National Program 104 is relatively small, comprising about 30 projects being done at 12 locations, but the range of its responsibilities is unusually broad, including all arthropods that directly affect agricultural animals or humans. Nevertheless, the methods and goals for each of the four research program components - which will be described below - are common to all the arthropods we study and serve as the foundation for product development.

The Action Plan is a strategy for reaching our research goal of protecting livestock and people from harmful arthropods. Because we can not anticipate every potentially important problem, and because technology and science move so rapidly, the Action Plan is modified as necessary. The Plan originates from an ongoing dialogue with our stakeholders, those who need resources unique to ARS to help solve their problems; these include livestock producers, property owners, pest management professionals, public officials, the Department of Defense and the Centers for Disease Control and Prevention (CDC). Stakeholder needs define the relevance of ARS research. Consultations take place at different levels. Most Research Units have their own customer advisory committees with whom they meet several times a year. Usually every two or three years a formal progress review of each unit is conducted that includes a panel of outside scientists and stakeholders. Every five years a Program-wide review is conducted prior to the formal process of amending the Action Plan and rewriting and reviewing five year project plans. The most recent NP 104 review covering termites and ants was held at New Orleans in February, 2003 and that for mosquitoes, ticks, screwworm and other vectors at Dallas in July, 2003. This Action Plan is based on the consensus developed at those two program reviews. Each project plan based on the Action Plan must pass rigorous scientific peer review by an outside blue ribbon panel, to be convened by the USDA Office of Scientific Quality Review in mid-2004, before being implemented.

NP 104 coordinates its activities with the programs for Animal Health (NP 103) and Crop Protection and Quarantine (NP 304). Synergy between the programs is encouraged by including National Program Leaders from these two programs on the NP 104 Program Team.

Research Locations

Area Wide Pest Management Research Unit (AWPMRU), College Station, Texas

Arthropod Borne Animal Diseases Research Laboratory (ABADRL), Laramie, Wyoming

Animal Diseases Research Unit (ADRU), Pullman, Washington

Animal Parasite Disease Laboratory (APDL), Beltsville, Maryland

Biological Control of Pests Research Unit (BCPRU), Stoneville, Mississippi

Chemicals Affecting Insect Behavior Laboratory (CAIBL), Beltsville, Maryland

Fire Ant Research Unit (FARU), Gainesville, Florida

Formosan Subterranean Termite Research Unit (FSTRU), New Orleans, Louisiana

Knipling-Bushland Livestock Insects Research Laboratory (KBLIRL), Kerrville, Texas

Midwest Livestock Insect Research Unit (MLIRU), Lincoln, Nebraska

Mosquito and Fly Research Unit (MFRU), Gainesville, Florida

Screwworm Research Unit (SRU), Panama

Certain arthropods (insects, ticks, mites) are serious threats to our agricultural economy and to human health. Billions of dollars are lost annually to diminished productivity, damaged animal products, restrictions on exports, and costly control and treatment.

Mosquitoes, ticks and flies transmit viruses, bacteria and parasites that cause a wide variety of diseases, including many transmissible to both animals and humans, such as West Nile virus and Lyme disease. Insects can also directly diminish the value of agricultural products and human enterprise. For example, screwworm destroys the value of hides and stunts the growth of cattle, fire ants make land unsuitable for pasture, and the Formosan subterranean termite causes more than a billion dollars of damage annually to wooden structures.

For more than 100 years the USDA has led world research on arthropods affecting livestock and people. It was Theobald Smith, a USDA scientist, who in 1890 discovered that ticks transmit cattle fever, a blood parasite that threatened to destroy the emerging beef cattle industry. This was the first proof of any arthropod borne disease and led to the program to dip cattle, eventually eradicating cattle fever from the US. The model of basic science, invention and implementation characterizes ARS research. Similarly, it was a thorough understanding of screwworm genetics and biology that led Edward F. Knipling and Raymond C. Bushland to devise the remarkable method of rearing and releasing billions of sterile male flies to competitively mate with female flies. Today all of North and Central America are screwworm free and the sterile insect technique (SIT) has been used to safely control many other insect pests.

It is through National Program 104 that USDA most closely supports the American military. Since the Second World War ARS scientists have closely cooperated with DOD in developing measures to protect US military personnel deployed to regions where vector borne diseases, like malaria and dengue, are endemic. In the 1940s ARS scientists demonstrated that the new insecticide DDT could stop epidemics of louse-borne typhus. This was followed by the discovery of DEET, still the world’s most effective mosquito repellent, the development of ultra-low volume fogging for mosquito control, and pioneering work on repellent treatment of clothing and bed netting. ARS and the Department of Defense are now testing the first repellent significantly better than DEET. All of these products have had significant impact on the civilian population, as well: the World Health Organization, for example, estimates that hundreds of thousands of young children have been spared death from malaria during the last 10 years by the use of treated bed nets.

