What diseases caused epidemics in nineteenth-century California?

Highly contagious diseases such as smallpox, syphilis, mumps, influenza, and measles were prevalent in California during the 1800s. Europeans were learning to control outbreaks of the deadly disease smallpox by vaccinating. However, when the Spanish and Mexican soldiers mixed with the Native Americans in California, epidemics of smallpox and measles spread rapidly through the native population. The people had no immunity to these European diseases, and though some survived, many died within days after contracting them. Captain Richardson helped the Franciscan friars vaccinate for smallpox among many of the neophytes who had been at the California missions, but smallpox and other diseases returned, again and again, to cause havoc among the coastal people, resulting in severe suffering and death. In the Franciscan Mission Dolores (located in San Francisco), where on average 1,000 neophytes lived and worked, more than 300 might die in one year due to these diseases.