Bird flu, also known as avian flu or avian influenza, is an infection by viruses normally residing in healthy, wild birds. Avian influenza, however, can cause serious illness and death in domesticated birds such as chickens, turkeys and ducks, according to the Centers for Disease Control and Prevention. Avian influenza in humans has been seen since 1997, and is contracted mainly through contact with infected birds. The effects of avian influenza in humans can be fatal.
Features
The Writing Committee of the World Health Organization, or WHO, Consultation on Human Influenza A/H5 published their findings in the September 2005 issue of the "New England Journal of Medicine" on human cases of avian influenza and reported most occurrences have occurred in previously healthy children and young adults residing in Africa, Asia, Europe and the Near East. Although a rare disease in humans, more than half of people infected with the virus die from the infection. The Centers for Disease Control and Prevention, or CDC, has expressed concern regarding the ability of the avian influenza virus to mutate, confounding diagnosis, treatment and prevention. Most cases are transmitted from infected poultry but there are rare sporadic occurrences of human-to-human transmission of the avian influenza virus.
Clinical Course
The clinical course of the effects of avian influenza in humans, as reported in the WHO study, begins with an incubation period of two to 17 days during which time the virus multiplies. The initial clinical symptoms are usually a high fever and lower respiratory symptoms including a productive cough and shortness of breath. Diarrhea, vomiting, abdominal pain and bleeding gums are also seen early in the course of the illness. Without effective treatment, progressive respiratory distress and multi-organ failure ensues, followed by death at an average of nine to 10 days after onset of symptoms.
Diagnosis
Early symptoms of avian influenza resemble other kinds of influenza-type illnesses, and the diagnosis of avian influenza cannot be made on the basis of symptoms alone. The CDC reports the definitive diagnosis is usually made by identifying the virus on nasal or throat swabs from patients with suspected avian influenza. Sometimes blood tests are done to determine if the patient has developed a specific immune response against avian influenza virus, confirming an infection by the virus.
Treatment
According to the World Health Organization, initiation of aggressive therapy early in the course of avian influenza may decrease mortality. Patients with suspected avian influenza are hospitalized on presentation and started on broad-spectrum antibiotics and sometimes steroids. Patients are also placed on antiviral therapy, but the CDC warns the avian influenza virus that infects humans is resistant to the antiviral drugs, amantadine and rimantadine, but sensitive to the newer antiviral drugs, oseltamivir and zanamivir.
Prevention
Avian influenza cannot be passed from properly cooked poultry and eggs to humans. The CDC recommends a 20-second handwash with soap and water before and after handling raw poultry along with careful sanitation of cooking utensils. Masks and gowns should be worn around patients with suspected avian influenza. According to the CDC, a vaccine effective against avian influenza virus was approved by the U.S. Food and Drug Administration in 2007 but is not available for public use as of 2010.
