Hydatid disease is caused by -

The larval stage is present in the animals including man,giving rise to hydatid cyst.Sheep ,pigs,cattle ,horse ,goat and man may act as intermediate host. Hydatid cyst involve liver , lung,brain,hea,kidney,spleen,bone,musclesetc. Liver is the commonest site and right lobe is frequently involved.The disease remains symptomless for many years.Chronic abdominal discomfo may be present in case of liver cyst.Cyst in the lungs are asympotomatic but may cause cough , breathlessness or chest pain (refer pgno:107 baveja 3 rd edition)