The number of additional human West Nile virus (WNV) cases increased by 60 during the past week in California, bringing the state’s total to a nation-leading 488, according to the California Department of Public Health (CDPH) Tuesday.

California WNV map/CDPH
California WNV map/CDPH

The new cases were reported from the following counties: Butte (1), Contra Costa (1), Glenn (1), Kern (2), Kings (1), Los Angeles (18), Orange (15), Riverside (4), San Bernardino (2), San Joaquin (2), Santa Clara (1), Stanislaus (3), Sutter (2), Tehama (1), Tulare (1), and Yolo (5).

The 2014 WNV case count is more than double what was seen in 2013 at this time (236) and more than triple the 5-year-average of 153 cases.

An additional fatalities was also reported bringing that total to 16.

Both Orange and Los Angeles counties are reporting cases in the triple digits with 172 and 105 cases, respectively.

Last month, Dr. Ron Chapman, director of the California Department of Public Health (CDPH) and state health officer said, “The proportion of mosquitoes infected with West Nile virus is at the highest level ever detected in California.” A serious drought in the state is the likely catalyst for an increase in mosquito population.

West Nile virus (WNV) is a mosquito-borne disease that was originally found in Africa. In 1999, it was detected in the eastern United States; since then the virus has spread throughout the United States and is well established in most states, including California. For more infectious disease news and information, visit and “like” the Infectious Disease News Facebook page

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