Validity and Reproducibility of Techniques for Diagnosis of Feline Otodectic Mange
World Small Animal Veterinary Association World Congress Proceedings, 2009
C.P. Souza1,2; V.P. Perez1; F.B. Tavares1; G.G. Verocai2; M. Bulbi1
1Universidade Estácio de Sá, Rio de Janeiro, Brazil; 2Universidade Federal Rural do Rio de Janeiro, Seropédica, Brazil

The objective of the present study was to evaluate the validity and reproducibility of the direct visualization of the mite on ear smear and the pinnal pedal reflex on the diagnostic of the parasitism by Otodectes cynotis in cats. Two hundred cats were submitted to both techniques during physical examination from January to October, 2007. Animals were domiciliated or maintained in animal shelters in Rio de Janeiro State, Brazil. In accordance to the literature, the mite visualization under optic microscopy is considered the standard test, and then used as well. Validity of both techniques was determined by calculating sensibility, specificity and predictive values. The Kappa index of agreement was utilized to evaluate reproducibility. On 98 (49%) cats the infestation was diagnosed by the optic microscope. In regards to direct mite visualization, 66 (33%) cats were diagnosed as parasitized. The values for sensibility, specificity, positive and negative predictive values and Kappa index were: 67.3, 100, 100, 76.1% and 0.68, respectively. Eighty-seven (43.5%) animals were positive to pinnal pedal reflex. The obtained values for sensibility, specificity, positive and negative predictive values and Kappa index were: 88.8, 100, 100, 90.3% and 0.88, respectively. The otodectic mange diagnosis by direct mite visualization presented low sensibility and high specificity, what do not classify it as a good technique. In contrast, the pinnal pedal reflex had high specificity and sensibility. Nevertheless, inconsistent aspects have been demonstrated about this technique, because it may present positive results for several other pruritic diseases as stated in the literature. And authors do not consider it a valid technique for specific otoacariasis diagnosis, since it does not effectively detect the parasite. In addition, another technique often used for diagnosis of otodectic mange in small animals is the otoscopy. This appears to be a useful method when dealing with dogs. However, feline handling is considerably more difficult and also this technique is not considered as accurate as the standard method, as demonstrated by studies using cats and dogs. Therefore, can be suggested that both techniques are not enough accurate for the diagnosis of otodectic mange in cats, and may be used as complementary tools to the standard test when possible.

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C.P. Souza
Universidade Estácio de Sá
Rio de Janeiro, Brazil