Objectives

To study the prevalence, clinical signs and treatment of Dirofilaria immitis.

Materials & Methods

A total of 198 guard dogs and household dogs from Tabriz northeast of Iran were examined parasitologocally and clinically for heartworm disease. Twelve of infected dogs were treated with melarsomine (Rhon Merieux) at 2.5 mg/kg b.w. and ivermectin at 5µg/kg b.w. and supportive treatments whenever necessary.

Results

Thirty dogs harbored D.immitis of which 4 were amicrofilaraemic. According to the severity of clinical signs 3 groups with no obvious clinical signs (class1, 13 dogs) with moderate clinical signs (class2, 8 dogs) and with severe clinical signs (class3, 9 dogs, 5 microfilaraemic and 4 amicrofilaraemic) were identified in dogs with heartworm disease. Eleven out of twelve dogs selected for treatment were successfully treated but one died post treatment due to sever dirofilariosis and pulmonary thromboembolism.

Conclusion

Dirofilariosis is enzootic in Tabriz and produce subclinical and clinical signs. No relation exists between the number of circulating microfilariae and the severity of the disease. About 50% of severe cases were among amicrofilaraemic dogs. Thus occult dirofilariosis are likely associated with the more sever clinical signs. Melarsomine and ivermectin can be used successfully for treatment of infected dogs.