dirofilariasis dirofilariasis dirofilariasis is an infection by parasites of the genus dirofilaria. it is transmitted through a mosquito bite; its main hosts include dogs and wild canids. these can give rise to granulomas in the pulmonary artery. some common symptoms include cough, fever and pleural effusion. it may also appear on x-rays of the chest. dirofilariasiscomparison of probable dirofilaria repens (left) and dirofilaria immitis (right)specialtyinfectious diseases causes it can be caused by: dirofilaria immitis dirofilaria repens dirofilaria tenuis diagnosis dirofilariasis is often diagnosed by the examination of tissue obtained as part of the diagnostic investigation of coin lesions. blood tests are not yet helpful in the diagnosis of dirofilariasis in humans. treatment treatment with tetracycline antibiotics has been reported to damage dirofilaria immitis, often causing death of adult worms.