transmission of west nile virus infection from mosquitoes

On Friday, the third day of August, 2018, a lady who was admitted at the Calicut medical college was diagnosed with West Nile Virus infection and the news ran it’s rounds in all the TV channels. That news got the attention because of fresh memories of the Nipah virus infection still lingering in the minds of everyone who speak malayalam. So,, what is this West Nile Virus? Is it dangerous just like the Nipah virus? You can find out all the answers in this article.

 

Overview

  • West Nile Virus (WNV) can lead to fatal neurological diseases in humans. However, about 80% of infected persons do not show any symptoms and the disease subsides automatically. In the remaining 20% of infected persons, when the virus enters the brain, encephalitis, meningitis, just like the Nipah virus disease can happen which eventually will lead to death.
  • The West Nile Virus is transmitted from infected birds to humans through the bites of infected mosquitoes. Animals like horses, cattle are also affected by the bites of infected mosquitoes.
  • Treatment of neurological diseases is supportive and requires hospitalisation.
  • Vaccines fro humans are not yet available, but for horses, it’s available.
  • The only way to stay away from this viral disease is by prevention which will be dealt with in detail later.
  • Reference –> World Health Organization

 

Transmission

  • Human to human transmission through casual contact doesn’t take place in WNV
  • Infected mosquitoes are the main source of infection to humans and other animals
  • Mosquitoes becomes infected when they feed on infected birds which are the natural virus hosts
  • Transmission through blood, saliva and other body fluids can take place. Mother to child infections have been reported.
  • Healthcare workers can become infected if proper infection control measures are not adopted
  • Infections from affected animals to humans through meat, poultry can occur

Signs and Symptoms

About 80% of infected persons do not develop any symptoms at all. The rest 20%, however can either develop West Nile fever or West Nile neurological diseases.

Symptoms of West Nile fever include:

  • Fever
  • Tiredness
  • Skin rash, particularly over the trunk
  • Headache
  • Lymph node enlargement with pain
  • Nausea, vomiting
  • Body aches

Approximately one in 150 infected persons progress to severe West Nile disease with deadly neurological effects, just like the Nipah virus disease. Persons above the age of 50 years and those with severe immune compromised state, like for example those who have received transplant organs are at much higher risk of the severe West Nile disease. The severe disease progresses through the following stages:

  • Severe headache
  • High grade fever
  • Convulsions
  • Loss of consciousness
  • Disoreintation
  • Stupor
  • Coma
  • Tremor
  • Muscle weakness
  • Paralysis

Diagnosis and Treatment

Blood and cerebrospinal fluid samples are taken for the demonstration of IgG and IgM antibodies by ELISA. Other tests like rTPCR, virus isolation by cell culture can also be used for the diagnosis of WNV.

Treatment is often supportive in hospital conditions. Intravenous fluids, respiratory support, and prevention of secondary infections are the main treatment strategies.

No vaccines against WNV are yet available.

 

Prevention

This is by far the best and only effective method to stay away from West Nile Virus infection. We at BeingTheDoctor always give more importance to the preventive aspect of all diseases and WNV is no exception. So, here are the important preventive steps that everyone should follow:

  • Make yourself less vulnerable to mosquito bites, particularly at dawn and dusk. Use long sleeve shirts, pants, light coloured clothes, mosquito repellants, mosquito nets, etc.
  • Read this article to learn how to keep mosquitoes away!
  • Reduce the mosquito breeding sites by discarding standing water in empty bottles, cups, coconut shells, tyres, etc
  • Persons involved in animal husbandry and slaughter business should wear protective gloves and adopt the infection control measures
  • Report any dead birds or animal cases to nearby vetenary hospital or healthcare worker like ASHA
  • Educate others on the preventive aspect of this disease
  • Healthcare workers, particularly lab technicians should strictly adhere to the standard infection control measures while dealing with any kind of test samples.
  • Visit your nearby hospital if fever persists for more than 3 days, especially if you belong to the epidemiological region.

That’s it. Everything that you need to know about the new villain in town, the West Nile Virus. Share this article with your friends and family on all your favourite social medias and let’s hope that the WNV doesn’t take the same route that Nipah virus did.

Dr Prasoon

Dr Prasoon

Author at BeingTheDoctor
Dr Prasoon, founder of BeingTheDoctor is a qualified medical practitioner who finds time to write articles on "health" and his "clinical experiences". He is currently engaged in providing primary health care services in rural India. Learn more in the "about" page.
Dr Prasoon
West Nile Virus Fever is Here!
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