experts say many Californians were affected by one strain , five by other strains . About 70 % of the people who could show health signs were unvaccinated . Outbreak occurred in 2004 among visitors to two Disney theme parks .
Officials say 131 Californians were affected by one strain , five by other strains . About 70 % of the people who could show health records were unvaccinated . Outbreak began in December among visitors to two Disney theme parks .