The Relationship between Water, Sanitation and Schistosomiasis: A Systematic Review and Meta-analysis

PLoS Neglected Tropical Diseases

Volumn 8, Issue 12, 2014, Pages

  Grimes, Jack E T ^a   Croll, David ^b,c   Harrison, Wendy E ^a   Utzinger, Jürg ^b,c   Freeman, Matthew C ^d   Templeton, Michael R ^a  

^a IMPERIAL COLLEGE LONDON   (United Kingdom)

^b SWISS TROPICAL AND PUBLIC HEALTH INSTITUTE   (Switzerland)

^c UNIVERSITY OF BASEL   (Switzerland)

^d EMORY UNIVERSITY   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

PRAZIQUANTEL;

ARTICLE; BIBLIOGRAPHIC DATABASE; CONFIDENCE INTERVAL; DATA PROCESSING; DISEASE TRANSMISSION; ENVIRONMENTAL FACTOR; ENVIRONMENTAL SANITATION; FOREST PLOT; HUMAN; HYGIENE; PLOTS AND CURVES; PUBLIC HEALTH; PUBLICATION; PUBLISHING; QUALITY CONTROL; RISK ASSESSMENT; SCHISTOSOMA HEMATOBIUM; SCHISTOSOMA JAPONICUM; SCHISTOSOMA MANSONI; SCHISTOSOMIASIS; SENSITIVITY ANALYSIS; SOCIAL ASPECT; SOCIOECONOMICS; SURVIVAL; WATER QUALITY; CROSS-SECTIONAL STUDY; META ANALYSIS; SANITATION; STANDARDS; STATISTICS AND NUMERICAL DATA; WATER SUPPLY;

CROSS-SECTIONAL STUDIES; HUMANS; SANITATION; SCHISTOSOMIASIS; WATER QUALITY; WATER SUPPLY;

EID: 84925856004     PISSN: 19352727     EISSN: 19352735     Source Type: Journal    
DOI: 10.1371/journal.pntd.0003296     Document Type: Article

References (106)

