July 2022

Animal: Dog (Canis lupus familiaris), Caucasian Shepherd, 8-year-old, female.

Organ: Lung, pulmonary artery.

History: Severe dyspnea, anorexia, apathy, coughing, and exercise intolerance. The dog lived in an area surrounded by industrial fish farming pools.

Necropsy findings: Postmortem changes consisted of severe cyanosis, bilateral pulmonary densification, and multiple widespread areas of hemorrhage and necrosis within the lung (cobblestone appearance). On cross section, the pulmonary arteries contained numerous adult nematodes measuring between 2 and 2.5 cm in length.

Histopathological findings: Lung, pulmonary artery: The wall of the pulmonary artery is diffusely thickened and the lumen is partially obliterated by a large organizing thrombus containing numerous adult nematodes. Additionally, within the lung parenchyma, there are multiple and often coalescing granulomas centered on large numbers of nematode larvae and eggs.

Diagnosis: Lung, pulmonary artery: Diffuse, severe, chronic, proliferative endarteritis with organizing thrombus and numerous intravascular and intralesional adult nematodes.

Etiology: Angiostrongylus vasorum, Angiostrongyloidae family, Metastrongyloidae superfamily, Strongylida order, Rhabditae class, Nematoda phylum.

Comments: Angiostrongylus vasorum, also known as French heartworm, is a metrastrongyloid nematode located in the pulmonary arteries and the right side of the heart in canids. A. vasorum has a heteroxenous biological cycle: an essential development stage in an intermediate host (terrestrial gastropods, mollusks) or paratenic hosts (for example frogs, lizards, mice, rats, etc.). The natural end host is the red fox (Vulpes vulpes), but other species such as the domestic dog (Canis lupus familiaris) may be affected.


Morgan, E., & Shaw, S. (2010). Angiostrongylus vasorum infection in dogs: continuing spread and developments in diagnosis and treatment. Journal of Small Animal Practice, 51(12), 616-621.

Investigation and photo by: Andrada Negoescu, Andrei Ungur, Corina Toma. Department of Pathology, Faculty of Veterinary Medicine, Cluj-Napoca, Romania.