Information on Avian Influenza
Avian influenza refers to the disease caused by infection with avian (bird) influenza (flu) Type A viruses. These viruses occur naturally among wild aquatic birds worldwide and can infect domestic poultry and other bird and animal species. Avian flu viruses do not normally infect humans. However, sporadic human infections with avian flu viruses have occurred.
What is Avian Influenza?
Commonly known as bird flu, the disease usually spreads from bird to bird but may sometimes spread from birds to humans. Though human to human transmission — which takes place mostly after intimate and constant physical contact — is rare, the infection is virulent and, in an estimated 60% of cases, fatal. India is one of 6 nations in which the disease keeps surfacing among birds — during the last outbreak among poultry in Karnataka this May, 33,000 birds had to be culled. There is no vaccine against H5N1.
According to WHO, some avian influenza viruses such as A(H5N1) and A(H7N9) “have caused serious infections in people”, with “the majority of human cases… (being) “associated with direct or indirect contact with infected live or dead poultry”. There is no evidence that the disease spreads to people through properly cooked food, even though “controlling the disease in animals is the first step in decreasing risks to humans”, says WHO.
What are the symptoms of the disease?
In humans, the symptoms of an H5N1 infection are the same as that of any other seasonal flu — fever, bodyache, sore throat, runny nose, headache, fatigue, etc.; however it can turn serious very quickly, and lead to respiratory distress. There was a phase of panic after scientists reported that a mutated bird flu virus could cause a human pandemic, and there were reports of such a mutation having been engineered in the laboratory through what is called an antigenic shift.
How Is Bird Flu Diagnosed?
The U.S. Food and Drug Administration has approved a test designed to identify avian influenza. The test is called influenza A/H5 (Asian lineage) virus real-time RT-PCR primer and probe set. It can offer preliminary results in only four hours. However, the test isn’t widely available.
Auscultation (a test that detects abnormal breath sounds)
White blood cell differential
Nasopharyngeal culture
Chest X-ray
What’s the Treatment for Bird Flu?
Different types of bird flu can cause different symptoms. As a result, treatments may vary. In most cases, treatment with antiviral medication such as oseltamivir (Tamiflu) or zanamivir (Relenza) can help reduce the severity of the disease. However, the medication must be given within 48 hours after symptoms first appear. The virus that causes the human form of the flu can develop resistance to the two most common forms of antiviral medications, amantadine and rimantadine. These medications shouldn’t be used to treat the disease.
