tailieunhanh - RISK OF PULMONARY TUBERCULOSIS ASSOCIATED WITH EXOGENOUS REINFECTION AND ENDOGENOUS REACTIVATION IN A SOUTH INDIAN RURAL POPULATION-A MATHEMATICAL ESTIMATE*

It has been reported that a substantial proportion of the new cases arise from the previously infected population. Hence, it appears that exogenous reinfection and/or endogenous reactivation play a major role in the development of post-primary disease. Though the risk of disease due to recent infection is known, the risk of disease associated with exogenous reinfection and endogenous reactivation has not been computed in Indian conditions. The data collected during a longitudinal study by NTI, Bangalore was analysed to estimate the above mentioned risk rates. The risk of disease associated with exogenous reinfection was per year compared with yearly due to endogenous reactivation. To test the validity of the computed risk. | Ind. J. Tub. 1990 37 63 RISK OF PULMONARY TUBERCULOSIS ASSOCIATED WITH EXOGENOUS REINFECTION AND ENDOGENOUS REACTIVATION IN A SOUTH INDIAN RURAL POPULATION-A MATHEMATICAL ESTIMATE . Krishnamurthy 1 and K. Chaudhuri2 Summary It has been reported that a substantial proportion of the new cases arise from the previously infected population. Hence it appears that exogenous reinfection and or endogenous reactivation play a major role in the development of post-primary disease. Though the risk of disease due to recent infection is known the risk of disease associated with exogenous reinfection and endogenous reactivation has not been computed in Indian conditions. The data collected during a longitudinal study by NTI Bangalore was analysed to estimate the above mentioned risk rates. The risk of disease associated with exogenous reinfection was per year compared with yearly due to endogenous reactivation. To test the validity of the computed risk rates these were applied to the interval between the 3rd and 4th surveys. It was then estimated that 64 new cases should have been diagnosed in that survey interval as against 57 cases actually diagnosed. It was also estimated that of the total population would be having recent infection 13 would be previously infected with recent infection and with previous infection but no recent infection leaving who are not infected at all uninfected . Among the new cases diagnosed 28 would have progressive primary disease 41 cases arise due to exogenous reinfection and 31 due to endogenous reactivation. In other words the population with recent infection contributes 28 of the total new cases the reinfected population contributes 41 and the infected population without further reinfection contributes the remaining 31 of the total new cases. Introduction It is estimated that about one third of the Indian population are infected with National Tuberculosis Institute 1974 . It is also reported