Since 1996, avian influenza, or bird flu, has affected several hundred people worldwide via infectious transmission from birds to humans. While many patients suffer only transitory health effects, the World Health Organization reports that more than half of all cases end in fatality.
This strain of influenza virus A has 25 known subtypes and may yet create one that tranmits more easily among humans or resists existing treatments. Americans who visit certain countries in Europe, Africa, Asia and the Pacific Islands, or who work with poultry, risk serious effects from this rare but aggressive virus.
Conjunctivitis
Many avian influenza patients share the symptoms of eye infections, or conjunctivitis, to which mild cases may be limited. Infected eyes become red, watery, sticky and itchy, and may crust over. The U.S. Centers for Disease Control and Prevention reports cases of conjunctivitis in patients who handled dead birds, bird droppings and bird nesting materials.
Respiratory Problems
More serious respiratory health effects may be associated with infection by some bird flu virus subtypes, including H5N1, the most destructive subtype to date. The MayoClinic.com points out that flu-like symptoms take two to five days to develop after patients contact infected birds.
Fever and chills may precede nasal symptoms of sneezing, runny nose and sinus congestion. A persistent cough may lead to a sore throat.
Digestive Upset
The CDC reports that gastrointestinal health effects accompany other symptoms in some cases of bird flu infection. Whether the direct cause was eating undercooked poultry or eggs remains unclear, but symptoms of nausea, diarrhea and vomiting were linked with avian flu viruses in patients' blood. The Mayo Clinic advises people to cook poultry meat to 165 degrees F and to avoid raw eggs in order to prevent bird flu infection.
Lung Disease
A day or two after contracting avian influenza, patients may suffer a set of extreme breathing health effects called acute respiratory distress syndrome. Breathing symptoms may intensify so rapidly that patients may not have time to notify a doctor before emergency conditions arise, according to MedlinePlus, a service of the National Institutes of Health.
A severe inflammation of the lining of the lungs restricts oxygen transfer and causes labored, rapid breathing in an attempt to compensate. Permanent lung damage or complications can ensue.
Organ Failure
Complications of acute respiratory distress syndrome occur in about 30 percent of patients who develop it, MedlinePlus reports. A reduction in blood pressure will exacerbate low blood-oxygen levels, threatening the vital organs.
Intensive care medical treatment for complications of avian influenza may succeed but cause collapsed lung side effects. Unsuccessful respiratory treatment can result in respiratory arrest, kidney or liver failure, cardiac arrest and death.
