AAAR 34th Annual Conference
October 12 - October 16, 2015
Hyatt Regency
Minneapolis, Minnesota, USA
Abstract View
Viability and Particle Size Distribution of Airborne Influenza Virus from Acutely Infected Pigs
Montserrat Torremorell, CARMEN ALONSO, Peter Raynor, Peter Davies, College of Vet Med, University of Minnesota
Abstract Number: 503 Working Group: Primary and Secondary Aerosols from Agricultural Operations
Abstract Transmission of airborne influenza A virus (IAV) depends in part, on the particle size that the virus associates with. This association will influence the distance the particles (and associated viruses) are transported, the location of deposition within the respiratory tract after inhalation, and the survivability and infectivity of IAV in aerosols. Thus, the objective of this study was to characterize the size distribution of the particles that transport airborne IAV, and assess the virus viability for each particle size range.
A group of 10 out of 12 pigs were intra-nasally and intra-tracheally infected with an H1N1 IAV (4.4x106 TCID50/ml). Pigs were sampled daily for shedding and air samples were collected for 1 hour using an Andersen cascade impactor (ACI) sampler able to collect particles as a function of particle size (8 stages that measure particles from 10 to 0.4 microns). Total airborne particles were analyzed using an optical particle counter. Oral fluids, clinical signs, coughing and lethargy scores were collected at each air sampling event. Samples were analyzed by quantitative RT-PCR IAV, and virus viability tested on MDCK cell culture. Total quantity of virus RNA per volume of air (m3), and total particle counts by size (0.3-10 µm) and day were analyzed during the study.
IAV was detected in air samples collected for 9 days after infection. IAV was detected in all particle size ranges in quantities ranging from 4.2x102 RNA copies/ m3 in the smallest particles (0.4-0.7µm) to 3.63x106 in the largest particles (9.0-10.0µm). Results from virus viability demonstrated the presence of infectious IAV in particles larger than 2.1µm.
Our results indicate that IAV can be found in a wide range of particle sizes while airborne. There was higher quantity of virus in larger particles and virus viability was dependent on the size particle the IAV viruses associated with. This information is important to assess the risk of airborne transmission of IAV.
This project was founded by the National Pork Board and University of Minnesota Signature Program