1. Steinmann P, Keiser J, Bos R, Tanner M, Utzinger J, (2006) Schistosomiasis and water resources development: systematic review, meta-analysis, and estimates of people at risk. Lancet Infect Dis 6: 411–425.
2. Gryseels B, Polman K, Clerinx J, Kestens L, (2006) Human schistosomiasis. Lancet 368: 1106–1118.
3. Colley DG, Bustinduy AL, Secor WE, King CH, (2014) Human schistosomiasis. Lancet 383: 2253–2264.
4. Rollinson D, (2009) A wake up call for urinary schistosomiasis: reconciling research effort with public health importance. Parasitology 136: 1593–1610.
5. Evan Secor W, (2012) The effects of schistosomiasis on HIV/AIDS infection, progression and transmission. Curr Opin HIV AIDS 7: 254–259.
6. King CH, Dickman K, Tisch DJ, (2005) Reassessment of the cost of chronic helmintic infection: a meta-analysis of disability-related outcomes in endemic schistosomiasis. Lancet 365: 1561–1569.
7. Ferrari TC, Moreira PR, (2011) Neuroschistosomiasis: clinical symptoms and pathogenesis. Lancet Neurol 10: 853–864.
8. WHO (2013) Schistosomiasis: progress report 2001–2011, strategic plan 2012–2020. Geneva: World Health Organization.
9. McManus DP, Gray DJ, Li Y, Feng Z, Williams GM, et al. (2010) Schistosomiasis in the People's Republic of China: the era of the Three Gorges Dam. Clin Microbiol Rev 23: 442–466.
10. Okwuosa VN, Osuala FO, (1993) Toxicity of washing soaps to Schistosoma mansoni cercariae and effects of sublethal concentrations on infectivity in mice. Appl Parasitol 34: 69–75.
11. Birrie H, Balcha F, Erko B, Bezuneh A, Gemeda N, (1998) Investigation into the cercariacidal and miracidiacidal properties of endod (Phytolacca dodecandra) berries (type 44). East Afr Med J 75: 311–314.
12. WHO UNICEF (2013) Progress on sanitation and drinking-water - 2013 update. Geneva: World Health Organization.
13. Hunter JM, Rey L, Chu K, Adekolu-John E, Mott KE (1993) Parasitic diseases in water resources development: the need for intersectoral negotiation. Geneva: World Health Organization.
14. Evans AC, Stephenson LS, (1995) Not by drugs alone: the fight against parasitic helminths. World Health Forum 16: 258–261.
15. Utzinger J, Bergquist R, Xiao SH, Singer BH, Tanner M, (2003) Sustainable schistosomiasis control - the way forward. Lancet 362: 1932–1934.
16. Singer BH, de Castro MC, (2007) Bridges to sustainable tropical health. Proc Natl Acad Sci USA 104: 16038–16043.
17. Utzinger J, Raso G, Brooker S, de Savigny D, Tanner M, et al. (2009) Schistosomiasis and neglected tropical diseases: towards integrated and sustainable control and a word of caution. Parasitology 136: 1859–1874.
18. Spiegel JM, Dharamsi S, Wasan KM, Yassi A, Singer B, et al. (2010) Which new approaches to tackling neglected tropical diseases show promise? PLoS Med 7: e1000255.
19. Utzinger J, N'Goran EK, Caffrey CR, Keiser J, (2011) From innovation to application: social-ecological context, diagnostics, drugs and integrated control of schistosomiasis. Acta Trop 120 Suppl 1: S121–S137.
20. Anonymous (2012) Progress in sanitation needed for neglected tropical diseases. Lancet 379: 978.
21. Gazzinelli A, Correa-Oliveira R, Yang GJ, Boatin BA, Kloos H, (2012) A research agenda for helminth diseases of humans: social ecology, environmental determinants, and health systems. PLoS Negl Trop Dis 6: e1603.
22. Prichard RK, Basáñez MG, Boatin BA, McCarthy JS, Garcia HH, et al. (2012) A research agenda for helminth diseases of humans: intervention for control and elimination. PLoS Negl Trop Dis 6: e1549.
23. Bockarie MJ, Kelly-Hope LA, Rebollo M, Molyneux DH, (2013) Preventive chemotherapy as a strategy for elimination of neglected tropical parasitic diseases: endgame challenges. Phil Trans R Soc B 368: 20120144.
24. Freeman MC, Ogden S, Jacobson J, Abbott D, Addiss DG, et al. (2013) Integration of water, sanitation, and hygiene for the prevention and control of neglected tropical diseases: a rationale for inter-sectoral collaboration. PLoS Negl Trop Dis 7: e2439.
25. WHO (2013) Sustaining the drive to overcome the global impact of neglected tropical diseases: second WHO report on neglected diseases. Geneva: World Health Organization.
