Exotis ISSN 2398-2985

Ferrets

Dirofilariasis

Synonym(s): Heartworm disease, Infection with Dirofilaria immitis

Contributor(s): Cathy Johnson-Delaney, David Perpinan

Introduction

  • Dirofilariasis or heart worm disease is an uncommon disease.
  • Ferrets are considered aberrant hosts.
  • Dogs are primary reservoir.
  • Cause: Dirofilaria immitis.
  • Signs: similar to those seen in the dog (exercise intolerance, dyspnea, lethargy, ascites, coughing, anorexia, weakness, anemia and cyanosis).
  • Diagnosis: history, auscultation, radiography/angiography, echocardiography, heartworm antigen testing, microfilariae testing, complete blood count, serum chemistries.
  • Treatment: adulticide therapy, symptomatic treatment, transvenous heartworm extraction, microfilaricide therapy, 
  • Prognosis: fair to guarded if asymptomatic infection; poor if symptomatic.

Pathogenesis

Etiology

  • Caused by an infection with Dirofilaria immitis.
  • Most commonly found in the right ventricle, cranial vena cava, main pulmonary artery.
  • Cause villous endarteritis.
  • May develop severe heart disease with only a single worm, although burdens of up to 21 worms have been reported. Fatal right sided heart failure has occurred with 2 adult worms causing mechanical obstruction of blood flow.
  • The susceptibility and life cycle of D. immitis have been studied extensively in ferrets and were found to be similar to those in dogs.
  • Because of the ferret’s small size, the clinical presentation more closely resembles that of infected cats.

Predisposing factors

General

  • Ferrets housed outdoors in endemic areas are at risk.
  • Endemic areas include Atlantic and Gulf coasts of the United States, tropical and semi-tropical areas, some Mediterranean countries and Australasia.
  • Transmission in unlikely in regions or seasons where the ambient temperatures are not on average higher than 18°C/65°F during a 30-day period.

Pathophysiology

  • D. immitis is a filarial parasite that is transmitted by mosquitoes, which serve as a vector and intermediate host for the parasite.
  • Microfilaria are ingested by mosquitoes (usually from female mosquitoes feeding on microfilaria-positive dogs). 
  • Mosquito deposits infective third stage larvae into the skin, which then migrate subcutaneously to the thorax and vascular system.
  • Microfilaria can be found within the small pulmonary arteries of as many as 50-60% of infected animals.

Epidemiology

  • Uncommon disease of ferrets.

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.
  • Bradbury C, Saunders A B, Heatley J J, Gregory C R, Wilcox A L & Russell K E (2010) Transvenous heartworm extraction in a ferret with caval syndrome. J Am Anim Hosp Assoc 46 (1), 31-35 CABI.
  • Wagner R A (2009) Ferret cardiology. Vet Clin North Am Exotic Anim Pract 12 (1), 115-134 ScienceDirect.
  • McCall J W (1998) Dirofilariasis in the domestic ferret. Clin Tech Small Anim Pract 13 (2), 109-112 PubMed.

Other sources of information

  • Fox J G & Mariani R P (2014) Eds Biology and Disease of the Ferret. 3rd edn. Wiley Blackwell, USA. pp 835.
  • Mayer J & Donnelly T M (2013) Clinical Veterinary Advisor: Birds and Exotic Pets. Elsevier, USA. pp 752.
  • Morrisey J K & Kraus M S (2012) Ferrets: Cardiovascular and other Diseases. In: Ferrets, Rabbits and Rodents: Clinical Medicine and Surgery. 3rd edn. Eds: Quesenberry K E & Carpenter J W. Saunders, St. Louis, USA. pp 62-77.
  • Lewington J H (2007) Cardiovascular Disease. In: Ferret Husbandry, Medicine and Surgery. 2nd edn. Eds: Lewington J H. Butterworth-Heinemann, Oxford, UK. pp. 275-284.
  • Antinoff N (2002) Clinical Observations in Ferrets with Naturally Occurring Heartworm Disease and Preliminary Evaluation of Treatment with Ivermectin with and without Melarsomine. In: Proc Symposium American Heartworm Society: Recent Advances in Heartworm Disease. pp 45-47.


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