Dengue hemorrhagic fever is caused by -
Hypersensitivity or enhancement response to sequintial dengue virus infection in person sensitised by prior exposure to other serotupes of the viru REF:\p> ANATHANARAYANAN MICROBIOLOGY NINTH EDITION PAGE.523
Type I dengue virus
Reinfection with same serotype of dengue virus
Reinfection with different serotype of dengue virus
Infection in an immunocompromised host
Virology