The Department of Health and Consumption activates entomological surveillance of mosquitoes carrying the West Nile virus (WNV) during the first week of May. In addition, a social media campaign has been launched, involving all pharmacies in Andalusia, coordinated by the CACOF (Andalusian Council of Official Pharmacists), recommending that the population strengthen protection measures against this virus, especially among vulnerable individuals with compromised immunity.
Thus, the Directorate General of Public Health and Pharmaceutical Regulation emphasizes the need to use registered topical mosquito repellents, cover most of the body with light-colored clothing, avoid strong odors (perfumes, scented soaps…) as they attract mosquitoes, and avoid going out at dawn and dusk, which are peak mosquito activity times.
Likewise, Health reminds of the need to reinforce domestic measures: install mosquito nets, use domestic insecticides/ambient repellents or turn off unnecessary lights as light attracts mosquitoes.
Another key measure is to prevent stagnant water areas where mosquitoes breed, so it is recommended to properly maintain pools, swimming pools, and washbasins and empty any accumulated water that may go unnoticed in gardens, pots, toys, or buckets.
In the case of livestock farms, it is also advised to regularly renew animal watering troughs, avoid water from puddles on vehicle tracks or roads, leaks from taps or broken pipes, as well as in watering troughs with leaks or poor renewal.
Authorized and registered repellents
Using body repellents is a good option to protect exposed areas of the body from bites (neck, hands…), but they must be appropriate to age and specific situation, so it is recommended to carefully read the labeling instructions; ensure the repellent is authorized and registered (the registration number should appear on the packaging information); follow application instructions and test it on a small area of the skin beforehand to avoid allergic reactions. The product should be applied to the hand to spread it on the skin, avoiding contact with eyes, mucous membranes, wounds, and sensitive areas. Special caution should be exercised when applying repellents in the case of children under three years old, pregnancy and lactation, and pre-existing health issues.
In general, repellents may contain DEET (N,N-diethyl-m-toluamide), Icaridin, Citriodiol or PMD, IR 3535 (Ethyl butylacetylaminopropionate), and essential oils (geraniol, lavender…) at different concentrations. These ingredients have been proven to be effective and safe when used according to instructions, although their effectiveness depends on factors such as the active ingredient and its concentration, ambient temperature, exposure to water, simultaneous use of sunscreens, and individual’s level of sweating.
The Department of Health and Consumption reminds that repellent protects against bites, but does not kill the insect, so despite its use, the rest of the recommendations should also be followed. Moreover, it is requested to take extra protection measures at festivals and pilgrimages that will take place in upcoming dates in high-risk municipalities.
Infection with WNV is a zoonosis transmitted by mosquitoes of the Culex genus. The virus is transmitted among birds through the bites of infected mosquitoes, which is their natural cycle. Humans and other mammals can be incidentally infected, without new transmissions occurring from them. According to published risk assessments, around 80% of WNV infections in humans are asymptomatic. West Nile Fever (WNF) is the most common clinical presentation. Elderly individuals and immunocompromised people are at higher risk of developing West Nile Neuroinvasive Disease.
Increase in traps and other measures
The Comprehensive Surveillance and Control Program for West Nile Fever Vectors for the 2025 season also expands entomological surveillance, based on mosquito trapping and virus detection through PCR, both in the number of traps and the covered territory and time. Thus, the number of traps is increased from 27 to 120, all Andalusian provinces are included (all Andalusian municipalities have a risk level: low, medium, or high) and it starts in May, a month earlier than in 2024 and two months earlier than in 2023.
It is noteworthy the mobilization of all health promotion and prevention actors from the Department of Health and Consumption (Family nurses, school and community references, 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, which will allow for a greater capacity and speed in diagnostic response.
Furthermore, coordination with other administrations through working groups for the season preparation that began in winter is strengthened, as well as support to municipalities through more visits by public health agents to affected municipalities since March (over 400 agents deployed throughout the territory). The population communication plan is also improved, to make it an active part of vector surveillance and control.
The goal of this program update is to increase assistance to municipalities and councils in preparing for vector control, early identification of virus arrival, mobilization of other health actors, and better communication and support to the population in case of alert situations.
