Diagnosis of heartworm disease in dogs may be made by identification of microfilaria in the blood, by observation of thoracic radiographic abnormalities and two-dimensional echocardiography can project images of adult heartworms.

Two hundred of stray dogs were studied by modified Knott method for Dirofilaria immitis and six dogs were infected. Results of CBC indicated absolute eosinophilia (4254/µl) and results of serum biochemical analysis were normal. Radiographic signs included enlargement of right side of heart and mix alveolar and interstitial densities in the caudal lobes of the lungs. Echocardiography revealed the presence of heartworms as hyperechoic densities within the right atrial and ventricular cavities. Adult worms were easily identified as parallel echogenic lines separated by a hypoechoic region. Therefore echocardiography appears to be a sensitive procedure, which can be used in combination with thoracic radiography to improve accuracy of diagnosis of heartworm disease in dogs.