The California Department of Public Health on Friday confirmed the state’s first human West Nile virus case of this year, providing evidence that the virus is spreading to humans by the bite of infected mosquitoes.

State health officials from the department also revealed that the first case of human West Nile virus occurred in the Kings County. However, the officials didn’t reveal the condition of the victim.

The announcement came after the West Nile virus was detected in three dead birds found in San Diego, San Mateo and Orange.

Meanwhile, the Environmental Health Department’s Katie Nelson warned, “A hard rain might cause an influx of nuisance waterborne mosquitoes at first. But if you follow that up with a very hot and dry period, that’s when Culex mosquito populations will increase.”

The risk of serious illness from West Nile virus to most people remains low, but a few individuals suffer serious illnesses like encephalitis and meningitis. Children, the elderly and people with conditions like hypertension and diabetes face a higher risk of getting sick.