title: Risk profiling of hookworm infection and intensity in southern Lao People's Democratic Republic using Bayesian models.
abstract: BACKGROUND
  Among the common soil-transmitted helminth infections, hookworm causes the highest burden. Previous research in the southern part of Lao People's Democratic Republic (Lao PDR) revealed high prevalence rates of hookworm infection. The purpose of this study was to predict the spatial distribution of hookworm infection and intensity, and to investigate risk factors in the Champasack province, southern Lao PDR.
  
  
  METHODS
  A cross-sectional parasitological and questionnaire survey was conducted in 51 villages. Data on demography, socioeconomic status, water, sanitation, and behavior were combined with remotely sensed environmental data. Bayesian mixed effects logistic and negative binomial models were utilized to investigate risk factors and spatial distribution of hookworm infection and intensity, and to make predictions for non-surveyed locations.
  
  
  RESULTS
  A total of 3,371 individuals were examined with duplicate Kato-Katz thick smears and revealed a hookworm prevalence of 48.8%. Most infections (91.7%) were of light intensity (1-1,999 eggs/g of stool). Lower hookworm infection levels were associated with higher socioeconomic status. The lowest infection levels were found in preschool-aged children. Overall, females were at lower risk of infection, but women aged 50 years and above harbored the heaviest hookworm infection intensities. Hookworm was widespread in Champasack province with little evidence for spatial clustering. Infection risk was somewhat lower in the lowlands, mostly along the western bank of the Mekong River, while infection intensity was homogeneous across the Champasack province.
  
  
  CONCLUSIONS
  Hookworm transmission seems to occur within, rather than between villages in Champasack province. We present spatial risk maps of hookworm infection and intensity, which suggest that control efforts should be intensified in the Champasack province, particularly in mountainous areas.
authors.affiliation: Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland.
authors.forename: Armelle
authors.initials: A
authors.lastname: Forrer
authors.affiliation: Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland.
authors.forename: Penelope
authors.initials: P
authors.lastname: Vounatsou
authors.affiliation: Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland; National Institute of Public Health, Ministry of Health, Vientiane, Lao People's Democratic Republic.
authors.forename: Somphou
authors.initials: S
authors.lastname: Sayasone
authors.affiliation: Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland; Faculty of Basic Sciences, University of Health Sciences, Vientiane, Lao People's Democratic Republic.
authors.forename: Youthanavanh
authors.initials: Y
authors.lastname: Vonghachack
authors.affiliation: Faculty of Basic Sciences, University of Health Sciences, Vientiane, Lao People's Democratic Republic.
authors.forename: Dalouny
authors.initials: D
authors.lastname: Bouakhasith
authors.affiliation: Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland.
authors.forename: Jürg
authors.initials: J
authors.lastname: Utzinger
authors.affiliation: National Institute of Public Health, Ministry of Health, Vientiane, Lao People's Democratic Republic.
authors.forename: Kongsap
authors.initials: K
authors.lastname: Akkhavong
authors.affiliation: Department of Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland; University of Basel, Basel, Switzerland.
authors.forename: Peter
authors.initials: P
authors.lastname: Odermatt
mesh_terms: D000328:Adult; D000818:Animals; D001499:Bayes Theorem; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D005243:Feces / Q000469:parasitology; D005260:Female; D005843:Geography; D006725:Hookworm Infections / Q000453:epidemiology*; D006801:Humans; D007812:Laos / Q000453:epidemiology; D008297:Male; D015233:Models, Statistical; D015995:Prevalence; D018570:Risk Assessment; D012307:Risk Factors; D012499:Sanitation / Q000706:statistics & numerical data; D012987:Soil / Q000469:parasitology; D011795:Surveys and Questionnaires
chemical_list: D012987:Soil
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