Yellow fever and several species of mosquitoes. In cities, it is spread primarily by "Aedes aegypti", a type of mosquito found throughout the tropics and subtropics. The virus is an RNA virus of the genus "Flavivirus". The disease may be difficult to tell apart from other illnesses, especially in the early stages. To confirm a suspected case, blood sample testing with polymerase chain reaction is required. A safe and effective vaccine against yellow fever exists, and some countries require vaccinations for travelers. Other efforts to prevent infection include reducing the population of the transmitting mosquito. In areas where yellow fever is common
1793 Philadelphia yellow fever epidemic the personal letters, which are largely held by Quaker colleges in the area. While Powell did not write a scholarly history of the epidemic, his work reviewed its historical importance. Since the mid-twentieth century, scholars have studied aspects of the epidemic, first in papers. For example, Martin Pernick's "Politics, Parties, and Pestilence: Epidemic Yellow Fever in Philadelphia and the Rise of the First Party System," developed statistical evidence to show that Republican doctors generally used Rush's therapies and Federalist doctors used Kuhn's. Scholars celebrated the 200th anniversary of the epidemic with the publication of papers on various aspects of the