Scientists in Desperate Race With Bird Flu
Will Killer Flu Bug Emerge Before We Are Ready?
Bird Flu: Early Symptoms, Frequent Death continued...
The earliest symptom of bird flu is a lot like that of human flu: a sudden high fever. After that, the symptoms tend to be different. Bird flu patients only sometimes have a runny nose. They tend to have lower respiratory symptoms, especially cough and shortness of breath. Other early symptoms may include diarrhea, vomiting, abdominal pain, lung pain, and bleeding from the nose and gums.
There may also be symptoms highly unusual for flu. Two patients had brain infections and diarrhea but not respiratory symptoms.
Typically, about five days after illness onset, patients have shortness of breath. Severe breathing problems are common; there may be bloody sputum. Patients often progress to acute respiratory distress in about six days, which requires oxygen therapy and may require assisted breathing with a machine. Multiple organ failure is common. Death usually comes from respiratory failure.
The disease has been particularly deadly for children. In Thailand, 89% of patients under the age of 15 years died an average of nine or 10 days after illness onset.
Early Treatment May Help
Two flu drugs are active against bird flu: Tamiflu and Relenza. Tamiflu is taken orally, while Relenza must be inhaled. Because bird flu can infect organs other than the lungs, Tamiflu is considered the treatment of choice.
However, treatment must begin very soon after symptoms appear. Hayden and colleagues say that for severe cases of H5N1 bird flu, it's reasonable to use high doses of Tamiflu -- double the usually recommended dose.
A Bird Flu Pandemic
What experts worry about is that bird flu could learn to spread more easily among humans. This could happen in two ways. The bird virus could simply adapt to humans over time. Or a person could get infected with bird flu and human flu at the same time. Two viruses infecting the same person could swap gene segments. This "reassortant" virus might end up with the gene that lets it spread among humans.
It seems very easy for this to happen. Is it possible that for some reason bird flu just can't evolve into a human flu?