West Nile Virus infection: all you need to know

West Nile Virus infection

West Nile Virus is the leading cause of mosquito-borne disease. It is most commonly spread to humans by the bite of infected mosquitos. Most people infected by West Nile Virus either do not show any symptoms or have some mild symptoms like headache and fever. There is no development of a vaccine or medication to treat the West Nile Virus infection.

What is West Nile Virus?

West Nile virus is a positive sense, single-stranded RNA virus that causes West Nile fever. It belongs to the flavivirus genus which also contains the Zika virus, dengue virus, and yellow fever virus. Its genome is approximately 11,000 nucleotides long (genome is the complete set of DNA or RNA in an organism) and flanked by 5′ and 3′ non-coding stem-loop structure.

Like most other flaviviruses it is also an enveloped virus with icosahedral symmetry. WNV is a 45-50 nm virion covered with a relatively smooth protein shell. The RNA genome is bound to capsid proteins which are 105 amino acid residues long to form the nucleocapsids. Actually, the second big part of a virus is the protein coat to protect itself. That coat is called the capsid. The capsid protects the core and helps in infecting the other new cells surrounding them. Some viruses have another coat or shell called an envelope.

The natural host of West Nile Virus is the birds and mosquitoes. Over 300 species of birds have been found infected by the virus such as the American crow, Blue Jay, etc. And it has also been found in large species of the mosquitoes but the most significant for the viral transmission is the Culex Species that are feed by birds.

west nile virus transmission

The causes of West Nile Virus was explored by Dr. Robyn Klien at Washington University in St. Louis. She found out that the West Nile Virus infection increases cytokines and chemokines in the blood, making the blood brain barrier more leaky and susceptible to infection.

Symptoms of West Nile Virus

Most people infected with West Nile Virus do not get sick and 1 out 5 human show mild symptoms like fever and other symptoms.

Mild infection symptoms

  • Fever
  • Headache
  • Body aches
  • Vomiting
  • diarrhea
  • fatigue
  • skin rash

Serious infection Symptoms

Less than 1% of people get serious infection by the virus i.e., neurological infection, inflamation of the brain and of the membrane of the brain and spinal cord.

  • High fever
  • severe headache
  • neck stiff
  • Disorientation and confusion
  • stupor or coma
  • Tremors and muscle jerking
  • seizures
  • Partial paralysis or muscle weakness

If you are infected by West Nile Virus than there is a chance of developing into a serious infection but only 1% of people have changes of serious infection. The changes depend on several factors such as age that is being older puts you at higher risk and other factors can be if you have certain diseases like cancer, diabetes, hypertension, etc. And sometimes organ transplants too.

The incubation period – the period between you are bitten by the infected mosquito and apperance of symptoms of the illness – ranges from 2 to 14 days.


  • Unclog roof gutter
  • Empty the unused swimming pool, water coolers, pots, etc.
  • Change the water of birdbaths and pet bowls.
  • Avoid unnecessary exposure of the body to the mosquitos when they are more prevalent.
  • wear long sleeves and full pants while outdoor.

The simplest way is to use mosquitoes repellent and do not allow them to breed in your surrounding.

There are other ways in which the transmission can be possible for the infection. In some cases, the West Nile Virus can be spread through organ transplantation and blood transfusion. There are also reported that viruses can be transmitted from mother to baby during pregnancy or breast-feeding.


The virus was first discovered in UGANDA in 1937 and was first detected in North America in 1999. West Nile virus has been reported in Europe, Africa, Asia, Australia, and North America. According to the Centre for disease control infection of the West Nile Virus is Seasonal temperate zones. The climate that is temperate such as America and Europe shows a high peek of infection from July to October. Mostly the infection is at its peak on a seasonal basis as warmer and humid climate and geographically also.

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