title: Enterobiasis and strongyloidiasis and associated co-infections and morbidity markers in infants, preschool- and school-aged children from rural coastal Tanzania: a cross-sectional study.
abstract: BACKGROUND
  There is a paucity of data pertaining to the epidemiology and public health impact of Enterobius vermicularis and Strongyloides stercoralis infections. We aimed to determine the extent of enterobiasis, strongyloidiasis, and other helminth infections and their association with asymptomatic Plasmodium parasitaemia, anaemia, nutritional status, and blood cell counts in infants, preschool-aged (PSAC), and school-aged children (SAC) from rural coastal Tanzania.
  
  
  METHODS
  A total of 1,033 children were included in a cross-sectional study implemented in the Bagamoyo district in 2011/2012. Faecal samples were examined for intestinal helminth infections using a broad set of quality controlled methods. Finger-prick blood samples were subjected to filariasis and Plasmodium parasitaemia testing and full blood cell count examination. Weight, length/height, and/or mid-upper arm circumference were measured and the nutritional status determined in accordance with age.
  
  
  RESULTS
  E. vermicularis infections were found in 4.2% of infants, 16.7%, of PSAC, and 26.3% of SAC. S. stercoralis infections were detected in 5.8%, 7.5%, and 7.1% of infants, PSAC, and SAC, respectively. Multivariable regression analyses revealed higher odds of enterobiasis in children of all age-groups with a reported anthelminthic treatment history over the past six months (odds ratio (OR): 2.15; 95% confidence interval (CI): 1.22 - 3.79) and in SAC with a higher temperature (OR: 2.21; CI: 1.13 - 4.33). Strongyloidiasis was associated with eosinophilia (OR: 2.04; CI: 1.20-3.48) and with Trichuris trichiura infections (OR: 4.13; CI: 1.04-16.52) in children of all age-groups, and with asymptomatic Plasmodium parasitaemia (OR: 13.03; CI: 1.34 - 127.23) in infants. None of the investigated helminthiases impacted significantly on the nutritional status and anaemia, but moderate asymptomatic Plasmodium parasitaemia was a strong predictor for anaemia in children aged older than two years (OR: 2.69; 95% CI: 1.23 - 5.86).
  
  
  CONCLUSIONS
  E. vermicularis and S. stercoralis infections were moderately prevalent in children from rural coastal Tanzania. Our data can contribute to inform yet missing global burden of disease and prevalence estimates for strongyloidiasis and enterobiasis. The association between S stercoralis and asymptomatic Plasmodium parasitaemia found here warrants further comprehensive investigations.
authors.affiliation: Bagamoyo Research and Training Centre, Ifakara Health Institute, Bagamoyo, United Republic of Tanzania. nsalim@ihi.or.tz.|Department of Pediatrics and Child Health, Muhimbili University Health and Allied Sciences, Dar es Salaam, United Republic of Tanzania. nsalim@ihi.or.tz.|Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland. nsalim@ihi.or.tz.|University of Basel, Basel, Switzerland. nsalim@ihi.or.tz.
authors.forename: Nahya
authors.initials: N
authors.lastname: Salim
authors.affiliation: Bagamoyo Research and Training Centre, Ifakara Health Institute, Bagamoyo, United Republic of Tanzania. schindler.tobi@gmail.com.|University of Basel, Basel, Switzerland. schindler.tobi@gmail.com.|Department of Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute, Basel, Switzerland. schindler.tobi@gmail.com.
authors.forename: Tobias
authors.initials: T
authors.lastname: Schindler
authors.affiliation: Bagamoyo Research and Training Centre, Ifakara Health Institute, Bagamoyo, United Republic of Tanzania. uabdul@ihi.or.tz.
authors.forename: Ummi
authors.initials: U
authors.lastname: Abdul
authors.affiliation: Bagamoyo Research and Training Centre, Ifakara Health Institute, Bagamoyo, United Republic of Tanzania. julian.rothen@gmx.ch.|University of Basel, Basel, Switzerland. julian.rothen@gmx.ch.|Department of Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute, Basel, Switzerland. julian.rothen@gmx.ch.
authors.forename: Julian
authors.initials: J
authors.lastname: Rothen
authors.affiliation: Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland. blaise.genton@unibas.ch.|University of Basel, Basel, Switzerland. blaise.genton@unibas.ch.|Department of Ambulatory Care and Community Medicine, Infectious Disease Service, Lausanne University Hospital, Lausanne, Switzerland. blaise.genton@unibas.ch.
authors.forename: Blaise
authors.initials: B
authors.lastname: Genton
authors.affiliation: Bagamoyo Research and Training Centre, Ifakara Health Institute, Bagamoyo, United Republic of Tanzania. olweno@ihi.or.tz.
authors.forename: Omar
authors.initials: O
authors.lastname: Lweno
authors.affiliation: Bagamoyo Research and Training Centre, Ifakara Health Institute, Bagamoyo, United Republic of Tanzania. alisraby@yahoo.com.
authors.forename: Alisa S
authors.initials: AS
authors.lastname: Mohammed
authors.affiliation: Bagamoyo Research and Training Centre, Ifakara Health Institute, Bagamoyo, United Republic of Tanzania. jmasimba@ihi.or.tz.
authors.forename: John
authors.initials: J
authors.lastname: Masimba
authors.affiliation: Bagamoyo Research and Training Centre, Ifakara Health Institute, Bagamoyo, United Republic of Tanzania. kmwebi@ihi.or.tz.
authors.forename: Denis
authors.initials: D
authors.lastname: Kwaba
authors.affiliation: Bagamoyo Research and Training Centre, Ifakara Health Institute, Bagamoyo, United Republic of Tanzania. sabdulla@ihi.or.tz.
authors.forename: Salim
authors.initials: S
authors.lastname: Abdulla
authors.affiliation: Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland. marcel.tanner@unibas.ch.|University of Basel, Basel, Switzerland. marcel.tanner@unibas.ch.
authors.forename: Marcel
authors.initials: M
authors.lastname: Tanner
authors.affiliation: University of Basel, Basel, Switzerland. claudia.daubenberger@unibas.ch.|Department of Medical Parasitology and Infection Biology, Swiss Tropical and Public Health Institute, Basel, Switzerland. claudia.daubenberger@unibas.ch.
authors.forename: Claudia
authors.initials: C
authors.lastname: Daubenberger
authors.affiliation: Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland. s.knopp@unibas.ch.|University of Basel, Basel, Switzerland. s.knopp@unibas.ch.|Department of Life Sciences, Wolfson Wellcome Biomedical Laboratories, Natural History Museum, London, United Kingdom. s.knopp@unibas.ch.
authors.forename: Stefanie
authors.initials: S
authors.lastname: Knopp
mesh_terms: D000740:Anemia / Q000453:epidemiology; D000818:Animals; D002648:Child; D002662:Child Health Services; D002675:Child, Preschool; D060085:Coinfection; D003430:Cross-Sectional Studies; D017229:Enterobiasis / Q000150:complications / Q000453:epidemiology* / Q000401:mortality; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D015995:Prevalence; D012044:Regression Analysis; D012424:Rural Population; D012574:Schools; D017171:Strongyloides stercoralis / Q000302:isolation & purification; D013322:Strongyloidiasis / Q000150:complications / Q000453:epidemiology* / Q000401:mortality; D013636:Tanzania / Q000453:epidemiology