The recent West Nile virus outbreak is the largest seen in the country, according to the Centers for Disease Control and Prevention (CDC). The number of cases this year are the highest recorded since West Nile was first detected in the US in 1999.
The West Nile virus has been reported in 47 states so far, with the number of cases totaling 1,1118 and 41 deaths. Approximately 75 percent of the cases have been reported from only five states -- Texas, Mississippi, South Dakota, Oklahoma, and Louisiana -- with almost half of the cases being reported from Texas. Five hundred and eighty-six (586) cases and 21 deaths have been confirmed in the Lone Star state, according to the Texas Department of State Health Services. Dallas County was the hardest hit with a total of 270 cases and 11 deaths.
Health officials are saying they expect the number of cases to rise even more dramatically. Reported cases tend to peak in mid-August, and it takes a couple of weeks for new cases to show up in the official count.
The worst year on record for West Nile virus was 2003 when there were 9,862 cases and 264 deaths recorded across the country. Fifty-six (56) percent of those cases were neuroinvasive, meaning the infection had spread to the patients' brains.
Why this year is turning out to be worse than others isn't exactly clear, but some experts believe it is because of the changes in weather that have been happening across the country. Dr. Lyle Petersen, director of the Division of Vector-Borne Infectious Diseases at the CDC, said:
"It is a very complicated ecological cycle. Hot weather, we know from experiments in the laboratory, can increase the transmission of the virus."
The CDC recommends that people use insect repellent containing DEET, wear long sleeves, and get rid of stagnant water to prevent the spread of the disease.