What is West Nile Virus/ How is it transmitted and symptoms

2024-08-08 12:48:00, Shëndeti VASIL LLAJO

What is West Nile Virus/ How is it transmitted and symptoms

VASIL LLAJO

The West Nile virus has been circulating in Albania and the Balkan countries for the past month. It is transmitted by the bite of ordinary "infected" mosquitoes. It belongs to the family of Arboviruses with monoclonal RNA genomes.

It was first isolated in the West Nile area of ??Uganda in 1937, from where it got its name. In 80% of cases the exposure is without symptoms, in 20% it causes fever, headache, vomiting, muscle weakness, exanthems on the skin (mainly shoulder and chest). In 1% of cases it can be manifested by affecting the central nervous system such as encephalitis, meningitis, very rarely and death (less than 1/1000 cases).

Mosquitoes get the virus from the blood of birds infected with this virus. Birds are also carriers of the virus. There is no vaccine for humans. There is no specific therapy either. Treatment is symptomatic and determined by the clinic and its severity. The laboratory tests performed in this case are IgM and IgG antibodies.

IgM antibodies appear the first 8 days after exposure to the virus. They are made in the blood and in the cerebrospinal fluid (for patients affected by the Central Nervous System).

The analysis of IgM antibodies is the first analysis, which is performed in patients who have shown symptoms. It is worth noting that if the patient has no symptoms, it is not recommended to perform these tests. The positive presence of IgM (positive IgM) indicates that the patient is affected by the virus. If the presence of IgM antibodies is negative, this analysis is repeated after a few days.

IgG is also produced, simultaneously with IgM. When both are positive, it indicates current exposure of the organism to this virus. The presence of only IgG (IgG positive) indicates an earlier exposure to the virus, months or years ago.

However, it is possible that after the third week from the onset of symptoms, IgG will be positive and IgM will be negative.
This is where laboratory interpretation comes into play, according to scientific criteria. To evaluate the clinical course of the disease, the test of IgM and IgG is repeated after 3-4 weeks, to see if the level of the antibody titer has increased or decreased.

Another route of transmission of the virus is through blood, i.e. if blood is transfused from a patient infected with the Nile virus to another patient. If the disease appears in a baby, who is fed only with mother's milk, then the mother should be examined to determine the route of transmission through the mother's milk. This happens rarely. However, this route of transmission is scientifically confirmed.

There is also the PCR method, the determination of the nucleic acid of the virus by molecular biology, to determine whether the organism is affected by the virus. With this method, the virus is detected before the appearance of antibodies.

Since the most common period of appearance of this pathology is related to the period of multiplication and appearance of mosquitoes, it is recommended to take measures to fight against them. It is worth noting that this disease is transmitted by ordinary mosquitoes and not by any "special" mosquitoes./CNA