HOUSTON -- More mosquitoes have tested positive for West Nile virus, bringing the total to 17, KPRC Local 2 reported Tuesday.

Four samples came from two new ZIP codes -- 77060 and 77530.

Mosquitoes have previously tested positive for West Nile virus from trapping sites in the following ZIP codes: 77004, 77013, 77016, 77028, 77050, 77077, 77345, 77506, 77536 and 77571.

Officials with the Harris County Public Health and Environmental Services Mosquito Control Division are spraying the infected areas Sunday through Thursday beginning at dusk.

Health officials said two people have been infected with West Nile virus -- one in Harris County and one in Dallas County.

West Nile Virus Information

In severe cases, West Nile virus can develop into encephalitis, inflammation of the brain, or meningitis, inflammation of the membrane surrounding the brain.

However, most people infected with the virus suffer from flu-like symptoms, including fever, headache, body aches, a skin rash or swollen lymph glands.

Symptoms usually develop in three to 15 days after being infected.

There is no specific treatment for West Nile encephalitis.

West Nile Virus Symptoms In Humans

• Flulike illness, with moderate to high fever
• Headache
• Muscle weakness or joint pain
• Fatigue
• Nausea
• Possible seizures
• Paralysis
• Respiratory symptoms

West Nile Virus Symptoms In Animals

• Loss of appetite
• Depression
• Fever
• Weakness
• Convulsions

To help eliminate mosquito-breeding sites and prevent mosquito-borne diseases, residents should do the following.

• Wear long pants and long-sleeve shirts when outdoors, particularly at dawn and dusk.
• Make sure screens on windows and doors are in good condition.
• Use mosquito repellent when outdoors. Use repellent that is less than 10 percent DEET on children.
• Eliminate standing water, old tires, cans and blocked gutters from property.
• Maintain swimming pools. Empty, invert or cover swimming pools when not in use.
• Keep birdbaths clean. Change the water at least once a week.
• To control mosquitoes inside a house, use a flying insect spray.