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Avian influenza in humans
Last reviewed: 19.11.2021
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Avian influenza is an acute zoonotic infectious disease with predominantly fecal-oral mechanism of transmission of the pathogen. It is characterized by a pronounced febrile-intoxication syndrome, lung damage with the development of respiratory distress syndrome and high lethality.
ICD10 code
J10. Influenza caused by an identified virus.
What causes avian influenza in humans?
Avian influenza is caused by strains of influenza A, which usually infects only wild birds (sometimes swine). Infection with these strains has recently been found in humans.
Most human infections are caused by strains of avian influenza type H5N1, but a certain role is played by H7N7, H7N3, H9N2. In wild animals, the infection is asymptomatic, but leads to a high lethality of wild birds. The first case of human disease was detected in 1997 in Hong Kong. Transmission to humans occurs from infected sick poultry. In 2003-2004, people were infected with avian influenza strains in various Asian regions (H9N2 and 2005 - H5N1), in Canada (H7N3) and the Netherlands (H7N3). Although most cases involve contact with an infected bird, there may have been a transmission from person to person in the Netherlands and Asia.
All influenza viruses are capable of rapid mutations, which increases the possibility of avian influenza viruses to be transmitted from person to person. This can occur as a result of direct mutation or recombination with human strains in a human or intermediate host. Many experts believe that when the virus acquires these properties, a pandemic will break out.
What are the symptoms of avian flu?
Avian influenza (influenza A (H5N1)) has an incubation period that is 2-3 days with fluctuations from 1 to 7 days.
Avian influenza H5N1 causes severe respiratory symptoms. The death rate was 37% for the epidemic in 1997 and nearly 80% for the 2004 epidemic. H7 infection most often causes conjunctivitis, although several patients had influenza-like symptoms during an outbreak in the Netherlands and one patient (out of 83) died.
What's bothering you?
How is avian influenza diagnosed?
When identifying patients with clinical symptoms in places where there are avian influenza patients or infected birds, one should think about this infection. If the patient returned from the area where there were cases of avian influenza, he should undergo a PCR analysis to detect influenza A. Do not try to cultivate the virus. If suspected or detected and confirmed, the disease should be reported to the Center for Disease Control and Prevention.
What do need to examine?
How to examine?
How is Avian Flu Treated?
Avian influenza is treated with oseltamivir and zanavir is indicated in usual dosages. The epidemic of 2004 showed that the strain H5N1 is resistant to amantadine and remantadine. Prevention is carried out by the destruction of infected bird accumulations.
What is the prognosis of avian influenza?
Avian influenza has an unfavorable prognosis. Mortality is 50-80% in the second week of the disease.