Efficacy of Plant Essential Oils for the Repellents Against Chiggers (Leptotrombidium Imphalum) Vector of Scrub Typhus
Wuttikon Rodkvamtook PhD*, Anchana Prasartvit MSc**, Chaiwat Jatisatienr PhD***, Araya Jatisatienr PhD***, Jariyanart Gaywee PhD*, Praphathip Eamsobhana PhD****
Affiliation : * Armed Forces Research Institute of Medical Science (AFRIMS), Royal Thai Amy, Bangkok , Thailand ** Department of Disease Control, Ministry of Public Health, Nonthaburi, Thailand *** Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai, Thailand **** Department of Parasitology, Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok, Thailand
Scrub typhus caused by the Orientia tsutsugamushi. Rodents, particularly rats, serve as principal reservoir hosts. Infection in man is transmitted by the, chigger bite. Repellents provide an effective agent of protecting individuals from chigger. In the present study 6 plant essential oils were tested for evaluation of their repellent activity against the chigger, Leptotrombidium imphalum. The results showed that Clove oil was significantly more effective than others with ED50 and EC50 of 0.420 mg and 2.3%, followed by Zingiber oil (8.458 mg and 42.3%), Vetiver oil (19.582 mg and 97.9%), Turmeric oil (24.343 mg and 121.7%), Orange oil (27.310 mg and 136.6%) and Boesenbergia oil (30.486 mg and 152.4%). These results suggested that Clove oil was the most efficient repellent against chigger which is the vector for scrub typhus.
Keywords : Scrub typhus, Chigger, Repellent, Essential oil
