[Two cases of pulmonary tuberculosis with an intra-familial transmission route].

Two patients with smear-positive adult-type pulmonary tuberculosis (TB) were admitted to our hospital. The patients in case 1 and case 2 were a 33-year-old woman and a 33-year-old man, respectively. None of the patients' family members had any apparent symptom indicating TB. However, the father of patient 1 was found to have recurrent TB with a positive smear in the contact investigation. The mother of patient 2 was then admitted to a hospital with acute respiratory failure caused by recurrence of TB. Her sputum sample also turned out to be smear-positive. Restriction fragment length polymorphism (RFLP) analysis of the isolates revealed identical DNA patterns in each pair of family members. These cases were typical examples of intra-familial infections involving young adults and their parents. This route of transmission is still important in areas with low prevalence of the disease.