Infectious Disease
Ten human cases of West Nile virus reported in the US - Update
By Ben Wasserman
Jul 15, 2006 - 2:23:00 PM

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July 14 (foodconsumer.org) - West Nile virus (WNV) seems less active in the U.S. this year. As of July 11, the virus has been reported in a total of ten human cases in the country, according to the Centers for Disease Control and Prevention.

Six new human cases of West Nile has been reported since June 27 from Kern County (1), California; Brown County (1), South Dakota; Platte County (1) and Saline County (1), Nebraska; Marion County (1), Iowa; Jasper County (1), Missouri, according to U.S. Geological Survey.

Before June 27, four human cases of West Nile virus were reported from Colorado (Weld County 1), Mississippi (Copiah County 1) and Texas (Dallas County 1 and Harris County 1).

Of the ten cases, seven (70%) were reported as West Nile meningitis or encephalitis (neuroinvasive disease), three (30%) were reported as West Nile fever (milder disease), and 0 (0%) were clinically unspecified at this time.

In 2005, West Nile virus reportedly infected 3000 Americans among whom 119 died from the infection. Most commonly seen complications are meningitis/encephalitis and fever. The most affected states include Arizona (113/5, cases/death toll), California (880/19), Colorado (106/2), Illinois (252/13), Louisiana (171/11), Nebraska (188/5), South Dakota (229/2), and Texas (195/11).

According to the CDC, over 15,000 people in the U.S. have tested positive for West Nile Virus infection since 1999, including over 500 deaths.
The risk for a person to contract West Nile virus is low, and among the infected, less than 1% develop serious illness from the WNV, the USGS.gov says.

Those at highest risk for serious illness resulting from West Nile virus infection are the elderly aged 50 or older and those with lowered immune systems. However, because people of all ages can develop serious illness, it is important for everyone to protect themselves from mosquito bites to minimize the risk of infection.

Most people who are infected by the West Nile virus experience no symptoms or mild, flu-like symptoms. Approximately 80 percent of people who are infected with West Nile virus do not show any symptoms at all. It is estimated that about 20% of people who become infected with WNV will develop West Nile fever. Symptoms include fever, headache, tiredness, and body aches, occasionally with a skin rash (on the trunk of the body) and swollen lymph glands. While the illness can be as short as a few days, even healthy people have reported being sick for several weeks.

Severe symptoms associated with West Nile Viral infections include high fever, severe headache, stiff neck, disorientation, tremors, muscle weakness, paralysis and coma. Symptoms from infection generally appear within 2-14 days after the bite of the mosquito.

It is estimated that approximately 1 in 150 persons infected with the West Nile virus will develop a more severe form of disease. Serious illness can occur in people of any age, however, people over age 50 and some immunocompromised persons (for example, transplant patients) are at the highest risk for getting severely ill when infected with WNV.

West Nile virus is transmitted mostly by the bite of an infected mosquito. In a very small number of cases, WNV also has been spread through blood transfusions, organ transplants, breastfeeding and even during pregnancy from mother to baby.

As of July 11, 2006, West Nile virus has been found in birds, animals or mosquito from the following states: Arizona, Arkansas, California, Florida, Idaho, Illinois, Indiana, Iowa, Massachusetts, Michigan, Minnesota, Mississippi, Missouri, Nebraska, New York, North Dakota, Ohio, Oklahoma, Pennsylvania, South Dakota, Tennessee, Texas, Utah, Virginia, West Virginia, Wisconsin, and Wyoming.

While the chance for a person to get infected with West Nile virus is low, there is no treatment for WNV infection. The best thing people can do to reduce the risk of West Nile infection is to avoid mosquito bites.


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