Detection of an avian lineage influenza A(H7N2) virus in air and surface samples at a New York City feline quarantine facility

Background In December 2016, an outbreak of low pathogenicity avian influenza ( LPAI ) A(H7N2) occurred in cats at a New York City animal shelter and quickly spread to other shelters in New York and Pennsylvania. The A(H7N2) virus also spread to an attending veterinarian. In response, 500 cats were transferred from these shelters to a temporary quarantine facility for continued monitoring and treatment. Objectives The objective of this study was to assess the occupational risk of A(H7N2) exposure among emergency response workers at the feline quarantine facility. Methods Aerosol and surface samples were collected from inside and outside the isolation zones of the quarantine facility. Samples were screened for A(H7N2) by quantitative RT ‐ PCR and analyzed in embryonated chicken eggs for infectious virus. Results H7N2 virus was detected by RT ‐ PCR in 28 of 29 aerosol samples collected in the high‐risk isolation (hot) zone with 70.9% on particles with aerodynamic diameters >4 μm, 27.7% in 1‐4 μm, and 1.4% in <1 μm. Seventeen of 22 surface samples from the high‐risk isolation zone were also H7N2 positive with an average M1 copy number of 1.3 × 10 3 . Passage of aerosol and surface samples in eggs confirmed that infectious virus was present throughout the high‐risk zones in the quarantine facility. Conclusions By measuring particle size, distribution, and infectivity, our study suggests that the A(H7N2) virus had the potential to spread by airborne transmission and/or direct contact with viral‐laden fomites. These results warranted continued A(H7N2) surveillance and transmission‐based precautions during the treatment and care of infected cats.