The surveillance program, led by Antonio Sanz, revealed that although there were isolated peaks of mosquito activity in Málaga, Huelva, and Sevilla, the overall density remained low. All virological analyses for the West Nile virus returned negative results, providing a reassuring outlook after the colder months.

In Málaga, between December and March, three peaks exceeding 80 transmitting species specimens were observed, with two other captures reaching 50. In Huelva and Sevilla, activity surges were detected in March, coinciding with the onset of spring. Huelva province recorded a peak of 346 transmitting species captures in mid-March, while Sevilla registered a peak of 50 captures.

Other provinces also showed varied patterns: Almería had intermittent activity with low peaks, reaching 76 specimens in mid-March. Córdoba showed no winter activity but experienced a sudden increase from March. Granada stood out with an isolated peak of almost 60 captures in March. In Cádiz, intermittent activity was noted with a peak in mid-January, and in Jaén, activity was virtually nonexistent, except for a small record in mid-December 2025.

These figures contrast sharply with previous summer and autumn records, when captures occasionally exceeded 1,000 specimens per trap, and even 10,000 in specific cases, indicating much higher mosquito densities during those seasons. The West Nile Fever Vector Surveillance and Comprehensive Control Program has become annual, maintaining active surveillance throughout winter for early virus detection and to anticipate potential epidemiological scenarios.

During March and April, monitoring continues with 38 sentinel traps in municipalities that were on alert last season, with bi-weekly control transitioning to weekly in May, when all 120 Ministry traps will be installed. Currently, 117 Andalusian municipalities begin the high circulation season at a high-risk level, 302 at a medium level, and 366 at a low level, representing 13 more municipalities at a high level than the previous year.