West Nile virus travels on the Culex mosquito and is also circulating in the South, according to an expert.

" The human cases of West Nile identified in Latina are causing a stir because they are among the first of the year and because they have been reported as indigenous to the Lazio region. However, this virus , as indicated by various reports from the Istituto Superiore di Sanità (ISS), including last year, in addition to being highly present and endemic in Northern Italy, especially in the Po Valley, also circulates in Southern Italy , particularly in animals: birds, which are the main host, and mosquitoes. And there have also been confirmed cases in the past in other regions of Central and Southern Italy." Sara Epis , associate professor of parasitology at the University of Milan and member of the board of directors of the Italian Society of Parasitology, outlined the situation to Adnkronos Salute.

West Nile virus, the expert explains, "is transmitted by mosquitoes we call 'nocturnal,' especially Culex pipiens . These mosquitoes also circulate in central and southern Italy. In these areas, we've also seen birds testing positive for the virus, and birds are the main 'reservoir' of the pathogen. In short, the presence of indigenous human cases is not surprising." There will be more cases as we enter the typical West Nile season. "We will certainly see them in Northern Italy, where the first infections were already recorded in June, especially in the Northeast. To put this into perspective, last year there were more than 450 confirmed cases of West Nile in Italy, including deaths. In more or less recent years, the figure has consistently hovered around 400 diagnosed cases, with a peak concentrated in the months of July and especially August, followed by a tail-off in September."

What kind of host are humans for this virus? "West Nile virus is essentially maintained in nature by transmission from infected mosquitoes and birds, which are the reservoir," the parasitologist explains. "So these mosquitoes, which are 'ornithophilous,' bite birds, but they can also accidentally bite humans and equines, particularly horses. However , both equines and humans are dead-end accidental hosts . In humans, the virus does not reach high enough blood concentrations to allow infection of other mosquitoes through their bite, thus preventing the transmission cycle from continuing. The West Nile virus cycle is maintained by mosquitoes, which act as vectors and amplifiers, and birds, which are the main reservoir of the virus."

As a trend, Epis observes, "over the years we have seen an increase in cases of arboviruses, probably because there is an expansion underway, so much so that monitoring plans are in place for these arboviruses, including West Nile and Usutu viruses. What is driving this? Climate change is certainly aiding this process, favoring an increasingly stable presence of mosquitoes. Higher temperatures and mild winters favor the survival of mosquito vectors (particularly Culex pipiens) and accelerate their reproductive cycle, increasing populations and extending the transmission season. And the role of birds , their increased presence in urban environments, is likely also contributing. But there could be many factors contributing to this trend."

How can you protect yourself? "By being careful, during the night, to use repellent, wear appropriate clothing with long sleeves, and thus avoid exposure to possible bites in areas where we know the virus is circulating," he concludes.