Iowa is currently experiencing the biggest mumps epidemic in the United States in 17 years, more than one third of the state being affected. 245 confirmed or probable cases have been so far reported by local authorities, being caused by the same strain of mumps which has infected thousands of people in the UK. While the authorities are still trying to find where the outbreak originated from, neighboring states Illinois, Minnesota and Nebraska are preparing for the infection. One theory is that the disease was brought from England, possibly by a college student because 23% of cases were found in colleges. Iowa state epidemiologist Dr. Patricia Quinlisk confirmed that the epidemic covered 1/3 of the state and spread across different groups of people. The previous epidemic of mumps occurred in 1988, when Kansas confirmed the infection in 269 people. Mumps is a very contagious disease, which infects the salivary glands. It spreads through saliva, by sneezing and coughing and being released from the nose and throat of an infected person. People who carry the disease experience swollen cheeks and jaw, soreness around the jaw area or pain in the neck or ear. Symptoms begin to show from 12 days to 3 weeks and about 30% of infected people do not show symptoms. About 25% of men experience swelling of the testicles caused by mumps, which, in some cases, lowers the fertility.