Avian influenza: diagnosis
Last reviewed: 23.04.2024
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Proper diagnosis of avian influenza in the early period is the starting point for organizing targeted treatment, timely antiepidemic measures and determining the prognosis. However, in the pathway to diagnosing avian influenza there are certain objective difficulties associated with the similarity of the clinical picture of this disease and other acute respiratory viral infections.
Preliminary diagnosis of influenza A (H5N1) can be based on the following epidemiological history and clinical manifestations:
- presence of reports of outbreaks of influenza A (H5N1) among the population of birds and animals or about cases of death of poultry in the patient's region of residence;
- contact with a sick person who confirmed infection with the influenza virus (H5N1) seven days before the appearance of the first clinical signs;
- contact with a patient with an unclear etiology, including those that ended up lethal, seven days before the appearance of the first clinical signs;
- an indication of the patient to travel to a country or territory where there are reports of an unfavorable epidemiological and / or epizootic situation for influenza A (H5N1);
- the presence of a professional risk of infection of the patient;
- high fever combined with difficulty breathing, coughing;
- Diarrhea (in the absence of admixture of blood in the feces).
The final diagnosis can be made after laboratory confirmation.
Laboratory diagnosis of avian influenza is based on methods of virological research, serological reactions, immunofluorescence analysis and PCR.
Differential diagnosis of avian influenza in humans
Taking into account that symptoms of respiratory tract infection appear in case of influenza A (H5N1), differential diagnostics of avian influenza with other acute respiratory infections is necessary: "traditional" influenza (A, B), severe acute respiratory syndrome, parainfluenza, respiratory syncytial. Adenovirus and enterovirus infections, as well as legionellosis and ornithosis.
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