Alternative treatments for southern cattle fever tick, Rhipicephalus microplus (Acari: Ixodidae) infested white-tailed deer hides

Authors: KLAFKE, GUILHERME - Department Of Energy; Miller, Robert; Thomas, Donald; BONILLA, DENISE - Animal And Plant Health Inspection Service (APHIS); HASEL, HALLIE - Animal And Plant Health Inspection Service (APHIS); DUHAIME, ROBERTA - Animal And Plant Health Inspection Service (APHIS); PIKE, CHELSEA - Texas Animal Health Commission; LANSFORD, T.R. - Texas Animal Health Commission; SCHWARTZ, ANDY - Texas Animal Health Commission; Perez De Leon, Adalberto - Beto

Submitted to: World Association for the Advancement of Veterinary Parasitology
Publication Type: Abstract Only
Publication Acceptance Date: 7/7/2019
Publication Date: 7/7/2019
Citation: Klafke, G.M., Miller, R., Thomas, D.B., Bonilla, D., Hasel, H., Duhaime, R., Pike, C., Lansford, T., Schwartz, A., Perez De Leon, A.A. 2019. Alternative treatments for southern cattle fever tick, Rhipicephalus microplus (Acari: Ixodidae) infested white-tailed deer hides. World Association for the Advancement of Veterinary Parasitology. 2019:311.

Interpretive Summary: Hides from hunted white-tailed deer are systematically inspected and treated with substances to kill ticks, also known as acaricides, before they leave areas in south Texas known to be at risk of infestation with cattle fever ticks. This is part of the operations by the Cattle Fever Tick Eradication Program to keep cattle, deer, and nilgai free of fever ticks, which are vectors of the microbes causing bovine babesiosis, a tick-borne disease that can kill cattle. Safer acaricides are needed to treat deer hides infested with fever ticks, specially the southern cattle fever tick (SCFT), scientifically known as Rhipicephalus microplus. The SCFT is an invasive tick species considered to be the most economically important external parasite of livestock worldwide. Here, we report the results of laboratory experiments conducted to determine if a commercial product containing essential oils obtained from plants, a worm able to kill ticks, and a household cleaning product could kill the SCFT as effectively as the synthetic acaricides currently used. Different groups of hides were artificially infested with adult and immature SCFT and each treated with one of the three test materials. The essential oil-based product was the most effective hide treatment killing all the immature SCFT, reducing female fertility by 94%, and killing 98% of the fully engorged females. These results indicate that the commercial essential oil product is a highly efficacious acaricide and a safer alternative to treat SCFT-infested deer hides.

Technical Abstract: Southern cattle fever tick (SCFT), Rhipicephalus microplus, is the most economically important invasive species of ticks in the United States. SCFT parasitizes cattle and also wild ungulates as the whitetailed deer (WTD), Odocoileus virginianus, which can spread tick populations posing a threat to the cattle fiver tick eradication program (CFTEP). Hunter killed WTD and other game hides are inspected for ticks and treated with coumaphos before they leave tick quarantined areas of Texas. Concerns over human intoxication have led the CFTEP to consider alternative treatment methods. Essentria® IC3 (EIC3), a plant essential oil-based product and entomopathogenic nematodes (EPN) (Steinernema carpocapse) are known to be lethal to ticks. Simple Green® (SG), a household cleaning product, has anecdotal information of insecticidal activity. The present study aimed to determine efficacy of EIC3, EPN and SG against adult ticks on deer hides. In vitro bioassays with adult and larval stages of SCFT were carried out to establish doses of EIC3 and SG to be used in the hides treatment. For the deer hide test, each hide (10 replicates) was inoculated with ten engorged female ticks and treated with one liter of EIC3 (6.25%), EPN (50,000 infective juveniles/ml), SG (100%) or water (control). After treatment the hides were rolled and placed into plastic bags and held at 8oC for 12 hours. After 12 hours, ticks were incubated to allow for egg laying and larval hatch determination. SG treatment resulted in low mortality rates both in vitro (10%) and in the hides (27%). EN resulted in even lower mortality (<15%). EIC3 was the most effective treatment tested against SCFT resulting in 100% mortality of larvae, 94% reduction of fertility of adults and 98% mortality of fully engorged females in treated hides. EIC3 can be used as an alternative to treat SCFT infested deer hides.