WHO, the World Health Organization, released an update to their Avian Flu Fact sheet yesterday, and it contains some worrisome information.
WHO AVIAN FLU FACT SHEET
Two clinical features of the Avian Flu are particularly troubling.
First, unlike normal Flu, which has an incubation period of 2 to 3 days, the Avian flu appears to incubate from 2 to 8 days, and as long as 17 days. Victims could carry the disease for more than two weeks before falling ill. It is unknown for how long before symptoms appear that the victim might be contagious.
Second, the Avian Flu apparently targets multiple organs in the human body, and is not just a respiratory illness. The following comes from the WHO fact sheet, and describes the course of the illness in humans :
Initial symptoms include a high fever, usually with a temperature higher than 38oC, and influenza-like symptoms. Diarrhoea, vomiting, abdominal pain, chest pain, and bleeding from the nose and gums have also been reported as early symptoms in some patients.
Watery diarrhoea without blood appears to be more common in H5N1 avian influenza than in normal seasonal influenza. The spectrum of clinical symptoms may, however, be broader, and not all confirmed patients have presented with respiratory symptoms. In two patients from southern Viet Nam, the clinical diagnosis was acute encephalitis; neither patient had respiratory symptoms at presentation. In another case, from Thailand, the patient presented with fever and diarrhoea, but no respiratory symptoms. All three patients had a recent history of direct exposure to infected poultry.
One feature seen in many patients is the development of manifestations in the lower respiratory tract early in the illness. Many patients have symptoms in the lower respiratory tract when they first seek treatment. On present evidence, difficulty in breathing develops around 5 days following the first symptoms. Respiratory distress, a hoarse voice, and a crackling sound when inhaling are commonly seen. Sputum production is variable and sometimes bloody. Most recently, blood-tinted respiratory secretions have been observed in Turkey. Almost all patients develop pneumonia. During the Hong Kong outbreak, all severely ill patients had primary viral pneumonia, which did not respond to antibiotics. Limited data on patients in the current outbreak indicate the presence of a primary viral pneumonia in H5N1, usually without microbiological evidence of bacterial supra-infection at presentation. Turkish clinicians have also reported pneumonia as a consistent feature in severe cases; as elsewhere, these patients did not respond to treatment with antibiotics.
In patients infected with the H5N1 virus, clinical deterioration is rapid. In Thailand, the time between onset of illness to the development of acute respiratory distress was around 6 days, with a range of 4 to 13 days. In severe cases in Turkey, clinicians have observed respiratory failure 3 to 5 days after symptom onset. Another common feature is multiorgan dysfunction, notably involving the kidney and heart. Common laboratory abnormalities include lymphopenia, leukopenia, elevated aminotransferases, and mild-to-moderate thrombocytopenia with some instances of disseminated intravascular coagulation.
While all of this may seem overly technical, the bottom line is, this is not your father’s influenza. This disease attacks the body in many insidious ways, and in severe cases, the treatment options are very limited.
