Eleven San Diego County residents have contracted malaria in the last month, and officials said the outbreak may be linked to a lagoon near Carlsbad. All of the victims have spent time near the the lagoon, which is a breeding ground for mosquitoes that transmit malaria. Health officials said the victims have contracted the mildest form of the disease. Malaria is not fatal in most cases and can generally be treated with medication over a two-week period. The symptoms include a high temperature, chills and headaches.