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United States Department of Agriculture

Agricultural Research Service

Title: Impact of Different Husbandry Conditions on Contact and Airborne Transmission of H5n1 Highly Pathogenic Avian Influenza Virus to Chickens

Authors
item Tsukamoto, K - NATL INST ANML HLTH-JAPAN
item Imada, T - NATL INST ANML HLTH-JAPAN
item Tanimura, N - NATL INST ANML HLTH-JAPAN
item Okamatsu, M - NATL INST ANML HLTH-JAPAN
item Mase, M - NATL INST ANML HLTH-JAPAN
item Mizuhara, T - TYUBU LIVST HYGIENE-JAPAN
item Swayne, David
item Yamaguchi, S - NATL INST ANML HLTH-JAPAN

Submitted to: Avian Diseases
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 7, 2006
Publication Date: March 1, 2007
Citation: Tsukamoto, K., Imada, T., Tanimura, N., Okamatsu, M., Mase, M., Mizuhara, T., Swayne, D.E., Yamaguchi, S. 2007. Impact of different husbandry conditions on contact and airborne transmission of H5N1 highly pathogenic avian influenza virus to chickens. Avian Diseases. 51(1):129-132.

Interpretive Summary: How highly pathogenic avian influenza (HPAI) viruses spreads between chickens is poorly understood. To better understand virus spread, we examined direct contact and transmission through the air by the H5N1 virus between chickens. We found that the contact transmission did occur inefficiently when a few chickens were infected, whereas the transmission was efficient when half of the chickens were infected. Transmission by air was also dependent on the number of infected chickens and was less efficient than contact transmission. These data together with field observations suggested that number of infected chickens, chicken house types and amount of environmental contamination might affect the H5N1 HPAI virus transmission efficiency to chickens.

Technical Abstract: Typically highly pathogenic avian influenza (HPAI) viruses spread very rapidly among chickens within sheds. However, the spread was slower than expected for the initial 10 days of the index farm in Japan during 2004. This slow spread as well as the lack of gross lesions, clinical signs or high mortality hindered the field veterinarian from reporting a suspect HPAI outbreak to the veterinary office. To understand the field conditions for the slow virus spread, we examined contact and airborne transmission of the H5N1 virus to chickens in a negative-pressure isolator using various numbers of infected chickens and separate compartments. We found that the contact transmission did occur inefficiently when one or two chickens were infected, whereas the transmission was efficient when four chickens were infected. Airborne transmission of the HPAI virus was also dependent on the number of infected chickens and was less efficient than contact transmission. These data together with field observations suggested that number of infected chickens, chicken house types and amount of environmental contamination might affect the virus transmission efficiency to chickens.

Last Modified: 4/19/2014
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