What is avian influenza?
Avian influenza, or bird flu, is a contagious disease of animals caused by viruses that normally infect only birds and, less commonly, pigs. Avian influenza viruses are highly species-specific, but have been known to infect humans. In domestic poultry, infection with avian influenza viruses causes two main forms of disease, distinguished by low and high extremes of virulence. The so-called “low pathogenic” form commonly causes only mild symptoms (ruffled feathers, a drop in egg production) and may easily go undetected. The highly pathogenic form is far more dramatic. It spreads very rapidly through poultry flocks, causes disease affecting multiple internal organs, and has a mortality that can approach 100%, often within 48 hours.
Avian influenza (also known as ‘bird flu’ or ‘avian flu’) is a contagious disease caused by viruses that normally infect only birds and, less frequently, pigs. These viruses do not tend to be transmitted from one species to another, but rarely, they can cross the species barrier to infect humans. In domestic poultry, infection with avian influenza viruses causes two main forms of disease: the so-called ‘low pathogenic form’ only causes mild symptoms. The high pathogenic form spreads very rapidly, causes disease affecting multiple internal organs, and has a mortality that can approach 100%, often only within 48 hours.
Avian influenza is a contagious viral infection that can affect all species of birds but can, less commonly, infect mammals. While all bird species are thought to be susceptible to infection, domestic poultry flocks are especially vulnerable to infections that can rapidly turn into epidemics. Wild birds may carry influenza viruses without becoming ill due to natural resistance. Wild waterfowl present a natural reservoir for these viruses and can be responsible for the primary introduction of infection into domestic poultry. Further evolution of these viruses amongst poultry may result in strains that are capable of causing a wide range of clinical illness, from no symptoms to a severe epidemic that kills up to 100 percent of infected birds.
Avian influenza, or bird flu or avian flu is an infection caused by avian (bird) influenza (flu) viruses. These flu viruses occur naturally among birds. Wild birds worldwide carry the viruses in their intestines, but usually do not get sick from them. However, bird flu is very contagious among birds and can make some domesticated birds, including chickens and ducks, very sick and kill them.
Avian influenza is a disease most commonly found among poultry. There are many subtypes of flu viruses, variants and strains that affect birds, other animals and even humans. The type of flu virus affecting birds and poultry flocks in Asia during recent months is called H5N1 highly pathogenic avian influenza (HPAI). This particular form of avian influenza is very deadly to poultry and can spread rapidly among an entire flock of birds. Other forms of the virus cause either no disease or mild disease in poultry and some wild birds.
