Prevalence of latent tuberculosis infection among people in house hold contact with pulmonary tuberculosis in Iran

Background and Aim : Latent tuberculosis infection (LTBI) is present in one-quarter of the world's people and is more likely spread to tuberculosis, especially at a young, diagnosis and treatment and prevention are an important part of the World Health Organization's(WHO) TB control program. We aimed to evaluate the prevalence of LTBI among Family member of TB cases in two high-burden provinces in Iran.Methods : ۶۶۸ house hold contacts of ۱۴۹ pulmonary tuberculosis cases were followed up retrospectively and prospectively in Gorgan and Zabol cities at ۰, ۳, ۱۲ and ۱۸ months after the start of the study. For LTBI diagnosis, tuberculin skin test (TST) and QuantiFERON®-TB Gold Plus (QFT-Plus) were performed.Results : A total of ۶۶۸ people, who had contact with an index TB case. The number of LTBI cases based on QFT or TST positive test was ۵۲.۹%. In children under ۵ years of age, the number of LTBI cases was ۳۳.۳%. LTBI cases in the age group over ۱۸ years with ۵ to ۱۸ years and less than ۵ years were significantly different, while there was no significant difference between the age group of less than ۵ years and ۵ to ۱۸ years.Conclusion : This study showed that most cases of infection occur before the diagnosis of the index or in the first step of the study. Therefore, we emphasize that the people living in close contact with an infectious TB case should be screened effectively and receive prophylactic therapy.

کلیدواژه ها:

Pulmonary tuberculosis ، Latent Tuberculosis ، Tuberculin skin test