The deaths were among six new reported cases. The people who died lived in Cumberland and Mercer counties.
All of the cases involved people over 50 years old.
Previously, two human cases of West Nile were reported this year in Middlesex and Union counties.
In a typical year, there are 13 human West Nile infections reported in New Jersey. Last year, the state had 14 human cases of WNV and one death.
This comes after the state's first human case of Eastern Equine encephalitis (EEE).
The New Jersey Department of Health and the New Jersey Department of Environmental Protection are urging residents to take precautions to protect themselves from mosquito-borne diseases and to reduce mosquito populations on their properties.
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Most people infected with West Nile or EEE will have no symptoms. For those who do, symptoms include fever, chills, body aches, and joint pains. Rarely, people may develop severe neurological illness, which often presents as meningitis or encephalitis.
Symptoms of severe illness include fever, severe headache, neck stiffness, vomiting, diarrhea, seizures, behavioral changes/confusion, limb weakness, and fatigue.
Older adults and people with weakened immune systems are at greater risk of developing severe illness. Specific laboratory tests are needed to confirm West Nile and EEE, so anyone with symptoms after a mosquito bite should contact their health care provider.