The West Nile Virus is back – and it’s entered California. According to CNN, two Stanislaus County women tried to give blood and found out they were infected with the virus. The cases are the first confirmed human cases in California this year. Check out the video:

West Nile Virus be transmitted by mosquitoes, but not from person to person. According to WebMD, most people who are infected with the West Nile virus will have no or minimal symptoms. An estimated 20% of infected people will develop West Nile fever: mild symptoms, including fever, headache, and body aches, occasionally with a skin rash on the trunk of the body and swollen lymph glands.

Severe infection (West Nile encephalitis or meningitis) can cause headache, high fever, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness, and paralysis. Only about one in 150 person infected with the West Nile virus will develop a more severe form of disease.

Still, it’s a good idea to take precautions against the virus. Mosquito bites are the most common route of West Nile virus infection, and health officials warn Californians to drain areas of standing water when possible, and use bug spray and other precautions to avoid exposure to bites.