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West Nile fever, what is the disease caused by a mosquito bite

Eight months spent in the hospital following a mosquito bite that gave him the West Nile fever. Protagonist of the story, told in these days on the Official of Modena, was a 77 year old from Cavidole di Castelnuovo. It all began last summer when Giulio Brighenti, this is the man’s name, begins to experience sudden tremors and is rushed to the emergency room. Within 48 hours, the 77-year-old ends up in intensive care, intubated and sedated until the diagnosis is made: it is West Nile fever transmitted by a mosquito bite. After two weeks Giulio Brighenti comes out of a coma but the rehabilitation process from the disease, which has deeply weakened the body, made it necessary 8 months of hospitalization in hospital.

So what is West Nile fever? And what are the risks?

According to what is reported on the site EpiCentro of the Higher Institute of Healthit is a disease caused by the West Nile virus (West Nile Virus, Wnv), isolated for the first time in 1937 in Uganda, precisely in the West Nile district, from which it takes its name.

The reservoirs of the virus, that is widespread in Africa, Western Asia, Europe, Australia and Americaare the wild birds but also the mosquitoes whose bites appear to be the main means of transmission to humans. West Nile fever in fact, it is not transmitted through contact with infected people.

How long after the puncture does the fever start?

According to the indications of the Istituto Superiore d Sanità, the incubation period from the moment of the infected mosquito bite varies between 2 and 14 daysbut it can come even 21 days in people with deficiencies in the immune system.

What are the symptoms of West Nile fever?

West Nile fever is infected in most people it does not involve any symptoms. It is estimated that only 20% of symptomatic cases, present mild ailments including fever, headache, nausea, vomiting, swollen lymph nodes and skin rashes. These are symptoms that can last a few days, more rarely a few weeks, and which tend to vary greatly depending on the age of the person. In children it is more frequent that a light fever occurs, in young people a medium-high fever, with redness of the eyes, headache and muscle aches, while in the elderly and in debilitated people, however, the symptoms can be more severe.

What are the consequences of West Nile fever?

Alone in rare cases West Nile fever entails severe symptoms that require hospitalization. Such symptoms include high fever, severe headache, muscle weakness, disorientation, tremors, visual disturbances, numbness, convulsions, up to paralysis and comahowever, occur on average only in less than 1% of infected people, that is in one in 150 people. In even rarer casesor in about one in a thousand patientsthe virus can cause lethal encephalitis.

How is West Nile fever diagnosed and treated?

To attest to the presence of West Nile fever are performed lab test carried out on serum and, where indicated, on cerebrospinal fluidto search for antibodies of the IgM type. It should be noted that these antibodies can persist for very long times in sick subjects, even up to one year: this means that the positivity of the tests can indicate not only an infection in progress but also a previous infection.

As for the treatment, there is no specific therapy. In most cases, the symptoms disappear on their own after a few days or they can last for a few weeks at the most. Alone in the rare more serious cases the hospitalization and the use of intensive care.

How to prevent the risks?

There is currently no vaccine for West Nile fever, so the only recommendation is that of try to reduce exposure to mosquito bites, using special repellants and wearing long pants and long-sleeved shirts when outdoors, especially at sunrise and sunset. Not only that, it is also important limit as much as possible those conditions in which mosquitoes can reproduce more easily: it is therefore advisable to frequently empty flower pots or other containers with stagnant water as well as frequently change the water in bowls for animals.

West Nile fever in children

According to what is reported on the site of the Bambino Gesù Hospitaleven in children, in 67% of cases, the disease occurs in a mild form characterized mostly by fever, headache, rash, muscle pain, or gastrointestinal symptoms. Specifically, the rash is type maculopapularthat is, it comes up with a area of ​​red skin on which there are small lesions in relief with respect to the cutaneous plane. Acute symptoms in children last 3 to 10 days in most cases, but in some they can last longer.

Even with regard to the little ones, forms involving the central nervous system (encephalitis and meningitis) they occur in only about 1% of infections. While encephalitis has been more commonly reported in the older age groups, meningitis is more frequently described in children. Small immunocompromised patients seem to have a greater risk of developing the disease in a severe form, however, according to what was reported by the experts of the Bambino Gesù Hospital, many cases described in the literature have occurred in previously healthy children. It is also good to keep in mind that once you recover from the virus, immunity lasts for life.

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Source: Vanity Fair

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