- A total of 693 cases of West Nile virus infections have been reported this year to the CDC.
- So far 10 people have died from the disease and it seems to be concentrated in Texas.
In the wake of 10 deaths due to West Nile virus, and hundreds of infections, authorities in Texas are spraying insecticide in the Dallas region, hoping to curb the spread of the disease, which can spread by mosquitoes.
A total of 693 cases of West Nile virus infections, including 26 deaths, were reported as of Aug. 14 to the Centers for Disease Control and Prevention (CDC). The number of cases reported by this second week in August is the highest since 1999, when the disease was first seen in the U.S., according to the CDC.
About 60 percent of this year's cases have involved the "neuroinvasive" form of West Nile infection, in which the nervous system is affected. Such cases can cause inflammation of neural tissues, such as meningitis and encephalitis. More than 80 percent of all reported cases were from six states (Texas, Mississippi, Louisiana, Oklahoma, South Dakota and California), and almost half of all cases have been reported from Texas.
Here are five things you need to know about West Nile virus:
West Nile virus is a type of virus called a flavivirus. Other viruses in this group cause dengue, yellow fever and Japanese encephalitis. Flaviviruses are commonly transmitted by ticks and mosquitoes. West Nile virus was first identified in Uganda in 1937, according to the National Institutes of Health (NIH).
It is likely that West Nile is spread from birds to people through mosquito bites, the NIH says. Early fall is the time of year that mosquitoes tend to have the highest levels of the virus, and human cases tend to peak around this time.
The virus can also be spread through blood transfusions and organ transplants. Pregnant women can transmit the virus to their fetus, and mothers can transmit it to babies through breast milk, the CDC says.