Yellow fever
Yellow fever

Yellow fever is a potentially deadly viral infection transmitted by infected mosquitoes. It is a flu-like disease characterized by jaundice and high body temperature. The virus damages the liver and the internal organs of the infected person and is highly fatal.

Nearly 2 lakh cases of yellow fever are reported worldwide each year as per World Health OrganizationOut of this 30 thousand deaths are occurring per year. Due to several factors such as climatic changes, reduced immunity, and urbanization, the number of people infected with the virus is increasing rapidly. So, let us understand the disease in detail to protect ourselves from getting infected.

Causes of yellow fever

A virus called the Flavivirus causes yellow fever. Mosquitoes transmit this virus from one person to the other during the bite. The disease does not spread by close contact with the infected person but can spread through blood transfusions.

People of any age can get yellow fever. But elderly patients are more at risk of getting infected.

Recognize the symptoms

The name of the disease is derived from the two main symptoms of the disease that is fever and jaundice which involves yellowing of the skin. Yellowing is due to the liver damage.

The disease develops very rapidly with symptoms occurring in three phases.

The initial phase of symptoms is evident within 3-6 days of exposure to the virus. This is the incubation period of the virus. Initial symptoms are not disease specific and are similar to those of the influenza viral infection. It includes headache, fever, chills, muscle and joint pains. However, initial symptoms are not seen in a few patients.

After the incubation period ends the acute phase begins during which the patient may experience flushing, back pain and loss of appetite in addition to the initial symptoms. This phase lasts for 3-4 days and most of the patients recover during this period. It is also considered as remission phase.

People who do not recover during the acute phase develop a more severe version of the disease called the toxic phase. Nearly 15% to 25% of the people with yellow fever enter the toxic phase and out of this nearly 50% of the patients die, while the other half can recover. During this phase, the symptoms of the acute phase reappear along with new and more serious symptoms. These include

  • Jaundice (yellowing of the skin and eyes),
  • Hepatitis (inflammation of the liver),
  • Abdominal pain,
  • Problems in the heart rhythm,
  • Seizures,
  • Shock and Multisystem organ failure
  • Delirium (a state of extreme confusion),
  • Vomiting (occasionally with blood),
  • Bleeding from the nose, eyes and mouth.

 

If you suspect that you have yellow fever, then immediately discontinue the use of aspirin and other NSAID drugs (non-steroidal anti-inflammatory drugs such as naproxen, or ibuprofen, etc.) as they can increase the risk of internal bleeding. A doctor can diagnose the disease from the symptoms and confirm the disease through blood tests to check the presence of the virus.

Is there a proper treatment available?

No treatment can cure the yellow fever. However, treatment to ease the symptoms is available. Supportive care is provided in the hospital to manage the symptoms of the disease. Additionally, the immune system enhancement is targeted during the treatment and needs hospitalization of the patient.

  • The patient will be given adequate fluids in the form of intravenous administration, to prevent dehydration. Along with this oxygen is administered to the patient.
  • Circulatory collapse can occur due to internal bleeding. Therefore, the blood pressure is monitored and maintained by giving drugs.
  • Blood lost through excess internal bleeding is replaced with transfusions. Few patients may be given plasma, rich in protein,s required for clotting of the blood.
  • In the case of kidney failure which may occur during the toxic phase, dialysis is recommended.
  • Other infections which can occur are also treated by giving antibiotics.

It is advisable that the patient stays away from mosquitoes to prevent the spread of the disease to other members around.

Taking preventive measures is the best way

Once you have encountered the disease, you will be resistant to the virus for your whole life. But to prevent the initial infection, you should get vaccinated against the virus. Children above the age of 9 months and adults who are planning to travel to countries like Africa and Latin America should get Flavivirus vaccine. A single dose of the vaccine offers protection for nearly 10 years, after which a new dose is to be taken.

Yellow fever vaccination can cause some serious side effects in few people and so it is not advisable for everyone. If you have any of the following conditions talk to your doctor before getting vaccinated:

  • Immuno-compromised system (as in HIV),
  • Cancer or thymus gland problems,
  • Pregnancy or breastfeeding,
  • Aged above 65 years,
  • Transplantations,
  • Vaccination is also not advised for patients who are allergic to eggs, chicken proteins or gelatin.

 

If you are exempted from vaccination, you can take up other measures to prevent the attack of the virus. You may use mosquito repellant or cover your legs, hands and head to prevent the mosquito bites. Avoid going outside during the peak hours of mosquitoes, that is, during the dawn and the dusk time. However, these measures are not as effective as vaccination.

There is no cure for yellow fever, prevention is the best strategy! So, get vaccinated against the virus now!

 

Reference:
  • http://www.who.int/mediacentre/factsheets/fs100/en/
  • Amanna IJ, Slifka MK2. Questions regarding the safety and duration of immunity following live yellow fever vaccination. Expert Rev Vaccines. 2016 Jun 20:1-15. [Epub ahead of print]
  • Wasserman S, Tambyah PA, Lim PL. Yellow fever cases in Asia: primed for an epidemic. Int J Infect Dis. 2016 Jul;48:98-103.

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