West Nile Fever (West Nile Fever) is a disease caused by the West Nile virus (West Nile Virus, WNV), a virus of the flaviviridae family, which has been first discovered and isolated in Uganda in 1937, precisely in the West Nile district (hence name). The virus can be found in Africa, West Asia, Europe, Australia and America.
The reservoirs of the virus are wild birds and mosquitoes (Culex most frequent type), whose bites are the main means of transmission of this virus to humans. Other means of infection documented, although much rarer, are organ transplants, blood transfusions and mother-to-fetus pregnancy. West Nile fever is not transmitted from person to person by contact with infected people. The virus can also infect other mammals, especially horses, but in some cases even dogs, cats, rabbits and others small animals.
Incubation and symptoms of West Nile disease
The incubation period from the time the bite of infected mosquito varies between 2 and 14 days, but can also last up to 21 days in subjects with deficiency of the immune system.
Most people infected show no symptoms of West Nile disease. Among symptomatic cases, about 20% have mild symptoms. These symptoms are fever, headache, nausea, vomiting, swollen lymph nodes and skin rashes. These symptoms may last for a few days, but in rare cases in can last for more than 2 weeks. But this depends entirely on the person who has been infected. In children is frequently a slight fever, symptoms in young people is characterized by high fever on average, red eyes, headaches and muscle aches. In elderly and debilitated, however, the symptoms can be more severe.
The diagnosis is mainly performed by laboratory tests (ELISA and immunofluorescence) performed on serum and, where indicated, on cerebrospinal fluid for the detection of IgM antibodies. These antibodies can persist for very long periods even in some patients (up to one year), so the positivity of these tests may indicate previous infections.
The samples are collected within 8 days of the onset of symptoms of West Nile disease. The result can be negative, so some patients might have to repeat the tests in order to be sure and to possibly exclude this disease. Alternatively, diagnosis may be obtained through PCR or viral culture on samples of serum and cerebrospinal fluid.
Unfortunately, at the moment there is no vaccine for the West Nile disease. Scientists are still studying the possibility of a vaccine, but right now, the best treatment for West Nile fever is prevention, which can be achieved through several ways. One of the most important aspects is to avoid mosquitoes and mosquito’s bites.
Therefore you should protect yourselves from mosquito bites and prevent any repetition easily, by using repellents and wearing long pants and long sleeved shirts when you are outdoors, especially at sunrise and sunset, by using mosquito nets, frequently emptying flower pots or other containers (e.g. buckets) with stagnant water, frequently changing water in bowls for animals and keeping the pool for the children in an upright position when not in use.
Therapy and treatment
At the moment there is no specific treatment for this disease, but in most cases, the symptoms of West Nile disease disappear in a few days or in a few weeks, depending on the immune system of the patient. You should know there are some severe cases in which the patients need to be hospitalized and need administration of intravenous fluids. These patients might also need to be assisted in breathing.