Question

The vector for yellow fever is…….

Answer 1

Hint: A vector is an organism which does not itself cause any disease but transmits the pathogen from one host to another. Example: Species of mosquito, serve as vectors for various diseases like deadly disease Malaria. In gene therapy, a virus is used as a vector, it is re-engineered and helps in delivering genes to the target cells.

Complete solution:
Yellow fever virus has RNA as genetic material and it belongs to the genus Flavivirus. It shows similarities with West Nile, St. Louis encephalitis, and Japanese encephalitis viruses.
This spread of this virus is caused mainly through the bite of infected Aedes mosquito or Haemagogus species of mosquitoes. Mosquitoes acquire this virus by sucking the blood on infected primates (human or non-human) and then can transmit the virus to other primates (human or non-human).
People infected with yellow fever virus (referred to as being "viremic") spread infection to mosquitoes only during a particular period which is a few days before the onset of fever and 5 days after onset of fever.
Yellow fever virus has three transmission cycles:
jungle (sylvatic),
inter­mediate (savannah),
Urban cycle.
The jungle (sylvatic) cycle:
In this the virus is transmitted from non-human primates (e.g., monkeys) to the mosquito species which are found in the forest canopy. The virus is then transmitted by mosquitoes to humans, when humans come in contact with the infected mosquito.

So the vector for yellow fever virus is the Aedes mosquito.

Note:
In Africa, an intermediate cycle also exists which involves transmission of virus from mosquitoes to those humans who are living or working in jungle border areas. In this cycle, the virus can spread directly from monkey to human or from human to human by the help of mosquitoes vector.The urban cycle involves trans­mission of the virus from viremic humans who were infected in the jungle to the mosquitoes living in urban areas primarily Aedes aegypti.