West Nile Virus (WNV)

New Jersey faces a persistent and evolving threat from vector-borne diseases (VBDs), primarily transmitted by mosquitoes and ticks. Surveillance data for 2025 indicate a significant circulation of viruses, particularly West Nile virus (WNV), which was detected as early as April—considerably earlier than historical norms. As of August 2025, WNV has been identified in mosquito pools across all 21 counties, with detections substantially higher than the five-year average. Critical highlights from current surveillance include high viral circulation in mosquitoes is being monitored, with 776 positive pools and several human cases reported. While human infections in 2025 are currently lower than the 41 cases and eight fatalities recorded in 2024, the "peak period" (mid-August to mid-September) is ongoing.