The city of Dallas and the state of Texas is facing a deadly outbreak of West Nile Virus. With at least 10 people dead in Texas, Dallas Mayor Mike Rawlings has declared a state of emergency for the city.

The emergency declaration will allow aerial spraying to take place which will kill the disease-carrying mosquitoes. Officials will ask the state to spray the entire city of Dallas just north of Interstate 30. Five planes will spray the area and the state will cover the $500,000 cost.

"The City of Dallas is experiencing a widespread outbreak of mosquito-borne West Nile virus and has caused and appears likely to continue to cause widespread and severe illness and loss of life," Mayor Michael Rawlings said, as quoted by The Australian.

Spraying will start Thursday. This will be the first time the city will be sprayed with an insecticide since 1966.

The United States as a whole is experiencing a huge spike of the West Nile virus, but Texas has been hit particularly hard. According to the Texas Department of State Health Services, 381 people have become ill due to West Nile virus.

"Texas is on track to have the most cases of West Nile illness since the disease first emerged in the state in 2002," it said in a statement.

All but eight states in the country have reported cases of West Nile virus in people, birds or mosquitoes. Eighty percent of the cases have been in Texas, Mississippi and Oklahoma.

"It is not clear why we are seeing more activity than in recent years," said Marc Fischer, a Center for Disease Control and Prevention medical epidemiologist told CNN. "Regardless of the reasons for the increase, people should be aware of the West Nile virus activity in their area and take action to protect themselves and their family."

An outbreak in Dallas could be happening after the city and the state of Texas had an unusually warm winter and rainy spring, creating the perfect conditions of a mosquito breeding ground.

West Nile virus is spread most between June and September, with  a peak in August. The virus is spread through mosquitoes that carry the disease. Those who are infected may experience symptoms including fever, headache, aches, joint pain, vomiting, diarrhea or rash.

It is rare for people to contract encephalitis or meningitis, which can lead to death due to the disease. Less than one percent have a case that severe. However those who face a greater risk include those over 50 or people who have conditions such as cancer, diabetes, kidney disease, or organ transplants.

There is currently no cure for West Nile virus and there is no vaccine to prevent it. Some people are able to recover on their own while others are hospitalized.

To reduce risk of contracting the disease, use bug spray to avoid mosquito bites.