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May/June 2014 Today's Veterinary Practice 67 ParasiTe ProTocols Peer reviewed tvpjournal.com Canine Pulmonary HelmintHs Recommendations from the Companion Animal Parasite Council Dwight D. Bowman, MS, PhD, Diplomate ACVM (Parasitology, Hon) Cornell University Susan E. Little, DVM, PhD, Diplomate ACVM (Parasitology) Oklahoma State University The mission of the Companion Animal Parasite Council (CAPC) is to foster animal and human health, while preserving the human–animal bond, through recommendations for the diagnosis, treatment, prevention, and control of parasitic infections. For more information, including detailed parasite control recommendations, please visit capcvet.org . H elminth parasites are regularly diagnosed in dogs in the U.S. Those in dogs typically fall into 1 of 2 categories: intestinal helminths or pulmonary helminths . Canine intestinal helminths were discussed in this column in the January/February 2014 issue, avail- able at tvpjournal.com; this article will address canine pulmonary helminths. PULMONARY HELMINTHS A surprisingly wide variety of helminths damage the pul- monary system of dogs and, at times, can cause severe, life-threatening respiratory disease (Table 1). • Dirofilaria immitis (heartworm) is by far the most important parasite of the canine pulmonary system, in- ducing severe morbidity and, in some cases, mortality. • Toxocara canis and Ancylostoma caninum are intestinal nematodes that migrate through the lungs as larvae. • Paragonimus kellicotti is a trema- tode that develops in cysts in the lung parenchyma. 1 • Angiostrongylus vasorum, the French heartworm, and the lung- worms Crenosoma vulpis, Eucole- us aerophilus, and Filaroides spe- cies also create pathology in canine lungs. While less familiar than heartworm, infection with these other pulmonary helminths can be very important in some canine patients. This article out- lines how dogs become infected and de- scribes appropriate treatment courses to manage the infections. Angiostrongylus vasorum Distribution. Once consid- ered exotic to North Amer- ica, A vasorum, commonly known as the French heart- worm, has in recent years been found in foxes and dogs in the Atlantic provinces of Canada as well as in the U.S. 2 Life Cycle. Dogs acquire infection when they eat infect- ed gastropod intermediate hosts (snails or slugs) or frog paratenic hosts. Upon ingestion, larvae first develop in abdominal lymph nodes before entering the portal cir- culation and moving to the pulmonary arteries and right ventricle. Once in the lungs, the nematodes mature to adults (Figure 1), mate, and produce eggs that lodge and Parasite ProtoCols For your PraCtiCe Table 1. life Cycle Summary: Helminths Found in the lungs of North american dogs PARASITE LOCATION OF ADULT HELMINTH IN DOG INTERMEDIATE HOST PARATENIC HOST NEMATODES Angiostrongylus vasorum Pulmonary arteries snail or slug Frog Crenosoma vulpis lumen of bronchi snail or slug None Dirofilaria immitis Pulmonary arteries Mosquito None Eucoleus aerophilus Tracheal and bron- chial epithelium None earthworm Filaroides hirthi lung parenchyma None None Filaroides osleri Nodules in trachea None None TREMATODES Paragonimus kellicotti cysts in lung parenchyma snail, crayfish Mammals Figure 1. Three adult female Angiostrongylus vasorum, showing the "barber pole" appearance caused by the reproductive tract wrapping around the intestinal tract of the worm. TVP_2014-0506_CAPC-CanineHelmiths_Part2.indd 67 5/24/2014 8:21:37 PM