Overview

• Harris County Public Health confirmed the first positive West Nile virus mosquito sample of 2025 in northwest Harris County, Texas, prompting immediate spray operations to reduce infection risks.
• UK Health Security Agency (UKHSA) detected West Nile virus genetic fragments in mosquitoes for the first time in the UK, collected from wetlands in Nottinghamshire in 2023.
• UKHSA assesses the risk to the public as very low, with no evidence of virus circulation in birds or mosquitoes beyond the detected fragments.
• Experts attribute the geographic spread of mosquito-borne diseases, including West Nile virus, to climate change creating favorable conditions for mosquito populations.
• Public health authorities in both regions are intensifying surveillance and urging residents to take precautions, such as reducing standing water and using insect repellents, to minimize exposure.