Further evidences on a new diagnostic approach for monitoring human Leishmania (L.) infantum chagasi infection in Amazonian Brazil
This was a prospective study carried out during a period over 2 years (May/2006–September/2008) with a cohort of 1,099 individuals of both genders, aged 1 year old and older, from an endemic area of American visceral leishmaniasis (AVL) in Pará state, Brazil. The object was to analyze the prevalence and incidence of human Leishmania (L.) infantum chagasi infection as well as the dynamics evolution of its clinical-immunological profiles prior identified: (1) asymptomatic infection (AI); (2) symptomatic infection (SI = AVL); (3) sub-clinical oligosymptomatic infection (SOI); (4) sub-clinical resistant infection (SRI) and; (5) indeterminate initial infection (III). The infection diagnosis was performed by using both the indirect fluorescent antibody test and leishmanin skin test with amastigotes and promastigotes antigens of L. (L.) i. chagasi, respectively. A total of 187 cases of infection were recorded in the prevalence (17%), 117 in the final incidence (6.9%), and 304 in the accumulated prevalence (26.7%), which provided the following distribution into the clinical-immunological profiles: AI, 51.6%; III, 22.4%; SRI, 20.1%; SOI, 4.3%; and SI (=AVL), 1.6%. The major finding regarding the dynamics evolution of infection was concerned to III profile, from which the cases of infection evolved to either the resistant profiles, SRI (21 cases, 30.8%) and AI (30 cases, 44.1%), or the susceptible SI (=AVL; 1 case, 1.5%); the latter 16 cases remained as III till the end of the study. These results provided the conclusion that this diagnostic approach may be useful for monitoring human L. (L.) i. chagasi infection in endemic area and preventing the high morbidity of severe AVL cases.
KeywordsEndemic Area Visceral Leishmaniasis Final Evolution Diagnostic Approach Cutaneous Leishmaniasis
We are grateful for the research technician team of the leishmaniasis laboratory of Evandro Chagas Institute (Health Ministry, Brazil).
This research was supported by Evandro Chagas Institute (Health Ministry, Brazil); Tropical Medicine Institute (Federal University of Pará state, Brazil); Wellcome Trust (London); Laboratório de Investigação Médica (LIM)-50 (Hospital de Clínicas (HC)-Faculdade de Medicina (FM)-Universidade de São Paulo (USP, Brazil), and Fundação de Amparo à Pesquisa do estado de São Paulo (FAPESP: 06/56319-1, Brazil).
This study was approved by the Ethics Committee in human research of Evandro Chagas Institute (Health Ministry, Brazil), protocol number 16/2003, and the Ethics Committee of research programs, Medicine School of São Paulo University, São Paulo state, Brazil, protocol number 0255/07.
Conflicts of interest statement
The authors have no conflicts of interest concerning the work reported in this paper.
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