Source: UNIVERSITY OF FLORIDA submitted to
IMPROVING MANAGEMENT OF THE BROWN DOG TICK, RHIPICEPHALUS SANGUINEUS, IN SOUTHEASTERN RESIDENTIAL ENVIRONMENTS
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
TERMINATED
Funding Source
Reporting Frequency
Annual
Accession No.
0219081
Grant No.
2009-34103-19907
Project No.
FLA-ENY-004920
Proposal No.
2009-00843
Multistate No.
(N/A)
Program Code
QQ.S
Project Start Date
Sep 1, 2009
Project End Date
Aug 31, 2012
Grant Year
2009
Project Director
Kaufman, P. E.
Recipient Organization
UNIVERSITY OF FLORIDA
G022 MCCARTY HALL
GAINESVILLE,FL 32611
Performing Department
Entomology and Nematology
Non Technical Summary
Overall goal: Reduce misuse and overuse of pesticides in homes that are ineffective against the brown dog tick (BDT). We will accomplish these goals through cooperative efforts of the Pest Control Industry (PCI), University and USDA collaborators in the southeastern US. Our research objectives include: 1) determination of BDT resistance to permethrin and fipronil; 2) Development of a discriminating dose bioassay to identify field-failure resistance with minimal on-animal rearing; 3) identify resistance mechanisms used by BDT. Through our extension objectives, we will deliver much-needed PCI management protocols and brochures. Residential areas account for a considerable portion of the Southern region and direct contact with pesticides occurs in homes far in excess than that in food and fiber, making this project highly relevant to stakeholders. Furthermore, >37% or >43 million US households have dogs. Through our results, PCI personnel will effectively target BDT infestations, thereby reducing pesticides applied in homes and around children. We expect that some tick populations in Florida are highly resistant to permethrin as a result of years of exposure. We expect, based on our preliminary results, that the mechanism for resistance will be through elevated esterase activity, as is seen in the closely related tick, Boophilus microplus. The results for fipronil are less certain. It is likely that resistance to fipronil is developing, particularly in homes with a longer history of tick infestations and interrupted use of FrontlineAr. The research component of this project will have two lasting impacts: 1. development of a discriminating dose test that will facilitate an improved tick management program for residences. 2. Identification of resistance mechanisms used by the BDT, and the provision of biological data necessary for development of rapid-screen molecular tests for resistance that do not require animal rearing of ticks.
Animal Health Component
(N/A)
Research Effort Categories
Basic
50%
Applied
50%
Developmental
(N/A)
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
31238301130100%
Goals / Objectives
1. Presence and level of Rhipicephalus sanguineus resistance to permethrin and fipronil using the FAO Larval Packet Test This objective will provide the basis for the remaining objectives. It will also provide the most useful information to residents. The application of these results will safeguard human health by reducing human exposures to ineffective pesticides. 2. Develop discriminating dose for permethrin and fipronil resistance in brown dog ticks This objective will provide useful information to pest control companies to aid their selection of appropriate pesticides. The application of these results will also safeguard human health by reducing human exposures to pesticides rendered ineffective by acquired resistance and will promote economic benefits to residents and other stakeholders by reducing the number of pesticide applications needed to eliminate a tick infestation. The discriminating dose aspect will also safeguard the environment by reducing ineffective pesticide applications, improve the choice of effective pesticides both inside and outside the home. Finally, a discriminating dose test will allow researchers anywhere to test submitted ticks either without animal-based, blood feeding (if engorged ticks are collected) or by feeding submitted ticks only once on cattle to obtain eggs. The cost savings alone make this a very attractive, option for a long-term program. Such a program could fairly easily be set up at an appropriate laboratory with a 30-day maximum turnaround for results. This corresponds to a label-rate reapplication interval for a residual interior application to an infested home. 3. Determination of resistance mechanisms in pyrethroid-resistant brown dog ticks This objective will provide the most useful information to researchers in the short term, however, knowing the resistance mechanisms aid residents and the environment in the long term for two reasons. First, by knowing the resistance mechanism, chemical classes that act on similar target sites can be avoided, thereby eliminating ineffective pesticide use. Second, after determining a resistance mechanism, we will have extremely valuable data that could be used to develop a rapid, cost effective screen for future tick submissions, with a turnaround time of a few days.
Project Methods
1. Overview of proposed investigations Brown dog ticks will be obtained from infested homes throughout Florida and other Southeastern states though Pest Control Industry (PCI) contacts. The effectiveness of subsequent acaricide treatments will be noted by the PCI representative. Ticks will be reared on rabbits under University of Florida Institutional Animal Care and Use Committee protocols. Each life stage will require a rabbit infested with approximately 100 mg of larvae or nymphs or 20-30 adults. One animal would be required for each generation. Adult ticks require approximately one week to oviposit and an additional 2-5 weeks to hatch. Emergent larvae will be divided into two groups. The first group will be returned to the tick colony for use in Objectives 2 and 3. The second group will be processed though the larval packet test (LPT) (live tick assays) (Obj. 1). After initial bioassays are complete (Obj. 1), we will develop the discriminating dose (from ticks returned to the colony). The ticks that succumb and survive the discriminating dose will be held separately and preserved for future molecular screening (not a part of this proposal). Additionally, for those ticks colonies found to have significant resistance to permethrin, we will conduct screenings looking for enzyme (esterase or monooxygenase) or target-site insensitivity resistance mechanisms. Should fipronil-resistant populations be identified, we will follow a similar protocol. 2. Techniques to be employed, including feasibility All techniques described in this proposal are standardized from previous work and therefore are highly feasible. Preliminary results with suspected-resistant brown dog ticks, described elsewhere in this proposal, are presumptive positive using this technique. We will utilize a high-dose resistance selection exposure to fix the genes in resistant tick populations using the LPT test. This process should take about 2 generations a >90% mortality. We will then perform synergist studies on the selected populations giving an indication if a metabolic mechanism is involved in resistance. This can be followed up with a native gel electrophoresis for verification. This technique should become a rapid bio-molecular test, as our preliminary data indicate. To determine if there is a target site mutation (insensitivity), we will utilize other chemicals with the same mode of action. Because enzymes work on specific chemicals, if a different chemical with the same mode of action confers resistance, a mutation in the target site is likely the cause of the resistance. Should this be the case, a PCR technique could be developed, but this is outside of the scope of this project. For fipronil, either dieldren or lindane could be used and for permethrin either DDT or cypermethrin could be used. Data analysis: Analysis of bioassay data will be with standard Probit techniques. Resistance Ratios will be generated and an evaluation of resistance level and predicted control will be incorporated into recommendations. The remainder of the objectives do not require statistical analysis.

