title: Searching for chronic hepatitis B patients in a low prevalence area--role of racial origin.
abstract: BACKGROUND
  Clinical studies for testing new drugs against hepatitis B ought to be carried out in low prevalence areas despite difficulties on patient recruitment. In such areas, relatives of chronic hepatitis B patients are considered to be at risk of acquiring the hepatitis B virus (HBV). The aim of this study was to evaluate the prevalence of HBV markers (anti-HBc, HBsAg and anti-HBs) in familial members of chronic hepatitis B (CHB) patients according to their origin (Asian or Western) in a low prevalence area, the city of São Paulo, Brazil.
  
  
  METHODS
  Twenty three Asian CHB probands and their 313 relatives plus 31 CHB probands of Western origin and their 211 relatives were screened for HBV serological markers; the study was carried out in the outpatient clinic of the University of São Paulo School of Medicine.
  
  
  RESULTS
  Mother to child transmission was greater in the Asian group whereas sexual transmission was more frequent in the Western group (p < 0.0001). Anti-HBc was positive in 90% and 57% of the Asian and Western parents (p = 0.0432) and in 97% and 33% of the Asian and Western brothers (p = 0.0001), respectively. HBsAg was more frequent among the Asian (66%) than the Western (15%) mothers (p = 0.0260) as well as among the Asian (81%) than the Western (19%) brothers (p = 0.0001). We could detect 110 new HBsAg-positive subjects related to the 54 index patients, being the majority (81%) of Asian origin.
  
  
  CONCLUSIONS
  In low prevalence area of hepatitis B, family members and household contacts of chronic HBV carriers are at high risk for acquiring hepatitis B.
authors.affiliation: Hepatology Branch, Dept of Gastroenterology, University of São Paulo School of Medicine, Brazil. skon@usp.br
authors.forename: Suzane Kioko
authors.initials: SK
authors.lastname: Ono-Nita
authors.forename: Flair José
authors.initials: FJ
authors.lastname: Carrilho
authors.forename: Rita A
authors.initials: RA
authors.lastname: Cardoso
authors.forename: Marcelo Eidi
authors.initials: ME
authors.lastname: Nita
authors.forename: Luiz Caetano
authors.initials: LC
authors.lastname: da Silva
mesh_terms: D000328:Adult; D044466:Asian People / Q000706:statistics & numerical data*; D001938:Brazil / Q000208:ethnology; D002353:Carrier State / Q000097:blood* / Q000175:diagnosis; D004279:DNA, Viral / Q000097:blood; D018562:Disease Transmission, Infectious / Q000706:statistics & numerical data; D005195:Family Relations; D005260:Female; D006510:Hepatitis B Antibodies / Q000097:blood*; D006514:Hepatitis B Surface Antigens / Q000097:blood*; D006515:Hepatitis B virus / Q000276:immunology*; D019694:Hepatitis B, Chronic / Q000208:ethnology* / Q000276:immunology / Q000635:transmission; D006801:Humans; D007124:Immunoenzyme Techniques; D008297:Male; D018579:Patient Selection; D015995:Prevalence; D012307:Risk Factors; D016036:Seroepidemiologic Studies; D044465:White People / Q000706:statistics & numerical data*
chemical_list: D004279:DNA, Viral; D006510:Hepatitis B Antibodies; D006514:Hepatitis B Surface Antigens