Volume 16, Number 4—April 2010
Limited Susceptibility of Chickens, Turkeys, and Mice to Pandemic (H1N1) 2009 Virus
|Animal and dose (virus strain)||No. animals||Route of inoculation||Swab samples||Tissue samples, no. positive/no. tested†||Seroconversion in NP-ELISA (no. positive/no. tested)‡|
|Chick||28||Intra–air sac||–||Day 2: 2/3; Day 4: 2/3; Day 8: 1/3||–|
|Chicken||5||Contact with infected pigs||–||NA||–|
|Turkey, 106 TCID50 (A/Regensburg/D6/2009)||6||Oculo-oronasal||–||NA||+ (3/6)|
|Turkey, 108 TCID50 (A/Bayern/74/2009)||6||Oculo-oronasal||+ (respiratory), – (cloacal)||NA||+ (4/6)|
|Poult||28||Intra–air sac||–||Day 2: 3/3; Day 4: 1/3; Day 6: 1/3||–|
|Turkey||5||Contact with infected pigs||–||NA||–|
|Mouse, 102–103 TCID50||8||Oculo-oronasal||NA||NA||–|
|Mouse, 104 TCID50||4||Oculo-oronasal||NA||NA||+ (3/4)|
|Mouse, 105 TCID50||4||Oculo-oronasal||NA||NA||+ (4/4)|
|Mouse, 105 TCID50||4||Intraperitoneal||NA||NA||–|
*NP, nucleoprotein; –, negative; NA, not applicable; +, positive; TCID50, 50% tissue culture infectious dose.
†Three juvenile chickens and turkeys inoculated through the air sac were killed on days 0, 2, 4, 6, 8, and 14 posinoculation, and left and right lung lobes were removed for analysis by real-time reverse transcription–PCR. Tissues from the left (inoculation site) lung lobe of 5 chicks and 4 poults killed at the indicated days postinfection were positive for virus RNA with high cycle threshold values (>35), and 1 additional poult was positive for virus RNA with a cycle threshold value of 27 on day 2 postinfection.
‡Seroconversion was verified by testing for antibodies against virus NP by commercially available ELISAs (ELISA Avian Influenza Type A; Pourquier, Montpellier, France, and FlockChek AI MultiS-Screen; IDEXX, Ludwigsburg, Germany).