The West Nile Virus

Mosquitoes, mosquitoes, mosquitoes!  Mosquitoes used to be a pesky nuisance. The high -pitched whine heard just before attack sent us into action. Splatting the intruder was protection from an unsightly bump.  Now we look at mosquitoes with some angst.  We look at the birds about us and are thrilled to see and hear a healthy cackling crow.  Why is our situation so different?  We are worried because some of our mosquitoes are carrying West Nile Virus.

What is West Nile Virus?

In an earlier article we mentioned that all viruses are selfish pieces of DNA or RNA.  These particles can con our bodies into being unwilling manufacturing sites to make more viruses.  The virus keeps invading until our immune system contains or eliminates the virus.  RNA virus types are the hardest for our body to contain because these viruses are especially good at hiding and invading.  West Nile Virus is such a virus.

West Nile Virus belongs to a family of viruses that have a coat (“toga”) that is fatty and appear yellow (“flavi”). Yellow also represents the jaundiced looked of affected people as the liver is attacked.  This is a nasty family of viruses that invade liver, nerve and brain.  West Nile Virus is a cousin of Yellow Fever, Dengue Fever, Eastern Equine Encephalitis and Western Equine Encephalitis.  But, amazingly, getting one of these viruses does not protect against West Nile Virus.

Just how worried do we have to be about West Nile Virus in Maryland?

There have been less than 20 cases of human West Nile Virus in Maryland.  There have been less than 10 cases of animals other than birds being infected.  The infected horse in Frederick County was in our very own Emmitsburg.  However, your pet or livestock will not give you West Nile Virus.  Only mosquitoes and some ticks can transmit the disease.  It is not necessary to put down an infected animal unless directed by a veterinarian.  Except for the West Nile Virus infection from organ transplants, humans do not give each other West Nile Virus.  It is not contagious like the flu. For some reason, states in the Midwest and South are more affected.

Where did West Nile Virus come from?

West Nile Virus was first known in Uganda in 1937, then, in the 1950’s it became a problem for Egypt, hence: West Nile Virus.  From there it spread to Asia, the Mid East and Eastern Europe.  Because the Culex mosquitoes, the main hosts of West Nile Virus, can survive our winters, it was only a matter of time before West Nile Virus would be imported to our country. Once in the United States in a preferred moderate climate such as ours the mosquito and the virus multiplied and migrated and multiplied again. 

Why did the West Nile Virus Spread so Quickly?

Three conditions in our area are conducive to the spread of West Nile Virus. 1) The infected hybernating Culex mosquito can easily make it though our mild winters. 2) There are many species of animals in our area that can be infected by West Nile Virus.  46 species of mosquitoes that host West Nile Virus feed on these animals and transfer the disease animal to animal and sometimes to humans.  These mosquitoes in turn bite other animals.  3) West NileVirus is a new disease to this area so there is little built up local immunity.

What symptoms might show someone is infected by West NileVirus?

West Nile Virus is very hard to diagnose.  The symptoms can act like Influenza, Strep or Hepatitis infections.  3 to 14 days after a mosquito bite, an infected person might experience mild cold symptoms or more intense symptoms such as headache, pain behind the eyes, neck stiffness, fever, cough, vomiting, jaundice, Scarlet Fever-type rash.  More serious signs are confusion and high fever.   Most people will recover from West Nile Virus. Only one in 150 people infected will show signs of serious illness. A very high fever, seizures, tremors, muscle weakness, confusion, and coma are bad signs.   Fatality is seen in 3 to 15 percent of all cases reported.

What tests are done to know it an infection is West Nile Virus?

If a person is very sick, a doctor will look for West Nile Virus infection.  Some tests include a spinal tap, a tissue biopsy and blood samples.  As stated before, there are many “toga”/”flavi” viruses. The first phase of testing looks only to see if a family of flavi virus is present.  If the tests are positive, then a second set of testing is used to determine West Nile Virus as the cause of disease. During this long process, most people infected with West Nile Virus will recover from the disease.  The testing is very expensive.  For these reasons, only the very sick undergo tests for West Nile Virus.    

What can be done if someone has West Nile Virus?

For most people infected with West Nile Virus, rest is all that is needed.  It is interesting that Tagamet, aka Cimetidine, (a cousin of Zantac and Pepcid) can give some protection during the disease.  (Cimetidine is also used by Dermatologists to treat viral warts). Some cautions on Cimetidine: it cannot be used by nursing mothers, it can cause gynecomastia (enlargement of male breasts), it cannot be used with many medicines, it is not to be used in children under 12.   Even if West Nile infection is diagnosed, Cimetidine should be used only with physician guidance.  Working with the physician to avoid low blood salt during the disease, will help prevent seizures.   For the very sick person, transfer to a hospital with an Infectious Disease specialist may be required.   

How can West Nile Virus infection be prevented?

Here are some everyday common sense ideas for prevention:

Dawn through early morning, and dusk are the times of day mosquitoes feed. These may to good times to avoid working outside. Wearing long sleeved clothing, slacks instead of shorts, shoes instead of sandals are ways to minimize mosquito bites.   Mosquito netting can protect children when they are outdoors. DEET (insect repellent designed by the US Army in 1946 just for mosquitoes and biting flies) and/or permethrin (Nix, Elimite, Acticin: what we use to get rid of scabies) sprayed on the clothes (not on the skin) will discourage mosquitoes from wanting to bite through the clothes to the skin.  There are companies that are in the business of bug-spray spurred on by client concerns over West Nile Virus.  A trip to the local hardware store or the web site will give you many products with DEET (N, N, Diethyl-metatoluamide, for those who need to know) and permethrin.

How can we stop West Nile Virus?

Spring, Summer and Fall are all active mosquito breeding times.  Keeping standing water emptied at least twice weekly will reduce successful mosquito breeding.  Reporting affected animals helps the CDC track the Disease.  Lately, there have been so many dead birds reported that not all are tested to confirm West Nile Virus.  Horses can be vaccinated against West Nile Virus.  While this is not 100% effective, vaccinating some of the hosts for West Nile Virus will reduce the number of infected mosquitoes.  Vaccination is made from cooked live Virus. The denatured virus cannot replicate.  So far there is no vaccine for humans. Lastly, there is much research being done on how to kill mosquitoes without creating undue harm to humans or at least to sterilize mosquitoes so they cannot breed.  Eventually, humans may become more immune to the disease.  Immunity from previous infection can confer 10 to 40 years of protection.                           

Where can we get more information about West Nile Virus. 

On the computer one can learn about West Nile Virus by using a search engine such as google or ixquick and simply typing West Nile Virus in the search section.  Information is available in English and Spanish.  There will be links to go to CDC (Center for Disease Control) and Maryland Department of Health & Mental Hygiene.  Phone numbers include Maryland Department of Agriculture (410) 841-5870 and Center for Veterinary Public Health (410) 767-5649.