Morphological variability of Demodex cati in a feline immunodeficiency virus-positive cat

Abstract

CASE DESCRIPTION A 17-year-old FIV-positive cat was evaluated because of weight loss during the preceding few months. The cat had a weight loss of 0.5 kg (1.1 lb) during the last month. Because of its FIV-positive status, the cat was confined indoors. CLINICAL FINDINGS A large nonpruritic area of alopecia with hyperpigmentation and comedones was present on the right lateral aspect of the neck. The chin had diffuse alopecia and comedones. Mild alopecia was present on the dorsal aspect of the muzzle. Trichography and microscopic examination of acetate tape imprint preparations and skin scrapings revealed a very morphologically heterogeneous population of Demodex mites. Micrometry of adult mites revealed a broad range of body lengths (92.68 to 245.94 μm), which suggested that as many as 3 Demodex spp might be present in the skin lesions of this cat. TREATMENT AND OUTCOME Owing to its concurrent disease, no treatment was initiated for the demodicosis, and the cat died spontaneously 14 days after the evaluation. Sequence analysis of the 16S rRNA gene of collected mites was performed. Analysis revealed that the 16S rRNA gene sequence of collected mites appeared 100% identical to the Demodex cati 16S rRNA gene sequence deposited in GenBank (JX193759). A similarity of 79.2% and 74.4% was found when the 16S rRNA gene sequence of collected mites was compared with that of Demodex gatoi (JX981921) and Demodex felis (KF052995), respectively. CLINICAL RELEVANCE Demodicosis in cats is often associated with underlying disease. In cats, FIV infection may lead to an altered immune response and induce species polymorphism of Demodex mites.

Sucessful treatment of feline demodicosis with orally sarolaner Case Report

“…Despite the morphological differences observed in the mites found in the present study, it is not possible to claim that the case described here consisted of co-infection between D. cati and D. gatoi. Taffin et al (2016) demonstrated in their study that mite morphology can be affected by the host's immune status. These authors noticed mites with different morphological presentations in a single animal and initially believed that their case involved co-infection between D. cati and D. gatoi.…”

Feline Demodicosis Case Report—First Molecular Characterization of Demodex Mites in Romania

“…Females had a total length of 219.0 ± 27.4 µm, with the gnathosoma measuring 16.2 ± 1.9 µm, the podosoma 58.7 ± 2.6 µm and the opisthosoma 143.9 ± 25.4 µm. Values of 181.7 ± 17.9 µm (males) and 219 ± 27.4 µm (females), representing the total length were reported by Taffin et al [7]. Smaller sizes, respectively 170.8 ± 1.4 µm (gnathosoma 24.3 ± 0.8 µm, podosoma 58.2 ± 0.9 µm, opisthosoma 88.4 ± 0.5 µm) [8] and 140-175 µm [7], representing the total length, were noticed in Demodex spp.…”

“…Values of 181.7 ± 17.9 µm (males) and 219 ± 27.4 µm (females), representing the total length were reported by Taffin et al [7]. Smaller sizes, respectively 170.8 ± 1.4 µm (gnathosoma 24.3 ± 0.8 µm, podosoma 58.2 ± 0.9 µm, opisthosoma 88.4 ± 0.5 µm) [8] and 140-175 µm [7], representing the total length, were noticed in Demodex spp. males.…”

“…The quick test (FIV Ab/FeLV Ag-Vet Expert) results came back positive for FIV Ab and negative for FeLV Ag. The feline immunodeficiency virus and feline leukemia virus (FIV and FeLV, respectively) are severe diseases that frequently affect domestic cats causing immunosuppression and consequently, predisposing felines to secondary diseases (such as, feline demodicosis) [7,12,13].…”

“…The most frequent locations identified in feline patients include the head (ears and periocular region), and the dorsal area. Feline demodicosis is generally manifested through well-defined alopecia, erythema and crusts, all of which are lesions that could evolve into pruritic, bacterial complications [6,7].…”