Dengue & Yellow Fever
Here’s a couple of Flaviviruses to watch out for.
There is an estimated 100 million cases per year and over 2.5 billion people at risk – virtually every country between the tropics of Capricorn and Cancer is now affected. 4 serotypes, and it is unusual to note that among the arboviruses (transmitted by Aedes mosquitoes) the humans are the natural hosts. Dengue fever (DF) is also known as ‘breakbone fever’ and. Although we know DF to have been around for many hundreds of years; it appears that Dengue Haemorrhagic Fever (DHF) emerged as an apparently new disease in SE Asia.
Symptoms include retro-orbital pain (pain behind the eye), a phobia of bright light, severe muscle pain, lymphadenopathy and, 50% of the time a rash presents. Bleeding manifestations may also show, although the more severe typically occur in children exposes to repeated infection although stroke and other major bleeds may complicate infection in adults.
There are no specific anti-viral treatments for Dengue and vaccines are only in the trial phases. The vaccine candidate furthest to progress through clinical trials, called CYD-TDV, still has not shown the protective efficacy desired.
This website is particularly helpful on the matter: http://www.denguevaccines.org/why-a-vaccine
Yellow Fever Virus
This is naturally transmitted between primates and various mosquitoes throughout Central America and Africa. Aedes aegypti transmits the virus to humans in urban cycles. It’s called ‘Yellow Fever’ because in severe disease, jaundice can be induced. Fulminant hepatic failures and gastrointestinal failure also occurs in severe disease.
The good news is that there is a highly effective vaccine, called 17D, which is a live-attenuated vaccine. It appears to provide protection for 30 – 35 years or more.
Border Cross (January, 2015)