Yellow fever is a serious infectious disease that can be transmitted by the bite of two types of mosquitoes, Aedes Aegypti or Haemagocus Sabethes . This disease causes symptoms like abdominal pain, headache and fever and should be treated in order to relieve the symptoms.
Here are the 10 most common doubts regarding this disease:
1. When to take the vaccine?
The yellow fever vaccine is indicated for all people living in areas at risk, such as the northern region of Brazil and some countries in Africa, but it must also be taken by people wishing to travel to these places, who work with rural tourism or who need to enter the forest of these regions and have never been vaccinated.
The vaccine can be taken 10 days before the trip to areas at risk of transmission of the disease, such as Brazil and Africa, and can be applied from 9 months of life. The vaccine is contraindicated to pregnant, immunocompromised, individuals with weakened immune systems, and people allergic to egg yolk. More information: Vaccine against yellow fever.
In 2018, the fractional vaccine, which contains 1/10 of the full vaccine dose and protects for 8 years, was also released. This measure is implemented when there is an epidemic of the disease to allow more people to be vaccinated.
2. What reactions can occur to the yellow fever vaccine?
Reactions to the vaccine are rare, but side effects such as skin rash, muscle pain, seizures, headache, fever, and general malaise may occur. The injection site usually gets sore, but putting a pebble of ice on the spot, doing a gentle massage helps relieve this discomfort.
3. What are the symptoms and when do they appear?
Symptoms of yellow fever include fever, headache, chills, nausea, vomiting, body aches, yellowing of the skin and eyes and bleeding gums and nose, dark stools and bloody urine. These symptoms appear between 3 and 7 days after being bitten by the mosquito. Learn more in Yellow Fever Symptoms.
In the most severe cases, symptoms such as heart problems, kidney and liver diseases and bleeding may occur. In severe forms, if the person does not receive medical assistance, he may die and must stay in the hospital for treatment.
4. What is the relationship between yellow fever and monkeys?
Gibbon type monkeys, which are very common in Brazil, are often affected by the yellow fever virus. So when the virus is circulating in your blood and it is stung by the mosquito Haemagogus Sabethes, it becomes infected and transmits the disease when it stings man.
5. Does yellow fever pass from one person to another?
The transmission of yellow fever is not made from individual to individual, as it is transmitted only by contaminated mosquitoes.
6. Why does the skin turn yellow?
The skin becomes yellow because the virus affects the liver preventing blood clotting factors from forming and increases the amount of bilirubin in the blood. As this bilirubin is yellow, its accumulation in the skin and eyes causes them to become yellow.
7. What is the difference between dengue fever and yellow fever?
Dengue fever and yellow fever are caused by different viruses and, therefore, dengue is only transmitted by Aedes Aegypti, while yellow fever can be transmitted by mosquitoes Aedes Aegypti or Haemagogus Sabethes.
In addition, the first symptoms of yellow fever are usually fever, vomiting and back pain, and early signs of dengue include joint pain, red patches on the skin, diarrhea and generalized tiredness. Both diseases can be prevented through vaccination and protective measures such as the use of repellents.
8. How is the treatment done?
The treatment for yellow fever is only to alleviate the symptoms that the disease causes through analgesic and antipyretic drugs that do not contain acetylsalicylic acid, which could lead to the death of the patient, and requires hospitalization to prevent the disease from developing into more severe cases.
9. What is the difference between wild and urban yellow fever?
There are two types of yellow fever:
- Wild yellow fever: It is transmitted by the bite of the mosquito Haemagogus Sabethes, which stings the monkey Gibbon, which often has the virus circulating in the blood, and then it stings the man;
- Urban yellow fever: It is transmitted by the bite of the mosquito Aedes aegypti, the same one that transmits dengue, but there are no cases registered in Brazil since 1940.
This indicates that for more than 70 years there are no cases of urban yellow fever in the country, and all recorded cases are of wild-type yellow fever.
10. When can the yellow fever vaccine fail?
Although rare, the yellow fever vaccine may fail and this may happen by reaction or because the vaccine did not work.
The reaction happens when the vaccine activates the immune system with a weakened virus, that is, it causes the person to develop a picture similar to that of the disease. Because of this possibility of reaction to the vaccine, it is not indicated people over 60 years or with diseases that compromise the immune system take it without medical recommendation.
Another case that characterizes vaccine failure is when the vaccine does not activate the immune system, and may be because of the immunity of the person who was very low at the time of the vaccine, because of a pre-existing infection with the same virus present in the vaccine or because the vaccine was taken when there was an infection developing in the person (incubation period).
