Yellow fever: symptoms, causes and treatment

This serious disease is transmitted through mosquito bites.

There are many diseases that exist and have existed in the world throughout history. Some of them, such as the Black Death, were a plague that wiped out a high percentage of the world's population. And the existence of serious diseases capable of causing pandemics is not just a thing of the past: there are still many diseases with no known cure and potentially fatal.

One of them has been causing outbreaks and epidemics in African and South American countries for centuries. This is yellow feverWe are going to talk about it in this article.

Yellow fever: description and symptoms

Yellow fever is one of the diseases classified as hemorrhagic fevers, which has caused and continues to cause hundreds of thousands of deaths each year. It is an endemic disease present mainly in African or South American areas, and even today it can still cause major epidemics. 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 the alteration of the liver and pancreas.

But this is not its only symptomIt is also common the presence of bleeding through the mouth, ears or eyes, internal bleeding, very high fevers, headaches, arrhythmias, hypoglycemia and if you reach stages of intoxication in addition to the above may appear convulsions, liver and kidney failure, even more severe bleeding, black vomiting due to expulsion of clotted blood, bradycardia, dehydration, delirium or coma. In severe cases it has a high potential to cause death, and does so in a high number of cases.

In other, milder cases, the disease is self-limiting and does not enter its most severe life-threatening phase.

Phases of infection

Yellow fever is a dangerous disease. Infection involves a series of phases in which the symptoms and severity of the disease vary, although not all people go through the last of these phases. A total of three phases can be identifiedto which we could add a previous one in the form of an incubation period.

Phase 0: Incubation period

From the time of the bite that transmits the virus that causes it until the appearance of the first symptoms, between three and six days usually elapse. During these days the virus is spreading through the organismwithout any symptoms appearing for the time being.

Phase 1: Acute phase

Several days after the bite, a series of symptoms typical of an infection usually appear: high fevers, nausea and vomiting, photophobia, headache, reddening of soft tissuesThe symptoms of the infection include high fevers, nausea and vomiting, photophobia, headache, reddening of soft tissues, flushing, lack of appetite and jaundice.

Phase 2. Remission

As a general rule, after several days of suffering from the symptoms described above, they usually subside and gradually disappear. In many cases the disease can stop at this stage, and the subject can recover.. However, in others the person may relapse and worsen again about a day later, entering the intoxication phase.

Phase 3: Intoxication

After several days of remission, some of those affected by yellow fever enter into a phase of intoxication in which symptoms reappear with great virulence.. This is the most severe phase of the disease.

During this phase, fever reappears and symptoms such as bleeding from the mouth, nose and eyes may also occur. There may also be problems or even kidney or liver failure. 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 disease its name. Pain in the abdomen, nausea and vomiting are also frequent.

Arrhythmias or bradycardia are not uncommon. At the cerebral level, in addition to fever, hallucinations and delirium, states of confusion and cerebral dysfunctions may appear. It is also possible that the subject may present convulsions or go into coma. Ultimately, there are often multiorgan failure and major hemorrhage may occur..

Unfortunately, about 25%-60% of the people who reach this stage do not manage to overcome the disease and die.

Causes of this disease

Yellow fever is a viral disease caused by infection with the yellow fever virus, which, like the viruses that cause diseases such as dengue fever, belongs to the Flavivirus genus.

This virus reaches humans through the bite of infected mosquitoes, generally of the Aedes genusgenerally of the Aedes or Haemagogus genera. The virus can be transmitted between monkeys and from monkey to human by mosquitoes in what is known as the jungle ecological cycle or between people in the urban ecological cycle.

There is also a combined cycle of the two previous ones, that of the sheet, in which infected mosquitoes, after biting apes, transmit the disease to humans and then, after biting other mosquitoes, transmit it to other people.

Yellow fever is not spread by contact with an infected person or their secretions.or their secretions.

Is there any treatment?

Yellow fever is a disease for which there is still no specific curative treatment. In case of infection, the intervention involves supportive treatment. It is essential to monitoring and maintenance of vital signs is essential.The use of dialysis in case of renal failure and the administration of fluids to maintain hydration and electrolyte balance. In addition, the use of antipyretics to reduce fever and Antibiotics (not for the virus but for possible bacterial infections that may appear during the illness) can be very useful.

Although there is no cure per se, we do have an effective vaccine against yellow fever, and in principle a single dose is necessary to protect for life. This is why the best way to treat yellow fever is to prevent it, and it is necessary to vaccination programs in countries where yellow fever is endemic, and vaccination in the case and to be vaccinated in case of traveling to those 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 medical evaluation prior to its application in some sectors of the population: pregnant women (except in high-risk situations), children under 9 months and over 60 years of age (also unless there is a high risk) and immunocompromised subjects or those allergic to eggs and egg derivatives.

At present, there are several initiatives to control 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 yellow fever through participation in vaccination campaigns, research, research, education and training. vaccination campaigns, research, health promotion and interaction with and interaction with local institutions and administrations.

Bibliographic references:

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