The Junta de Andalucía has declared an alert area for West Nile Virus in Constantina (Seville) after the detection of carrier mosquitoes. It is the fifth Andalusian locality this year.
The Junta de Andalucía has activated the alert for West Nile Virus in the Sevillian municipality of Constantina, after a trap set by the Diputación de Sevilla captured mosquitoes carrying the pathogen. The declaration, made this Saturday, places the Sierra Norte locality as the fifth in the autonomous community where the virus is detected in circulation in 2026.
A summer with increased vigilance
According to the Ministry of Presidency, Health and Emergencies, previous alert areas include the municipalities of Pulpí (Almería), Torredonjimeno (Jaén), Palomares del Río (Seville), and partially Benacazón, where detection occurred more than 1,500 meters from residential areas and did not require an alert. In Constantina, however, the proximity to inhabited areas has necessitated the activation of the protocol.
The Comprehensive Surveillance and Vector Control Programme for West Nile Fever establishes that once an area is declared on alert, three types of surveillance must be intensified: entomological (mosquitoes), animal, and human. Additionally, community promotion actions are activated and communication to the public is reinforced through pharmacies and nursing services to encourage protective measures.
Measures for the Town Hall and residents
The Town Hall of Constantina, governed by the PSOE, is obliged to intensify mosquito control and treatment measures during the alert period, which will extend until August 10. This includes acting not only in the urban area but also in larval breeding sites and adult refuges located up to 1.5 kilometres away. Furthermore, it must enhance information and awareness among residents.
“The declaration of the alert area means intensifying surveillance and activating community promotion actions so that citizens adopt the necessary protective measures,” states the Ministry's communiqué.
For residents, recommendations include avoiding water accumulation in pots, buckets, or inflatable pools, using repellents and mosquito nets, and wearing light-coloured clothing that covers arms and legs at dusk, when mosquitoes are most active. The Junta reminds that most infections are asymptomatic or present with mild symptoms similar to flu, but in older adults or those with weakened immune systems, it can lead to meningitis or encephalitis.
A mild case and increasing mosquito density
To date, in 2026 only one mild case of West Nile Fever has been diagnosed in Andalucía, specifically in Palomares del Río. However, health authorities warn of a progressive increase in the densities of female transmitting mosquitoes. In the last week, abundant densities have been recorded in Coria del Río, Isla Mayor, La Puebla del Río, Los Palacios, and Villafranca and Lebrija. In Gerena, La Carlota, and Bailén, densities were intermediate.
The West Nile Virus is transmitted through the bite of mosquitoes of the Culex genus, which become infected by biting carrier birds. It is not transmitted from person to person. The Junta insists that prevention is key and that citizen collaboration is essential to reduce mosquito breeding sites.
The alert in Constantina serves as a reminder that the virus continues to circulate in the province of Seville. Residents of the Sierra Norte must take extra precautions in the coming weeks, especially during cooler hours when mosquitoes are more active. The Town Hall has already begun applying larvicidal treatments in risk areas and distributing informational leaflets.
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