26. Campbell SJ, Savage GB, Gray DJ, Atkinson J-AM, Soares Magalhães RJ, et al. (2014) Water, sanitation, and hygiene (WASH): a critical component for sustainable soil-transmitted helminth and schistosomiasis control. PLoS Negl Trop Dis 8: e2651.
27. Prüss A, Kay D, Fewtrell L, Bartram J, (2002) Estimating the burden of disease from water, sanitation, and hygiene at a global level. Environ Health Persp 110: 537–542.
28. Jordan P, Bartholomew RK, Unrau GO, (1978) Further observations from St Lucia on control of Schistosoma mansoni transmission by provision of domestic water supplies. Bull World Health Organ 56: 965–973.
29. Wang L, Guo J, Wu X, Chen H, Wang T, et al. (2009) China's new strategy to block Schistosoma japonicum transmission: experiences and impact beyond schistosomiasis. Trop Med Int Health 14: 1475–1483.
30. King JD, Endeshaw T, Escher E, Alemtaye G, Melaku S, et al. (2013) Intestinal parasite prevalence in an area of Ethiopia after implementing the SAFE strategy, enhanced outreach services, and health extension program. PLoS Negl Trop Dis 7: e2223.
31. Asaolu SO, Ofoezie IE, (2003) The role of health education and sanitation in the control of helminth infections. Acta Trop 86: 283–294.
32. Freeman MC, Clasen T, Brooker SJ, Akoko DO, Rheingans R, (2013) The impact of a school-based hygiene, water quality and sanitation intervention on soil-transmitted helminth reinfection: a cluster-randomized trial. Am J Trop Med Hyg 89: 875–883.
33. Esrey SA, Potash JB, Roberts L, Shiff C, (1991) Effects of improved water supply and sanitation on ascariasis, diarrhoea, dracunculiasis, hookworm infection, schistosomiasis, and trachoma. Bull World Health Organ 69: 609–621.
34. Stroup DF, Berlin JA, Morton SC, Olkin I, Williamson GD, et al. (2000) Meta-analysis of observational studies in epidemiology: a proposal for reporting. Meta-analysis Of Observational Studies in Epidemiology (MOOSE) group. JAMA 283: 2008–2012.
35. Moher D, Liberati A, Tetzlaff J, Altman DG, (2009) Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement. PLoS Med 6: e1000097.
36. Kloos H, Quites HF, Oliveira RC, Loverde P, Gazzinelli A, (2012) Rural electrification in Brazil and implications for schistosomiasis transmission: a preliminary study in a rural community in Minas Gerais state, Brazil. Trop Med Int Health 17: 526–530.
37. Ziegelbauer K, Speich B, Mäusezahl D, Bos R, Keiser J, et al. (2012) Effect of sanitation on soil-transmitted helminth infection: systematic review and meta-analysis. PLoS Med 9: e1001162.
38. Stocks ME, Ogden S, Haddad D, Addiss DG, McGuire C, et al. (2014) Effect of water, sanitation, and hygiene on the prevention of trachoma: a systematic review and meta-analysis. PLoS Med 11: e1001605.
39. Strunz EC, Addiss DG, Stocks M, Ogden S, Utzinger J, et al. (2014) Water, sanitation, hygiene, and soil-transmitted helminth infection: a systematic review and meta-analysis. PLoS Med 11: e1001620.
40. Greenland S, (2000) Small-sample bias and corrections for conditional maximum-likelihood odds-ratio estimators. Biostatistics 1: 113–122.
41. BMJ (2004) Grading quality of evidence and strength of recommendations. BMJ 328: 1490.
42. Ebrahim A, El-Morshedy H, Omer E, El-Daly S, Barakat R, (1997) Evaluation of the Kato-Katz thick smear and formal ether sedimentation techniques for quantitative diagnosis of Schistosoma mansoni infection. Am J Trop Med Hyg 57: 706–708.
43. Jordan P, Christie JD, Unrau GO, (1980) Schistosomiasis transmission with particular reference to possible ecological and biological methods of control. A review. Acta Trop 37: 95–135.
44. Sow S, Polman K, Vereecken K, Vercruysse J, Gryseels B, et al. (2008) The role of hygienic bathing after defecation in the transmission of Schistosoma mansoni. Trans R Soc Trop Med Hyg 102: 542–547.
45. DerSimonian R, Laird N, (1986) Meta-analysis in clinical trials. Control Clin Trials 7: 177–188.
46. Egger M, Smith GD, Schneider M, Minder C, (1997) Bias in meta-analysis detected by a simple, graphical test. BMJ 315: 629–634.
