effectiveness of commercial air curtains as barriers to prevent flying insects from entering commercial aircraft.  Researchers with the Mosquito and Fly Research Unit in Gainesville, FL used air curtains to prevent house flies and mosquitoes from passing from a simulated jetway into a simulated aircraft.  This accomplishment was important because many airline companies are looking for non-pesticidal methods for preventing insect entry onto commercial aircraft.  Research showed that mounting air curtains vertically along the sides of the doorframe instead of the conventional overhead configuration was highly efficacious with less discomfort to subjects passing through the doorway.  Thus, research indicates that a commercial air curtain model for specific use at aircraft doors could be designed and used to prevent insect entry without the use of pesticides.

Regional integrated management of imported fire ant.  Effective fire ant repellents could be useful for excluding the ants from sensitive areas such as electrical junction boxes and nursery crop holding areas.  Scientists with the Biological Control of Pests Research Unit developed a new method for assessing repellency of compounds to imported fire ants.  The new assay takes advantage of the natural digging behavior of the ants, and will provide a new tool for rapid testing of candidate repellents.

Biology, Physiology, and Vector-Pathogen Interaction

Anaplasmosis:  A genomic approach to vaccine development.  Anaplasmosis is a prevalent arthropod-borne hemoparasitic disease that continues to constrain the production, movement and utilization of cattle worldwide.  ARS Scientists with the Animal Disease Research Unit in Pullman, WA, in collaboration with colleagues from Washington State University (WSU), discovered that cattle ticks in the U. S. are capable of transmitting foreign strains of anaplasmosis.  This finding highlights the danger of imported strains of anaplasmosis by demonstrating the competence of native vectors. 

Functional approaches to the control of babesiosis in cattle and horses.  Babesiosis is a serious disease that affects cattle in the tropics and subtropics, which could pose a threat to U. S. agriculture during resurgence of cattle tick populations.  ARS scientists made significant progress in 2004, in collaboration with WSU, in sequencing the genome of Babesia bovis, the causative agent of babesiosis vectored by cattle ticks.  This fundamental work will support future development of novel control measures based upon vaccination or gene knock-out strategies.

Origin, Development and Population Genetics of Stable Flies Affecting Pastured and Confined Livestock.  Stable flies are a leading pest of livestock, capable of causing decreases in weight gain and milk production of 25 and 60%, respectively, at high populations.  They are also pests of humans with the annoying habit of biting the lower legs.  Scientists at the Midwest Livestock Insects Research Unit in Lincoln, NE discovered that the primary source of stable flies feeding on pastured cattle were areas where large round hay bales were fed to cattle during the winter.  It was demonstrated that these sites were capable of producing in excess of 1 million flies each.  This important basic discovery has implications for more judicious pesticide placement as well as other, biologically-based control measures. 

Research in Lincoln is now focused exclusively on stable flies.  Prior to completing successful transfer of all screwworm research from Lincoln, NE to Panama, ARS scientists in Lincoln, NE and Fargo, ND collaborated to develop cryopreservation techniques for screwworm embryos.  Ten strains (5 mutant strains, 4 transgenic

strains and 1 strain used for mass production) were transferred to the National Center for Genetic Resources Preservation in Ft. Collins, CO.

Tools for insect vector biology.  The Arthropod-Borne Animal Diseases Research Laboratory has develop a genetic database of genes expressed in the midgut and salivary glands of the primary North American insect vector for bluetongue and epizootic hemorrhagic disease viruses.   Over 1700 adult serum-fed female midgut and almost 800 salivary gland expressed sequence tagged genes clusters were identified and made available in a national database.  This valuable dataset is an important new resource that will allow researchers to perform comparative genetics and other studies with the ultimate goal of developing new tools for risk assessment and control of insect-transmitted diseases of livestock.