Very rarely, smallpox has spread among people in small, enclosed spaces, probably through air in the ventilation system. Animals and insects donât spread the disease. Once a person is infected with the virus, 7 to 17 days can pass before they have any symptoms.
Portola Valley is an incorporated town in San Mateo County, California, United States. It was named for Spanish explorer Gaspar de PortolÃ¡, who led the first party of Europeans to explore the San Francisco Peninsula in 1769. The population was 4,353 at the 2010 census. Portola Valley is one of the forty wealthiest towns in the United States, with a median household income of $244,771 a year. Within the State of California, Portola Valley is ranked as the sixth wealthiest place. The zip code 94028, which encompasses the whole of Portola Valley, has the 9th most expensive housing prices within the country according to Forbes Magazine 2013.
Portola is located at 39Â°48â²37â³N 120Â°28â²11â³Wï»¿ / ï»¿39.810151Â°N 120.469843Â°Wï»¿ / 39.810151; -120.469843. According to the United States Census Bureau, the city has a total area of 5.4 square miles (14 km 2), all of it land. Portola lies in the northern Sierra Nevada near the southern border of the Cascade Range.