West Nile Virus raging in southwestern US states

HOUSTON - The West Nile Virus (WNV) has in recent months been raging in the southwestern US states of Texas, Louisiana, Oklahoma and Arkansas in what state health officials are calling the area's worst outbreak in several years.

In the United States, 41 lives have been lost in over a thousand WNV cases reported in 47 states -- three times the average annual rate -- with more than half of the cases and deaths occurring in Texas during the country's hottest season that doesn' t end until the end of September.

Twenty-eight lives have been lost as of Monday in the four southwestern US states. State heath departments in the states continue to issue cautionary advisories on their websites that show increasing numbers of reported WNV cases, people bitten by virus-carrying mosquitoes, since the summer hit subtropical temperatures in July. They also are publishing on department websites and through media releases proactive guidelines, steps people can take to minimize their risk of infection.

While cases have been reported in California and Chicago Illinois, the numbers do not show the increase that has been seen in Dallas County, Texas, where officials have declared a health emergency.

Though some health officials are pointing to the hot summer temperatures as a cause of the increase in cases, Chris Van Duesen, media relations spokesperson for the Texas Department of State Health Services, told Xinhua that there's no way to pinpoint a cause from contributing factors such as weather, numbers of mosquitoes and human behavior.

"We are certainly seeing more West Nile Virus than in recent years," Van Duesen said. "There's quite a bit of speculation, here and in other states. It's a fairly complex calculation as to what' s behind that. West Nile Virus is carried by mosquitoes, transmitted by mosquitoes, Different areas have high concentrations but as to why that is, it's unknown."

So far in Texas, there have been more than 550 cases, 22 of them fatal, reported and confirmed at the state level, Van Duesen said. The majority of the fatalities have been seen in the Dallas area, where officials resorted to aerial spraying of pesticides last week to help reduce the number of mosquitoes.

Van Duesen said the first cases in Texas were reported in 2002.

The WNV is estimated to be more than 1,000 years old, when it infected horses in Egypt and is suspected as the cause of early death in Alexander the Great. It wasn't isolated until 1937, when it was seen in a 37-year-old woman in Uganda.

Since 1937, the virus has been reported in Asia, Africa, Madagascar, India, Europe, Australia, Canada, Mexico, Central America and, beginning in 1999, the 48 contiguous states within the United States. While WNV is most commonly found in infected birds, it has been reported in other hosts. In 2007, WNV was found in a killer whale in Texas, broadening the known host range that also includes humans, horses, dogs, cats, bats and alligators.

The way to avoid infection from WNV is to repel the mosquitoes that carry and transmit the disease, Van Duesen said.

"We are advising people to dump out any standing water -- bird baths, potted plants -- any stagnant water where mosquitoes lay their eggs to deny mosquitoes a chance to hatch," Van Duesen said. "We're also advising people to use insect repellent and avoid being outside around dawn and around dusk."

In Harris County, Texas, which includes the city of Houston, Harris County Public Health and Environmental Services Director Dr. Rudy Bueno said there have been six neuroinvasive cases and no deaths. Within the city limits of Houston, there have been 12 more cases and one death, all age 45 and older.

Bueno said that the department works with local and state health departments when planning Harris County's annual aerial spraying each year and his department has launched a response page on its website to show videos and maps of the area where spraying is to occur later Wednesday.

"We have an extensive outreach network, a layered effect that combines education with outreach at schools and civic organizations," Bueno said.

The department surveys the Harris County area from mid-May to October, collecting dead birds and also live birds and mosquitoes at 168 trap sites throughout Harris County.

"We identify them, process them and test them for encephalitis, " said Bueno. "We also select birds and blood samples viable for testing and send them to the University of Texas Medical Branch in Galveston. Our part is to make sure we find the virus and treat the infected area while also educating people as to what they can do. I believe we minimize the effect of West Nile Virus on people. "

In the state of Oklahoma, the Oklahoma State Health Department has confirmed three people, all over age 50, among the 61 WNV cases reported, have died from the virus in Oklahoma. Thirty-nine have been diagnosed as the most serious neuroinvasive type, with 22 people who just displayed symptoms of fever. Thirty-eight people have been hospitalized so far.

"The number of West Nile cases we are seeing this year is the highest since 2007," said Pamela Williams, department spokesperson. "Unlike what we're seeing down in Texas, we don't have aerial spraying going on. The issue of mosquito control is an issue handled by the cities. Cities in the state are looking more closely at what they can do."

A Louisiana Department of Health and Hospitals report released August 17 cites two neuroinvasive deaths in the 53 cases so far attributed to WNV so far this year in that state. The fatalities are the first since 2008, the state's outbreak year that had 204 neuroinvasive cases and 24 deaths.

Ed Barham, public affairs officer for the Arkansas Department of Health said that there has been one death attributed to West Nile Virus among 15 cases this year so far.

"There were six cases last year, with no deaths," he said. " This year is the worst year since 2007, when we had 13 cases. Our worst year was 2002, the first year we had West Nile Virus, when we had 43 cases."

In New Mexico, there have been two cases and no fatalities so far, but Chris Minnick, spokesperson for the New Mexico Department of Health, said that it's still early in the monsoon season of August and September.

"We're just getting into the monsoon season, when all the moisture means more mosquitoes," Minnick said. "We have had cases every year since 2003, when West Nile Virus was first reported in the state, but it's nothing like we're seeing in Texas."

All four southwestern states that have reported fatalities from West Nile Virus have issued advisories asking people to protect themselves by using an insect repellent containing DEET on exposed skin and clothing when going outdoors. Also recommended are installation or repair of window and door screens to keep mosquitoes out, emptying containers of water before the water can stagnate and cleaning leaves and debris from rain gutters.

In Dallas County, Texas, posted advisories also call for people to wear loose clothing in light colors to further help avoid being targeted by mosquitoes.

The WNV, which was first reported in the U.S. in 1999, peaked in 2002 and 2003, when severe illnesses reached nearly 3,000 and deaths surpassed 260. Last year was mild with fewer than 700 cases. More than 30,000 people have since 1999 been infected by the virus in the country.