Abstract and Introduction
Purpose: A review of the avian influenza A/H5N1 virus, including human cases, viral transmission, clinical features, vaccines and antivirals, surveillance plans, infection control, and emergency response plans, is presented.
Summary: The World Health Organization (WHO) considers the avian influenza A/H5N1 virus a public health risk with pandemic potential. The next human influenza pandemic, if caused by the avian influenza A/H5N1 virus, is estimated to have a potential mortality rate of more than a hundred million. Outbreaks in poultry have been associated with human transmission. WHO has documented 258 confirmed human infections with a mortality rate greater than 50%. Bird-to-human transmission of the avian influenza virus is likely by the oral-fecal route. The most effective defense against an influenza pandemic would be a directed vaccine to elicit a specific immune response toward the strain or strains of the influenza virus. However, until there is an influenza pandemic, there is no evidence that vaccines or antivirals used in the treatment or prevention of such an outbreak would decrease morbidity or mortality. Surveillance of the bird and human populations for the highly pathogenic H5N1 is being conducted. Infection-control measures and an emergency response plan are discussed.
Conclusion: Avian influenza virus A/H5N1 is a public health threat that has the potential to cause serious illness and death in humans. Understanding its pathology, transmission, clinical features, and pharmacologic treatments and preparing for the prevention and management of its outbreak will help avoid its potentially devastating consequences.
The avian influenza A/H5N1 virus has the potential to cause devastating effects to agricultural poultry flocks and humans. Initially confined to Southeast Asia, the virus has now migrated to the Middle East, Europe, and former Soviet Union satellites. Outbreaks in poultry, primarily chickens and ducks, have been associated with human transmission. The World Health Organization (WHO) has documented 258 confirmed human infections with a mortality rate greater than 50%. WHO considers the avian influenza A/H5N1 virus a public health risk with pandemic potential and recommends that all nations develop a national influenza preparedness plan. The U.S. government has proposed a federal response, the Pandemic Influenza Plan.[3,4]
The next human influenza pandemic, if caused by the avian influenza A/H5N1 virus, is estimated to have a potential mortality rate greater than a hundred million.[5,6] The mathematical model estimates are based on the facts that humans have little or no immunity to the antigens of the influenza A/H5N1 virus and that the mortality rate so far has been approximately 57% for the cases that have been admitted to hospitals and reported to WHO. The number of human cases that may present to health care facilities is expected to far exceed bed capacity and resources for treatment.
Am J Health Syst Pharm. 2007;64(2):149-165. © 2007 American Society of Health-System Pharmacists
Cite this: Avian Influenza: A Review - Medscape - Jan 15, 2007.