The first clinical case of the Nile virus in the province of Córdoba, with the hospitalization of a resident of La Rambla, has triggered the alert in municipalities with a higher degree of density of potentially transmissible species, such as Montalban and Puente Genilwhere its monitoring stations have detected carrier mosquitoes throughout this summer.
As explained Ignacio Garcia BocanegraProfessor at the University of Cordoba, head of the Animal Health and Zoonoses Research Group and member of the Enzoem Competitive Research Unit, “the reason for the greater presence of the transmitting vector is none other than the climatologywhich this year has been very particular, with abundant rains in spring and high temperatures. We expected a rebound, just like what happened in 2020, where there were 77 people infected and eight deaths,” he explains.
However, “what usually happens is that preventive measures are applied late; must be taken beforenot when we already have the cases and the virus circulating,” explains the expert. The campaign is active in Alcaracejos, Peñarroya, Montalbán, the capital Córdoba, Puente Genil, Palma del Río, Fernán Núñez, Aguilar and Lucena, cities to which La Rambla is added.
WNV infection is a zoonosis transmitted by mosquitoes of the genus Culex (perexiguus, pipiens -the common mosquito-, modestus and laticinctus). They tend to proliferate, as García Bocanegra explains, because end of summer to beginning of winter and females can lay eggs from 50 to 200 eggs. “The areas where they breed are stagnant waters with some organic matter: flower pots, buckets or car wheel rubber“, says the professor, who emphasizes that “it circulates in Spain since 2010when the first clinical cases were detected.
The virus is transmitted in birds (corvids and ducks in particular) through the bite of infected mosquitoes, this is its natural cycle. “If the vector bites a human or other mammals, such as horses, they can be infected, but cannot transmit the disease, except through organ transplantation and blood transfusion.”
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Avoid outdoor activities around dawn and after dusk, when mosquitoes bite the most.
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Use of repellents for topical use (also on clothing) and environmental use. The National Epidemiological Surveillance Network recommends those based on DEET or others with active ingredients such as Icaridin, IR3535® and citrodiol.
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Lightweight clothing that covers most of the skin.
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Mosquito nets on doors and windows of houses.
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Avoid accumulations of peridomestic water (gardens, pots, tools, etc.).
However, “the 80 percent of infections are asymptomatic: That is, nothing happens to 8 out of 10 infected people, they develop antibodies and do not even realize they have been infected. 20% may have flu-like symptoms, such as headaches or muscle aches, but nothing else. And there is 1% of infected people, who belong to risk groups such as the elderly or immunocompromised, who develop a nervous-type disease, which causes serious neurological problems and even death,” explains the UCO researcher.
Mosquito lifespan
The mosquito species that most commonly transmits West Nile virus lives two or three weeks. “And during this period, it must bite an infected bird. “Once infected, the vector transmits it to its larvae.”
This professor predicts that treatments to prevent and eradicate the mosquitoes that transmit this virus “will have to to be implementedbecause there are more and more of them.
The density level of potentially transmissible species in an area corresponds to a scale of values of the number of potentially transmissible female mosquitoes captured. four degreesThe most dangerous would be the fourth, with the detection of more than a thousand mosquitoes. In Córdoba, Montalbán is in the 2nd grade and Puente Genil, in the 1st grade.
