Bird flu, also known as avian flu or avian influenza, in humans is caused by influenza A virus specific to birds. The disease derives its name from the fact that birds infected with influenza A virus transmit it to humans, causing avian flu. According to the World Health Organization (WHO), the outbreak of bird flu started in southeast Asia in 2003. The Centers for Disease Control and Prevention states that since its outbreak, 400 confirmed human infection fatalities of avian flu have been reported; however, no human causality has yet been reported in the United States.
Bird Flu Pandemic
According to AvianInfluenza.org, when the bird flu virus was transmitted to humans, it exchanged its genes with human influenza virus. This gave rise to a subtype of avian virus referred to as H5N1. The same disease was responsible for the flu pandemic in 1918, then known as the Spanish Flu. Nearly fifty million people succumbed to this disease during this pandemic.
Influenza in Birds
Avian viruses harbor themselves in the intestines of wild birds. The organisms are then are transmitted to domesticated birds such as chickens, ducks and turkeys through their saliva, feces and other body excretions. Bird flu has two major forms: The low pathogenic form is generally harmless, and infected persons show mild symptoms. The high pathogenic form is more contagious and affects internal organs of the infected person. The CDC states that failure to provide treatment for the high pathogenic form of infection can lead to death in 48 hours. In fact, this form of bird flu has been the one responsible for most human casualties. In absence of treatment, death occurs in 90 to 100 percent of cases.
Human Infection and Bird Flu
Most bird flu cases in humans result from direct contact with the poultry that is infected, the CDC states. This contact can be in the form of blood, droppings or undercooked meat. However, the CDC states that it is rare to contract the virus directly from animals. H5N1 at present is unable to efficiently transmit itself from one person to another.
Symptoms
Symptoms of H5N1 are very similar to that of flu. The most common are high fever, sore throat, cough, headache and aching muscles, and these are typically seen in low pathogenic form of infection. Symptoms like eye infection and pneumonia may develop in the high pathogenic form of infection. A clinical test can only confirm the type of infection. In severe cases, untreated high pathogenic form of infection can lead to severe symptoms like brain and heart inflammation and respiratory distress, which may be fatal. However, a medical checkup is necessary only if one has traveled to one of the affected countries and has developed any of the above mentioned symptoms after returning. WHO and CDC list such countries. To date no incidence of bird flu has been reported in America.
Treatment
According to WHO, oseltamivir (Tamiflu) and zanamivir (Relenza) are the two main drugs used for reducing the severity of influenza symptoms, and experts at the CDC expect that they would be effective in treating bird flu. However, their efficacy can be assured only if they are given within 48 hours of occurrence of symptoms. Older antiviral drugs such as rimantadine and amantadine can also be used for treating bird flu. However, WHO states that H5N1 may quickly develop resistance against them, making these drugs ineffective.
Precautions
Since at the present time bird flu is spread only through direct contact with infected birds, it is necessary to stay away from ill-looking domesticated or wild birds. While traveling to one of the affected countries, any kind of bird meat should only be consumed after it has been cooked properly. Washing and sanitizing the hands after handling poultry eggs significantly reduces the risk of getting the infection. Fowl pets should not be allowed to mix with wild birds as they also may get infected and pass on the infection.
