Teams in Uganda are trying to track down anyone who came into contact with patients infected with the Ebola virus, which has killed at least 14 people there this month, authorities said Monday. "This is very, very important, to trace every contact and to watch them for an incubation period of 21 days," World Health Organization spokesman Gregory Hartl said. The teams -- consisting of officials from Uganda's ministry of health, the U.S. Centers for Disease Control and Prevention and the WHO -- are part of an aggressive approach to try to stamp out the outbreak of the highly infectious virus. Ugandan President Yoweri Museveni spoke on state and private television Sunday urging his countrymen to be cautious. "I therefore appeal to you to be vigilant. Avoid shaking of hands; do not take on burying somebody that has died from symptoms which look like Ebola. Instead, call the health workers to be the ones to do it," he said. This month's outbreak in western Uganda initially went undetected because patients did not show typical symptoms, Health Minister Dr. Christine Ondoa told CNN yesterday.Patients had fevers and were vomiting, but did not show other typical symptoms, such as hemorrhaging.