Everyone Healthy Library
Condition / disease reference page from the Everyone Healthy database.
Some health conditions or symptoms can become urgent. Use this page for education, but seek help quickly if warning signs are present.
Get urgent medical care now if there is any severe, sudden, rapidly worsening or worrying symptom, especially:
Connected health information
Condition overview
Each sign/symptom opens its own page and links back to related conditions.
No linked drugs are listed yet.
Grouped by treatment type. These are educational database links, not personal treatment recommendations. Evidence labels are shown only where stored in the EH database.
No linked treatment or supportive options are listed yet.
These are pulled from both EH diagnostic-test link tables, including the older large test-link table.
This visual map shows biological markers/agents reported as increased or decreased with this condition. These are educational relationships only; test results must be interpreted by a qualified clinician because ranges vary by lab, method, age, sex and clinical context.
No markers in this group.
Introduction / full article
Influenza (often abbreviated to flu) is an infection of the respiratory system caused by an influenza virus. Throughout the world, outbreaks of influenza occur during the winter season. The illness occurs in epidemics, with large numbers of people all becoming sick at once. Usually, each outbreak can be attributed to one strain of influenza virus. These strains evolve continuously, meaning that the influenza virus differs from year to year.
Avian influenza is caused by several strains of influenza which normally affect wild birds. It is easily spread between birds – both wild and domestic – and sometimes even pigs, though rarely from animals to humans. In most cases, humans acquire avian influenza through very close contact with an infected bird.
The current strain of bird flu, H5N1, which is particularly concentrated in Asian and Middle-Eastern countries, causes an infection which cannot be spread to other people. Currently, the main concern regarding H5N1 is that it is likely to mutate, and potentially in such a way that the virus can be transmitted from person to person. This would facilitate the rapid spreading of avian influenza, leading to a worldwide pandemic. A vaccine against avian influenza is currently being developed.
