Characteristics of leprosy diagnosed through the surveillance of contacts: a comparison with index cases in Rio de Janeiro, 1987-2010

Abstract

Contact surveillance is an important strategy to ensure effective early diagnosis and control of leprosy; passive detection may not be as efficient because it is directly tied to the ready availability of heath care services and health education campaigns. The aim of this study was to reinforce that contact surveillance is the most effective strategy for the control of leprosy. The analysed data were obtained from a cohort of contacts and cases diagnosed through a national referral service for leprosy. We analysed data from patients diagnosed between 1987-2010 at the Souza Araújo Ambulatory in Rio de Janeiro. Epidemiological characteristics of leprosy cases diagnosed through contact surveillance and characteristics of passively detected index cases were compared using a conditional logistic regression model. Cases diagnosed by contact surveillance were found earlier in the progression of the disease, resulting in less severe clinical presentations, lower levels of initial and final disability grades, lower initial and final bacterial indices and a lower prevalence of disease reaction. In this respect, contact surveillance proved to be an effective tertiary prevention strategy, indicating that active surveillance is especially important in areas of high endemicity, such as Brazil.

Análise epidemiológica da hanseníase em um estado endêmico do nordeste brasileiroAnálisis epidemiológica de la lepra en estado endémico del nordeste brasileño

“…Consequently, this recognised indicator of quality was included in the WHO Enhanced Global Strategy for Further Reducing the Disease Burden Due to Leprosy and the Operational Guidelines (2011-2015), which exposes the idea of underreporting and the late diagnosis of cases (14)(15) . Accordingly, strategies used to ensure timely detection, the commitment of health teams in the active search for cases, health education and examining contacts are actions that have a direct influence on this indicator.…”

“…Accordingly, strategies used to ensure timely detection, the commitment of health teams in the active search for cases, health education and examining contacts are actions that have a direct influence on this indicator. A study conducted in 2012 found that the control of contacts is a highly effective strategy in the fight against leprosy and that active surveillance is especially needed in areas of high endemicity, such as Brazil (15) . Researchers (16) stated that a successful leprosy control programme requires prevention, early diagnosis, treatment and breaking the chain of transmission.…”

PCR-Based Techniques for Leprosy Diagnosis: From the Laboratory to the Clinic

“…It has been shown that good surveillance of patients' contacts has increased the detection rate of less severe clinical presentations with lower bacteriological indices [3], [4].…”

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) .…”

“…According to Hacker et al (9) , cases diagnosed through contact surveillance are detected earlier in the disease progression, have lower initial and fi nal bacterial indices, have lower initial and final disability grades, and have a lower prevalence of disease reactions. To achieve control of transmission through early diagnosis of leprosy, changes in the protocols for active leprosy case fi nding among contacts must be improved, including broadening the scope of investigation to neighbors within at least a 200-meter radius.…”