47. Higgins JP, Thompson SG, Deeks JJ, Altman DG, (2003) Measuring inconsistency in meta-analyses. BMJ 327: 557–560.
48. Knopp S, Stothard JR, Rollinson D, Mohammed KA, Khamis IS, et al. (2013) From morbidity control to transmission control: time to change tactics against helminths on Unguja Island, Zanzibar. Acta Trop 128: 412–422.
49. Knopp S, Person B, Ame SM, Mohammed KA, Ali SM, et al. (2013) Elimination of schistosomiasis transmission in Zanzibar: baseline findings before the onset of a randomized intervention trial. PLoS Negl Trop Dis 7: e2474.
50. Arndt MB, John-Stewart G, Richardson BA, Singa B, Van Lieshout L, et al. (2013) Impact of helminth diagnostic test performance on estimation of risk factors and outcomes in HIV-positive adults. PLoS One 8: e81915.
51. Fürst T, Ouattara M, Silué KD, N'Goran DN, Adiossan LG, et al. (2013) Scope and limits of an anamnestic questionnaire in a control-induced low-endemicity helminthiasis setting in south-central Côte d'Ivoire. PLoS One 8: e64380.
52. Sady H, Al-Mekhlafi HM, Mahdy MAK, Lim YAL, Mahmud R, et al. (2013) Prevalence and associated factors of schistosomiasis among children in Yemen: implications for an effective control programme. PLoS Negl Trop Dis 7: e2377.
53. Farooq M, Nielsen J, Samaan SA, Mallah MB, Allam AA, (1966) The epidemiology of Schistosoma haematobium and S. mansoni infections in the Egypt-49 project area. 2. Prevalence of bilharziasis in relation to personal attributes and habits. Bull World Health Organ 35: 293–318.
54. Howarth SE, Wilson JM, Ranaivoson E, Crook SE, Denning AM, et al. (1988) Worms, wells and water in Western Madagascar. J Trop Med Hyg 91: 255–264.
55. Umar AS, Parakoyi DB, (2005) The prevalence and intensity of urinary schistosomiasis among school children living along the Bakalori Dam, Nigeria. Niger Postgrad Med J 12: 168–172.
56. Dame JG, Banwat EB, Egah DZ, Shabi ME, (2006) Schistosomiasis among students in a local government area of Kaduna State in Northern Nigeria. Highland Med Res J 4: 60–69.
57. Abou-Zeid AHA, Abkar TA, Mohamed RO, (2012) Schistosomiasis and soil-transmitted helminths among an adult population in a war affected area, Southern Kordofan state, Sudan. Parasit Vectors 5: 133.
58. Dawet A, Benjamin CB, Yakubu DP, (2012) Prevalence and intensity of Schistosoma haematobium among residents of Gwong and Kabong in Jos north local government area, Plateau State, Nigeria. International Journal of Tropical Medicine 7: 69–73.
59. Nworie O, Nya O, Anyim C, Okoli CS, Okonkwo EC, (2012) Prevalence of urinary schistosomiasis among primary school children in Afikpo North Local government area of Ebonyi State. Annals of Biological Research 3: 3894–3897.
60. Al-Waleedi AA, El-Nimr NA, Hasab AA, Bassiouny HK, Al-Shibani LA, (2013) Urinary schistosomiasis among schoolchildren in Yemen: prevalence, risk factors, and the effect of a chemotherapeutic intervention. J Egypt Public Health Assoc 88: 130–136.
61. Awoke W, Bedimo M, Tarekegn M, (2013) Prevalence of schistosomiasis and associated factors among students attending at elementary schools in Amibera District, Ethiopia. Open J Prev Med 3: 199–204.
62. Reuben RC, Tanimu H, Musa JA, (2013) Epidemiology of urinary schistosomiasis among secondary school students in Lafia, Nasarawa State, Nigeria. Journal of Biology, Agriculture and Healthcare 3: 73–82.
63. Yang JZ, Zhao ZY, Li YS, Krewski D, Wen SW, (2009) A multi-level analysis of risk factors for Schistosoma japonicum infection in China. Int J Infect Dis 13: E407–E412.
64. Balen J, Raso G, Li YS, Zhao ZY, Yuan LP, et al. (2011) Risk factors for helminth infections in a rural and a peri-urban setting of the Dongting Lake area, People's Republic of China. Int J Parasitol 41: 1165–1173.
65. Kubasta M, (1964) Schistosomiasis mansoni in the Harar province. Ethiop Med J 2: 260–271.
66. Guimarães MD, Costa MF, de Lima LB, Moreira MA, (1985) [Clinico-epidemiological study of schistosomiasis mansoni in school children of Ilha, municipality of Arcos, MG (Brazil) 1983]. Rev Saude Publica 19: 8–17 (in Portuguese).