American livestock is threatened not only from indigenous arthropods and diseases but from potentially invasive ones. Screwworm and cattle fever have been eradicated from the US but continued vigilance is needed to prevent reinvasion. The red fire ant and Formosan subterranean termite both invaded the US on imported commodities in the 20^th century. The introduction of West Nile Virus in 1999 and its subsequent rapid spread across the US typifies the threat from introduced pathogens. In general, vector borne diseases are more difficult to predict and to control than are directly communicable diseases, such as brucellosis. Preparing for the next, unknown threat is one of the biggest challenges facing NP 104 scientists today. Most research in ARS on arthropods of veterinary, medical or urban importance can be classified into one of four components.

Problem Statement:

A thorough understanding of the habits of harmful arthropods is basic to the success of the other three components of NP 104. These are predominately observational and experimental studies done in the field by biologists trying to understand whole populations and their interaction with livestock or humans. It is essential to know, for example, not only which mosquitoes are capable of transmitting West Nile virus but which species are in fact responsible for transmission to horses and humans, where they breed and when they bite. It is only with that information that surveillance and control will be effective. How invasive species compete for local ecological niches influences control strategies. For example, the diversity of native ant species is diminished when fire ants invade and control efforts aimed at fire ants should leave the environment suitable for recolonization of native ants. The underground colonizing behavior of the Formosan subterranean termite is poorly understood, making the placement of toxic baits inefficient.

Goals:

1.1 Identify Aspects of Arthropod Behavior Vulnerable to Control.

1.1.1 Characterize the oviposition behavior of mosquitoes and midges and isolate environmental factors that attract or repel. (MFRU)

1.1.2 Determine the dispersal patterns, breeding habits and host attractions of horn flies, house flies and stable flies that may be useful in devising control strategies. (MLIRU; KBLIRL; MFRU)

1.1.3 Characterize the colonization behavior of Formosan termites and fire ants, and hybridization of invasive ants with native species. (FARU; FSTRU)

1.1.4 Perform and categorize genetic profiles and behavior of New World screwworm in South America and the Carribean in support of potential eradication efforts by APHIS. (SRU)

1.2 Epidemiology

1.2.1 Determine the role of species biology and population genetics in the transmission of arboviruses. (ABADRL; MFRU)

1.2.2 Determine the role played by filth-breeding flies in the epidemiology of bacterial diseases in livestock and humans. (MLIRU; MFRU)

1.2.3 Determine the role ticks play in the transmission of Lyme disease in cattle and of other pathogens in animals and humans. (APDL; KBLIRL)

1.2.4 Determine the role played by screwworm in the transmission of foot and mouth disease and other viral pathogens of livestock. (SRU)

Problem Statement:

Prevention is better than cure. The harm caused by arthropods, whether as disease vectors or by direct damage, is proportional to their numbers. The earlier that a vector or pest is recognized, the greater the opportunity for effective suppression. One goal is to develop faster, cheaper more sensitive means to detect animal or human pathogens - both endemic and exotic - in vectors. Another goal is to detect and measure the arthropod itself. Finally, a system that combines detection methods with knowledge of arthropod biology can theoretically predict dangerous population surges from correlated environmental factors. This work requires field scientists, biochemists, molecular biologists and specialists in geographic information systems.

Goals:

2.1 Detection and Diagnostics

2.1.1 Develop molecular or biochemical assays for the rapid detection of viruses and vertebrate parasites in dipteran vectors and in ticks. Tests will be both sensitive and specific when using whole arthropods in pools of at least five. Also develop assays capable of detecting potential exotic invasives or indigenous recombinants (e.g., West Nile and St Louis encephalitis viruses). (Laramie)

2.1.2 Develop accurate, sensitive and non-destructive methods for detecting hidden populations of ants or termites using applied physics. (New Orleans; Stoneville; FARU, Gainesville)

2.1.3 Design and test a model using GIS to direct fire ant control efforts. (Stoneville; FARU, Gainesville)

2.1.4 Design and test models using GIS and remote sensing to direct screwworm countermeasures (Panama)

2.2 Surveillance

2.2.1 Develop species specific traps that are light weight, inexpensive, low maintenance, and which are surrogates for individual human or livestock bait. Traps will preserve caught specimens for identification and pathogen detection for at least 12 hours. Traps will automatically register and transmit collection information. (MFRU, Gainesville).

2.2.2 Identify and synthesize host specific attractants and adapt for use in traps or bait stations. (MFRU, Gainesville; New Orleans; FARU, Gainesville; CAIBL, Beltsville; Kerrville)

2.2.3. Design and test a model using geographic information system (GIS) technology and remote sensing to predict the ideal placement of traps for vector and fly surveillance. The model will determine the optimum number of traps and how they should be redeployed based on collections as the season progresses. (MFRU, Gainesville; Laramie; Kerrville; Lincoln; Panama)

Problem Statement:

Advances in technology, especially in functional genomics - the cloning of genes expressed only during certain physiological or immunological states - have opened opportunities to engineer genetic and chemical methods to control harmful arthropods with little or no spillover into the environment or danger to beneficial species. Such strategies must start with a comprehensive grasp of the biology being targeted. For example, identification of carrier peptides activated at odor receptors in mosquitoes could lead to the design of chemical repellents that will inhibit blood feeding, but must be founded on a detailed understanding of host seeking behavior and sense organ ultrastructure to succeed. It would make little sense to study receptors in the antennae if the crucial recognition is done at sites in the legs. Similarly, isolation of receptors on tick or midge guts to parasites or viruses could lead to veterinary vaccines or blocking drugs, but an intimate knowledge of the interaction of pathogen and vector is needed first. Where necessary, research units will need to strengthen their capabilities in molecular biology, invertebrate pathology and physiology and must recruit skilled personnel to take advantage of the new technology.

