West Nile Virus

About

West Nile virus is an infection causing agent transmitted by mosquitoes. Exposure to mosquitoes carrying West Nile virus increases your risk of getting infected.

West Nile virus is common in areas such as Africa, parts of Asia and the Middle East. It is also present in the United States and several other developed countries.

Most infected people do not display any signs or symptoms. Some may experience minor symptoms such as fever and mild headache while in a few the infection can lead to life-threatening complications, such as inflammation of the brain.

West Nile virus spreads to humans and other animals through infected mosquitoes. The incubation period, which is the time between the mosquito bite and appearance of symptoms, is usually 3-14 days. The overall risk of getting West Nile virus infection depends upon the time of the year, the geographic region you are in and the amount of time spent outside.

The disease does not spread through kissing or touching. However it can spread through other routes such as from breast-feeding mothers to children, during blood transfusion or through organ donation procedures. Those at risk should take care to protect themselves from mosquitoes.

Symptoms of West Nile virus

There is absence of signs or symptoms in most of the people infected with West Nile virus. Approximately, 20 percent of them display signs of mild infection known as West Nile fever.

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Following are the common signs and symptoms of West Nile fever:

• Fever
• Fatigue
• Headache, back pain and body aches
• Eye pain (occasionally)
• Skin rash (occasionally)
• Swollen lymph glands (occasionally)

In less than 1 percent of affected people, the virus causes a more complicated infection of the brain and surrounding membranes.

Such infections include –

• Inflammation of the brain (encephalitis)
• Inflammation of the brain and surrounding membranes (meningoencephalitis).
• Inflammation of the membranes surrounding brain and spinal cord (meningitis)
• Inflammation of the spinal cord (West Nile poliomyelitis)
• Acute flaccid paralysis — which is a sudden weakness in the arms, legs or muscles of the respiratory system.

Some of the signs and symptoms of these complicated symptoms include:

• High fever
• Severe headache and stiff neck
• Disorientation / and lack of co- ordination
• Muscle jerking /tremors
• Sudden muscle weakness or partial paralysis
• Stupor / coma
• Convulsions
• Pain

Usually, the signs and symptoms of West Nile fever last for a few days and resolve on their own, but the more serious signs can linger for a longer period of time. Some of the symptoms such as muscle weakness are permanent. If a person’s symptoms are serious then it is important to seek medical attention.

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Diagnosis & Treatment of West Nile Virus

The following tests help to confirm West Nile virus diagnosis:

• Blood tests - A blood test will reveal antibodies raised against the virus. A positive ribonucleic acid (RNA) test for the West Nile virus also helps to diagnose the illness.
• Lumbar puncture – Also known as spinal tap,this test is very useful in identifyingthe presence of West Nile virus in an affected person. A sample of the cerebrospinal fluid, which bathes the brain and spinal cord, is taken by inserting a needle between the lower vertebrae of the spine. This fluid sample is examined in the laboratory for the presence of virus.
• Brain tests - Electroencephalography (EEG) which analyses the electrical activity of the brain and Magnetic Resonance Imaging (MRI) of the brain may be carried out to diagnose the condition.

Most people may just require pain relievers and get better without major treatments. Care should be taken while administering aspirin, as those who are recovering from chickenpox or flu develop Reye's syndrome, a potentially life-threatening but rare condition. Encephalitis or meningitis needs to be treated in a hospital with intravenous fluids and medicines.

Interferon therapy as an option for treating encephalitis is being considered by scientists.

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Prevention of West Nile Virus

Prevention of West Nile viral infection can be brought about in the following way -

• Remove collections stagnant water near your house
• Empty swimming pools that are not in use
• Change water in birdbaths on a weekly(minimum) basis
• Remove old tires or containers that can hold water to prevent mosquitoes from breeding.
• Avoid unnecessary outdoor activity during dawn and dusk in areas where mosquitoes are prevalent. Dress appropriately while going out to avoid mosquito bites
• Apply mosquito repellent, whenever necessary