'We had expected when schools would open up (that) we would start seeing an increase in flulike illnesses,' said Sarah Kissell, a spokeswoman for the county Department of Public Health. Health officials declined to name the schools because of privacy concerns, but Kissell said outbreaks, defined as at least five suspected H1N1 virus infections, have occurred in recent weeks at two elementary schools, a high school and a university. But infections are clearly more widespread than at those four campuses. Educators in some districts confirmed infections at their schools, including Burbank Unified School District and Glendale Unified School District. Other districts declined to share detailed information. Pasadena school officials confirmed a handful of cases at their campuses, but refused to identify the schools. Los Angeles Unified School District officials said they are following the lead of the county health department and declined comment on whether they had any infections and, if so, at which campuses. Parents said the districts and the health department should be more forthcoming. 'I want to at least know if I should be prepared or concerned,' said William Torres of North Hills, whose two children attend elementary school. 'To keep me in the dark is not a good thing.' Young people are particularly susceptible to contracting the virus, and are on the priority list to receive a vaccine when it becomes available in October. H1N1 is highly contagious, but symptoms tend to be mild in healthy people. Unlike in spring 2008, officials do not plan to close schools if there is an outbreak. Instead, they are urging prevention -- washing hands frequently, sneezing into the elbow instead of the hand and getting the vaccine when it becomes available. Ill children should be kept home to avoid spreading the virus to their classmates, and can return to school once they are fever-free for 24 hours. 