What is yellow fever and how is it transmitted?

Yellow fever is a viral diseasehemorrhagic and acute. It is called “yellow” because one of its symptoms is jaundice or yellow skin, which some patients suffering from this disease present.

yellow fever it is transmitted by a mosquito carrying the virus. This is endemic to tropical parts of Africa and Central and South America. The main preventive measure against this disease is the vaccine.

Only a small percentage of yellow fever patients have severe symptoms.. Of these, half die between 7 and 10 days after contracting the disease. Therefore, it is an evil that can be fatal and against which all precautions must be taken.

What is yellow fever

Yellow fever is also known as “black vomit disease” or “American foulbrood”. According to the World Health Organization, Approximately 200,000 cases of this disease occur each year. These give rise to about 30,000 deaths in the same period.

The first Historical records of this disease date back to the time of the Maya.. In this culture there was talk of a disease that first struck monkeys and then man, and was characterized by a yellowing of the skin, similar to jaundice.

THE epidemics Yellow fever occurs when three conditions are met. The first is that an infected person introduces the virus into densely populated areas. Secondly, these areas have a high population of transmitting mosquitoes. And third, that the vast majority of people in that area are not vaccinated.


Yellow fever and its transmission
It takes a vector bite to be infected with yellow fever. This is possible only in some countries of the world.

The yellow fever virus is a arboviruses such Flaviviruses. Its transmission occurs through the mosquitoes of genera aedes AND Hemogogue. Some of these species live near houses, others in jungle areas, and still others in both habitats.

The yellow fever transmission mechanism is activated when a mosquito of the aforementioned species bites a sick person. In this way the mosquito becomes infected. Then that same mosquito bites another individual and then transmits the disease.

There are three transmission cycles for yellow fever. These are:

  • jungle. It is the type of transmission that basically occurs from one monkey to another. These cases take place in the jungle. It usually only affects a few humans, if they are in the area.
  • Intermediate. In this case, the yellow fever virus is transmitted from monkey to human and from human to human. This type of transmission is very common in small African villages.
  • urban. It occurs when the virus is transmitted from person to person, in large population concentrations. If individuals are not vaccinated, the potential for an epidemic is very high.

yellow fever symptoms

Yellow fever causes liver failure
The yellowish discoloration of the skin and mucous membranes, medically known as jaundiceit is common in yellow fever.

The symptoms of yellow fever are complex. After the mosquito bite, there is a incubation period, which lasts from 3 to 6 days.

There are no symptoms during this stage. Then the patient enters a new stage, called acute phase. During the acute phase there are symptoms such as fever, headache, body achesnausea and vomiting, dizziness, sensitivity to light, loss of appetite and redness of the face, eyes or tongue.

In some cases, the symptoms disappear after a few days. In other cases the patient enters the toxic phase which is very dangerous. It is when jaundice or yellowish color appears on the skin. There is also very strong vomiting, sometimes with blood.

There is also abdominal pain, bleeding, slow heart rate, liver and kidney failure, delusions, confusion, and sometimes coma. Up to half of cases that enter the toxic phase end in death..


The best form of prevention for yellow fever is the vaccine.. This offers effective immunity in up to 99% of cases, provided it was applied at least 30 days before contracting the virus. A single dose can prevent disease for life.

Anyone traveling to areas with potential yellow fever infection should be vaccinated. Although progress has been made against the disease, it is still present in many regions of the world.

In any case, if the person is not vaccinated and contracts the virus, good hospital care is able to reduce the risk of mortality. The important thing is to go to the health center as soon as the first symptoms are detected.

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