Before the discovery of the mode of transmission by Aedes aegypti mosquito in 1900 the Yellow fever was causing major epidemics in the Americas (North America and South America), Africa, and Europe. Despite the availability of an effective and safe vaccine for yellow fever, several hundred jungle yellow fever cases occur in South America every year, and thousands of jungle as well as urban cases of yellow fever occurs each year in Africa.

What is the causative agent of Yellow fever?

Yellow fever is caused by Yellow fever virus, a flavivirus. Yellow fever virus belongs to Flaviviridae family.

How yellow fever is transmitted?

Yellow fever is commonly transmitted by bite of Aedes aegypti mosquito. An urban cycle and a jungle cycle or sylvatic cycle (in Africa) of yellow fever virus exist, which involve Aedes mosquitoes and monkeys. Aedes aegypti mosquito is originally an African species, but has spread to other parts of the world.

What is Yaws?

Yaws is endemic or non venereal (not a sexually transmitted disease) treponematosis, which is caused by close relatives of Treponema pallidum (etiological or causative agent of venereal syphilis) subspecies pallidum. Other endemic or non venereal treponematoses are pinta and endemic syphilis. The difference of these endemic or non venereal treponematoses from venereal syphilis, can be made by the mode of transmission (syphilis is a sexually transmitted disease or STD and other are non-sexually transmitted), age at which these are acquired, geographic distribution, and clinical manifestations. The endemic or non venereal treponematoses are generally seen in rural areas of developing countries and due to that, these diseases are not studied well and diagnosis or treatment of these infections may be very difficult in absence of any well conducted study or any guideline on diagnosis or treatment.