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ARS Home » Pacific West Area » Pullman, Washington » Animal Disease Research » Research » Research Project #430480

Research Project: A Pioneering Approach to Tick Control: Anti-tick Toxins Delivered via a Tick Transmissible Pathogen

Location: Animal Disease Research

Project Number: 2090-32000-040-002-I
Project Type: Interagency Reimbursable Agreement

Start Date: Mar 1, 2016
End Date: Feb 28, 2023

1) demonstrate the anti-R. microplus effect of a protein toxin. 2) demonstrate B. bovis kinete stage specific promoters (an exclusive stage of the parasite within the tick). 3) generate a transgenic B. bovis expressing anti-tick protein toxin exclusively in kinete stage. 4) test transgenic B. bovis parasites as an anti-tick protein toxin delivery platform during cattle infestation.

Ticks are obligate hematophagous ectoparasites that cause significant economic losses to the livestock industry directly and through transmission of tick-borne pathogens. It is estimated that ticks and tick-borne diseases cause annual losses of > US $20 billion worldwide. In developing countries, the loss of livestock caused by ticks and tick-borne diseases result in increased poverty in rural areas where smallholder farms predominate. Currently, there are no effective vaccines that control ticks or tick-borne pathogens. The only effective method to minimize tick burdens and to control transmission of tick-borne pathogens is the use of synthetic chemical acaricides. However, widespread acaricide use has caused acaricide-resistant tick populations and created environmental concerns. The recent discovery of Boophilus tick populations with multiple acaricide-resistances in Mexico raises concerns regarding geographic and numerical tick expansion into Boophilus free areas of the United States and a corresponding increase in the risk of transmission of tick-borne pathogens. Therefore, more effective, safer and environmentally friendly approaches to tick control are desirable. Bio-insecticides such as protein toxins derived from bacteria or spider venoms could reduce tick burdens if an appropriate delivery system were available. The novelty of this proposal is the use of live-attenuated parasites to express an anti-tick protein toxin during a parasite life stage that occurs exclusively within the tick-vector, thus specifically targeting and killing the tick. We intend to use an attenuated strain of Babesia bovis, a cattle pathogen, as the delivery system for our novel anti-tick protein toxin. This strategy has the dual benefit of providing a vaccine against bovine babesiosis while simultaneously working to reduce tick burden and pathogen transmission.