A Review of Highly Pathogenic Avian Influenza in Birds, With an Emphasis on Asian H5N1 and Recommendations for Prevention and Control

Abstract

Avian influenza is a disease of both veterinary and public health importance. Influenza A viruses infect a range of hosts, including humans, and can cause significant morbidity and mortality. These viruses have high genetic variability, and new strains develop through both mutation and reassortment. Modes of transmission as well as the location of viral shedding may differ both by host species and by viral strain. Clinical signs of influenza A virus infection in birds vary considerably depending on the viral subtype, environmental factors, and age, health status, and species of the bird and range from decreased egg production and gastrointestinal manifestations to nervous system disorders and respiratory signs. Most commonly, peracute death with minimal clinical disease is observed in poultry infected with a highly pathogenic avian influenza virus. There are various prevention and control strategies for avian influenza, including education, biosecurity, surveillance, culling of infected animals, and vaccination. These strategies will differ by institution and current federal regulations. Each institution should have an established biosecurity protocol that can be properly instituted. Lastly, human health precautions, such as proper hand hygiene, personal protective equipment, and employee health monitoring, are imperative for at-risk individuals.