title: [Dengue virus serotype 2 strains isolated from the epidemic occurred in Santiago de Cuba in 1997].
abstract: BACKGROUND
  during the Cuban epidemic that occurred in Santiago de Cuba in 1997, there was observed increasing severity in the course of time, in terms of proportion of serious dengue haemorrhagic cases and deaths that could be due to the emergence of escape mutants to neutralization with greater virulent potential.
  
  
  OBJECTIVE
  to study some biological attributes of a group of strains isolated at different points of time during the Santiago de Cuba epidemic in 1997.
  
  
  METHODS
  nine DENV-2 strains were studied. The cytopathogenic effect, the viral growth in C6/36 HT and VERO cell lines, the virus plaque sizes, the sensitivity to temperatures, the neurovirulence in newborn mice and the influence of the pH in the union of the virus to the cell as well as in the multiplication medium were all evaluated.
  
  
  RESULTS
  the strains isolated at the end of the epidemic differed from those of the beginning showing increased neurovirulence in newborn mice and higher viral titers and greater cytopathogenic effect in HT C6/36 cells. On the other hand, the virus and the cell union was favored by acid pH when testing strains from the beginning of the epidemic, whereas this union was favored by the basic PH in the strains isolated at the end of the epidemic
  
  
  CONCLUSIONS
  the present study managed to show that in addition to the previously observed genotypical changes, there were phenotypical differences among the strains isolated at different points of time in the epidemic; all these aspects may be associated with differences in the viral fitness and/or in the virulent potential of these strains.
authors: Instituto de Medicina Tropical "Pedro Kourí", La Habana, Cuba. rosmari@ipk.sld.cu
authors: C Rosmari
authors: CR
authors: Rodríguez-Roche
authors: Liudmila
authors: L
authors: López Matilla
authors: C Mayling
authors: CM
authors: Alvarez Vera
authors: Luis
authors: L
authors: Morier Díaz
authors: C María G
authors: CM
authors: Guzmán Tirado
mesh_terms: D003462:Cuba / Q000453:epidemiology; D003715:Dengue / Q000453:epidemiology* / Q000821:virology*; D003716:Dengue Virus / Q000145:classification*; D004196:Disease Outbreaks; D006801:Humans; D012703:Serotyping