STOCKTON (CBS13) — Public health officials announced Wednesday that a 74-year-old Stockton woman was the first confirmed case of West Nile Virus in San Joaquin County this year.

The woman was reportedly hospitalized in September and later died, but her cause of death has not yet been determined, according to San Joaquin County Public Health Services.

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The woman was one of 70 Californians who have tested positive for the virus as of October 8. Health officials caution that those most at risk for contracting the virus are those aged 50 and up and those with pre-existing health conditions including, but not limited to, diabetes and hypertension.

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The county Public Health Services said that while most who contract the virus don’t get sick and the risk of becoming seriously sick is low, about 1% of people with the virus can develop serious illnesses like meningitis or encephalitis. Officials advise the public to take measures to avoid being bitten by mosquitoes.

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Any significant mosquito infestations and daytime biting mosquitoes in the county should be reported to the Mosquito Vector and Control District.