Dirofilaria immitis (heartworms).
D000818:Animals; D004183:Dirofilaria immitis / Q000302:isolation & purification; D004184:Dirofilariasis / Q000453:epidemiology* / Q000662:veterinary; D004283:Dog Diseases / Q000453:epidemiology; D004285:Dogs; D006801:Humans; D014481:United States