Progress 09/01/09 to 08/31/12

Outputs
OUTPUTS: Clientele contacts to the University of Florida with brown dog tick infestations from outside sources included 37 residential sites and three dog kennels during the active period of this project. We contacted 16 Florida dog kennels, with six positive responses. During the project, we obtained 26 brown dog tick colonies, with 12 providing sufficient ticks or from which successful rearing generated adequate numbers of viable larvae to be included in the results. In total, 11 colonies were screened for resistance to permethrin, six against fipronil and three were used in synergist studies. PCR and protein activity screenings were conducted on selected colonies where resistance was found. PARTICIPANTS: Dr. Phillip E. Kaufman, UF; Amanda Eiden, Ph.D. student; Dr. Faith Oi, UF; Dr. Robert Miller, USDA, ARS, KBLIRL Dr. Emma Weeks, UF; Lucas Carnohan, UF; Mark Halvorsen, UF; Lois Wood, UF; Corie Ritchie, UF Dr. Phil Kaufman is the project PI and provided oversight for all objectives. Dr. Faith Oi provided guidance and training for the graduate student working on the project. Dr. Robert Miller provides guidance on resistance testing and training for the graduate student. Amanda Eiden conducted all laboratory studies. Dr. Emma Weeks, Lucas Carnohan, Mark Halvorsen, Lois Wood and Corie Ritchie assisted with laboratory studies and tick rearing. TARGET AUDIENCES: Florida's residents, small animal veterinarians, dog kennel operators, and dog shelter operators. Many of the topics of this project are utilized in Dr. Kaufman's Medical and Veterinary Entomology courses taught at the University of Florida. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
A concentration of 0.442% permethrin was determined to kill 99.9% of larval brown dog ticks (BDT) in our assay and was considered the diagnostic dose to be used for future screening. We identified that one strain of BDT that demonstrated over 98% survival at a 10% permethrin exposure. All strains tested showed at least 20% survival at three-times the diagnostic concentration of permethrin. The diagnostic concentration for fipronil was 0.146, with the greatest resistance ratio >2.7-fold. Homeowners have been notified of results and their acaricide application practices have been altered. Our program has developed several extension brochures and a website that are now available and described in the extension component report for this project. Following test results and conversations with clientele, we have been re-contacted by clientele to express the successes they have had when following our updated guidelines.

