Health

West Nile Virus Alert: 15 Andalusian Municipalities on High Alert

By Dr Natalie Singh - Health Editor Updated July 28, 2026

San Juan de Aznalfarache has been declared an alert zone for West Nile virus circulation by the Directorate General of Public Health and Pharmaceutical Regulation of the Department of the Presidency, Health and Emergencies of the Junta de Andalucía. According to regional health authorities, the municipal designation follows the detection of virus-carrying mosquitoes within traps managed by the Provincial Council of Seville’s surveillance system. Alongside the new declaration in San Juan de Aznalfarache, health officials extended an existing alert in neighboring Palomares del Río until August 11. With these updates, a total of 15 municipalities across Andalusia are currently designated as alert zones due to confirmed viral circulation in vectors, equids, or birds.

Active Alert Zones and Geographic Spread Across Andalusia

According to the Integrated Vector Surveillance and Control Program for West Nile Fever, the current 15 municipalities under alert comprise Torredonjimeno in Jaén; Salobreña in Granada; Almensilla, Aznalcázar, Bollullos de la Mitación, Coria del Río, Constantina, Gelves, La Puebla del Río, Mairena del Aljarafe, Palomares del Río, San Juan de Aznalfarache, and Villamanrique de la Condesa in the province of Seville; and Fuengirola alongside Las Lagunas in Mijas, Málaga. Additional viral circulation was detected in Benacazón, Seville, and Bujalance, Córdoba. However, because those specific capture points were located more than 1.5 kilometers away from urban population centers, formal alert declarations were not required under regional protocols. Meanwhile, Pulpí in Almería concluded its monitoring period as an alert zone on July 24.

Surveillance Protocols and Vector Control Mandates

Under regional public health regulations, declaring an alert zone triggers a mandatory minimum four-week monitoring period. This status remains active until a comparable timeframe passes without any new human cases or viral detection in mosquito vectors, birds, or equids. The designation requires local authorities to intensify entomological, animal, and human surveillance, while boosting community awareness campaigns via primary care nursing and local pharmacies. Local administrations face strict operational timelines for mosquito management. According to the Junta de Andalucía, San Juan de Aznalfarache must maintain intensified mosquito control and treatment measures through August 24, while Palomares del Río must continue its reinforced vector treatments through August 11.

Human Cases and Environmental Monitoring Data

Mosquitoes carrying West Nile Virus found throughout 21Country

Public health records show that five mild cases of West Nile fever have been diagnosed in Andalusia this year. These cases were identified in Palomares del Río, Villamanrique de la Condesa, La Puebla del Río, and Coria del Río following laboratory studies performed on 262 individuals, arbovirus screening on 104 patients presenting with viral meningitis, and 950 negative screenings from blood donor banks. In the animal health sector, viral circulation was confirmed in two wild birds out of 208 tested. The Junta de Andalucía reported that passive surveillance identified two imperial eagle chicks found sick in Doñana National Park, far from residential areas. No West Nile virus circulation has been detected in equids during the current season. Since the onset of peak mosquito density periods, testing programs have analyzed 3,585 samples across 213 traps. Surveillance data shows a progressive increase in mosquito populations, with high densities of vector-competent female mosquitoes recorded in Coria del Río, Isla Mayor, La Puebla del Río, Los Palacios y Villafranca, Palomares del Río, and Villamanrique de la Condesa.