Missouri Department of Health and Senior Services
P.O. Box 570
Jefferson City, MO 65102

For Immediate Release:
July 26, 2004

Contact:
Dr. Howard Pue, DVM
State Public Health Veterinarian, or
Karen Yates
DHSS Vector-Borne Disease Coordinator
573-751-6113

Missouri's First Probable Case of West Nile Virus Reported

The Missouri Department of Health and Senior Services (DHSS) announced today that the state's first case of West Nile virus infection has been reported in an eight-year-old boy from St. Charles County. An investigation by the St. Charles County Department of Community Health and the Environment indicates the child may have been infected in either Missouri or Maricopa County, Arizona. The latter is currently the 2004 human case epicenter for West Nile virus infection. However, since the child lives in Missouri, DHSS will report the case to the U.S. Centers for Disease Control and Prevention.

County and state public health officials believe it is prudent to announce that the child may have been infected in Missouri, although where the infection actually occurred will never be known for certain.Three dead birds out of 21 submitted from St. Charles County so far in 2004 have tested positive for West Nile virus and two positive mosquito pools were collected in the county during the last week of June.Missouri's first two West Nile virus cases last year occurred on August 11. By the end of 2003, Missouri had recorded a total of 64 West Nile virus human disease cases with 8 related deaths.

"I know that with the first West Nile virus case being reported earlier this season, people may be concerned that it is a sign this will be a bad year for the virus in Missouri," said Dr. Howard Pue, State Public Health Veterinarian. "That may or may not be the case, but it is much too early to tell, and we have no good way to forecast how many cases we will have or where West Nile virus activity will be the highest. What DHSS and Missouri's local public health agencies can do is continue to look for West Nile virus-infected birds, mosquitoes, and horses. When we find them, we will alert people in those areas that they could be at increased risk of contracting West Nile virus disease from infected mosquitoes, and they can then take additional precautions to avoid being bitten."

"Although we have an early case this year, because we can't look ahead to the coming season, our public health message is still the same as before: West Nile virus is something to be aware of but people should not worry about it. We can all play an important part in protecting ourselves, our families, and our communities from this mosquito-borne virus by taking some very simple but effective protective actions. It is still a rare virus with very few people getting seriously ill from it."

Pue said that, like many diseases, prevention is the simplest and most effective way to combat the spread of West Nile virus. The best ways to prevent infection are using effective insect repellents containing DEET if going outside in the morning and evening (mosquitoes' most active feeding times), and making sure homes and communities are protected by ridding properties of debris that can hold water and serve as breeding grounds for mosquitoes that can carry the virus.

He said DEET-containing insect repellent should be applied to thin clothing and exposed skin. The repellent can also be safely used on young children by following directions on the product label. It also helps to wear long sleeve shirts and pants when outdoors at dusk and dawn to cover the skin. He added that homes should be mosquito-proofed by ensuring doors and windows have screens.

West Nile virus, like most mosquito-borne viruses, is found in wild and domestic birds. When a mosquito feeds on an infected bird, it can pick up the virus and transmit it to other non-infected birds. Occasionally, infective mosquitoes will feed on mammals such as horses and humans, and transmit the virus to them.

Most people infected with West Nile virus do not develop any symptoms. Sometimes, though, mild illness results one-to-two weeks after exposure with symptoms such as fever, headache, body aches, skin rash, and swollen lymph nodes. Less than one percent of infected people may develop a serious illness that includes encephalitis (inflammation of the brain). These persons might experience headache, high fever, neck stiffness, disorientation, convulsions, and muscle weakness. People over the age of 50 are at higher risk for developing these serious complications of West Nile virus infection. Infection may prove fatal, especially among the elderly, in a small number of those who develop encephalitis. West Nile virus is not transmitted directly from birds to humans or from person-to-person.

Medical care should be sought as soon as possible for persons who have symptoms suggesting severe illness. There is no specific treatment for West Nile virus infection or vaccine to prevent it. Treatment of severe illness includes hospitalization, use of intravenous fluids and nutrition, respiratory support, prevention of secondary infection, and good nursing care.

Pue said that people who observe an unusual number of dead birds, especially crows, blue jays, and sparrows, are encouraged to report the incident to their city or county health department. Health officials will then determine whether the event should be investigated and whether bird specimens should be submitted to a laboratory for testing. There are many things that can kill birds besides this virus, and therefore not all dead-bird sightings are investigated.

Procedures for New Case Reporting DHSS will this year again list all new cases on its web site (www.dhss.state.mo.us/WestNileVirus/index.html) in a line listing that gives the gender, age, and county of residence of each case. DHSS is encouraging news reporters and citizens to utilize the web site to follow the progression of the disease in the state. Any major developments in Missouri's West Nile virus situation will be announced through news releases. Human case data posted on the web site represent cases that are under investigation, and are therefore provisional and subject to change.

Furthermore, DHSS urges physicians to request analysis of specimens only from patients who currently show symptoms of possible West Nile virus infection. Because evidence of infection from last year can still be found in blood samples, a person's symptoms play an important role in differentiating a current infection from one acquired in a previous year. All human cases listed on the DHSS web site will be screened to eliminate the reporting of individuals who were infected in 2003.

For more information on West Nile virus, contact your local health department or the Department of Health and Senior Services at 1-800/392-0272 or 573/751-6113, or visit the DHSS web site at www.dhss.state.mo.us/WestNileVirus/index.html.

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