67. de Lima e Costa MFF, Magalhães MHA, Rocha RS, (1987) Water-contact patterns and socioeconomic variables in the epidemiology of schistosomiasis mansoni in an endemic area in Brazil. Bull World Health Organ 65: 57–66.
68. Barreto ML, (1991) Geographical and socioeconomic factors relating to the distribution of Schistosoma mansoni infection in an urban area of north-east Brazil. Bull World Health Organ 69: 93–102.
69. de Lima e Costa MFF, Rocha RS, Leite MLC, Carneiro RG, Colley D, et al. (1991) A multivariate analysis of socio-demographic factors, water contact patterns and Schistosoma mansoni infection in an endemic area in Brazil. Rev Inst Med Trop São Paulo 33: 58–63.
70. Marcal Junior O, Hotta LK, Patucci RM, Glasser CM, Dias LC, (1993) Schistosomiasis mansoni in an area of low transmission. II. Risk factors for infection. Rev Inst Med Trop São Paulo 35: 331–335.
71. Coura-Filho P, Rocha RS, Farah MW, da Silva GC, Katz N, (1994) Identification of factors and groups at risk of infection with Schistosoma mansoni: a strategy for the implementation of control measures? Rev Inst Med Trop São Paulo 36: 245–253.
72. de Lima e Costa MFF, Rocha RS, Magalhaes MH, Katz N, (1994) [A hierarchical model for analysis of socio-economic variables and water contact patterns associated with the hepatosplenic form of schistosomiasis]. Cad Saúde Pública 10 Suppl 2: 241–253 (in Portuguese)
73. Rodrigues RN, Murta C, Teixeira Junior MA, Cury GC, Rocha MO, (1995) Clinical-epidemiologic study of schistosomiasis mansoni in Ponte do Pasmado, a village in the municipality of Itinga, state of Minas Gerais, Brazil, 1992. Rev Inst Med Trop São Paulo 37: 81–85.
74. Soares MS, Barreto MG, da Silva CL, Pereira JB, Moza PG, et al. (1995) Schistosomiasis in a low prevalence area: incomplete urbanization increasing risk of infection in Paracambi, RJ, Brazil. Mem Inst Oswaldo Cruz 90: 451–458.
75. Watts S, El Katsha S, (1995) Changing environmental conditions in the Nile delta: health and policy implications with special reference to schistosomiasis. Int J Environ Heal R 5: 197–212.
76. Coura-Filho P, Rocha RS, Lamartine SS, Farah MW, de Resende DF, et al. (1996) Control of schistosomiasis mansoni in Ravena (Sabara, state of Minas Gerais, Brazil) through water supply and quadrennial treatments. Mem Inst Oswaldo Cruz 91: 659–664.
77. Firmo JOA, Costa MF, Guerra HL, Rocha RS, (1996) Urban schistosomiasis: morbidity, sociodemographic characteristics and water contact patterns predictive of infection. Int J Epidemiol 25: 1292–1300.
78. da Silva AA, Cutrim RN, de Britto e Alves MT, Coimbra LC, Tonial SR, et al. (1997) Water-contact patterns and risk factors for Schistosoma mansoni infection in a rural village of northeast Brazil. Rev Inst Med Trop São Paulo 39: 91–96.
79. Ximenes R, Southgate B, Smith PG, Guimaraes Neto L, (2003) Socioeconomic determinants of schistosomiasis in an urban area in the Northeast of Brazil. Rev Panam Salud Publica 14: 409–421.
80. Al-Shibani LA, El-Heggiagi MB, Burshan NM, Bassiouny HK, (2007) Development of schistosomal school-based health education model for Yemeni schoolchildren. J Egypt Soc Parasitol 37: 649–658.
81. Matthys B, Tschannen AB, Tian-Bi NT, Comoe H, Diabate S, et al. (2007) Risk factors for Schistosoma mansoni and hookworm in urban farming communities in western Côte d'Ivoire. Trop Med Int Health 12: 709–723.
82. Palmeira DCC, de Carvalho AG, Rodrigues K, Couto JLA, (2010) [Prevalence of Schistosoma mansoni infection in two municipalities of the State of Alagoas, Brazil]. Rev Soc Bras Med Trop 43: 313–317 (in Portuguese)
83. Cundill B, Alexander N, Bethony JM, Diemert D, Pullan RL, et al. (2011) Rates and intensity of re-infection with human helminths after treatment and the influence of individual, household, and environmental factors in a Brazilian community. Parasitology 138: 1406–1416.
84. Kabatereine NB, Standley CJ, Sousa-Figueiredo JC, Fleming FM, Stothard JR, et al. (2011) Integrated prevalence mapping of schistosomiasis, soil-transmitted helminthiasis and malaria in lakeside and island communities in Lake Victoria, Uganda. Parasit Vectors 4: 232.
