Efficacy of white tailed deer (Odocoileus virginianus) treatment for cattle fever ticks in southern Texas, USA

Authors: CURRIE, CHASE - Comanche Maverick Ranch Wildlife; HEWITT, DAVID - Texas A&M University; ORTEGA-S, ALFONSO - Texas A&M University; SCHUSTER, GRETA - Texas A&M University; CAMPBELL, TYLER - East Wildlife Foundation; Lohmeyer, Kimberly - Kim; Perez De Leon, Adalberto - Beto

Submitted to: Journal of Wildlife Diseases
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/4/2019
Publication Date: 7/2/2020
Citation: Currie, C., Hewitt, D., Ortega-S, A., Schuster, G., Campbell, T., Lohmeyer, K.H., Perez De Leon, A.A. 2020. Efficacy of white tailed deer (Odocoileus virginianus) treatment for cattle fever ticks in southern Texas, USA. Journal of Wildlife Diseases. 56(3):588-596. https://doi.org/10.7589/2015-11-304.
DOI: https://doi.org/10.7589/2015-11-304

Interpretive Summary: White-tailed deer are a host for cattle fever ticks and are a concern for tick control programs in south Texas. Oral (ivermectin treated corn) and topical (permethrin on hair coat) tick control treatments have been developed for deer; however, the efficacy of these treatments have not been determined for cattle fever ticks in south Texas. The objective of this study was to evaluate the control efficacy of these tick treatments by 1) measuring exposure rates of deer to ivermectin and permethrin, 2) determine the relationship between cattle fever ticks on deer and exposure to ivermectin and permethrin, and 3) determine if photos from remote cameras at treatment sites can be used as a measure of treatment. The visitation rate of 327 deer to four treatment bait sites was monitored using remote cameras for two years. There appeared to be no relationship between the presence of permethrin on the hair coat and the likelihood of being infested with cattle fever ticks. The probability of tick infestation decreased as ivermectin levels increased in male and female deer. Oral treatment with ivermectin appears to be more effective in controlling cattle fever ticks than topical treatment with permethrin.

Technical Abstract: White-tailed deer (Odocoileus virginianus) serve as a host for cattle fever ticks (Rhipicephalus (Boophilus) microplus and R. (B.) annulatus) (CFT), therefore, deer are a concern for CFT control programs in southern Texas. Systemic (oral delivery of ivermectin) and topical (permethrin on pelage) treatment devices have been developed for white-tailed deer; however, the efficacy of these treatment options has not been determined for CFT in southern Texas. Therefore, our objectives were to evaluate the effectiveness of CFT treatment strategies by 1) measuring exposure rates of deer to the acaricides permethrin and ivermectin, 2) determining the relationship between CFT on deer and exposure to the acaricides, and 3) determine if photos from remote cameras at medicated baits sites can be used as a measure of acaricide treatment. We captured 327 deer on 4 sites in southern Texas. Deer visitation to medicated bait sites was monitored using remote cameras from March 2010-February 2012. There was no relationship between the presence of permethrin and the probability of being infested with CFT (P = 0.336). The probability of infestation with CFT decreased as serum ivermectin levels increased for male (n = 18, P = 0.098) and female (n = 33, P < 0.001) deer. Our results indicate ivermectin may be more effective in treating CFT than permethrin, thus it would be worthwhile to develop topical acaracides other than permethrin for treating white-tailed deer in southern Texas.