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United States Department of Agriculture

Agricultural Research Service

Research Project: Intervention Strategies to Control and Prevent Disease Outbreaks Caused by Avian Influenza and Other Emerging Poultry Pathogens

Location: Exotic and Emerging Avian Viral Diseases Research Unit

Title: Reduction in airborne virus using modifications of simulated home slaughter of asymptomatic H5N1 HPAI virus infected chickens

Authors
item Swayne, David
item Clark, Andrew -

Submitted to: Options for the Control of Influenza Conference
Publication Type: Abstract Only
Publication Acceptance Date: July 1, 2013
Publication Date: September 5, 2013
Citation: Swayne, D.E., Clark, A. 2013. Reduction in airborne virus using modifications of simulated home slaughter of asymptomatic H5N1 HPAI virus infected chickens [abstract]. Abtracts for 8th Options to Control Influenza Congress, Cape Town, South Africa, September 5-10,2013. p.424.

Interpretive Summary: Background: The majority of human infections with H5N1 high pathogenicity avian influenza (HPAI) virus have occurred in the village setting of developing countries with the primary exposure risk being direct contact with live or dead poultry in the household or neighborhood. In Egypt, the majority of the human H5N1 HPAI virus infections with clinical disease have been in women and children and they are the high risk group who tend, play with, slaughter and prepare the household poultry for consumption. Halal slaughter of poultry requires free movement of the bird during the death struggle, which tends to create a viral plume thereby enhancing human exposure by inhalation. Experimentation was undertaken to develop a method for reduction of airborne virus by performing halal slaughter in a closed container with no further movement restriction. Critical elements are that the method be acceptable to Islamic authorities as proper halal slaughter, that it be affordable in terms of normal village income, that it be simple and culturally acceptable. Previously, simulated home slaughter of asymptomatic H5N1 HPAI virus infected chickens in a biosafety level 3 enhanced (BSL-3E) facility generated airborne virus, and chickens and ferrets housed in same airspace as the slaughter process became infected and died. Conducting the slaughter step of H5N1 HPAI virus-infected non-vaccinated chickens in a plastic bag greatly reduced the virus transmission through the air to ferrets. However, the availability and quality of plastic bags that can be access in Egypt is limited. A study was conducted to determine if a common household item, the hala pot with sliding the lid, hala pot slaughter with lifting lid, and a modified plastic bucket slaughter with lid that allows scald water to be pored through a hole in the lid, could be used in place of a plastic bag to reduce airborne H5N1 HPAI virus following slaughter of H5N1 HPAI virus infected chickens. Materials and Methods: Adult White Leghorn chickens were inoculated intranasally (IN) with 6 log10 mean embryo infectious doses (EID50) of HPAI A/Vietnam/1203/2004 (H5N1) and at 24 hours post-inoculation (PI), six groups of chickens were slaughtered and air samples taken at 1½ feet from slaughter area. The standard slaughter protocol used: 1) kill step (1 min), 2) Scald step (60-62C) (1 min), 3) defeather step (2 min), 4) eviscerate step (2 min), and 5) cleanup step (1 min). The three experiments were conducted: 1) 5 hens slaughtered by hala pot method with lid slide compared to 5 hens slaughtered by standard method, 2) 5 hens slaughtered by hala pot method with lid slide compared to 5 hens slaughtered by hala pot method with lid lift, and 3) 5 hens slaughtered by modified bucket method (pouring scald water through lid hole) compared to 5 hens slaughtered by hala pot method with lid slide. Results: The oral swabs for all 30 inoculated birds were positive for virus indicating infection in the chickens. The air sample taken during the slaughter of 5 chickens by standard method had high virus titers (2.9log10 EID50’s/1.0ml large particles, 1.23log10 EID50’s/1.0ml for small particles, no virus in fine particles) while hens slaughtered by hala pot method with lid slide had low virus titer (1.5log10 EID50/1ml for large sized particles; no virus in small or fine particles). The air sample taken during the slaughter of 5 chickens by hala pot method with lid slide had low virus titer (0.97log10 EID50’s/1.0ml large particles, no virus in small or fine particles) at 1.5 ft from slaughter table while hens slaughtered by hala pot method with lid lift had slightly higher virus titer (1.5log10/1ml for large sized particles). The air sample taken during the slaughter of 5 chickens by hala pot method with lid slide had low virus titer (1.7log10 EID50’s/1.0ml large particles, no virus in small or fine particles) while hens

