Dr. Kamran Khan, St. Michael's Hospital (IMAGE) St. Michael's Hospital Caption Researchers led by Dr. Kamran Khan of St. Michael's have mapped the worldwide pathways through which yellow fever virus could spread by analyzing global patterns of airline travellers, the environmental conditions needed to enable transmission of the virus within a city, and countries' requirements for travellers to provide proof of yellow fever vaccination upon entry. Credit St. Michael's Hospital Usage Restrictions Credit St. Michael's Hospital License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.