title: Clinical, epidemiological, and spatial characteristics of Vibrio parahaemolyticus diarrhea and cholera in the urban slums of Kolkata, India.
abstract: BACKGROUND
  There is not much information on the differences in clinical, epidemiological and spatial characteristics of diarrhea due to V. cholerae and V. parahaemolyticus from non-coastal areas. We investigated the differences in clinical, epidemiological and spatial characteristics of the two Vibrio species in the urban slums of Kolkata, India.
  
  
  METHODS
  The data of a cluster randomized cholera vaccine trial were used. We restricted the analysis to clusters assigned to placebo. Survival analysis of the time to the first episode was used to analyze risk factors for V. parahaemolyticus diarrhea or cholera. A spatial scan test was used to identify high risk areas for cholera and for V. parahaemolyticus diarrhea.
  
  
  RESULTS
  In total, 54,519 people from the placebo clusters were assembled. The incidence of cholera (1.30/1000/year) was significantly higher than that of V. parahaemolyticus diarrhea (0.63/1000/year). Cholera incidence was inversely related to age, whereas the risk of V. parahaemolyticus diarrhea was age-independent. The seasonality of diarrhea due to the two Vibrio species was similar. Cholera was distinguished by a higher frequency of severe dehydration, and V. parahaemolyticus diarrhea was by abdominal pain. Hindus and those who live in household not using boiled or treated water were more likely to have V. parahaemolyticus diarrhea. Young age, low socioeconomic status, and living closer to a project healthcare facility were associated with an increased risk for cholera. The high risk area for cholera differed from the high risk area for V. parahaemolyticus diarrhea.
  
  
  CONCLUSIONS
  We report coexistence of the two vibrios in the slums of Kolkata. The two etiologies of diarrhea had a similar seasonality but had distinguishing clinical features. The risk factors and the high risk areas for the two diseases differ from one another suggesting different modes of transmission of these two pathogens.
authors.affiliation: National Institute of Cholera and Enteric Diseases, Kolkata, India.
authors.forename: Suman
authors.initials: S
authors.lastname: Kanungo
authors.forename: Dipika
authors.initials: D
authors.lastname: Sur
authors.forename: Mohammad
authors.initials: M
authors.lastname: Ali
authors.forename: Young Ae
authors.initials: YA
authors.lastname: You
authors.forename: Debottam
authors.initials: D
authors.lastname: Pal
authors.forename: Byomkesh
authors.initials: B
authors.lastname: Manna
authors.forename: Swapan K
authors.initials: SK
authors.lastname: Niyogi
authors.forename: Banwarilal
authors.initials: B
authors.lastname: Sarkar
authors.forename: Sujit K
authors.initials: SK
authors.lastname: Bhattacharya
authors.forename: John D
authors.initials: JD
authors.lastname: Clemens
authors.forename: G Balakrish
authors.initials: GB
authors.lastname: Nair
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D002771:Cholera / Q000453:epidemiology / Q000382:microbiology*; D016000:Cluster Analysis; D003967:Diarrhea / Q000453:epidemiology / Q000382:microbiology*; D005260:Female; D006801:Humans; D007194:India / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D011159:Population Surveillance; D011204:Poverty Areas; D012307:Risk Factors; D062206:Spatial Analysis; D014504:Urban Health; D014734:Vibrio cholerae / Q000302:isolation & purification; D014736:Vibrio parahaemolyticus / Q000302:isolation & purification*