Causes of Yellow Fever


Contrary to the common belief, Yellow Fever does not spread from one person to the other through personal contact. This viral disease is usually contracted when a person gets bitten by an infected female mosquito that belongs to the Aedes Aegypti species. Other mosquitoes like the Aedes Albopictus (also known as the Tiger Mosquito) can also be a vector for the Yellow Fever virus. These mosquitoes have been known to thrive in and around human habitations and can breed in even the cleanest water. Though the Center for Disease Control and Prevention (CDC) has identified 45 countries that are at a risk of Yellow Fever transmission, this disease is mainly prevalent in regions of South America and Africa.

Yellow Fever affects not only humans, but monkeys as well. This means that a person can contract the disease even if there are no reported cases of Yellow Fever in an area. The virus can be transmitted back and forth between humans, monkeys or both. The cycle of Yellow Fever infection usually follows these steps:  

  • A female Aedes Aegypti mosquito bites a human or a monkey that has already been infected with Yellow Fever.
  • The virus infiltrates the mosquito’s bloodstream and settles in its salivary glands, thereby infecting it.
  • The infected mosquito passes on the virus, when it bites another human or monkey.
  • The virus enters the new host’s bloodstream, causing them to contract Yellow Fever.
One of the less-common causes of yellow fever is the direct transmission of the virus into a person's blood, through an infected needle. 
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