A tale of two neglected tropical infections: using GIS to assess the spatial and temporal overlap of schistosomiasis and leprosy in a region of Minas Gerais, Brazil.
BACKGROUND
Despite public health efforts to reduce the global burden of leprosy, gaps remain in the knowledge surrounding transmission of infection. Helminth co-infections have been associated with a shift towards the lepromatous end of the disease spectrum, potentially increasing transmission in co-endemic areas.


OBJECTIVE
Using this biologically plausible association, we conducted a geographic information systems (GIS) study to investigate the spatial associations of schistosomiasis and leprosy in an endemic area of Minas Gerais (MG), Brazil.


METHODS
Data on new cases of Mycobacterium leprae and Schistosoma mansoni infections from 2007-2014 were retrieved from the Brazilian national notifiable diseases information system for seven municipalities in and surrounding Vespasiano, MG. A total of 139 cases of leprosy and 200 cases of schistosomiasis were mapped to a municipality level. For one municipality, cases were mapped to a neighborhood level and a stratified analysis was conducted to identify spatial associations.


RESULTS
A relative risk of 6.80 [95% confidence interval (CI) 1.46 - 31.64] of leprosy was found in neighborhoods with schistosomiasis. Incidence rates of leprosy increased with corresponding incidence rates of schistosomiasis, and the temporal trends of both infections were similar.


CONCLUSIONS
The associations found in this project support the hypothesis that helminth infections may influence the transmission of leprosy in co-endemic areas.
Augusta University/University of Georgia Medical Partnership, Athens, GA, United States.
David Alexander
DA
Phillips
Escola de Medicina, Faculdade da Saúde e Ecologia Humana, Vespasiano, MG, Brasil.
José Antonio
JA
Ferreira
Emory University School of Medicine, Department of Pediatrics, Atlanta, GA, United States.
Deidra
D
Ansah
Escola de Medicina, Faculdade da Saúde e Ecologia Humana, Vespasiano, MG, Brasil.|Secretaria Municipal de Saúde, Vespasiano, MG, Brasil.
Herica Sa
HS
Teixeira
Emory University, Department of Environmental Science, Atlanta, GA, United States.
Uriel
U
Kitron
Escola de Medicina, Faculdade da Saúde e Ecologia Humana, Vespasiano, MG, Brasil.
Thelma de
T
Filippis
Secretaria Municipal de Saúde, Vespasiano, MG, Brasil.
Marcelo H de
MH
Alcântara
Emory University School of Medicine, Department of Medicine, Division of Infectious Diseases, Atlanta, GA, United States.
Jessica K
JK
Fairley
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001938:Brazil / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D060085:Coinfection / Q000453:epidemiology*; D019353:Endemic Diseases; D005260:Female; D040362:Geographic Information Systems; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D007918:Leprosy / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D058069:Neglected Diseases / Q000453:epidemiology*; D012307:Risk Factors; D012555:Schistosomiasis mansoni / Q000453:epidemiology*; D062211:Spatio-Temporal Analysis; D055815:Young Adult