The General Directorate of Public Health and Pharmaceutical Management of the Ministry of Health and Consumption of the Andalusian Regional Government has declared alert areas in the neighborhoods of Retamar-El Toyo, with 11,000 inhabitants, and El Alquián, with 6,000 inhabitants, in the municipality of Almería after confirming the circulation of the West Nile virus (WNV) in mosquitoes captured in traps located in these areas. Likewise, it has raised the risk level from low to high for the entire municipality of Almería. This is the first declaration of an alert area and elevation of the risk level this season.
Health and Consumption sent the National Microbiology Center-Carlos III Institute in Madrid the samples of female mosquitoes collected on June 11 in El Retamar to confirm the positive result for WNV detected by our laboratories. The detection of these mosquitoes in a low-risk municipality confirms the working hypothesis of the Comprehensive Surveillance and Control Program for West Nile Fever Vectors for 2025 and reinforces the decisions made: no Andalusian municipality is exempt from the risk of WNV circulation and entomological surveillance precedes human surveillance.
The Ministry immediately communicated the information and decision to the Almería City Council and convened a meeting for this Saturday attended by the delegate of the Regional Government of Andalusia, Aránzazu Martín; the territorial delegate of Health and Consumption, Juan de la Cruz Belmonte; the mayor of Almería, María del Mar Vázquez; the councilor for Environmental Sustainability and Energy, Antonio Urdiales, and the company Athisa, responsible for pest control and environmental health in the municipality of Almería, which has been carrying out preventive treatments since April, to coordinate the joint action plan.
The meeting held at the Almería City Council was attended by the delegate of the Regional Government, Aránzazu Martín; the territorial delegate of Health and Consumption, Juan de la Cruz Belmonte; the mayor of Almería, María del Mar Vázquez; the councilor for Environmental Sustainability and Energy, Antonio Urdiales, and the company Athisa, responsible for pest control and environmental health in the municipality of Almería.
The declaration of the alert area, for a minimum period of four weeks or until no new cases are reported or the circulation of the virus in the mosquito vectors of this disease, birds, or equids in this territory is detected for an equivalent period, implies intensifying the three surveillances (entomological, animal, and human) in the area, activating promotion actions in schools and residences in the surrounding area, and reinforcing communication actions to the population through community pharmacies and nursing to adopt the necessary protection measures against WNV.
On the other hand, local administration must intensify control and treatment measures for mosquito transmitters of the disease during the period when the area is on alert.
Update of the Comprehensive Vector Surveillance and Control Program for WNV
In February of this year, the Ministry of Health and Consumption approved the update of the Comprehensive Vector Surveillance and Control Program for West Nile Fever for the 2025 season, in which more than 250 professionals participated from municipalities, provincial governments, scientific groups, public health inspectors, and companies, through meetings held between December and January.
This program establishes that all municipalities in Andalusia are included in some level of risk, and therefore, all have a need for virus control because it was found in the previous season that mosquito species transmitting (culex) are present throughout the Andalusian territory. These risk levels have been reduced to three (low, medium, and high) for easier understanding by all stakeholders, including the population, as well as the prevention and control measures associated with each level. In total, there are 103 municipalities at high risk, 313 at medium risk, and 369 at low risk.
The medium and high levels correspond to territories where the circulation of the West Nile virus has already been evidenced. The high level corresponds to evidence of WNV circulation near populations in any of the last three seasons. Thus, all municipalities should incorporate mosquitoes into their existing pest control programs (rodents, cockroaches, processionary caterpillars), diagnose potential larval sites within population centers or very close to them, and monitor them (in the case of low and medium risk) and, in high-risk municipalities, these measures should be extended to the entire municipal territory, with special attention to larval or adult refuge sites within 1.5 km of populations.
In March, all municipalities were informed of their risk level and public health inspectors (over 400 deployed throughout Andalusia) contacted them to provide technical advice on implementing surveillance and control measures, covering the entire year with the aim of keeping mosquito populations as low as possible when the peak virus circulation period arrives, from June to October.
Additionally, in the Special Monitoring Areas (La Janda in Cádiz and Bajo Guadalquivir in Seville), which account for over 95% of confirmed cases since 2021, the Ministry of Health and Consumption has implemented a surveillance of mild cases of WNV (non-neuroinvasive forms), where other pathogens have been ruled out, through PCR. 80% of infections in humans are asymptomatic. Around 20% of infected individuals present flu-like symptoms characterized by fever, headache, fatigue, myalgia, general malaise, nausea, vomiting, and sometimes a maculopapular rash and lymphadenopathy. Less than 1% of those infected develop severe neurological conditions (meningitis, encephalitis, or flaccid paralysis).
Similarly, the program expands entomological surveillance, based on mosquito trapping and virus detection through PCR, both in the number of traps and in the covered territory and time. Thus, the number of traps has increased from 27 to 120, all Andalusian provinces are included, and surveillance started in May, a month earlier than in 2024 and two months earlier than in 2023.
The program also improves the predictive model to assess the risk of WNV circulation, integrating the model developed by CSIC-Doñana, supplemented with data from the Ministry, including new variables such as land use, infected birds, or vector presence, among others.
It is also worth mentioning the mobilization of all actors involved in health promotion and prevention by the Ministry of Health and Consumption (family and community nurses, RELAS -Local Health Action Network- and pharmacies) in high-risk municipalities and the creation of a second reference laboratory in Andalusia, at the Virgen del Rocío University Hospital, in addition to the one at the Virgen de las Nieves University Hospital, to increase diagnostic capacity and speed of response.
Furthermore, coordination with other authorities is strengthened through winter preparation working groups, support to municipalities with more visits from public health agents to affected municipalities since March. The communication plan to the population is also improved to make them an active part of vector surveillance and control.
The objective of this program update is to increase support to municipalities and provincial governments in preparing for vector control; identify the early arrival of the virus; mobilize other health actors and communicate and better accompany the population in case of an alert situation.
Recommendations to the population
The Ministry of Health and Consumption has launched a social media campaign, in which all pharmacies in Andalusia also participate, coordinated by the CACOF (Andalusian Council of Official Pharmacies), recommending to the population to strengthen protection measures against this virus, especially among vulnerable individuals with compromised immunity.
Thus, the General Directorate of Public Health and Pharmaceutical Management emphasizes the need to use registered mosquito repellents (compounds such as DEET, Icaridin, Citriodiol, IR 3535, and essential oils at different concentrations and for topical use), cover most of the body with light-colored clothing and avoid strong odors (perfumes, scented soaps) as they attract mosquitoes.
Health authorities remind the population to reinforce domestic protection measures such as installing mosquito nets, using domestic insecticides/airborne repellents or turning off lights when not needed, as light attracts mosquitoes. Another essential measure is to avoid creating stagnant water areas, where mosquitoes breed their larvae, so it is recommended to properly maintain pools, swimming pools, and washbasins and to empty any water that may accumulate and go unnoticed in gardens, pots, toys, or buckets.
For livestock farms, it is also advised to regularly clean animal watering troughs; avoid water from puddles on vehicle tracks or roads, water leaks from taps or broken pipes, leaking water troughs, or those with poor renewal.