In the mild yellow fever cases the only symptoms are mild fever and headache lasting for a few days, but in the more severed cases there is severe headache, backache, and high fever, followed by jaundice and vomiting (often black vomit), and diarrhoea. The death rate varies from epidemic to epidemic. In the 1940 Sudanese epidemic the death rate was 10 per cent. One attack is followed by lifelong immunity.
Cause. A virus.
Source. The disease is endemic in monkeys, but it is very mild among them. It is from these that most epidemics or sporadic cases originate.
Yellow Fever Route
The yellow fever virus can be found in the blood of an infected monkey or of an infected human being. A mosquito biting either of these may then bite someone else and thus convey the disease.Sporadic cases occur in people living near forests, when a man is bitten by a mosquito which has previously bitten an infected monkey (jungle yellow fever). When, however the disease reaches a more quickly populated areas, or a town, then it is transmitted from man to man by the mosquito, and in this case the mosquito is usually one particular species called Aedes aegypti (urban yellow fever).
Yellow Fever Susceptibles. Any person living in a yellow fever zone who has not had an attack previously, and has not been vaccinated against yellow fever.
Yellow Fever Prevention
1. Control of the mosquito, especially in cities.2. Yellow fever vaccination. There is a vaccine which has to be administered only once every 10 years, subcutaneously. The vaccine confers absolute protection. It is not in mass use in some parts of the world like East Africa, because of the very few cases reported there. It is, however, necessary for anyone in a yellow fever zone (including places like East Africa) who is going abroad to be vaccinated, and to obtain an international certificate.
It is also necessary for everyone entering a yellow fever zone for the first time to be vaccinated and obtain a certificate.
The main concern about yellow fever is to prevent its spreading to India and the Far East, where there are both monkeys and mosquitoes which would be capable of carrying it (receptive areas).
Something you need to know: Until the coming of aeroplanes it was never possible for yellow fever to spread to the East, because of the short incubation period, but with modern methods of air travel, a sufferer could easily take it to the East and cause a terrible epidemic there. Thus, a further precaution the insides of all aeroplanes in the tropics are sprayed with DDT before the doors are opened on landing.
Yellow Fever Treatment
There is no specific treatment, but complications are treated as they arise. Patients should be nursed under a net in bed during the acute stage, to prevent them infecting other mosquitoes, thus causing another muliplications of yellow fever infections.