Technical Abstract: Background: The majority of human infections with H5N1 high pathogenicity avian influenza (HPAI) virus have occurred in the village setting of developing countries with the primary exposure risk being direct contact with live or dead poultry in the household or neighborhood. In Egypt, the majority of the human H5N1 HPAI virus infections with clinical disease have been in women and children and they are the high risk group who tend, play with, slaughter and prepare the household poultry for consumption. Halal slaughter of poultry requires free movement of the bird during the death struggle, which tends to create a viral plume thereby enhancing human exposure by inhalation. Experimentation was undertaken to develop a method for reduction of airborne virus by performing halal slaughter in a closed container with no further movement restriction. Critical elements are that the method be acceptable to Islamic authorities as proper halal slaughter, that it be affordable in terms of normal village income, that it be simple and culturally acceptable. Previously, simulated home slaughter of asymptomatic H5N1 HPAI virus infected chickens in a biosafety level 3 enhanced (BSL-3E) facility generated airborne virus, and chickens and ferrets housed in same airspace as the slaughter process became infected and died. Conducting the slaughter step of H5N1 HPAI virus-infected non-vaccinated chickens in a plastic bag greatly reduced the virus transmission through the air to ferrets. However, the availability and quality of plastic bags that can be access in Egypt is limited. A study was conducted to determine if a common household item, the hala pot with sliding the lid, hala pot slaughter with lifting lid, and a modified plastic bucket slaughter with lid that allows scald water to be pored through a hole in the lid, could be used in place of a plastic bag to reduce airborne H5N1 HPAI virus following slaughter of H5N1 HPAI virus infected chickens. Materials and Methods: Adult White Leghorn chickens were inoculated intranasally (IN) with 6 log10 mean embryo infectious doses (EID50) of HPAI A/Vietnam/1203/2004 (H5N1) and at 24 hours post-inoculation (PI), six groups of chickens were slaughtered and air samples taken at 1½ feet from slaughter area. The standard slaughter protocol used: 1) kill step (1 min), 2) Scald step (60-62C) (1 min), 3) defeather step (2 min), 4) eviscerate step (2 min), and 5) cleanup step (1 min). The three experiments were conducted: 1) 5 hens slaughtered by hala pot method with lid slide compared to 5 hens slaughtered by standard method, 2) 5 hens slaughtered by hala pot method with lid slide compared to 5 hens slaughtered by hala pot method with lid lift, and 3) 5 hens slaughtered by modified bucket method (pouring scald water through lid hole) compared to 5 hens slaughtered by hala pot method with lid slide. Results: The oral swabs for all 30 inoculated birds were positive for virus indicating infection in the chickens. The air sample taken during the slaughter of 5 chickens by standard method had high virus titers (2.9log10 EID50’s/1.0ml large particles, 1.23log10 EID50’s/1.0ml for small particles, no virus in fine particles) while hens slaughtered by hala pot method with lid slide had low virus titer (1.5log10 EID50/1ml for large sized particles; no virus in small or fine particles). The air sample taken during the slaughter of 5 chickens by hala pot method with lid slide had low virus titer (0.97log10 EID50’s/1.0ml large particles, no virus in small or fine particles) at 1.5 ft from slaughter table while hens slaughtered by hala pot method with lid lift had slightly higher virus titer (1.5log10/1ml for large sized particles). The air sample taken during the slaughter of 5 chickens by hala pot method with lid slide had low virus titer (1.7log10 EID50’s/1.0ml large particles, no virus in small or fine particles) while hens slaughtered by modified bucket method incorporating scald with kill step had no virus recovery from air sample. Conclusion: Alternative methods for holding birds during the kill step of halal slaughter have impact on reducing airborne virus concentration from the highest being in standard open-barrel method, followed by hala pot with lid lift, then hala pot with slide lid and then modified bucket method with no virus in air.

Last Modified: 9/1/2014
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