More cases of West Nile in Italy than last year. But even more cases than those recorded in 2018, considered by experts to be an exceptional year for the circulation of this virus that is transmitted through the bite of mosquitoes.
According to the latest bulletin of integrated surveillance (published by the Istituto Superiore di Sanità on August 24), from the beginning of June 2022 to August 23, 301 infections in humans were confirmed, of which 160 occurred in a neuro-invasive form and 15 patients died. From the beginning of June to 22 August 2018, on the other hand, 255 cases were confirmed, of which 103 in a neuro-invasive form and 10 deaths.
The numbers of 2022 are also higher than the years after 2018. Until 25 August 2021 there were only 18 confirmed cases of West Nile infection, of which 12 in a neuroinvasive form. In 2020, up to August 26, there were 22 cases, of which 16 were neuro-invasive. Up to 21 August 2019 there had been 14 cases, of which 6 in a neuroinvasive form. In none of the three years were there any deceased patients.
West Nile, symptoms and how it is transmitted
West Nile is a bird virus that is transmitted to humans through infected mosquito bites. The incubation period is variable, from 2 to 14 days. In most people, the infection is asymptomatic, those with symptoms, however, have fever, headache, muscle and joint pain, vomiting, diarrhea, swollen lymph nodes and skin rashes and, as has merciless the ISS, they can last a few days – in rare cases a few weeks. The age and health conditions of those affected by the virus can prolong its duration, it is no coincidence that the elderly and those with diabetes and hypertension risk more serious consequences.
The most severe symptoms, which affect less than 1% of those who contract the infection, are high fever, severe headaches, muscle weakness, disorientation, tremors, visual disturbances, numbness, convulsions.
West Nile, because the diffusion has increased
If 2022 is proving to be the year with the greatest spread of the West Nile virus, the cause would be to be found in the low rainfall of recent months. Due to the drought, less water stagnation was recorded, so the mosquitoes found themselves sharing the breeding environments with migratory birds. This is why the virus, which comes from birds, came into contact more easily with mosquitoes which then transmit it to humans, as explained by biologist Fabrizio Montarsi of the Experimental Zooprophylactic Institute of the Venezie.
West Nile, the most affected regions
In Italy, the regions most affected this year were Veneto, Piedmont, Lombardy, Friuli-Venezia Giulia and Emilia Romagna. However, some cases have also been recorded in Tuscany and Sardinia, while in Europe the virus has spread mainly in Greece, Austria, Romania and Slovakia.
West Nile, controls and prevention
To keep the virus under control, since 2008, its presence is detected every year during the period of activity of mosquitoes, thanks to an active surveillance plan throughout the territory, issued by the Ministry of Health and implemented by the Higher Institute of Health with the contribution of the experimental zooprophylactic institute of Abruzzo and Molise.
There is currently no vaccine, so prevention is essential. First of all, it is useful to reduce exposure to mosquito bites, by using repellent products or by covering the most exposed parts of the body, especially outdoors, at sunrise and sunset. Among the precautions also empty the flower pots frequently and avoid water stagnation.
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