Table of contents:
- Definition
- What is yellow fever?
- How common is yellow fever?
- Symptoms
- What are the signs and symptoms of yellow fever?
- When should I see a doctor?
- Before traveling
- After traveling
- Cause
- What causes yellow fever?
- How is yellow fever transmitted?
- Risk factors
- What increases my risk for yellow fever?
- Diagnosis
- How do doctors diagnose yellow fever?
- Treatment
- What are my treatment options for yellow fever?
- What are some lifestyle changes or home remedies that can be done to treat yellow fever?
- Prevention
- What precautions can I take to avoid yellow fever?
- Vaccinations
- Protection from mosquito bites
- Vector control
- Epidemic preparedness and response
Definition
What is yellow fever?
Yellow fever or yellow fever is an acute viral hemorrhagic disease transmitted by mosquitoes. The word "yellow" in the term refers to jaundice which affects some patients.
The viruses that cause this condition are found in tropical areas of Africa and South and Central America. When infected in humans, the yellow fever virus can damage the liver and other internal organs and can be fatal.
How common is yellow fever?
A total of 47 countries in Africa and South and Central America are endemic areas for this condition. According to WHO data-based research, there were 84,000-170,000 cases of severe yellow fever and 29,000-60,000 deaths.
Sometimes, tourists visiting the area may carry the disease to other countries. To prevent transmission, many countries ask for a yellow fever vaccination alert before issuing a visa. Especially if tourists come, or have visited a yellow fever endemic area.
WHO also estimates 200,000 cases of yellow fever worldwide each year. Yellow fever is increasing due to decreased immunity to infection in local populations, deforestation, climate change and high urbanization.
In the last century (17 to 19), this condition has spread to North America and Europe. It caused massive outbreaks that disrupted economies, development, and devastated populations (in some cases).
Yellow fever can be treated by reducing risk factors. Talk to your doctor for more information.
Symptoms
What are the signs and symptoms of yellow fever?
The name yellow fever comes from its 2 main symptoms: fever and yellowish skin. Yellowing occurs due to liver damage, hepatitis. In some people, yellow fever has no early signs, but for some others, the initial symptoms appear 3 to 6 days after exposure to the virus from a mosquito bite.
If the infection has entered an acute phase, you may experience signs and symptoms such as:
- Fever
- Headache
- Muscle pain, especially in the back and knees
- Sensitive to light
- Nausea, vomiting or both
- Loss of appetite
- Dizzy
- Red eyes, face, or tongue.
These signs and symptoms usually improve and go away within a few days.
Although signs and symptoms may disappear 1 or 2 days after the acute phase, some people with acute yellow fever enter the toxic phase. In this phase, acute signs and symptoms return, even worsen and endanger lives, such as:
- Yellowing of the skin and whites of the eyes
- Abdominal pain and vomiting, sometimes blood
- Less urination
- Bleeding from the nose, mouth and eyes
- Slow heartbeat (bradycardia)
- Liver and kidney failure
- Brain dysfunction, including delirium, seizures and coma.
The toxic phase of yellow fever can be fatal and result in loss of life.
There may be signs and symptoms not listed above. If you have concerns about a particular symptom, consult your doctor.
When should I see a doctor?
Before traveling
- Four weeks or more before your trip, make an appointment with your doctor if you are going to an area where yellow fever is present, so that you can discuss whether you need the vaccine.
- If you have less than 4 weeks to prepare, keep in touch with your doctor. Ideally, you can still be vaccinated for at least 3 to 4 weeks before traveling to an area where yellow fever is present, to give the vaccine time to work. Your doctor will help you determine if you need the vaccine and can provide instructions on how to stay healthy while abroad.
After traveling
- Seek medical care immediately if you have recently traveled to an area where there is yellow fever and you experience signs or symptoms of the intoxication phase of yellow fever.
- Call your doctor if you experience mild symptoms after traveling to an area where yellow fever is present.
Cause
What causes yellow fever?
Yellow fever is usually transmitted to humans through the bite of an infected mosquito. Humans cannot spread yellow fever through casual contact, although it can be transmitted through blood with contaminated needles.
Several species of mosquitoes carry the yellow fever virus, some thrive in urban areas, some in forest areas. The mosquitoes that thrive in the forest also transmit yellow fever to the monkeys which are the hosts of the disease.
How is yellow fever transmitted?
The yellow fever virus is an arbovirus from the flavivirus genus that is transmitted by mosquitoes with Aedes and Haemogogus . Mosquito species live in a variety of habitats, some around the house (domestic), in the forest (wild), and in both (semi-domestic).
There are three types of transmission cycles, namely:
- Yellow fever sylvatic (or forest)
In tropical rainforests, monkeys, which are the main source of yellow fever, are bitten by wild mosquitoes of the Aedes species and Haemogogus , which transmits the virus to other monkeys. Sometimes, humans who work or travel into the forest are bitten by infected mosquitoes and contract the disease.
- Yellow fever intermediate
In this type of transmission, the demi-domestic mosquito infects monkeys and humans. Increased interaction between humans and infected mosquitoes leads to increased transmission.
Epidemic development can occur in many separate villages. This is the most common type of plague in African countries.
- Urban yellow fever
Major epidemics arise when infected humans carry the virus into densely populated areas with high densities of mosquitoes Aedes aegypti . It can be made worse when most people have low or non-existent immune systems because they have never been vaccinated or have been exposed to yellow fever.
