New Heartworm Species Found in North America

## New Species of Heartworm Found in North America A new species of heartworm, Angiostrongylus vasorum, has been discovered in a black bear and a coyote in Tennessee. This marks the first documented case in a bear and the first coyote host in the state. ## What is Angiostrongylus vasorum? Angiostrongylus vasorum, commonly known as French heartworm, is a cardiopulmonary nematode that has historically been confined to Europe and a few other regions. It has only been reported in North America a handful of times, including in Canada and a single fox in West Virginia. ## How was the discovery made? The discovery was made by two University of Tennessee graduate students, working independently on a black bear and a coyote, who each found the parasite in their respective study animals within two weeks of each other. The bear had come from the Smoky Mountains, and the coyote was from just south of the Kentucky border in northeastern Tennessee. ## What are the implications of this discovery? The discovery of Angiostrongylus vasorum in a black bear and a coyote in Tennessee has significant implications for wildlife and domestic dogs in the region. The parasite is considered the most pathogenic lungworm of dogs and can cause severe respiratory distress, coughing, and pneumonia. ## How does Angiostrongylus vasorum differ from Dirofilaria immitis? Angiostrongylus vasorum differs from Dirofilaria immitis in appearance, transmission, and diagnosis. The adults of Angiostrongylus vasorum are smaller and have a pinkish hue, and they can sit inside the vessel wall, making them harder to detect. The parasite also requires a gastropod, such as a snail or slug, as an intermediate host, whereas Dirofilaria immitis is transmitted through mosquito vectors. ## What are the diagnostic challenges of Angiostrongylus vasorum? The diagnostic challenges of Angiostrongylus vasorum include the fact that it can cross-react with Dirofilaria antigen tests, and it requires a gastropod as an intermediate host. Affected dogs shed dorsal-spined L1 larvae in their feces, which eventually get into a gastropod, making diagnosis more complex. ## What can be done to minimize transmission? To minimize transmission of Angiostrongylus vasorum, it is essential for veterinarians to stay current with continuing education and be aware of emerging parasites. Dogs can get infected by eating a snail or slug carrying the L3 stage, and frogs have also been shown to be a paratenic host, so there are potentially different routes of infection. Regular monitoring and testing for heartworms, as well as controlling snail and slug populations, can help minimize the risk of transmission.