West Nile Virus – How do I catch it?

November 12, 2012

West Nile Virus – How do I catch it?

The vast majority of people catching the West Nile Virus will have no symptoms at all, others may have very minor symptoms, not even being aware that they are ill. However for a very few people, when they are infected, it will lead to encephalitis, myelitis or meningitis. These three conditions all refer to swelling in or around organs. Encephalitis is when the brain swells. Swelling around the spinal cord is called myelitis. Meningitis is where the tissue around the brain and spinal cord become swollen. However it must be re-emphasized that the percentage of people who will seriously be affected is very low.

West Nile Virus is spread by mosquitoes which have been infected by people, animals or birds which carry the infection. If anyone is bitten by an infected mosquito then they can catch the virus. However the virus does not have a particularly virulent nature because there is no way that, if you are infected, that you can spread it to other people. Normally people or animals can only become infected through being bitten by an infected mosquito.

However it has been discovered that blood transfusions or organ transplants can spread the virus. The United States now routinely screens all donated blood to check for the virus. There is also a view that mothers can transmit the virus to the baby, either through pregnancy and birth, or breast milk. Even armed with these facts, the CDC still recommends that mothers breast feed their babies because presently with the facts available the benefits of breast feeding far outweighs the risk of West Nile Virus.

If you do catch the virus then you should expect to fully recover from it, perhaps never even knowing that you had it. However certain age groups such as children and old people have a higher risk of having seizures or brain damage. The older you are the higher the risk of contracting encephalitis and if you are over 70 you have a higher risk of dying.

West Nile Virus – What to look for?

Roughly 80% of those with West Nile Virus will have no symptoms. If symptoms are seen it is normally 3 to 14 days after the infected mosquito bit the person. The mild symptoms are very flu -like, presenting themselves as a fever, headaches, aching body or sore eyes. Sometimes a rash will be present typically on the chest, arms and back. The patient will feel tired, have a loss of appetite and may be nauseas and vomiting. In rare case swollen glands are seen. These symptoms normally last less than a week.

The very small percentage of people who contract a more severe case of West Nile Virus can be ill for weeks or months. These patients may have spinal cord and brain issues leading to headaches and a high fever. Further indications may be a stiff neck or paralysis, confusion, and tremors, convulsions, or muscle weakness. Ultimately the patient may end up in a coma and in extremely rare cases West Nile virus can cause death.

West Nile Virus – Can it be diagnosed?

West Nile Virus can easily be diagnosed by a blood test. Initially your doctor will ask if you remember being bitten by a mosquito, or if it was a probability. If there is a possibility of the virus the doctor will take blood to test for antibodies to the virus. If they are present then you have West Nile Virus. If you have been seriously ill the doctor may take another blood test a few weeks later to compare the amount of antibodies with the first test to confirm that you really are on the road to recovery. Another test which can be carried out is the lumbar puncture. The fluid drawn off, which surrounds your brain and is present in your spinal cord, is tested for antibodies. A MRI can check the brain for swelling if encephalitis is suspected.

What is the Treatment?

If you are typical then your body deals with the infection. There is no medical treatment. Just the usual advice; stay at home until you feel better and drink lots of fluids and take a paracetamol if you have aches and pains. If the case is severe then perhaps you will have to be hospitalized. Intravenous drips are a common treatment, if the patient is having breathing difficulties then a ventilator may be required.

How can you prevent infection?

You cannot prevent infection but you can take steps to reduce the risk of mosquito bites. Initially find out if the virus is in your region. The local health department will have that information. The following standard advice to avoid mosquito bites may also help:

  • If there may be mosquitoes present always use insect repellent.

  • Long-sleeved shirts and long trousers give added protection.

  • Stop mosquitoes breeding; do not leave any standing water around the house.

  • Mosquitoes are most active at dawn and dusk so stay indoors at these times.

Work continues on a vaccine to prevent West Nile Virus but as yet no breakthrough has occurred.

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