The Ministry of Health and Consumer Affairs of the Government of Andalusia announced on Monday that seven new cases of West Nile virus (WNV) were confirmed last week in two people from Mairena del Aljarafe, one person in Palomares del Río, another person in Aznalcázar, one in Bollullos de la Mitación, another in the Sevillian capital and one in the municipality of Jaén, Linares. Of these cases, three have already been discharged and the death of a person from Mairena with previous pathologies has been confirmed. Seven people have now died from this infection.
According to the epidemiological studies carried out and according to the probable date of exposure of the cases, “almost all of their exposures took place around the first half of August”, as reported by the Commission in a press release. On the other hand, the presence of WNV was detected in the captures made in the Cádiz municipalities of Benalup Casas Viejas and Vejer de la Frontera; in the Sevillian municipality of Las Cabezas de San Juan; and in Montalbán in Córdoba.
Likewise, thanks to the integration of surveillance, Public Health informs that the Doñana Biological Station of the Higher Center for Scientific Research (CSIC) has also located the presence of WNV in mosquitoes captured in the rural environment of the Dehesa de Abajo de La Puebla del Río in Seville and in Zufre, in Huelva. In turn, the presence of the West Nile virus has been detected in seven horses: three in the Cádiz municipality of Jerez de la Frontera, one in Aznalcázar, one in El Pedroso, one in La Rinconada and one in Villamanrique de la Condesa; the latter three in the province of Seville, reported by the Ministry of Agriculture, Fisheries, Water and Rural Development.
Salud y Consumo has informed municipal officials of the public health actions that they must adopt as provided for in the Programme for the Surveillance and Comprehensive Control of Vectors Transmitting West Nile Fever (WNF) in Andalusia to “significantly reduce” the probabilities of transmission to the population. population, in addition, based on the analysis of the weekly results of the species, densities and circulation of the virus, it maintains continuous monitoring of the mosquito surveillance and control actions carried out by the pest control companies contracted by the Provincial Councils of Cádiz and Seville to control peri-urban areas and specifically, with regard to actions inside the cities, carrying out weekly “on-site” checks and follow-up meetings with the most affected municipalities and the companies they have commissioned.
High levels in Los Palacios and Villafrancay in La Puebla del Río
In addition, the weekly report of Public Health concludes that the population densities of females of potentially transmissible mosquito species are high (Grade III and IV) in Los Palacios and Villafranca (Seville) and in La Puebla del Río, in the east of Brazo del Río. (Seville) and at medium levels (Grade II) in Villamanrique de la Condesa (Seville) and Vejer de la Frontera (Cádiz).
According to the density data obtained from different sources of information, it can be concluded that the densities of transmitting mosquitoes have decreased significantly in the province of Seville in most of the traps, maintaining medium or high densities in the traps of Villamanrique de la Condesa (south of the city), La Puebla del Río (Brazo del Este) and Los Palacios and Villafranca (northwest of the city).
Likewise, the detection of West Nile virus has decreased in captured mosquitoes, its absence in most of the traps in this province during the last week of August. Regarding the province of Cádiz, last week a “moderate decrease” in capture densities was detected, although the circulation of the virus continues in the rural areas of Vejer de la Frontera and Benalup Casas Viejas during the last week of August.
WNV infection is a zoonosis transmitted by Culex mosquitoes. The disease affects southern, eastern and western European countries. The virus is transmitted between birds through the bite of infected mosquitoes, which is its natural cycle. Humans and other mammals can be infected collaterally, without further transmission occurring. Approximately 80% of human WNV infections are asymptomatic.
FNO is the most common clinical presentation. Older and immunocompromised people are at higher risk of developing West Nile neuroinvasive disease. The Ministry of Health and Consumer Affairs emphasizes the need for the population to maintain preventive measures to avoid mosquito bites during the hours of greatest activity of the species that transmit this disease, at dawn and after dusk, both individual and domestic. These recommendations should include avoiding accumulations of water to prevent them from being used for the development of mosquito larvae.
