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Comparison of parasitic mite retrieval methods in a population of community cats

Milley, Catherine, Dryden, Michael, Rosenkrantz, Wayne, Griffin, Joya, Reeder, Christopher
Cheyletiella, Demodex, Notoedres cati, Otodectes cynotis, Siphonaptera, acetates, ambient temperature, cats, chiggers, confidence interval, ears, feces, parasitic mites, potassium hydroxide, river valleys, Ohio River, United States
This study compared methods of mite retrieval from community cats in the Ohio River Valley region of the USA and determined incidence of parasitic mites in this region. In total, 493 community cats were humanely trapped and anesthetized for a trap–neuter–return program. Cats received a dermatologic examination, ear swabs, superficial skin scraping, flea combing, acetate tape preparation and feces collection. All samples were examined microscopically. Large volumes of hair and scale from flea combing were dissolved in 10% potassium hydroxide and centrifuged with Sheather’s solution. Fecal samples were mixed with Sheather’s solution, filtered and centrifuged. Ear swabs were significantly (P <0.05) better than other methods for finding chigger mites and Otodectes cynotis, and skin scraping was significantly better than ear swabs for finding Cheyletiella species. Only cats with O cynotis had clinical lesions. Mites remained identifiable for 6 months at room temperature. Mite incidence rates were as follows: Notoedres cati (1/493 cats), 0.002 (95% confidence interval [CI] 0–0.006); Lynxacarus radovskyi (2/493 cats), 0.004 (95% CI 0–0.01); Demodex gatoi (5/493 cats), 0.01 (95% CI 0.001–0.019); chigger mites (10/493 cats), 0.02 (95% CI 0.008–0.033); Cheyletiella species (12/493 cats), 0.024 (95% CI 0.011–0.038); and O cynotis (124/493 cats), 0.252 (95% CI 0.213–0.29). Ear swabs are recommended when O cynotis or chigger mites are suspected. Skin scraping is more likely to yield positive results than ear swabs, but was not significantly better than acetate tape preparations, flea combing or fecal flotation for finding Cheyletiella species. Mites can remain identifiable for prolonged periods at room temperature. With the exception of O cynotis, the incidence of feline parasitic mites in the Ohio River Valley region of the USA is low; however, D gatoi and L radovskyi were present in the area and should be considered in cats with dermatologic disease attributable to them. In this population of community cats, asymptomatic carriage of mites was common.