Yellow fever reach the stomach of the mosquito, and if the virus concentration is high enough, the virions can infect epithelial cells and replicate there. From there, they reach the haemocoel (the blood system of mosquitoes) and from there the salivary glands. When the mosquito next sucks blood, it injects its saliva into the wound, and the virus reaches the bloodstream of the bitten person. Transovarial and transstadial transmission of the yellow fever virus within "A. aegypti", that is, the transmission from a female mosquito to her eggs and then larvae, are indicated. This infection of vectors without a previous blood meal
History of yellow fever The entire Mississippi River Valley from St. Louis south was affected, and tens of thousands fled the stricken cities of New Orleans, Vicksburg, and Memphis. An estimated 120,000 cases of yellow fever resulted in some 20,000 deaths. Memphis suffered several epidemics during the 1870s, culminating in the 1878 epidemic (called the Saffron Scourge of 1878), with more than 5,000 fatalities in the city. Some contemporary accounts said that commercial interests had prevented the rapid reporting of the outbreak of the epidemic, increasing the total number of deaths. People still did not understand how the disease developed or was transmitted, and