Twelve-hour duration testing of cream formulations of three repellents against Amblyomma americanum.
The repellent efficacies of the U.S. military repellent 33% N,N-diethyl-3-methylbenzamide (deet), 10% and 20% (1S, 2'S) 2-methylpiperidinyl-3-cyclohexene-1-carboxamide (SS220) and 10% and 20% 1-methyl-propyl-2-(hydroxyethyl)-1-piperidinecarboxylate (Bayrepel) cream formulations on human volunteers against the lone star tick Amblyomma americanum (L.) were evaluated in a simulated forest floor environment over a 12-h testing period. At 2-h intervals, volunteers, with repellent applied in a 5-cm-wide band around each ankle, stood for 5 min in plastic tubs containing leaf litter and 100 host-seeking A. americanum nymphs. Ticks were allowed to remain on a volunteer's feet and ankles for an additional 5 min after the volunteer exited the tub. All repellent formulations provided high levels of protection for the entire 12 h. No ticks crossed 5-cm-wide bands of 20% SS220 and Bayrepel during any challenge, and thus 100% protection was afforded throughout the test. These formulations showed a long-lasting efficacy hitherto unknown in tick repellents intended for use on human skin.
Carroll
J F
JF
Animal Parasitic Diseases Laboratory, United States Department of Agriculture (USDA), Agricultural Research Service (ARS), Beltsville Agricultural Research Center, Beltsville, Maryland, USA. john.carroll@ars.barc.usda.gov
Benante
J P
JP
Klun
J A
JA
White
C E
CE
Debboun
M
M
Pound
J M
JM
Dheranetra
W
W
D000287:Administration, Topical; D000328:Adult; D000818:Animals; D018592:Cross-Over Studies; D053138:Cyclohexenes; D003671:DEET; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D007302:Insect Repellents / Q000008:administration & dosage / Q000494:pharmacology*; D026863:Ixodidae / Q000187:drug effects* / Q000502:physiology*; D008297:Male; D009758:Nymph / Q000187:drug effects / Q000502:physiology; D010880:Piperidines; D012867:Skin / Q000469:parasitology*; D012903:Smell / Q000502:physiology; D013997:Time Factors; D016896:Treatment Outcome
D053138:Cyclohexenes; D007302:Insect Repellents; D010880:Piperidines; C500473:SS220; D003671:DEET; C483506:picaridin