title: Risk analysis for occurrences of schistosomiasis in the coastal area of Porto de Galinhas, Pernambuco, Brazil.
abstract: BACKGROUND
  Manson's schistosomiasis continues to be a severe public health problem in Brazil, where thousands of people live under the risk of contracting this parasitosis. In the Northeast of Brazil, schistosomiasis has expanded from rural areas to the coast of Pernambuco State, where the intermediate host is Biomphalaria glabrata snails. This study aims at presenting situational analyses on schistosomiasis at the coastal locality of Porto de Galinhas, Pernambuco, Brazil, by determining the risk factors relating to its occurrence from the epidemiological and spatial perspectives.
  
  
  METHODS
  In order to gather prevalence data, a parasitological census surveys were conducted in 2010 in the light of the Kato-Katz technique. Furthermore, malacological surveys were also conducted in the same years so as to define the density and infection rates of the intermediate host. Lastly, socioeconomic-behavioral survey was also conducted to determine the odds ratio for infection by Schistosoma mansoni. Based on these data, spatial analyses were done, resulting in maps of the risk of disease transmission. To predict the risk of schistosomiasis occurrence, a multivariate logistic regression was performed using R 2.13 software.
  
  
  RESULTS
  Based on prevalence, malacological and socioeconomic-behavioural surveys, it was identified a prevalence of 15.7% in the investigated population (2,757 individuals). Due to the malacological survey, 36 breeding sites were identified, of which 11 were classified as foci of schistosomiasis transmission since they pointed out snails which were infected by Schistosoma mansoni. Overall, 11,012 snails (Biomphalaria glabrata) were collected. The multivariate regression model identified six explanatory variables of environmental, socioeconomic and demographic nature. Spatial sweep analysis by means of the Bernoulli method identified one statistically significant cluster in Salinas (RR = 2.2; p-value < 0.000), the district with the highest occurrence of cases.
  
  
  CONCLUSIONS
  Based on the resulting information from this study, the epidemiological dimensions of this disease are significant and severe, within the scenario of schistosomiasis in Pernambuco state. The risk factors which were identified in the predictive model made it clear that the environmental and social conditions influence on the schistosomiasis occurrences.
authors.affiliation: Laboratory of Parasitology, Vitoria Academic Center, Federal University of Pernambuco, Recife, Pernambuco, Brazil. elainnechristine@hotmail.com.
authors.forename: Elainne Christine de Souza
authors.initials: EC
authors.lastname: Gomes
authors.forename: Onicio Batista
authors.initials: OB
authors.lastname: Leal-Neto
authors.forename: Fernando José Moreira
authors.initials: FJ
authors.lastname: de Oliveira
authors.forename: Julyana Viegas
authors.initials: JV
authors.lastname: Campos
authors.forename: Reinaldo
authors.initials: R
authors.lastname: Souza-Santos
authors.forename: Constança Simões
authors.initials: CS
authors.lastname: Barbosa
mesh_terms: D000293:Adolescent; D000328:Adult; D000818:Animals; D001700:Biomphalaria; D001938:Brazil / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D004199:Disease Vectors; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D018570:Risk Assessment; D012307:Risk Factors; D012550:Schistosoma mansoni; D012555:Schistosomiasis mansoni / Q000453:epidemiology* / Q000635:transmission; D012908:Snails / Q000469:parasitology; D055815:Young Adult