title: Sero-prevalence of Leishmania donovani infection in labour migrants and entomological risk factors in extra-domestic habitats of Kafta-Humera lowlands - kala-azar endemic areas in the northwest Ethiopia.
abstract: BACKGROUND
  Visceral leishmaniasis (VL) or kala-azar cases in seasonal labour migrants from highland areas are addressed to travel history to the Metema-Humera lowlands, northwestern Ethiopia. Factors that affect the incidence of VL in extra-domestic habitats were not evaluated. The aim of this study was to evaluate sero-prevalence of Leishmania donovani infection in randomly selected labour migrant workers and entomological risk factors which might affect the incidence of kala-azar.
  
  
  METHODS
  Sero-prevalence of L. donovani infection in labour migrants was obtained from Direct Agglutination Test (DAT) using blood samples. Logistic regression analysis was used to correlate the possible risk factors with L. donovani infection. The season for L. donovani infection or Phlebotomus orientalis bite was estimated from the study of population dynamic of P. orientalis in areas where the blood was sampled.
  
  
  RESULTS
  A total of 7, 443 P. orientalis (1,748 female and 5,695 male) were collected from agricultural fields and thickets of Acacia seyal using 461 CDC light traps. The highest mean number of P. orientalis/trap in the thickets of A. seyal and agricultural fields were 46.9 and 43.9 in March and April respectively. The mean P. orientalis/trap for November - May dry season in agricultural fields (11.39) and thickets of A. seyal (25.30) were higher compared to 0.66 in fields and 3.92 in thickets during June - August weeding season. Of the total 359 labour migrants screened using DAT, 45 (12.5%) were DAT-positive (≥1:800) for L. donovani infections. Very high titers (1:12800) were found in 3 (0.8%) individuals who had the risk of kala-azar development. Statistically significant p-values and odd ratio (OR) for staying in the areas both in the weeding and harvesting seasons (p = 0.035; OR = 2.83) and sleeping in the agricultural fields (p = 0.01; OR = 15.096) were positively correlated with L. donovani infection. Night harvest (p = 0.028; OR = 0.133) and knowledge about sign or symptoms (p = 0.042; OR = 0.383) were negatively associated with this infection.
  
  
  CONCLUSIONS
  Sleeping in open agricultural fields was related with L. donovani infections in labour migrants during June-August weeding season.
authors.affiliation: Department of Medical Parasitology, School of Biomedical and Laboratory Sciences, College of Medicine and Health Sciences, University of Gondar, Gondar, Ethiopia. wossensegedlemma@yahoo.com.|Department of Zoological Sciences, College of Natural Science, Addis Ababa University, Addis Ababa, Ethiopia. wossensegedlemma@yahoo.com.
authors.forename: Wossenseged
authors.initials: W
authors.lastname: Lemma
authors.affiliation: Department of Zoological Sciences, College of Natural Science, Addis Ababa University, Addis Ababa, Ethiopia. habte_tm@yahoo.com.
authors.forename: Habte
authors.initials: H
authors.lastname: Tekie
authors.affiliation: Department of Biology, College of Natural Science, Jigjiga University, Jigjiga, Ethiopia. solyar2005@yahoo.com.
authors.forename: Solomon
authors.initials: S
authors.lastname: Yared
authors.affiliation: Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia. meshesha_b@yahoo.com.
authors.forename: Meshesha
authors.initials: M
authors.lastname: Balkew
authors.affiliation: Aklilu Lemma Institute of Pathobiology, Addis Ababa University, Addis Ababa, Ethiopia. teshomegm@gmail.com.
authors.forename: Teshome
authors.initials: T
authors.lastname: Gebre-Michael
authors.affiliation: Department of Microbiology and Molecular Genetics, The Institute for Medical Research Israel-Canada, The Kuvin Centre for the Study of Infectious & Tropical Diseases, The Hebrew University - Hadassah Medical School, The Hebrew University of Jerusalem, Jerusalem, 91120, Israel. alonw@ekmd.huji.ac.il.
authors.forename: Alon
authors.initials: A
authors.lastname: Warburg
authors.affiliation: Department of Microbiology, Immunology & Parasitology, Faculty of Medicine, Addis Ababa University, Addis Ababa, Ethiopia. hailu_a2004@yahoo.com.
authors.forename: Asrat
authors.initials: A
authors.lastname: Hailu
mesh_terms: D000293:Adolescent; D000328:Adult; D000383:Agriculture; D000818:Animals; D017753:Ecosystem; D019353:Endemic Diseases; D005002:Ethiopia / Q000453:epidemiology; D005260:Female; D006801:Humans; D007303:Insect Vectors / Q000469:parasitology; D007893:Leishmania donovani / Q000235:genetics / Q000302:isolation & purification*; D007898:Leishmaniasis, Visceral / Q000453:epidemiology* / Q000635:transmission; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D012621:Seasons; D016036:Seroepidemiologic Studies; D014171:Transients and Migrants; D055815:Young Adult