Fever West Nile: what it is and how it prevents

In the last few days the news of the First victim of the year in Italy of the West Nile virustransmitted by mosquitoes: an 82 -year -old Lazio woman, infected in Fondi, in the Pontine hinterland, died following the neurological complications of the disease. But what is the fever West Nile? What mosquitoes do they transmit it? What symptoms causes, and how do you recognize? Is there to worry? Let’s try to respond to some of the most popular curiosities about this disease.

The West Nile virus is a family virus of Flaviviridaeidentified for the first time in 1937 in Uganda in the West Nile district, which gave its name to the disease. It is widespread in Africa, West Asia, Europe, Australia and America and is more frequently transmitted to man from the common mosquito (Culex Pipiens): Not an invasive species such as the tiger mosquito that transmits the dense, but but one of the most popular native species in our country.

However, other species of mosquitoes are also vectors, and all the factors that favor the spread of these insects, such as the presence of swampsabundant irrigation of the fields, climate change (abundant rains, high temperatures) can favor the increase in contacts. The West Nile virus is transmitted from man to man.

The West Nile virus causes a fever (fever West Nile) classified as arbovirosis: So the infectious diseases caused by arthropods are called, insects such as mosquitoes.

The disease, which has an incubation time of 2-14 days from the puncture, In 80% of cases it does not give any symptoms. In 20% of cases, generally in young adults, it causes light symptoms (fever, headache, nausea, vomiting, enlarged lymph nodes, skin rashes) which is resolved spontaneously. In less than 1% of infected people (1 person every 150 contagions), generally elderly people or with a compromised immune system, more serious forms can be presentedwith neurological symptoms (severe headache, disorientation, tremors, vision disorders, torpor, convulsion, paralysis, coma). In one case out of 1000 the virus can cause lethal brain.

As he explained to Courier Emanuele Nicastri, director of the unit of high intensity infectious diseases of the National Institute of infectious diseases Lazzaro Spallanzani in Rome, in the most serious cases after the presentation of the symptoms is generally assisted to an improvement, followed by a worsening with alterations of consciousness and confusion. In that case you have to accompany the patient immediately to the emergency room.

In healthy people, West Nile fever It is not a disease that must arouse particular alarmism: In most cases it is not even felt and in one case out of five it causes normal ailments associated with an influence.

However it is important that citizens are Find out about the prevention methods And that the health authorities take under control of its diffusion, to intervene by argin the contagions.

For the most fragile and for the elderly and in the areas most affected by the disease, as is now the Pontine Province (in the surroundings of Latina, in Lazio) it is appropriate to begin to conceive the prevention of mosquito stings like a health prophylaxis And not only as an anti-purrital caution. Wearing clear and long clothes, using repellents and mosquito nets, avoiding stationing in areas frequented by mosquitoes from sunset to dawn are small precautions that everyone can implement.

Another trick is Eliminate stagnant waterfor example from sauces, in bowls for animal water or in swimming pools, where mosquitoes lay eggs. Health authorities can possibly decide for targeted disinfestations, even if it is not possible to completely eliminate common mosquitoes. West Nile fever is prevented as follows: there are no vaccinesnor specific care.

In addition to the case of the elderly deceased, probably infected between 10 and 12 July, there are six other cases confirmed by Spallanzani, all in the same area, between Latina and its province (Priverno, Fondi and Cisterna). I am All indigenous cases and not imported from other regions or other countries. In four cases, the situation of patients does not cause concern, while two infected, two 63 and 72 -year -old men with previous diseases, have had neurological complications and are hospitalized in a Latin hospital.

According to the latest updates of the Istituto Superiore di Sanità, on 20 July 2025 there were 10 cases confirmed of infection by West Nile Virus in humans in Italy since the beginning of the year, including those just described in Lazio. The other three since the beginning of the year had occurred in Piedmont, Emilia Romagna and Veneto (two with neurological complications and only one with fever, in no case lethal).

In 2024 the total cases of West Nile viruses identified in Italy were 460: in 272 people the disease had caused neurological symptoms and 20 people died. In a good slice of cases (46) the virus was present in asymptomatic form and was discovered by chance in blood donors. The region most affected by West Nile Virus last year It was Veneto.

Anyway, The presence of this virus in Italy is not new. The first fever outbreak West Nile He was discovered in the summer of 1998 In the area surrounding the Padule di Fucecchio, the most extensive Italian internal swamp found in Tuscany, with some clinical cases in horses (animals such as man affected by the virus).

In 2002 the national surveillance plan for the virus was activated and, since 2008 and every year since then, cases have been found in humans, in at least 14 Italian regions (Emilia-Romagna, Veneto, Lombardy, Sardinia, Sicily, Friuli-Venezia Giulia, Piedmont, Molise, Tuscany, Basilicata, Lazio, Puglia, Calabria, Liguria).

The West Nile virus is therefore endemic in our country And its circulation, thanks to the conditions that favor mosquitoes, has gradually increasing. The worst year has so far been 2018, with 606 human cases confirmed of infection, 239 have manifested themselves in the neuroinvasive form.