Testing for West Nile Virus

When testing for the viral infection West Nile Virus, which is becoming more and more common, there are a few methods of testing. However, there is one method that has surfaced that is the most useful in detecting the virus early on before it progresses. This method envoles nucleic acid in plasma in blood testing and is formally called nucleic acid amplification testing (NAAT). As of 2006, this method had not been used on symptomatic patients and was only being tested on blood samples from donors. On the other hand, serology is the most common way of diagnostic testing for West Nile Virus. Doctors are beginning to test patients using both of these methods though. They will get a serum sample along with a plasma sample from patients who are suspected and being tested to see if they do have the West Nile Virus.















This is a graph showing the different outcomes of the different ways of testing for WNV in a study done in 2003. Each method of testing is targeting a different part of the genome of this virus.  A recent study on rhesus macaques helped researchers a little bit more about the timeline of the west nile virus. They discovered that the "precise time of WNV infection was known, have
suggested that central nervous system involvement occurs during the second or third week after the initial virus infection. In fact, many patients with symptoms of West Nile encephalitis
already have WNV-specific IgM antibodies in their serum and/or CSF when they are first admitted to the hospital [10, 12, 24]. This is probably one reason why it is uncommon to isolate WNV from blood or CSF of West Nile encephalitis cases at the time of hospitalization(674 Experimental Infection of Rhesus Macaques)." Although it is harder to understand the virus in the human body they are getting closer based on experimental studies.




Tilley, Peter; Journal of Infectious Diseases;  Nucleic Acid Testing for West Nile Virus RNA in Plasma Enhances Rapid Diagnosis of Acute Infection in Symptomatic Patients. 15 May 2006  Vol. 193 Issue 10, p1361-1364, 4p; http://ezp.tccd.edu:2134/ehost/detail?vid=5&hid=108&sid=6d56c7aa-07de-46e0-9b4b-54043b83bcb3%40sessionmgr115&bdata=JnNpdGU9ZWhvc3QtbGl2ZSZzY29wZT1zaXRl#db=syh&AN=20808835

Journal of Infectious Diseases; Experimental Infection of Rhesus Macaques with West Nile Virus:Level and Duration of Virema and Kinetics of the Antibody Response After Infection; 2/15/2004, Vol. 189 Issue 4, p669-676, 8p.; http://ezp.tccd.edu:2134/ehost/pdfviewer/pdfviewer?sid=6d56c7aa-07de-46e0-9b4b-54043b83bcb3%40sessionmgr115&vid=8&hid=25

Detailed Record

Introduction to West Nile Virus

The first case of West Nile Virus was in 1937 in Uganda, Africa, and since then the virus has spread to countries all around the world. West Nile is a virus that is most commonly spread through the bite of a mosquito that carries this virus. The way that mosquitos are infected is by biting a bird that carries the infection, resulting in them now beginning to be a transmitter. There are two lineages of West Nile Virus. Lineage I, is the one that is most susceptible to humans encountering. In fact, all of the cases of infected people in North America have been related to lineage I. Lineage II is in enzootic foci in Africa where there have been no reported outbreaks as of June 15, 2004. Although one lineage may be more viral and threatening to human infection, both lineages are neuroinvasive.

Most of those who are bitten and infected with the virus are asymptomatic, meaning they do not produce any symptoms of being ill. Those who do show symptoms are often described as flu-like. The incubation period of the virus developing in the infected body can vary between 3 and 14 days. Symptoms will occur from about 3 to 6 days. Symptoms may also include headaches, fever, chills, and backache. Those who experience these symptoms should seek medical attention and be tested. Patients may not test positive for this until weeks after being infected and showing symptoms.

There is no treatment of West Nile Virus to cure patients. There are only ways to reduce symptoms and prevent further infection. A vaccine is being developed to help prevent to virus from infecting humans. Recently, there have been cities that have had high infection rates that do a ariel spray to help prevent infection.

Lewis, Mark; Bulletin of Mathematical Biology; Jan2006, Vol. 68 Issue 1, p3-23, 21p, 3 Graphs; Traveling Waves and Spread Rates for a West Nile Virus Model.;http://ezp.tccd.edu:2134/ehost/detail?vid=10&hid=10&sid=4aaa9d61-29bd-4128-87ff-912c72a0c5bd%40sessionmgr11&bdata=JnNpdGU9ZWhvc3QtbGl2ZSZzY29wZT1zaXRl#db=syh&AN=28463816

American Journal of Health-System Pharmacy; West Nile virus infection; 6/15/2004, Vol. 61 Issue 12, p1235-1241, 7p. http://ezp.tccd.edu:2134/ehost/detail?vid=7&hid=10&sid=4aaa9d61-29bd-4128-87ff-912c72a0c5bd%40sessionmgr11&bdata=JnNpdGU9ZWhvc3QtbGl2ZSZzY29wZT1zaXRl#db=syh&AN=13383668