title: Environmental Factors Associated with High Fly Densities and Diarrhea in Vellore, India.
abstract: Diarrhea causes significant morbidity and mortality in Indian children under 5 years of age. Flies carry enteric pathogens and may mediate foodborne infections. In this study, we characterized fly densities as a determinant of infectious diarrhea in a longitudinal cohort of 160 urban and 80 rural households with 1,274 individuals (27% under 5 years of age) in Vellore, India. Household questionnaires on living conditions were completed at enrollment. Fly abundance was measured during the wet and dry seasons using fly ribbons placed in kitchens. PCRs for enteric bacteria, viruses, and protozoa were performed on 60 fly samples. Forty-three (72%) fly samples were positive for the following pathogens: norovirus (50%), Salmonella spp. (46.7%), rotavirus (6.7%), and Escherichia coli (6.7%). Ninety-one episodes of diarrhea occurred (89% in children under 5 years of age). Stool pathogens isolated in 24 of 77 (31%) samples included E. coli, Shigella spp., Vibrio spp., Giardia, Cryptosporidium, and rotavirus. Multivariate log-linear models were used to explore the relationships between diarrhea and fly densities, controlling for demographics, hygiene, and human-animal interactions. Fly abundance was 6 times higher in rural than urban sites (P < 0.0001). Disposal of garbage close to homes and rural living were significant risk factors for high fly densities. The presence of latrines was protective against high fly densities and diarrhea. The adjusted relative risks of diarrheal episodes and duration of diarrhea, associated with fly density at the 75th percentile, were 1.18 (95% confidence interval [CI], 1.03 to 1.34) and 1.15 (95% CI, 1.02 to 1.29), respectively. Flies harbored enteric pathogens, including norovirus, a poorly documented pathogen on flies.
authors.affiliation: Tufts Medical Center, Boston, Massachusetts, USA.
authors.forename: Stefan
authors.initials: S
authors.lastname: Collinet-Adler
authors.affiliation: Christian Medical College, Vellore, India.
authors.forename: Sudhir
authors.initials: S
authors.lastname: Babji
authors.affiliation: Christian Medical College, Vellore, India.
authors.forename: Mark
authors.initials: M
authors.lastname: Francis
authors.affiliation: Christian Medical College, Vellore, India.
authors.forename: Deepthi
authors.initials: D
authors.lastname: Kattula
authors.affiliation: Christian Medical College, Vellore, India.
authors.forename: Prasanna Samuel
authors.initials: PS
authors.lastname: Premkumar
authors.affiliation: Christian Medical College, Vellore, India.
authors.forename: Rajiv
authors.initials: R
authors.lastname: Sarkar
authors.affiliation: Christian Medical College, Vellore, India.
authors.forename: Venkat Ragava
authors.initials: VR
authors.lastname: Mohan
authors.affiliation: Tufts Medical Center, Boston, Massachusetts, USA Christian Medical College, Vellore, India.
authors.forename: Honorine
authors.initials: H
authors.lastname: Ward
authors.affiliation: Christian Medical College, Vellore, India.
authors.forename: Gagandeep
authors.initials: G
authors.lastname: Kang
authors.affiliation: Christian Medical College, Vellore, India.
authors.forename: Vinohar
authors.initials: V
authors.lastname: Balraj
authors.affiliation: Christian Medical College, Vellore, India Tufts University, Medford, Massachusetts, USA elena.naumova@tufts.edu.
authors.forename: Elena N
authors.initials: EN
authors.lastname: Naumova
mesh_terms: D000818:Animals; D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D002675:Child, Preschool; D003967:Diarrhea / Q000453:epidemiology* / Q000382:microbiology / Q000821:virology; D004175:Diptera / Q000254:growth & development* / Q000382:microbiology / Q000821:virology; D004777:Environment; D005260:Female; D006801:Humans; D007194:India / Q000453:epidemiology; D007223:Infant; D007231:Infant, Newborn; D007303:Insect Vectors / Q000254:growth & development* / Q000382:microbiology / Q000469:parasitology; D008297:Male; D011156:Population Density; D012621:Seasons; D014780:Viruses / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*