First Report of Neotrombicula autumnalis Infestation in a Cat and a Dog from Corfu (Greece) and in a Cat from Limassol (Cyprus)

Introduction

T rombiculosis is a parasitic dermatopathy caused by the larval stage of trombiculid or harvest mites. Of the several hundred mites of the family Trombiculidae (Phylum Arthropoda, Class Arachnida, Subclass Acarina), Neotrombicula autumnalis is the most common species parasitizing humans, dogs, cats, other domestic and wild mammals, reptiles, and birds in Europe (Takahashi et al. 2004, Guarneri et al. 2005, Schöler et al. 2006, Cakiroglu et al. 2008, Literak et al. 2008). Only the larval stage is parasitic, whereas nymphs and adults live in the soil feeding on plants and small insects (Guarneri et al. 2005). The reddish to orange, 0.2–0.4 mm in diameter, 6-legged larvae seek a suitable host where they remain attached for up to 15 days. They inject lytic enzymes into the dermis using their chelicerae, and they feed on tissue fluids (Nuttall et al. 1998, Guarneri et al. 2005). The disease is seasonal, occurring mostly during summer and autumn (Nuttall et al. 1998, Guarneri et al. 2005, Schöler et al. 2006). Infested dogs and cats have macular erythema, papules, vesicles, wheals, scales, and crusts that are commonly accompanied by pruritus and are usually located on areas that are in contact with the ground and vegetation, such as the head, ear pinnae, ventral abdomen, perineum, and legs (Nuttall et al. 1998, Smal et al. 2004, Takahashi et al. 2004). In addition, N. autumnalis is considered a possible vector of Anaplasma phagocytophilum and Borrelia burgdorferi sensu lato, bacteria of medical and veterinary importance (Fernández-Soto et al. 2001, Kampen et al. 2004, Literak et al. 2008).

Case Report

Between July, 2010, and December, 2011, 2 cats (a 5-year-old castrated male domestic longhair cat and an intact female domestic shorthair, stray cat of unknown age) and one dog (1-year-old spayed female, cross-breed) that lived in Chrisida, Corfu (first cat and the dog) and in Limassol, Cyprus (second cat) were examined because of mild pruritus (1/3) and skin lesions including alopecia (2/3), hypotrichosis (2/3), erythematous macules (1/3), papules (1/3), and orange crusts (3/3) that were located on the head (3/3), axillae (1/3), and ventral abdomen (1/3). In all 3 cases, skin scrapings revealed N. autumnalis larvae (Fig. 1) that were identified to the species level according to standard morphological criteria (Taylor et al. 2007). Fipronil (Frontline, Merial) spot on was administered in the first cat and the dog and resulted in almost complete clinical cure and resolution of the skin lesions after 2 weeks. In the second cat a selamectin (Stronghold, Pfizer) spot on was administered but the response remains unknown.

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FIG. 1.

Numerous Neotrombicula autumnalis larvae in a skin scraping from a cat with trombiculosis. Magnification, 100×.

Discussion

The clinical presentation of our cases was compatible with what is reported in the literature (Nuttall et al. 1998, Smal et al. 2004, Takahashi et al. 2004), with the exception that pruritus had been observed only in 1 animal (the first cat). Because pruritus is considered the result of a hypersensitivity reaction to the mite (Nuttall et al. 1998), its absence from the dog may be attributed to a recent infestation, whereas in the second stray cat it was not possible to be aware on its presence or not.

Infestation by N. autumnalis is quite common in central and northern Europe; for example, on the basis of a survey conducted in private veterinary practices in the United Kingdom, it was diagnosed in 1.4% of the dogs and in 0.6% of the cats with dermatopathies (Hill et al. 2006). In addition, this parasite has been found in southern European countries like Italy and Turkey (Guarneri et al. 2005, Cakiroglu et al. 2008), and other species of the same genus (N. carpathica, N. inopinata) are present in Albania, states of former Yugoslavia and Bulgaria (Literak et al. 2008). On the contrary and to the best of our knowledge, this is the first confirmed localization of N. autumnalis in Corfu and Limassol because prior to 2010 veterinary dermatologists had not reported cases of trombiculiasis nor had the Laboratory of Parasitology and Parasitic Diseases of the Faculty of Veterinary Medicine, Aristotle University of Thessaloniki received samples of this parasite from veterinarians. However, a case of N. autumnalis infestation in a dog from the island of Paros, Greece, has been recently reported (V. Kontos, E. Papadogiannakis, A. Lambrou, S. Kontos, M. Styliara. Rare case of Neotrombicula autumnalis infestation in a dog. 12^th Hellenic Veterinary Congress, Athens, April 2012, proceedings on CD). For these reasons, we believe that N. autumnalis may have been recently introduced in Greek islands like Corfu and in Cyprus, although it is not possible to exclude the possibility of being present but unrecognized for years.

Migrating birds or transported terrestrial species are responsible for the introduction of N. autumnalis in an island (Literak et al. 2008). For both Corfu and Cyprus, which are tourist destinations, importation of infested dogs and cats seems a possible explanation. After being introduced in a naïve area, these mites may be easily established because they can withstand a wide variety of environmental conditions, including low and high temperatures, low relative humidity, and various levels of soil moisture and pH (Schöler et al. 2006).

Local veterinarians should be aware of this disease and recommend parasiticides that are effective for both the treatment and prevention of trombiculosis for all dogs and cats that live in areas where the parasite is present. To this purpose, the best available evidence supports the monthly use of fipronil spray in dogs and selamectin spot on in cats (Nuttall et al. 1998, Leone and Albanese 2004), although the latter is an off-label use of the drug. The same parasiticides should also be applied to all traveling pets for their own protection and to avoid the introduction of the mite in naïve areas. Finally, local physicians should be informed of the presence of these mites to include trombiculosis in the differential diagnosis of pruritic papular to vesicular eruptions of humans (Guarneri et al. 2005) and to recommend preventive measures.