Characterisation of cattle anal odour constituents associated with the repellency of Rhipicephalus appendiculatus
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Adults of the Brown Ear Tick (Rhipicephalus appendiculatus) have a predilection for feeding inside and around the ears of cattle and other hosts. A previous study has shown that the tick locates the host ears by ‘push–pull’ deployment of a repellent blend emitted at the anal region and an attractant blend emitted at the ears. Interestingly, the two odours play reverse roles with Rhipicephalus evertsi, which prefer to feed around the anal region. The present study was undertaken to characterize the major constituents of the cattle anal odour and to evaluate their repellence to R. appendiculatus. The anal odour was trapped with reverse-phase C18-bonded silica, Porapak Q and Super Q placed in an oven bag attached at the anal region of the cattle for 6 h. The adsorbents were then removed and extracted with dichloromethane, and the extracted compounds analyzed by linked gas chromatography-mass spectrometry (GC–MS). The major constituents of the odour were o-xylene, 4-hydroxy-4-methyl-2-pentanone, 4-methyl-2-methoxyphenol, ethylbenzene, 2,6,6-trimethyl-[1S(1α,β,5α)]bicycloheptanes, 5-ethoxydihydro-2(3H)-furanone, 3-methylene-2-pentanone, 5-methyl-2-phenyl-1H-indole, and 3-pentanone. The repellency of the available compounds (o-xylene, 4-hydroxy-4-methyl-2-pentanone, 4-methyl-2-methoxyphenol, ethyl benzene, 3-methylene-2-pentanone, and 3-pentanone) and blends was evaluated using a dual choice tick climbing assay at different doses. The anal odour showed repellence with RD75 of 0.39. Of the compounds tested, 4-methyl-2-methoxyphenol was found to be most repellent (RD75 = 0.56) and 3-pentanone least repellent (RD75 = 622.7). The blend of the six constituents showed RD75 of 0.34, comparable to that of the crude anal odour blend. A series of subtractive bioassays with one constituent of the 6-component blend missing was also carried out. Subtraction of 3-methylpentanone gave the most repellent blend (RD75 = 0.097), whereas subtraction of 4-methylguaiacol gave the least repellent blend (RD75 = 160.7) consistent with the high individual activity of this phenol. The study lays down useful groundwork for on-host deployment of controlled-release of a selected repellent or blend to disrupt the tick’s ability to locate its preferred feeding site.
KeywordsRhipicephalus appendiculatus Repellence of cattle anal odour Composition Active constituents and blends
This work was supported by funds from National Council of Science Technology (Grant No. NCST/5/003/W44). We also acknowledge Dr Rajindar K. Saini, of ICIPE for facilitating in the purchase of synthetic chemicals, Wanyama Kaye (ICIPE) for assisting in running GC–MS of the cattle anal odours, and E. Maina Kenyatta University for technical support.
Compliance with ethical standards
Conflict of interest
The authors declare no conflict of interest.
Human and animal rights statement
All applicable international, national, and/or institutional guidelines for the care and use of animals were followed. This article does not contain any studies with human participants performed by any of the authors.
- African Union-Interafrican Bureau for Animal Resources (2011) Pan African animal health yearbook 2011. Pan African animal health yearbook, 2011:xiii + 90 pp. http://www.au-ibar.org/pan-african-animal-health-yearbook. Accessed 2 Dec 2017
- Drummond R (1983) Tick-borne livestock diseases and their vectors. Chemical control of ticks. Wild Anim Revolut (FAO) 36:28–33Google Scholar
- Garcia-Garcia JC, Montero C, Redondo M, Vargas M, Canales M, Boue O, Rodriguez M, Joglar M, Machado H, Gonzalez IL (2000) Control of ticks resistant to immunization with Bm86 in cattle vaccinated with recombinant antigen Bm95 isolated from the cattle tick, Boophilus microplus. Vaccine 18:2275–2287CrossRefGoogle Scholar
- Irvin AD, Brocklesby DW (1970) Rearing and maintaining Rhipicephalus appendiculatus in the laboratory. J Inst Anim Tech 21:106Google Scholar
- Kogo K, Michuki G, Okemo P, Skilton R, Kemp S, Muthee M, Hassanal A. The role of microbes in cattle ears in the production of volatile semiochemical blend attractive to the Brown Ear tick. Rhipicephalus appendiculatus (In Preparation)Google Scholar
- Mbogo KS, Kariuki PD, McHardy N, Payne R (1995) Training manual for veterinary staff on immunization against East Coast fever using the ECFiM system. Kenya Agricultural Research Institute and Overseas Development Administration of UKGoogle Scholar
- Norval R, Perry D, Young S (1992) The epidemiology of theileriosis in Africa. Academic Press, London, p 481Google Scholar
- Saini RK, Orindi BO, Mbahin N, Andoke JA, Muasa PN, Mbuvi DM, Muya CM, Pickett JA, Borgemeister CW (2017) Protecting cows in small holder farms in East Africa from tsetse flies by mimicking the odor profile of a non-host bovid neglected tropical diseases. PLoS Negl Trop Dis 11:10CrossRefGoogle Scholar
- Spickett AM (1998) Acaricide and resistance. Vet Ectoparasitol Protozool 1:113Google Scholar
- Walker BJ (1974) The ixodid ticks of Kenya: a review of present knowledge of their hosts and distribution. The Eastern Press Limited, LondonGoogle Scholar