West Nile fever virus
The article provides basic information about the West Nile fever virus, its routes of transmission, its diagnostic methods, and its treatment options.
West Nile fever virus (WNV) is part of the genus Flavivirus, the family Flaviviridae, which circulates in Africa, West Asia and the Middle East. It was first isolated in 1937 from a feverish woman in the West Nile region (Uganda), and therefore got its name. Later, it became clear that VLZN is one of the most common representatives of flaviviruses. It has caused sporadic outbreaks of disease in humans and animals in Europe, and in 1999 the first reports of virus detection in the United States appeared, where in 2003 alone, more than 9,000 cases of infection were reported. were registered, including 200 fatalities.
The disease is a zoonotic infection. The main hosts of the virus are wild birds, which have a prolonged and severe viremia sufficient to infect the mosquitoes that transmit the infection. West Nile fever virus can be transmitted to humans and other animals through the bite of infected mosquitoes, however, a person is infected "by accident" and is unable to maintain the cycle of life of the virus due to the transient nature of viremia. However, blood-to-human transmission of VLZN has been recorded during organ transplants and breastfeeding.
As a rule, West Nile fever virus causes a relatively mild illness - West Nile fever, which manifests as flu-like symptoms: fever (moderate to high), headache (usually frontal), myalgia , arthralgia, weakness, nausea and respiratory symptoms. Of particular concern in this regard has been the frequent increase in fatal high-risk encephalitis caused by IDD in recent years, which has allowed a number of scientists to speculate on the emergence of new strains of virus. neurovirulent.
The main diagnostic method is the detection of IgM antibodies against West Nile fever virus in blood plasma or cerebrospinal fluid. Their presence in the cerebrospinal fluid indicates damage to the central nervous system, because normally antibodies cannot penetrate the blood-brain barrier. Due to cross-reactivity with other members of the genus Flavivirus, it is necessary to evaluate the results of serological tests with caution. Computed tomography and nuclear magnetic resonance, as a rule, do not show changes in the early stages of damage to the central nervous system, although pathological lesions in the region of the bridge, thalamus and gray central nuclei of the brain may be detected in some cases.
In most patients, the infection takes place in a mild form and does not require any specific treatment. To date, there is no therapeutic agent having a persistent effect against VLZN. A number of approaches, including the use of interferon-α 2b and large doses of immunoglobulins, have shown promising results in animal models, but experience with their use in clinical practice is limited to individual cases. New drugs and vaccines are being developed for West Nile fever.