What is yellow fever characterized with? Read the article to prevent this dangerous infection.
What's yellow fever and how bad is it? Yellow fever is an acute viral disease, which is transferred by mosquitoes. It is characterized by heavy changes in blood, high temperature of body, damage of liver and kidneys.
Yellow fever history
For the first time yellow fever virus was described in 1647-1648 during epidemic outbreak of illness in Caribbean region where the activator was delivered from Africa. In the next centuries in America, Africa and even Europe the illness accepted character of heavy epidemics with a high lethality quite often. The largest epidemics were observed the beginning of the 20th century during construction of Panama Canal, when about 10 000 people died from this illness. In the 1950th years in America more than 1.5 thousand patients were mentioned, and in 1960-1962 in Ethiopia were more than 200 000 patients and more than 30 000 dead.
Transfer of yellow fever mosquito was established by Cuban doctor C. Finlay in 1881. 20 years later, in 1901, American researchers under the leadership of Major W. Reed allocated a virus in Cuba. In experiments on volunteers, they have proved its transfer by Aedes mosquitoes. In 1933, A. Stokes in Ghana and D. Sooper in South America established a natural origin of the illness. Development and implementation of actions for a fight against mosquitoes considerably promoted restriction of disease distribution.
Yellow fever countries
According to the latest data, annually in the world there are 200 000 cases of yellow fever, 30 000 of which (it is about 90%) come to end with death in Africa.
This virus is epidemical in tropical regions of Africa and Latin America with general population more than 900 million people.
In Africa, 508 million people living in 31 countries are exposed to risk. Other population, which put lives in risk, lives in 13 countries of Latin America. Bolivia, Brazil, Colombia, Peru and Ecuador are exposed to the greatest jeopardy.
Insignificant number of delivered cases comes in countries free from yellow fever. In spite of the fact that this illness was never registered in Asia, this region is exposed to risk, as there are conditions necessary for transmission of infection in it.
For the last two decades the number of cases of yellow fever has increased as a result of decreasing immunity of population to the infection, deforestation, urbanization, population shift and climate change.
Yellow fever symptoms
The following symptoms are characteristic for the initial stage:
- Temperature of body increases to 40 degrees. Usually to third day temperature falls down (it can keep till 8 days). Then it increases again, but doesn't reach initial values;
- Fever and headache;
- Pain in muscles of back, legs and hands;
- Nausea and vomiting;
- Reddening of face and top part of trunk;
- Puffiness of eyelid, swelling of lips, yellowness;
- Mucous of mouth and tongue get bright red color;
- Patients have sleeplessness and speeded-up pulse;
- Liver and a spleen are increased and painful;
- From the beginning of yellow coloring of whites of eyes decreases arterial pressure. Then skin gets blue coloring;
- There are nasal bleedings, bleeding of gums;
- At the final stage of development of initial stage, two outcomes are possible: lethal or transition of disease to remission stage.
Remission is characterized with:
- Improvement of general state;
- Puffiness and high temperature of body fall down;
- In several hours, condition of patient sharply worsens. This is a sign of transition of disease in the next period.
These signs are characteristic for this period:
- Development of yellowness;
- Intestinal bleedings;
- Arterial pressure falls;
- Low pulse – to 40 beats per minute;
- Kidneys are affected.
Yellow fever treatment
Special treatment of yellow fever doesn't exist. It is possible to carry out only symptomatic therapy for prevention dehydration and decrease in temperature. Symptomatic therapy can promote improvement of results for seriously ill patients, but in poor regions, such therapy is available seldom.
Yellow fever vaccine is the most important measure for prevention of this disease. The vaccine is safe, available and is highly effective. It provides protection within 30-35 years. Vaccine provides effective immunity in a week after immunization for 95% of people.