mumbai in a first a pilot study is being rolled out in the city to gauge prevalence of latent tuberculosis it signals a giant shift in the tb control gameplan that has till now focussed on detection and treatment of active tb and not so much on preventionpeople with latent tb carry the bacterium but have no symptoms and cannot infect others but upto 10 can progress to active tb if the latent infection is left unaddressed an estimated 350 million indians are likely to have latent tb and preventing even a fraction can make a dent in the burden of new cases the study will be the first structured attempt to understand how widespread latent tb is in mumbai said dr mangala gomare bmcs executive health officerthe risk of developing active tb from latent infection increases more than 25 times among contacts of bacteriologically confirmed tb patients in this study close contacts of 125 newlydiagnosed tb patients will be traced and screened an active tb infection will be ruled out first in contacts following which a blood test interferongamma release assays called igra that measures an individuals immune reactivity to tb bacteria will be carried out the contacts will be started on a three to sixmonth preventive course of isoniazid and rifapentine based on the igra findings bmc and ngo share india will screen around 500 people taking at least 45 high risk contacts for each of the 125 positive casestb preventive treatment tpt that exists nationally has been limited in coverage till recently and extremely low on priority the survey will be the first step towards an overhaul of tpt that will see more funds infrastructure and manpower being pumped in till early this year tpt was offered only to children under five who had an active tb case in the house and people living with hiv now tpt has been extended to children above five and adult household contacts after an active tb infection has been ruled out in them people living with immunesuppressive conditions will be persuaded toodr pranita tipre mumbais tb officer said the study will go a step further and analyse how many comply with monthslong preventive course and document hurdles although treating latent infection can stop progression to active tb by almost 90 there are major adherence issues individuals who are otherwise healthy often drop out the pill burden that can range from 36182 tablets also acts as a damperdr tanu singhal a paediatric infectious disease expert at kokilaben hospital said preventive treatment is seldom advised due to low compliance and general lack of awareness among physicians most are not geared to think about prevention so few offer it she said adding that guidelines also state that it should be given to immunocompromised people such as diabetics and organ transplant patients but thats hardly the practice latent tb regimens also has other shortcomings it doesnt protect against repeated exposures which hinders its wide use in high tb burden settings like india a strong