Yellow fever: symptoms, causes and treatment

Many diseases exist and have existed in the world throughout history. Some of them, like the Black Death, caused a plague that wiped out a large percentage of the world’s population. And the existence of serious diseases that can cause pandemics is not just a thing of the past – there are still many diseases with no known cure and with the potential for death.

One of them has caused outbreaks and epidemics in African and South American countries for centuries. It’s yellow fever, Which we will talk about throughout this article.

    Yellow fever: description and symptoms

    One of the diseases classified as hemorrhagic fevers is known as yellow fever which has caused and continues to cause hundreds of thousands of deaths each year. It is an endemic disease present mainly in regions of Africa or South America, and still today it can lead to major epidemics.

    Yellow fever, also known as black vomiting disease, Siamese disease, or Barbados disease (where the first recorded case occurred), gets its name from one of its most characteristic symptoms, jaundice caused by damage to the liver and pancreas.

    But this is not his only symptom: It is also common to bleed from the mouth, ears or eyes, internal bleeding, very high fevers, headaches, arrhythmias, hypoglycemia and if you reach more stages of intoxication than the above may appear convulsions, liver and kidney failure, even more severe bleeding. , black vomiting due to expulsion of coagulated blood, bradycardia, dehydration, delirium or coma. In severe cases, it has a high potential to cause death, and it does in a large number of cases.

    In other cases, the milder, the disease is self-limiting and does not enter its most severe phase with the potential for death.

    Phases of infection

    Yellow fever is a dangerous disease. Infection involves going through a series of phases in which the symptoms and severity of the disease vary, although not all people go through the last one. We can identify a total of three phases, To which we could add a preview in the form of an incubation period.

    Phase 0: incubation period

    From the time the bite that transmits the virus that causes it to the onset of the first symptoms occurs, it usually takes between three and six days. during them the virus spreads through the body, Without any symptoms yet.

    Phase 1: acute phase

    Several days after the bite, a series of symptoms of an infection usually appear: high fever, nausea and vomiting, photophobia, headache appearRedness of soft tissue, hot flashes, lack of appetite and jaundice.

      Phase 2. Reference

      As a rule, after several days of suffering from the symptoms described above, they usually end up remitting, gradually disappearing. In many cases, the disease can stop at this point, and the subject recovers. However, in others, the person may relapse and get worse about a day later, entering into a state of intoxication.

      Phase 3: Poisoning

      After several days of remission, some people with yellow fever enter a phase of intoxication during which symptoms reappear with great virulence. This is the most serious phase of the disease.

      During this phase, the fever returns and symptoms such as bleeding from the mouth, nose and eyes may also occur. They also usually have problems or even kidney or liver failure. In fact, it is in this phase of the disease that jaundice most often appears, giving the skin the yellowish color that gives the skin disease its name. Abdominal pain, nausea and vomiting are also common.

      It is also not uncommon for arrhythmias or bradycardia to occur. In the brain, in addition to fever, hallucinations and delusions, states of confusion and cerebral dysfunction may appear. The subject may also have seizures or go into a coma. In short, they usually occur major multi-organ errors and bleeding.

      Unfortunately, people who enter this phase (in a window of 25% to 60%) fail to overcome the disease and die.

      The causes of this disease

      Yellow fever is a viral disease, a product of infection with the yellow fever virus, which, like dengue fever, belongs to the genus Flavivirus.

      It’s a virus it reaches humans through the bite of infected mosquitoes, Usually of the genera Aedes or Haemagogus. The virus can be transmitted between monkeys and from monkeys to humans by mosquitoes in what is called the wild ecological cycle or between people in the urban ecological cycle.

      There is also a combined cycle of the previous two, that of the leaf, in which mosquitoes infected after biting monkeys transmit the disease to a human, and then after other mosquitoes bite it, they pass it on to other people. .

      Yellow fever it is not spread through contact with an infected person, Nor with its secretions.

      Is there a treatment?

      Yellow fever is a disease for which there is still no specific cure today. In case of infection, the intervention involves supportive treatments. it’s essential monitor them and keep them vital, Perform dialysis for renal failure and administer fluids to maintain hydration and electrolyte balance. In addition, the use of antipyretics to lower fever and antibiotics (not for the virus but for possible bacterial infections that may appear during it) can be very helpful.

      Although there is no cure per se, we have an effective vaccine against yellow fever, being in principle necessary a single dose to protect oneself for life. This is why the best way to treat yellow fever is to prevent it, if necessary. establish vaccination programs in countries where the disease is endemic and get vaccinated in case you travel to these countries. Another measure is based on mosquito population control, a measure that has proven effective in several countries.

      However, the vaccine may be contraindicated or require a medical evaluation prior to its application in certain sectors of the population: pregnant women (except at high risk), under 9 months and over 60 years, except in cases of high risk) and immunocompromised or ovum – allergic subjects and derivatives.

      There are currently several initiatives aimed at controlling yellow fever, such as the EYE program organized by the cooperation between the World Health Organization, UNICEF and Gavi-alliance for vaccines. This program aims to protect, prevent and control possible outbreaks of fever by participating in vaccination campaigns, research, health promotion and interaction with local institutions and administrations.

      Bibliographical references:

      • World Health Organization. (2014) Yellow fever. Small bites of big threats.
      • Soteras, I. (sf). Yellow fever. World Health Organization [Online]. Available at: http://www.who.int/es/news-room/fact-sheets/detail/yellow-fever.

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