The Mitsuda reaction in persons with and without household exposure to leprosy.

It is a well established fact that persons exposed to lepromatous leprosy in the household have a much higher risk of contracting leprosy than persons who are not subject to such exposure but who are apparently comparable in other respects. In the studies of the Leonard Wood Memorial (American Leprosy Foundation) and the Department of Health of the Philippines carried out in Cordova and Talisay. eebu, Philippines. the relative risks for these two groups were found to be about eight to one (4) . The risk for those exposed to the tuberculoid type was less than twice as high as for unexposed persons. The prevalence of leprosy as determined by examination of the entire population was 20.4 per 1,000 for Cordova in 1948, and 17.6 per 1,000 for Talisay in 1950-51. About one-third of the cases in each locality were of the lepromatous type. In view of the emphasis being given to reactivity to lepromin, either acquired naturally or induced by BCG, as an indication of resistance, a comparison of the results of the lepromin test in persons known to have lived in household association with leprosy patients with the results in other persons resident in these municipalities is of timely interest. Chatterjee (1) found that children with family contact showed a lower percentage of lepromin reactors than tasual contacts or noncontacts of similar ages. Apparently the chance of becoming positive WBI le8llened by cloae contact. Cochrane et a.l (2) reported a similar result, but the numbers of healthy contact and noncontact children included were small. Souza Campot tit al (7) tested 185 children, 2 to 16 years of age, of leprous parenti. Of these, 148 were separated at birth from their parenti, and 87 were separated after varying intervals of exposure up to several months. The ages are not given in detail. The percentages of Mitauda reactors were 89.2 for the exposed children, and 48.0 for those separated at birth. A different type of study was made by Dharmendra and Jaikaria (8 ), who compared lepromin results obtained on 295 penona in Bankura, West Bengal, where leprosy was highly prevalent, with those on 270 penona in villages in the Punjab where it was uncommon. The percentagea of penona of all agea who reacted to lepromin were 59.0 in Bankura and 86.0 in the Punjab. Age distributiona are given, and adjustment for differences, uaing the total population of both areas as a standard, changes these figu.rea to 61.9 per cent and 32.7 per cent, respectively. Accepting the comparison aa fair in other respects, lepromin politivCf! wcre twicc na f requent In a n area where leprosy waa frequent 81 in one where it wall uncommon.