For many people, parasites are the stuff of nightmares. These organisms take up residence in their human hosts and feed on the nutrients of the person, causing both minor ailments as well as serious and sometimes life-threatening illness. Many people think parasites may be acquired only in developing and third-world countries or as a parting gift on an exotic vacation. However, a new report from the Centers for Disease Control and Prevention finds these buggers are very much alive in the U.S. Millions of Americans develop parasitic infections and symptoms often go unnoticed or are misdiagnosed. These microscopic creatures are typically picked up through food and water. An infection can lead to serious health problems, including seizures, blindness, pregnancy complications, heart failure and even death.