Exploring poor water, sanitation, and hygiene (WASH) as factors related to leprosy transmission in Minas Gerais, Brazil Público
Ojo-Akosile, Tolulope (Spring 2021)
Abstract
Background: While leprosy is associated with poverty, it is not completely clear which factors, such as substandard and crowded housing conditions, unsafe drinking water, poor sanitation, or limited access to health care are driving this association. Given data suggesting that water and contaminated environments could be reservoirs for Mycobaterium leprae and that co-infections with water, sanitation, and hygiene (WASH)-associated helminths may increase susceptibility to leprosy, we aimed to explore the association of WASH factors, socioeconomic status (SES), and the residential environment with leprosy. Methods: A case-control study was conducted in the municipalities of Governador Valadares, Minas Gerais, Brazil, between June 2016-December 2018. Individuals ages three years or older were recruited as cases or community-matched controls. Cases were diagnosed by dermatologic experts with confirmatory skin slit smears for the bacillary index. Questionnaires were administered on socioeconomic status, education, occupation, and WASH factors. Descriptive and statistical analyses were conducted to identify WASH associations with leprosy and helminth infections in residential environments. Results: Seventy-nine cases of leprosy, 96 household contacts, and 81 controls (non-household contacts) were recruited. 51.5% were female with a mean age of 40 years. 75.2% (n=112) of the participants had piped water as their water source, and 54.5% (n=85) acknowledged they did not treat water. Multivariate logistic regression revealed an association with larger household sizes with leprosy (aOR = 1.34; 95% CI 1.07, 1.68), and an unexpected positive association with the presence of a piped sewer system (aOR=4.67; 95% CI 1.51, 14.45). In a contrast, those with leprosy were less likely to have household plumbing (versus a well or unimproved sources) (aOR=0.39; 95% CI 0.13, 1.18) or to treat their water (aOR=0.52; 95% CI 0.25, 1.06), although these did not reach statistical significance. 6.6% of individuals had positive stool exams for Schistosoma mansoni, 29.9% were positive for schistosoma antibodies, and 19.9% for strongyloides antibodies. The residential environment was not associated with leprosy and strongyloides; however, schistosoma was found to be associated with rural dwellers, 41.9% of those dwelling in rural community had schistosoma antibodies (p<0.001). Conclusion: These associations suggest that WASH factors could be related to leprosy and supports other emerging research in this field. Still, there is a need for further research on the association of WASH and leprosy disease, more specifically the potential mechanisms of bacterium exposure and viability of M. leprae in the environment.
Table of Contents
Chapter 1: Introduction………………………………………….…... 1-4
Chapter 2: Literature Review………………………………..………5-18
Overview……………………………………………………............……..5
Leprosy……………………………...………………………...........…......6
Schistosomiasis………………………………………………...........…… 7
Leprosy and schistosomiasis in Brazil……………………..........…....9
Epidemiology of Schistosoma mansoni in Brazil….....………...…..12
Role of WASH in leprosy and schistosomiasis………………............13
Risk factors for leprosy, schistosomiasis, co-infections……....…….16
Chapter 3: Manuscript…………………………………….......……… 19-34
Abstract……………………………………………………................……. 19
Introduction……………………………...…………….….............……... 20
Methods…………………………………………………….................…… 22
Results……………………………………………………................……....24
Discussion………………………………………………................………. 29
Chapter 4: Public Health Implications and Recommendations…... 35
References…………………………………………………........………. 36-46
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