85. Alembrhan A, Tadesse D, Zewdneh T, (2013) Infection prevalence of Schistosoma mansoni and associated risk factors among schoolchildren in suburbs of Mekelle city, Tigray, Northern Ethiopia. MEJS 5: 174–188.
86. Fentie T, Erqou S, Gedefaw M, Desta A, (2013) Epidemiology of human fascioliasis and intestinal parasitosis among schoolchildren in lake Tana Basin, northwest Ethiopia. Trans R Soc Trop Med Hyg 107: 480–486.
87. Mahmud MA, Spigt M, Bezabih AM, Lopez Pavon I, Dinant G-J, et al. (2013) Risk factors for intestinal parasitosis, anaemia, and malnutrition among school children in Ethiopia. Pathog Glob Health 107: 58–65.
88. Barbosa FA, (1966) [Schistosomiasis morbidity]. R Br Malar Suppl: 3–159 (in Portuguese)
89. Guimarães DC, De Barros HL, Katz N, (1985) A clinical epidemiologic study in a schistosomiasis mansoni endemic area. Rev Inst Med Trop São Paulo 27: 123–131.
90. Noman MA, Alshargby SA, Kadi HO, Mansoor T, Rahman RA, et al. (2012) Spread of internal parasites among the student of Al-Shaheed Al-Noman school, Widi Jadeed villages, Taiz province-Republic of Yemen. C J BioMed 6: 18–24.
91. Stephenson LS, Elliot TC, Kinoti SN (1986) Water, sanitation and knowledge about urinary schistosomiasis in a Kenyan coastal community: a study combining ethnographic and survey techniques. In: Stephenson LS, editor. Schistosomiasis and Malnutrition. Ithaca: Cornell University, Division of Nutritional Sciences. pp. 69–192.
92. Jones MF, Brady FJ, (1946) The removal of the cercariae of Schistosoma mansoni from water by filtration through diatomaceous silica in a small model filter. Public Health Rep 61: 1538–1543.
93. Jones MF, Brady FJ, (1947) Effects of water treatment processes on schistosome cercariae. Bull Natl Inst Health 2: 109–130.
94. Coles GC, Mann H, (1971) Schistosomiasis and water works practice in Uganda. East Afr Med J 48: 40–43.
95. Ayad N, (1974) A short review of the epidemiology of schistosomiasis in Africa. Egypt J Bilharz 1: 9–27.
96. Jordan P, Woodstock L, Unrau GO, Cook JA, (1975) Control of Schistosoma mansoni transmission by provision of domestic water supplies. A preliminary report of a study in St Lucia. Bull World Health Organ 52: 9–20.
97. Bakr IM, Arafa NA, Ahmed MA, Mostafa MH, Mohamed MK, (2009) Prevalence of intestinal parasitosis in a rural population in Egypt, and its relation to socio-demographic characteristics. J Egypt Soc Parasitol 39: 371–381.
98. Siegal FM, (1968) Schistosomiasis hematobia in preschool children of Ibadan, Nigeria. Am J Trop Med Hyg 17: 737–742.
99. Soares Magalhães RJ, Barnett AG, Clements ACA, (2011) Geographical analysis of the role of water supply and sanitation in the risk of helminth infections of children in West Africa. Proc Natl Acad Sci USA 108: 20084–20089.
100. Erko B, Abebe F, Berhe N, Medhin G, Gebre-Michael T, et al. (2002) Control of Schistosoma mansoni by the soapberry endod (Phytolacca dodecandra) in Wollo, northeastern Ethiopia: post-intervention prevalence. East Afr Med J 79: 198–201.
101. Gazzinelli A, Velasquez-Melendez G, Crawford SB, LoVerde PT, Correa-Oliveira R, et al. (2006) Socioeconomic determinants of schistosomiasis in a poor rural area in Brazil. Acta Trop 99: 260–271.
102. Barbosa LM, Silva LK, Reis EA, Azevedo TM, Costa JM, et al. (2013) Characteristics of the human host have little influence on which local Schistosoma mansoni populations are acquired. PLoS Negl Trop Dis 7: e2572.
103. WHO UNICEF, WSSCC (2000) Global water supply and sanitation assessment: 2000 report. Geneva: World Health Organization.
104. Dalton PR, Pole D, (1978) Water-contact patterns in relation to Schistosoma haematobium infection. Bull World Health Organ 56: 417–426.
105. Kloos H, Gazzinelli A, Van Zuyle P, (1998) Microgeographical patterns of schistosomiasis and water contact behavior; examples from Africa and Brazil. Mem Inst Oswaldo Cruz 93 Suppl 1: 37–50.
106. Esrey SA, Habicht JP, (1986) Epidemiologic evidence for health benefits from improved water and sanitation in developing countries. Epidemiol Rev 8: 117–128.