The detection traps for this type of mosquito located in Campillos (Málaga), Montalbán (Córdoba) and Villamanrique de la Condesa (Seville), reflect an upward trend in the population of Culex perexiguus, a species of West Nile Virus-transmitting mosquito, according to the latest report from the Andalusian General Directorate of Public Health and Pharmaceutical Regulation. These three municipalities are in grade II, that is, with a population of transmitting species of around 100-500 mosquitoes.
However, the report reveals that the population density of female mosquitoes potentially transmitting West Nile Virus remains relatively low, especially the species Culex perexiguus.
In addition, there has been a decrease in population density in the municipality of Malaga (in the area of the mouth of the Guadalhorce) currently classified in Grade III (last week in Grade IV). For this reason, the local area must continue with the appropriate vector surveillance and control measures, as the Board has stated in a statement.
The real-time analyzes carried out to date and taking into account the captures up to July 7 in the traps in the provinces of Cádiz, Córdoba, Málaga and Seville and up to July 14 in the province of Huelva, all of them reveal the absence of West Nile Virus.
Entomological surveillance (mosquito surveillance) is the key tool for the early identification of West Nile virus circulation in Andalusia, allowing the adoption of appropriate surveillance and control measures aimed at reducing the risk to the Andalusian population.
Periodic monitoring of vector populations (mosquitoes) by means of traps located at strategic points, allows us to know the different species of mosquitoes, the population density and the detection of the presence of West Nile virus in transmitting species such as Culex perexiguus, Culex pipiens, Culex modestus and Culex laticinctus.
The locations for the traps are located in 27 Andalusian municipalities, either because they are classified as high or moderate risk areas or to obtain information on the progress of the vector in territories with lower risk levels. The objective pursued is the early detection of the increase in the density of transmitting mosquitoes and the circulation of the virus in mosquitoes in order to inform the local administration to intensify surveillance, control and communication actions in their territory, thus reducing the chances of transmission to humans.
The criterion that has been used to locate the traps in the selected territories has been that of areas where a significant abundance of the four main vector species (mosquitoes) of the virus is expected prior to their greatest presence in population centers, that is, areas with the presence of stagnant water with low salinity.
On the other hand, in Andalusia more entomological surveillance activities are carried out on mosquitoes that transmit the West Nile virus. It is worth noting the work of the Doñana Biological Station (CSIC) itself with 7 trapping stations in the province of Seville and the execution of the Arboprevent Project that includes 800 sampling points in the provinces of Seville, Huelva and Cádiz, of which 400 are being sampled this year and 400 during 2024. The Mosquito Control Service of the Huelva Provincial Council has 23 trapping stations by appointment. gives province.
In addition, this information is coordinated and integrated with other surveillance carried out on horses and birds, by the regional animal health and wildlife authorities, and with human epidemiological surveillance, all of which are also monitored from this General Directorate.