Goals:

3.1 Genomics and Host-Pathogen Interaction

3.1.1 Use ultrastructural methods, as well as expressed sequence tag (EST) and bacterial artificial chromosome (BAC) libraries, to investigate the basis of tick digestion, salivation, egg production and susceptibility to protozoan parasites of livestock. Identify and clone genes crucial to these processes and design agents that will inhibit or disrupt their actions. (KBLIRL; ADRU; AWPMRU; APDL)

3.1.2 Help organize and participate in an international consortium to sequence the entire genome of the tick Boophilus microplus and manage the bioinformatics to allow comparison of homologous genes in different genera. (KBLIRL; ADRU)

3.1.3 Use differential expression and other methods to isolate and characterize membrane receptors, immune response and other factors crucial to susceptibility of diptera to vertebrate pathogens. Identify and clone genes crucial to these processes and design agents that will inhibit or disrupt their actions. (MFRU; ABADRL)

3.1.4 Identify food animal genotypes naturally resistant to blood feeding arthropods, characterize the mechanisms, and isolate the responsible genes. (KBLIRL; CAIBL)

3.1.5 Use functional genomics and other methods to investigate the social behavior and susceptibility to biological control agents of fire ants and Formosan termites. Identify and clone genes responsible for pheromone production, detoxification enzymes and other metabolic products useful in developing new forms of control. (FARU; FSTRU)

3.1.6 Determine the feasibility of genetically transforming screwworm flies into male-only lines. (SRU)

3.2 Neural, Sensory, and Reproductive Biology

3.2.1 Investigate the neural and sensory ultrastructure of ticks and diptera. In particular, localize and characterize changes in neurosecretion in response to toxic insult. (AWPMRU; MFRU)

3.2.2 Characterize and isolate pheromones and other social cues used by ants and termites in colonization and foraging, and by diptera and ticks in mating and host finding. (FSTRU; FARU; MLIRU; CAIBL; MFRU; APDL)

3.2.3 Develop measurements of electrophysiological activation for use in selecting vector repellents (CAIBL; MFRU)

Problem Statement:

The ultimate goal of NP 104 research is to prevent harm by controlling the agent. Although eradication of an arthropod from the U.S. can be achieved - as was done for screwworm and the black legged tick - suppression is usually more realistic. Chemical control plays an important role, especially during epidemics when danger is great and speed critical. This is particularly crucial in the special role ARS plays in devising means to protect deployed U.S. military. Over the longer period, however, chemical pesticides are often expensive, harmful to beneficial species and the environment, and prone to select for resistance. Precisely targeted methods of delivery, such as toxic baits for termites, or self-sustaining biological agents, such as baculovirus lethal for mosquito larvae, will continue to be major goals. Those entrusted with protecting livestock and people must have a large armamentarium from which to select the most appropriate combination of weapons.

Goals:

4.1 Chemical Pesticides and Repellents

4.1.1 Develop the capacity to test existing compounds for toxicity against diptera and ticks that transmit disease. Develop and use computational models for rapidly screening and predicting efficacy of available compounds from configural extrapolation. Devise formulations or combinations of compounds that can be used in regions anywhere in the world, without foreknowledge of resistance patterns. (MFRU; CAIBL; KBLIRL; ABADRL)

4.1.2 Develop and test novel means of applying pesticides and repellents that are more efficient, inexpensive and selective, including the development of toxic baits, methods to bond agents to material, and area repellents. (MFRU; CAIBL; FSTRU)

4.1.3 Identify and test new classes of topical and area repellents from previously synthesized or natural volatiles. Develop carrier formulations. (CAIBL; MFRU; FSTRU; APDL)

4.2 Biological Control

4.2.1 Identify, isolate, cultivate, characterize and test natural pathogens and predators of vectors and pests. Develop methods to enhance the specificity and lethality of control agents (FSTRU; BCPRU; FARU; MFRU)

4.2.2 Develop cryopreservation methods for the indefinite archiving of screwworm embryos. (SRU)

4.3 Area-wide Control

4.3.1 Integrate biological and chemical suppression techniques with knowledge of behavior and dispersion to develop and test large area prevention and control strategies. (all)

4.3.2 Identify and colonize New World screwworm genotypes as potential mass rearing replacements. (SRU)

4.3.3 Improve the efficiency and reduce the cost of screwworm production (SRU)