July 20, 2012 8:42 am Whooping Cough Returns A record number of whooping cough cases are expected this year. So far in 2012, there have been more than 18,000 cases reported to the Centers for Disease Control and Prevention. US & World Videos 1:43 Traces of bird flu virus found in 1 in 5 samples of pasteurized milk, FDA says 2:42 Mother, surrogate celebrate a perfect ending to their long journey 1:12 Watch: Why vaccines are contributing to improved public health 1:53 The Helix School in San Rafael growing with the community 3:33 Bay Area sees slight improvement in air quality, annual report shows