Intracardiac heartworms in dogs: Clinical and echocardiographic characteristics in 72 cases (2010‐2019)

Abstract

Background: Heartworms, a cause of pulmonary hypertension (PH) in dogs, can migrate from the pulmonary arteries into the heart resulting in life-threatening caval syndrome (CS). Objectives: To describe clinical and echocardiographic characteristics in dogs with intracardiac heartworms including estimated heartworm burden and frequency of PH and pigmenturia. Animals: Seventy-two client-owned dogs with heartworms. Methods: Retrospective study. Data collected from an electronic medical records search for dogs with intracardiac heartworms included clinicopathologic, echocardiographic, and procedural findings. Dogs with heartworms isolated to the pulmonary arteries were excluded. Results: Estimated intracardiac heartworm burden was low in 14 of 72 (19%) and high in 58 of 72 (81%) dogs. The majority were small breed (54/72; 75%; 29/72; 40% Chihuahuas) and had a high likelihood of PH (67/72; 93%). Pigmenturia was the second most common clinical finding (31/72; 43%) after lethargy (32/72; 44%). Anemia (37/55; 36%), pigmenturia (30/58; 52%), and bilirubinuria (28/36; 78%) were significantly more common in dogs with a high worm burden (P < .05). Based on the presence of anemia, pigmenturia, and clinical signs, 18 of 72 dogs (25%) were considered to have CS. Conclusions and Clinical Importance: Although the majority of dogs with intracardiac heartworms had a high worm burden and high likelihood of PH, only 25% had clinical evidence of CS. Echocardiography is a useful tool to identify intracardiac heartworms, detect likelihood of PH, and could be useful for staging heartworm positive small breed dogs for intracardiac heartworm migration.

First Autochthonous Infection of a Cat with Dirofilaria immitis in Austria

“…Forty-six of these mosquitoes were found in Burgenland. In none of these 205 mosquitoes has DNA of D. immitis been found to date but several dogs in a local shelter, all originating from Hungary, tested positive for D. immitis [ 25 ].…”

Hematological parameters of dogs for parasitism Dirofilaria immitis

“…Since scientists have proven significant pathogenicity of nematodes of the species Dirofilaria immitis Leidy, 1856, it is important to establish various criteria that determine the severity of the disease in animals, including hematological parameters (Donahoe et al, 1976;Maerz, 2020;Romano et al, 2021). Our research has shown that the severity of deviations from the hematological parameters of dogs with heartworm disease caused by parasitism of D. immitis depends on the level of microfilaremia.…”

“…This is due to the localization of these parasites in the right ventricle and pulmonary arteries. Severe disorders of all body systems, especially cardiovascular, can cause animal death (Hoch & Strickland, 2008;Maerz, 2020;Romano et al, 2021).…”

Differential diagnosis of Dirofilaria immitis nematodes (Nematoda, Onchocercidae)

“…The dirofilariasis of dogs caused by the species Dirofilaria immitis (Nematoda, Onchocercidae) is the most pathogenic and widespread in the world. Its danger is confirmed by the high mortality of infected animals, poor results in their treatment and the specific cycle of parasite development, with the infection occuring through the bites of blood-sucking insects, the mosquitoes (González-Morteo, 2015;Silaghi et al, 2017;Romano et al, 2021). Thus, the diagnostics of dirofilariasis today remain a topical issue.…”

“…The most common and pathogenic of them is the species Dirofilaria immitis Leidy, 1856, due to the localization of these parasites in the right ventricle and pulmonary arteries. D. immitis causes severe disorders of all body systems, especially the cardiovascular one, and death (Hoch & Strickland, 2008;Maerz, 2020;Romano et al, 2021). The definitive hosts of helminths are more than 30 species of animals (dog, domestic and wild cat, fox, wolf, coyote, dingo, bear, panda, beaver, raccoon, ferret, coati, otter and a number of other mammals).…”