West Nile Virus, What Is It? How To Keep From Being Infected

By Magdalena Stuehrmann

As was reported earlier today in West Chester Today, Chester County’s Health Department detected the presence of West Nile virus in trapped mosquitoes in East Goshen and West Goshen this week.  

Though this is not by any means a cause for panic, it is a cause for caution.   

West Nile virus is not an uncommon disease in the eastern United Sates, but it is not a disease that should be taken lightly.

This mosquito borne member of the viral family called flavivirus was not found in the Western hemisphere until the first case was reported in New York City in 1999. Since then, the virus has spread down through the East Coast and to several Southern and Midwestern states.

The West Nile virus is a member of a family of flaviviruses.  Viruses are not categorized as living things, and are more in the classification of parasites because they cannot reproduce on their own. Viruses instead reproduce by infecting a susceptible host cell, in this case a human body cell, and inserting its own viral genetic information (in this case RNA) into the nucleus of the host cell.

Click to enlarge

Before the West Nile virus can reach human host cells, it must first be carried by a female mosquito. The mosquito becomes the carrier of the virus by first biting an infected creature, almost always a bird.

Crows and jays are the most common avian carriers of the disease, though over 100 other species have been identified as carriers of the virus.

Mosquito then bites a human, transmitting the virus to the human in the mosquito’s saliva, which the mosquito uses to keep the person being bit from feeling the bite.

Luckily, West Nile virus cannot be spread by direct human-to-human contact, which makes it easier to control.

The virus can be spread between humans through blood transfusions and organ transplants, though the risks of getting the disease are far outweighed by the benefits of such procedures. There is the possibility that it may also be transmitted from mother to infant through breast-feeding, though this is still debated.

Anyone has the possibility of contracting West Nile virus, but the possibility of a person developing a more severe form of the disease is increased if that person has a condition that might weaken the immune system, such as HIV, or has recently undergone an organ transplant or chemotherapy, or is either very young or of an older age.

Though West Nile virus sounds like a very scary disease, and it can have serious complications, eighty percent of those infected with the virus show no symptoms of having the disease or experience only mild, flu-like symptoms that last for only a few days.

Symptoms of West Nile virus usually exhibit themselves between 3 and 14 days after infection occurs.

About 20 percent of patients develop what is called West Nile fever – the symptoms include a fever, headache, body aches, a skin rash on the trunk of the body, swollen lymph glands, abdominal pain, muscle aches, nausea, diarrhea, lack of appetite, sore throat or vomiting.

These are symptoms of a mild case of West Nile virus, but should probably be investigated by a physician to ensure that there are no underlying complications.

1 in every 150 patients with the disease develops very serious conditions called West Nile meningitis or West Nile meningoencephalitis. West Nile meningitis is an inflammation of one or more of the three meninges, or layers of membranes that surround the brain.

This can be caused by either the presence of the virus in the meninges due to the virus crossing over the blood-brain barrier, or by the body’s own immune reaction to the virus.

West Nile meningoencephalitis is a condition that resembles both meningitis and encephalitis, a swelling of the brain, at the same time. The presence of either of these very serious conditions may be indicated by the following symptoms: headache, muscle weakness, paralysis, high fever, neck stiffness, disorientation, tremors, convulsions, or a stupor, which is a state of impaired consciousness, extreme lethargy and reduced activity to external stimuli of the patient.

The presence of any of these symptoms requires immediate medical attention, as they are potentially lethal and debilitating through serious brain damage if they are not treated immediately and properly.

Treatment for the more mild cases of West Nile virus is simply treatment of the symptoms – there is no specific treatment for West Nile virus.

A physician will determine the proper treatment of the patient by taking into consideration a wide variety of factors about the specific person and the way the virus has affected them.

There is not currently a vaccine for West Nile virus and it is still rather rare for West Nile virus infection to occur in humans.  So the best way to avoid having to worry about all these complications is to avoid contracting the disease in the first place.

Some simple steps people can take to avoid being bitten by infected mosquitoes include:

• Use mosquito repellent with DEET. and apply to both clothing and exposed skin.
• Wear long sleeves and pants that have been treated with DEET repellents
• Stay indoors at the peak times for West-Nile-carrying mosquitoes, which are dawn, dusk, and early evening.
• Fix any holes in screens
• Remove standing water sources around the home. 
• Don't handle any dead birds as they may have the West Nile virus infection.

Though West Nile virus can have some very serious complications and should be taken seriously, it is certainly not a panic-worthy occurrence, as most cases are quite mild, and, with proper precautions, it is possible to avoid contracting the disease in the first place.