Active Surveillance of Hansen's Disease (Leprosy): Importance for Case Finding among Extra-domiciliary Contacts

Abstract

Hansen's disease (leprosy) remains an important health problem in Brazil, where 34,894 new cases were diagnosed in 2010, corresponding to 15.3% of the world's new cases detected in that year. The purpose of this study was to use home visits as a tool for surveillance of Hansen's disease in a hyperendemic area in Brazil. A total of 258 residences were visited with 719 individuals examined. Of these, 82 individuals had had a previous history of Hansen's disease, 209 were their household contacts and 428 lived in neighboring residences. Fifteen new Hansen's disease cases were confirmed, yielding a detection rate of 2.0% of people examined. There was no difference in the detection rate between household and neighbor contacts (p = 0.615). The two groups had the same background in relation to education (p = 0.510), household income (p = 0.582), and the number of people living in the residence (p = 0.188). Spatial analysis showed clustering of newly diagnosed cases and association with residential coordinates of previously diagnosed multibacillary cases. Active case finding is an important tool for Hansen's disease control in hyperendemic areas, enabling earlier diagnosis, treatment, decrease in disability from Hansen's disease and potentially less spread of Mycobacterium leprae.

Spatial distribution of leprosy in Brazil: a literature review

“…Table 1, Table 2 and Table 3 show the articles' summaries according to the scale used: two evaluated regions/ mesoregions 14,15 ; 13 used the scale of municipalities 10,[16][17][18][19][20][21][22][23][24][25][26][27] ; 4 evaluated districts [28][29][30][31] ; 6 studied neighborhoods [32][33][34][35][36][37] ; 7 analyzed the census tracts [38][39][40][41][42][43][44] ; and 3 investigated households [45][46][47] . Within each scale, the articles were organized by location: Brazil, Northern, Northeast, Midwest, and Southeast regions.…”

“…Within each scale, the articles were organized by location: Brazil, Northern, Northeast, Midwest, and Southeast regions. In all, 4 approached Brazil 10,16-18 , 7 studied the Northern region or the states of the Amazon region 14,19,20,[38][39][40]45 , 11 focused on the Northeast region [21][22][23]28,[32][33][34][35][36]40,41 , 4 the Midwest region 15,29,37,46 , and 12 the Southeast region [24][25][26][27]30,31,36,37,[42][43][44]47 .…”

“…The importance of intra-domiciliary transmission was confirmed by comparing it with the probability that multibacillary carriers will be infected even before the clinical manifestation of the disease 17,35,46 . Transmission was also identified in the neighborhood and school environment 39,45 .…”

Presence of Mycobacterium leprae DNA and PGL-1 antigen in household contacts of leprosy patients from a hyperendemic area in Brazil

“…Several other reports have observed a high concentration of leprosy cases in individual households (Sales et al, 2011;Düppre et al, 2012;Dos Santos et al, 2013) and extra-domiciliary contacts (Moura et al, 2013). This indicates the necessity of preventive measures against leprosy that are efficient in hyperendemic areas.…”

New strategies for active finding of leprosy cases in the Amazonian region

“…Although the single epidemiological surveillance tool currently available is effi cient at detecting new cases of leprosy (and other skin diseases) in the investigation of household contacts (9) (10) , recent evidence from northeastern Brazil indicates that investigating extra-domiciliary contacts is effi cacious; the rates of detection were similar between household contacts (2.9%) and neighbors (2.1%), and active case fi nding among extra-domiciliary contacts increased the number of diagnosed cases by 72.4% (11) . Furthermore, a study conducted in northwestern Bangladesh, a densely populated area in which leprosy is highly endemic, suggested that the neighbors of leprosy patients might be a high-risk group (12) (13) .…”