Blood Meal Analysis for the Detection and Identification of Host DNA in the Gut Contents of Ornithodoros coriaceus
AuthorLong, Amber Kristine
AdvisorTeglas, Mike B.
Agriculture, Veterinary and Rangeland Sciences
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Ornithodoros coriaceus ticks are the vector for the disease epizootic bovine abortion, an abortive disease of cattle that can cause significant revenue losses in the beef cattle industry, in the western United States. The transmission cycle of the etiologic agent is unknown and it has not been determined whether there is a vertebrate reservoir host for the disease. Research into the composition of blood meals of arthropod vectors has been shown to provide evidence to link vector species to specific hosts which can be used to determine possible disease reservoirs. To determine if host identification through blood meal analysis could be performed on field caught Ornithodoros coriaceus, markers from three mitochondrial genes, 18S rDNA, 12S rDNA, and cytochrome b, were used to detect host DNA in the gut contents of the soft tick vector. Polymerase chain reaction in combination with reverse line blot showed that the cytochrome b marker could accurately identify host DNA in ticks, fed experimentally on a known host blood, on day 175 post-feeding in 92.9% of ticks, in 40% of ticks on day 196, and only 26.7% of ticks at day 207. The cytochrome b marker was not useful in identifying host DNA from ticks caught in the field. The 12S markers could discriminate between vertebrate DNA to the genus level but probes, designed for identification in reverse line blot, did not differentiate between species. The 18S marker was non-discriminatory and could not be used for further analysis.