**3. A brief history of YF**

The cause of YF was unknown, but it was thought to be contracted either by coming into contact with "effluvia" from those stricken by the disease or with fomites such as cloth‐ ing, sheets, and other articles that patients had used. Fear of contracting the contagion led people to shun their neighbours and friends and even to abandon loved ones. "It just tore society apart" [17]. Known today to be spread by infected mosquitoes, yellow fever was long believed to be a miasmatic disease originating from rotten vegetable matter and oth‐ er putrefying filth, and most believed the fever to be contagious. There were many de‐ bates regarding the agent that caused YF and Carlos Findlay was the first to suggest that mosquitoes transmitted the disease [8,9]. Text box 1 indicates some of the key milestones in the history of YF [18].

The earliest description of yellow fever is found in a Mayan manuscript in 1648, but by ge‐ nome sequence analysis it appears that yellow fever virus evolved from other mosquitoborne viruses about 3000 years ago [19]. Yellow fever originated in Africa and in the 1500s yellow fever virus was probably introduced into the New World via ships carrying slaves from West Africa. Epidemics soon became common in the coastal communities of South and Central America and along the southern and eastern seaboard of North America as far north as Boston. Between 1668 and 1893, there were more than 135 epidemics in the USA [17]. Large epidemics occurred throughout the 18th and 19th centuries in the Caribbean islands, the United States, Africa, Europe, West Indies, and South America.
