title: Viability and fertility of human hepatic hydatid cysts.
abstract: BACKGROUND
  The adequate treatment for hydatidosis requires a knowledge of certain aspects related to the survival of infectious agents, especially protoscoleces. The aim of this study is to evaluate the viability of protoscoleces in human hepatic hydatid cysts in order to determine the prevalence of their fertility and to study the association with variables typical of the host and of the parasite.
  
  
  METHODS
  A cross-sectional study was done in biological material (the fluid from human hepatic hydatid cysts). The viability criteria used were: ovoid form, invaginated scolices and intact calcareous corpuscles, the presence of vibrating movements, and the absence of "vital" staining. The cysts were grouped as univesicular cysts (UVC), multivesicular cysts (MVC) and abscessed cysts (LAHO). Fertility was defined as living protoscoleces in relation to the total number of protoscoleces. Descriptive statistics were for the calculation of the prevalence of fertility, analytical statistics for the comparison of groups, and a multivariate analysis for the examination of the association between cyst fertility and clinical variables.
  
  
  RESULTS
  A total of 163 cysts with a median diameter of 15 cm were studied in this way. Of these lesions, 79 (48.5%) were UVC, 54 (33.1%) MVC, and 30 (18.4%) LAHO. On 99 occasions (60.7%), macroscopic communication was evident in the bile duct, and a prevalence of general fertility of 57.1% (94.4% for MVC, 53.2% for UVC, and 0% for LAHO, with a value of P<0.001). Association with location, type, and diameter of the cyst, and presence of biliary communications was verified by applying a bivariate analysis, and association between fertility and the variables of the type of the cyst and the existence of biliary communications was verified employing a multivariate analysis (P values of 0.004 and <0.001, respectively).
  
  
  CONCLUSIONS
  The prevalence of fertility found was low. The main prevalence of fertility was observed in MVCs. Fertility is associated with the type of cyst and the presence of biliary communications.
authors.affiliation: Department of Surgery, Universidad de La Frontera, Casilla 54-D, Temuco, Chile. cmantero@ufro.cl
authors.forename: Carlos
authors.initials: C
authors.lastname: Manterola
authors.forename: Manuel
authors.initials: M
authors.lastname: Vial
authors.forename: Angélica
authors.initials: A
authors.lastname: Melo
authors.forename: Carlos
authors.initials: C
authors.lastname: Oberg
authors.forename: Flery
authors.initials: F
authors.lastname: Fonseca
mesh_terms: D000818:Animals; D001707:Biopsy, Needle; D016009:Chi-Square Distribution; D003430:Cross-Sectional Studies; D004444:Echinococcosis, Hepatic / Q000175:diagnosis* / Q000601:surgery*; D004446:Echinococcus / Q000302:isolation & purification / Q000472:pathogenicity*; D006801:Humans; D007150:Immunohistochemistry; D016015:Logistic Models; D012307:Risk Factors; D012494:Sampling Studies; D012680:Sensitivity and Specificity; D018709:Statistics, Nonparametric