Pulmonary Tuberculosis in Household Contact of Patients with Active Tuberculosis in Ahwaz, Iran (2003-2005)

Objectives: To determine the prevalence of tuberculosis (TB) among the household contacts. Methodology: It is a retrospective descriptive study conducted in Ahwaz a city in the southwest of Iran, between October and February 2007. Medical files and epidemiological forms of documented TB cases and their contacts in Ahwaz Health Center over the three years period from 2003 to 2005 were reviewed. An index case(IC) was defined as the first TB case identified in the household. A household contact (HC) was defined as an individual who had resided in the household for at least thirty days prior to the diagnosis of tuberculosis in the index case. Secondary cases were defined as TB cases among contacts of the IC. Results: We found 69 patients as IC of TB. Secondary TB in HC and community contacts (CC) was 64 and 15 cases respectively. The studied contact population of 1293 individuals included 352 HC and 941 CC. The prevalence rate of TB for HC and CC was 18.2% and 1.5% respectively (p<0.05). The prevalence rate of TB from IC with smear positive pulmonary tuberculosis (SPPTB) and smear negative pulmonary tuberculosis (SNPTB) for HC and CC was 23.1%, 11.7% and 2.3%, 0.8% respectively (p<0.05). More than 95% of patients with TB in HC were middle aged or elderly. HIV seropositivity and history of IDU addiction was detected in 18.7% of HC with tuberculosis (p<0.05). Conclusions: Tuberculosis is common among household contacts of index cases in Ahvaz (Iran), especially among middle aged and elderly, HIV-infected and IDU addict contacts.