In this condition, the infected mosquito transmits the virus from human to human.
Risk factors
What increases my risk for yellow fever?
You may be at risk if you travel to an area where mosquitoes carry the yellow fever virus. These areas include sub-Saharan Africa and South and North America.
Even though there are no recent reports of humans being infected in the area, that doesn't mean you are free from risk. It may be that the local population has been vaccinated and protected against the disease, or that cases of yellow fever have not been officially detected and reported.
Anyone can be infected with the yellow fever virus (yellow fever), but adults have a greater risk of developing severe disease.
Diagnosis
How do doctors diagnose yellow fever?
Diagnosing yellow fever based on signs and symptoms is difficult because at the beginning of this condition, the infection can mimic the symptoms of malaria, typhus, dengue fever, and other hemorrhagic fevers.
To diagnose your condition, your doctor will:
- Ask about your medical and travel history
- Take a blood sample for testing
Polymerase chain reaction (PCR) tests in your blood and urine can sometimes detect the early stages of the disease. In a later stage, tests of the immune system are needed (ELISA and PRNT).
Treatment
The information provided is not a substitute for medical advice. ALWAYS consult your doctor.
What are my treatment options for yellow fever?
There is no antiviral treatment proven to treat yellow fever. Treatment usually includes supportive care in the hospital, such as:
- Provides fluids and oxygen
- Maintain normal blood pressure
- Replace blood loss
- Provides dialysis for kidney failure
- Overcoming other infections that appear
- Some people receive plasma transfusions to replace blood proteins that trigger blood clots.
If you have yellow fever, your doctor will recommend that you stay indoors, away from mosquitoes, to avoid spreading the disease.
If you have had yellow fever, you will be immune to the disease for the rest of your life.
What are some lifestyle changes or home remedies that can be done to treat yellow fever?
Although there is no specific treatment for yellow fever, supportive home care is not recommended. Visitors to areas where yellow fever is endemic are also at risk for other dangerous conditions and should seek primary care immediately if fever occurs. Apart from yellow fever, malaria can appear up to 1 year later, regardless of prevention.
There are no effective home remedies for yellow fever, and patients should seek medical help immediately and follow directions carefully.
Prevention
What precautions can I take to avoid yellow fever?
Here are some precautions that might lower your risk of getting yellow fever:
Vaccinations
Vaccination is the most important thing in preventing yellow fever. The yellow fever vaccine is safe, easy, and at a low dose that can protect you from the disease in the long term. High doses of this vaccine are not required.
Several vaccination strategies are used to prevent yellow fever and its transmission. Routine infant immunization and vaccination campaigns are undertaken to increase protection in countries at risk.
In high-risk areas where vaccination rates are low, rapid introduction and control of outbreaks using mass immunization is essential. It is important to vaccinate most of the population at risk to avoid regional outbreaks.
People who are usually discouraged from getting vaccinated are:
- Infants under 9 months of age.
- Pregnant women, unless there is an outbreak of yellow fever and the risk of infection is high.
- People with a severe allergy to egg protein.
- People with severe immune deficiency due to symptoms of HIV / AIDS or other causes, or who have a thymus disorder.
Protection from mosquito bites
In addition to getting the vaccine, you can help protect yourself from yellow fever by protecting yourself from mosquitoes. Here's how:
- Avoid unnecessary outdoor activities when mosquitoes are active.
- Wear long sleeves and trousers when you are traveling to mosquito-infested areas.
- Stay in an air-conditioned room or one with a good air filter.
- If your accommodation does not have air circulation or air conditioning, use a mosquito net. An insecticide treated needle offers additional protection.
To ward off mosquitoes with mosquito repellents, use the following two things:
- Mosquito repellent for items
Use a mosquito repellent containing permethrin on your clothes, shoes, camping gear and mosquito nets. You can also buy camping clothes and gear that come with permethrin. Permethrin should not get on your skin.
- Anti-mosquito for skin
Products with active ingredients, such as DEET, IR3535, or picaridin allow long-term skin protection. Choose the concentration according to the duration of protection you need. The higher the concentration, the longer the effect will be seen.
Remember that chemical repellents can become myopic. Use sparingly as needed when you are outside.
Do not use DEET on the hands of young children or infants under two months of age. You can protect your child with a mosquito net or cover.
Vector control
The risk of yellow fever being transmitted in urban areas can be reduced by eliminating the breeding potential of mosquitoes, including by applying larvicides to water storage containers and places where water is stagnant.
Vector control and control are components of prevention and control that are transmitted by vectors, especially for the control of transmission in epidemic situations.
For yellow fever, vector surveillance targets Aedes aegypti and other Aedes species. This will help pinpoint where there is a risk of an urban outbreak.
Understanding the spread of mosquitoes within a country allows that country to make a priority for increasing surveillance, screening, and exercising vector control over specific areas.
Currently, there are limited health warehouses that provide safe, efficient, and cost-effective insecticides. This is due to the main vector resistance to common insecticides. It may also be due to security reasons or high registration fees.
Epidemic preparedness and response
Fast yellow fever detection and rapid response through emergency vaccination campaigns are essential to control the outbreak.
WHO recommends that countries at risk have at least one national laboratory that provides a blood test for yellow fever. Confirmed cases of yellow fever in an unvaccinated population are considered epidemic.
Cases that are confirmed in any context must be fully investigated. Investigative teams must assess and respond to outbreaks with emergency measures and a long-term immunization plan.