Experts: Cases in 2012 expected to break state record
Recent rainfall and warm temperatures have brought back an all too familiar worry for Texans. Swarms of mosquitos are not only threatening itchy bites, but also infection of the West Nile virus.
West Nile grabbed national attention in the 2000s when thousands of cases were reported throughout the United States. In 2002, the virus first appeared in Texas, claiming 13 lives in the state and a total of 284 lives nationwide, according to reports from the U.S. Center for Disease Control and Prevention. While West Nile–related deaths haven't stopped since then, fewer have been reported, with numbers dropping to 712 nationally in 2011, including two in Texas.
This year is set to be the state's worst for West Nile, with the Department of State Health Services reporting 733 confirmed cases and 30 fatalities by Sept. 4.
"We anticipate we'll outpace 2003, and that was our worst year in number of cases," DSHS spokeswoman Christine Mann said.
One fatality, a female in her 90s, has been reported in Williamson County. Five cases of West Nile fever and six cases of West Nile neuroinvasive disease were confirmed by Sept. 4, according to DSHS Before 2012, only five cases of West Nile had been reported in the county since 2002, the Williamson County and Cities Health District said.
"To give you an idea, from 2002 to 2007, we had five cases reported total, and no cases reported from 2007 up to now," WCCHD Communications Director Marcus Cooper said. "In my discussions with some of our experts, that doesn't mean there weren't West Nile cases in that time period, but they might not have been reported or may not have been diagnosed."
While all age groups are at risk of developing the virus, the very young and elderly are most susceptible to developing complications from West Nile, Cooper said. A person's immune system is a major factor in what he or she will experience.
If infected, eight out of 10 patients will not experience any symptoms, WCCHD said. Others may develop West Nile fever, marked with flu-like symptoms such as neck stiffness, headaches and muscle fatigue.
West Nile neuroinvasive disease, or WNND, which will affect one in 150 cases, is a more serious concern. WNND patients can develop central nervous system diseases such as meningitis or encephalitis, and 10 percent of cases end in death. Those who survive typically battle lifelong nervous system problems. In 2011, DSHS reported 20 cases of WNND, two of which were fatal, and 497 cases have been reported in Texas so far this year.
Figuring out why the virus is infecting large numbers again has not been easy, Cooper said.
West Nile is a yearlong threat; however, case numbers typically peak in the hottest months, July and August, around the time birds begin their autumn migrations. One theory is that when the birds leave, mosquitos turn their attention to humans, causing more contact, Cooper said.
He also suggested water left standing after the region's July rainfall could also have encouraged larvae hatchings and larger mosquito populations. Even urban developments, which increase the number of people mosquitos can target in an area, are being investigated as possible reasons for the peak case numbers.
"They're still trying to determine whether the changes in the weather conditions have impacted the growth and dispersement of mosquito gestation areas, the migration of birds in combination with the dry weather and whether standing water in flower pots, overturned tires and other types of man-made, urban pockets have created a situation where more mosquitos are turning towards humans as opposed to other animals they could feed off of," Cooper said. "There are no hard facts right now, but [scientists] consider all of those factors."
What is West Nile Virus?
West Nile is a virus that infects humans and is spread by mosquito bites.
What are the symptoms?
Patients infected with West Nile typically experience sickness similar to the flu, though a full range of symptoms can include high fever, muscle weakness, headache, rashes, stiff neck, disorientation, convulsions, paralysis and coma.
What should I do if I suspect I have West Nile?
Seek medical attention immediately. If your doctor believes you could have West Nile, a blood test can confirm the diagnosis. Treatment will be more effective the sooner West Nile is diagnosed.
How can it be prevented?
The Williamson County and Cities Health District offers these tips to prevent contracting West Nile:
- Eliminate standing water in wheelbarrows, rain gutters, buckets, plastic covers, toys or any other container where mosquitos can breed.
- Empty and change the water in pet drinking bowls, bird baths, fountains, wading pools, rain barrels and potted plant trays every four to five days to destroy potential mosquito habitats.
- Drain or fill temporary pools of water with dirt.
- Keep swimming pool water treated and circulating.
- Clean out rain gutters.
- Remove discarded tires or keep them dry and covered.
- Add an aerator to ponds and water gardens, or add fish that will eat mosquitos and larvae.
- Remove debris from ditches and low areas.
- Fill in ruts and holes that collect standing water.
Bug sprays containing DEET offer the best protection for bare skin, while permethrin, a chemical used in insecticides, is more effective on clothing. Sprays with picaridin, lemon oil eucalyptus and IR3535 can also be used.
Areas with stagnant water, including abandoned lots, should be reported to the WCCHD's Environmental Health Services by calling 943-3620 or the Williamson County Constable Precinct 3 Environmental Enforcement Services at 943-3317.
Where can I find more information?
Courtesy: Williamson County and Cities Health District