Felis ISSN 2398-2950

Cutaneous dirofilariosis

Synonym(s): Feline cutaneous dirofilariasis; Dirofilaria repens infection

Contributor(s): Gad Baneth, Georg Duscher, Prof Dr Anja Joachim

Introduction

  • Cause: infection with the parasitic nematode Dirofilaria repens  Dirofilaria repens.
  • Signs: the presenting signs are variable: from an asymptomatic presentation, which presumably accounts for the majority of cases, to localized dermatitis with nodules and alopecia, pruritus, and rarely generalized dermatitis.
  • Diagnosis: detection of microfilariae in peripheral blood.
  • Treatment: for adulticide treatment melarsomine is suggested  as for D. immitis (possibly with adverse reactions). The most recent studies show good results with moxidectin/imidacloprid as spot on once a month for 3 months.
  • Prevention: microfilaricidal treatment is suggested for prevention during the mosquito period in endemic areas. Macrocyclic lactones in various formulations are also suggested.
  • Prognosis: very good. Problematic usually in combination with other diseases leading to hypersensitivity reaction or if the parasite is situated in aberrant locations.

Pathogenesis

Etiology

  • Dirofilaria repens is a nematode parasiting the subcutaneous tissue or perimuscular connective fasciae of dogs, cats and wild canids.

Predisposing factors

General

  • In endemic areas it can be assumed to be common among dogs/cats. Due to the asymptomatic progress of infection the number of cases might be underestimated since they are not commonly reported.

Pathophysiology

  • Many details concerning D. repens infections are yet unclear and still await to be elucidated.
  • The adults live in painless nodules in the skin of appropriate hosts. The location of these nodules may have clincial importance when situated at aberrant locations, which is more frequently the case in unsuitable hosts.
  • Histopathological changes in organs are traced back to the combination of mechanical and immunopathological effects caused by adults, maturing larvae and microfilariae during heavy infections.

Timecourse

  • Adults live for several years in nodules.
  • Microfilariae live for months.

Epidemiology

  • The nematode is transmitted by mosquitoes (AedesAnophelesCulex, etc.) which are biological vectors and intermediate hosts at the same time.
  • In the intermediate hosts microfilariae, L2 (2nd stage larvae) and L3 (3rd stage larvae) can be found. The latter is the infective stage for transmission to the mammalian definitive hosts.
  • In the mammalian hosts (dogs, cats, wild canids),  L3 molt to L4 and later to immature adults. These mature and shed microfilariae, which can be taken up by mosquitoes.

Diagnosis

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Treatment

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Prevention

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Outcomes

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Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Fok E, Jacsó O, Szebeni Z et al (2010) Elimination of Dirofilaria (syn. Nochtiella) repens microfilariae in dogs with monthly treatments of moxidectin 2.5%/imidacloprid 10% (Advocate®, Bayer) spot-on. Parasitol Res 106 (5), 1141-9 PubMed.
  • Genchi M, Pengo G, Genchi C (2010) Efficacy of moxidectin microsphere sustained release formulation for the prevention of subcutaneous filarial (Dirofilaria repens) infection in dogs. Vet Parasitol 170 (1-2), 167-169 PubMed.
  • Traversa D, Aste G, Milillo P et al (2010) Autochthonous foci of canine and feline infections by Dirofilaria immitis and Dirofilaria repens in central Italy. Vet Parasitol 169 (1-2), 128-132 PubMed.
  • Miterpáková M, Antolová D, Hurníková Z et al (2008) Dirofilariosis in Slovakia - a new endemic area in Central Europe. Helminthologia 45 (1), 20-23 VetMedResource.
  • Hermosilla C, Pantchev N, Dyachenko V et al (2006) First autochthonous case of canine ocular Dirofilaria repens infection in Germany. Vet Rec 158 (4), 134-135 PubMed.
  • Tarello W (2003) Retrospective study on the presence and pathogenicity of Dirofilaria repens in 5 Dogs and 1 Cat from Aosta Vally. Schweiz Arch Tierheilkd 145 (10), 465-469 PubMed.
  • Baneth G, Volansky Z, Anug Y et al (2002) Dirofilaria repens infection in a dog: diagnosis and treatment with melarsomine and doramectin. Vet Parasitol 105 (2), 173-178 PubMed.

Other sources of information

  • Schwan EV (2009) Filariosis of domestic carnivores in Gauteng, KwaZulu-Natal and Mpumalanga provices, South Africa, and Maputo province, Mozambique. Doctoral thesis. University of Pretoria.
  • Genchi C, Guerrero J, McCall J W, Venco L (2007) Epidemiology and prevention of Dirofilaria infections in dogs and cats. Genchi C, Rinaldi L, Cringoli GVeterinary Parasitology and Parasitic diseases 8, Naples.
  • Genchi C, Venco L, Genchi M (2007) Guideline for the laboratory diagnosis of canine and feline Dirofilaria infections. In: Genchi C, Rinaldi L, Cringoli G Veterinary Parasitology and Parasitic diseases 8, Naples.
  • Grandi G, Zivicnjak T, Beck R (2007) Pathogenesis of Dirofilaria spp. infections. In: Genchi C, Rinaldi L, Cringoli G Veterinary Parasitology and Parasitic diseases 8, Naples.
  • Manfredi M T, Cerbo Ad, Genchi M (2007) Biology of filarial worms parasitizing dogs and cats. In: Genchi C, Rinaldi L, Cringoli GVeterinary Parasitology and Parasitic diseases 8, Naples.


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