Dermatitis associated with microfilariae (Filarioidea) in 10 dogs

Abstract

Dermatitis associated with micro®lariae of a nematode of the superfamily Filarioidea was diagnosed in 10 dogs from the western United States. Clinically, lesions were single or multiple papules and plaques with alopecia, scarring, erythema, ulceration, or crusting. Eight dogs had lesional pruritus. Microscopically, there was perivascular, periglandular, to interstitial in¯ammation, with many eosinophils and/or plasma cells, and scarring aecting the dermis and subcutis. Microgranulomas containing micro®laria were seen in six dogs. Micro®lariae were noted in microgranulomas or free in the dermis or subcutis, but not in vessels. In one case, an adult female nematode emerged from a biopsy sample that was placed in physiologic saline. Study of this nematode revealed that it was a ®larioid of the family Onchocercidae; it was identi®ed as Acanthocheilonema sp. (syn: Dipetalonema). Antigen tests of ®ve dogs were negative for Diro®laria immitis. The Knott tests and/or ®lter tests of nine dogs were negative for micro®lariae. An indirect¯uorescence antibody test of one dog was also negative for D. immitis. One dog was not evaluated for micro®lariae.

Current trends in canine dirofilariosis in Austria—do we face a pre-endemic status?

“…Canine subcutaneous dirofilariosis is most commonly an asymptomatic course, but it can also result in a variety of nonspecific dermal alterations (Genchi et al 2010;Petry et al 2015). Possible cutaneous changes are nodules, pruritus, thin and fragile skin and ocular conjunctivitis (Hargis et al 2002;Bourdeau and Roussel 2010;Albanese et al 2013). Typically, there are no inflammatory reactions or capsules located around the parasite, which actively moves under the connective tissue layers (Genchi and Kramer 2017).…”

Allergic dermatitis by Dirofilaria repens in a dog: clinical picture and treatment

“…Nodular lesions and other non-specific skin changes such as pruritic papulo-crostous dermatitis have been associated with filarial infections of the dog and cat, including heartworm (Hargis et al 1999;Tarello 2011), and with D. repens in particular (Kamalu 1991;Bredal et al 1998;Tarello 2002).…”

“…Dogs infected with subcutaneous adults and circulating first-stage microfilaria larvae (i.e., mf) of D. repens are often considered asymptomatic, although in some cases, the parasite causes subcutaneous nodules, diffused dermatitis, skin lesions, and pruritus (Hargis et al 1999).…”

“…Allergic reactions due to mf sensitization have also been reported (Hargis et al 1999), but descriptions of allergicmediated clinical pictures in dogs infected with D. repens are scanty.…”

Microfilaricidal efficacy of a single administration of Advocate® (Bayer Animal Health) in dogs naturally infected with Dirofilaria immitis or Dirofilaria repens

“…cough, exercise intolerance, dyspnea, tachypnea, syncope, respiratory failure and death (Simón et al, 2012). Subcutaneous dirofilariosis is either subclinical or presents with dermatitis, (sub)cutaneous nodules and lesions, pruritus and allergic reactions (Bredal et al, 1998;Hargis et al, 1999;McCall et al, 2008;Rocconi et al, 2012).…”