Mechanisms of Interspecies Transmission of Avian Influenza Viruses at the Human-Animal Interface: Examination of Animal Factors David E. Swayne* Exotic and Emerging Avian Viral Diseases Research Unit Southeast Poultry Research Laboratory USDA/Agricultural Research Service Athens, Georgia *Detailed as OFFLU Scientific Office World Organisation for Animal Health ( Paris, France
31
Embed
Mechanisms of Interspecies Transmission of Avian Influenza Viruses at the Human-Animal Interface: Examination of Animal Factors David E. Swayne* Exotic.
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Mechanisms of Interspecies Transmission of Avian Influenza
Viruses at the Human-Animal Interface: Examination of Animal Factors
David E. Swayne*Exotic and Emerging Avian Viral Diseases
Research Unit Southeast Poultry Research Laboratory
USDA/Agricultural Research ServiceAthens, Georgia
*Detailed as OFFLU Scientific OfficerWorld Organisation for Animal Health (OIE)
• Experimental cases: cats and red foxes (Reperant et al. EID 14:1835-41, 2008; Rimmelzwaan et al. AJP 168:176-83, 2006)
(Lipatov et al., PLOS Pathogens 7:e1000102, 2008)
Feeding pigs WS/05 infected chicken meat (100g, 1010 EID50) No lesions• No weight loss• No changes in food consumption • No behavioralabnormalities• No virus rectal swabs or GI tissues
• Transmission by consumption of infected meat• Respiratory infection, no evidence of digestive infection
System IN IG Meat Meat-IGTonsil + - + -Respiratory
– High incidence of HPAI virus in eggs laid by infected hens before death – Moderate concentration of HPAI virus in such eggs– Standard pasteurization temperatures and times kill HPAI virus in
liquid and dried egg products– Cooking kills HPAI virus
Swayne & Beck, Av. Pathol. 33(5):512-518, 2004
• Conclusions:• Most poultry products are consumed cooked or pasteurized• H5N1 HPAI has not been a Food Safety issue for humans
Conclusions: • Home slaughter of chickens generates aerosols & large droplets• Home slaughter of infected chickens generates airborne virus• Can transmit H5N1 HPAIV to chickens & ferrets when exposed in same air space as slaughter of infected asymptomatic chickens• Takes lower dose to infect than via IN inoculation (IN-CID50 = 103 EID50)
• Ferrets exposed at 150 cm for 1 hr to slaughter of VN/1203/04 infected chickens; 3 of 4 ferrets became infected & died
75 cm150 cm300 cm
Intervention Strategies
Determine what interventions will reduce H5N1 HPAIV in air samples and reduce transmission of the virus to ferrets in relation to the location where slaughter of asymptomatic H5N1 HPAIV-infected chickens is performed:
•Standard home slaughter process versus the kill step in a plastic bag (Andrew Clark and Mohammad Hassan)
• Non-vaccinated versus vaccinated chickens
Study Design
• White leghorn chickens, 24 hr post-H5N1 HPAIV inoculation intranasally (106 EID50, A/VN/1203/2004): do home slaughter •1 hr, 5 chicken study per treatment group• Measure virus in air – high volume air sampler
• Future: Repeat using a 5 gallon plastic bucket and kitchen pan/lid (sustainable and consistent)
• Developing a 12 panel cartoon for CDC/WHO to communicate the new process
• Examining the LPM processes that produce airborne virus and develop mitigation steps
• Transmission occurs through various routes of exposure, mechanisms of infection and vehicles
• In mouse model, conjunctival infection has been demonstrated, especially feasible with H7 AIV
• In the pig model, consumption of WS/05 H5N1 infected meat caused respiratory infection via tonsil and pharynx exposure
• In ferret model, consumption of two H5N1 HPAIV caused non-fatal respiratory infection while one H5N1 HPAIV caused lethal infection with initiation of infection in both respiratory and digestive tracts
• When processing H5N1 HPAI infected chickens, home slaughter process produces aerosols & large droplets which contain virus
Conclusions
Conclusions
• Using Bag technique for the kill step on asymptomatic H5N1 HPAIV-infected chickens, there was a reduction in number of virus+ air samples, reduced quantity of virus in air samples and reduced transmission of HPAIV to ferrets• Using H5N1 HPAIV-infected but vaccinated chickens, prevented virus+ air samples and prevented transmission of H5N1 HPAIV to ferrets• Simple intervention strategies may prevent transmission of HPAIV from birds to humans