Publications

  • Kaufman, P.E. 2010. Managing the blood suckers: Fleas and ticks. Southeast Pest Management Conference. University of Florida, Gainesville, FL. May 03, 2010.
  • Oi, F. M. 2011. Ticks by Way of Bed Bugs, Florida Pest Pro, Jan 2011, p. 28, 30; circulation of 10,000
  • Eiden, A., P. Kaufman, and F. Oi. 2012. Acaricide resistance in brown dog tick populations in Florida. 9th Arbovirus Surveillance and Mosquito Control Workshop. St. Augustine, FL. March 29, 2012.
  • Eiden, A.L., P.E. Kaufman, F.M. Oi, M.J. Dark and R. Miller. 2012. Status of acaricide resistance in the brown dog tick. Livestock Insect Workers Conference, Kalispell, MT.
  • Eiden, A.L., P.E. Kaufman, F.M. Oi. 2012. Acaricide resistance in Florida Rhipicephalus sanguineus populations. Florida Entomological Society Meeting, Jupiter Beach, FL. July 23, 2012.
  • Eiden, A.L., P.E. Kaufman, F.M. Oi, M.J. Dark and R. Miller. 2012. Acaricide resistance in Rhipicephalus sanguineus. Society of Vector Ecology Annual Meeting. St. Augustine, FL. September 24, 2012.
  • Eiden, A.L., P.E. Kaufman, F.M. Oi, M.J. Dark and R. Miller. 2012. Determination of acaricide resistance in Rhipicephalus sanguineus and evaluation of resistance mechanisms. Annual Meeting of the Entomological Society of America, Knoxville, TN. November 12, 2012.


Progress 09/01/10 to 08/31/11

Outputs
OUTPUTS: To date, six colonies of brown dog tick have been established. Four have been screened for fipronil resistance. Three have been screened for permethrin resistance and two await testing. Resistance demonstrated in several strains. PARTICIPANTS: Amanda Eiden, Ph.D. student; Dr. Faith Oi, UF; Dr. Robert Miller, USDA, ARS, KBLIRL Dr. Phil Kaufman is the project PI and provided oversight for all objectives. Dr. Faith Oi provided guidance and training for the graduate student working on the project. Dr. Robert Miller provides guidance on resistance testing and training for the graduate student. Amanda Eiden conducted all laboratory studies. TARGET AUDIENCES: Florida's residents, small animal veterinarians, dog kennel operators, and dog shelter operators. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
Initial screening of three brown dog tick colonies preliminarily suggests that permethrin resistance is present. Fipronil resistance is present in at least one strain. Homeowners have been notified and their acaricide application practices have been altered.

Publications

  • Oi, F. M. 2011. Ticks by Way of Bed Bugs, Florida Pest Pro, Jan 2011, p. 28, 30; circulation of 10,000


Progress 09/01/09 to 08/31/10

Outputs
OUTPUTS: To date, four colonies of brown dog tick have been established. Three of these have been submitted for initial permethrin insecticide screening, with resistance demonstrated in all three strains. PARTICIPANTS: Amanda Eiden, Ph.D. student; Dr. Faith Oi, UF; Dr. Robert Miller, USDA, ARS, KBLIRL Dr. Phil Kaufman is the project PI and provided oversight for all objectives. Dr. Faith Oi provided guidance and training for the graduate student working on the project. Dr. Robert Miller provides guidance on resistance testing and training for the graduate student. Amanda Eiden conducted all laboratory studies. TARGET AUDIENCES: Florida's residents, small animal veterinarians, dog kennel operators, and dog shelter operators. Many of the topics of this project are utilized in Dr. Kaufman's Medical and Veterinary Entomology courses taught at the University of Florida. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
Initial screening of three brown dog tick colonies preliminarily suggests that permethrin resistance is present.

Publications

  • No publications reported this period