Detection of influenza A virus in aerosols in hospitals and analysis of the HA gene

Abstract

Objective To understand the contamination condition of aerosols in hospitals by influenza virus and to analyze the the viral etiology of influenza A virus based on HA gene. Methods Four sites of out-patient infusion center were selected for collecting aerosol samples both in general hospital (hospital A) and pediatric hospital (hospital B) in Huai’an of Jiangsu province. Thirty-two aerosol samples were collected by BIO Capturer-5, 16 samples from each of the two hospitals in Huai’an. Fourteen nasopharyngeal swab samples from patients in fever clinics were collected, 7 samples per hospital. All samples were rapidly detected by real-time RT-PCR. The target HA gene was obtained by mean of nested RT-PCR and were sequenced. The genetic and phylogenetic analysis based on HA genes was computed. Results In hospital A, influenza A (H3N2) virus was detected from 1 aerosol sample and in 6 nasopharyngeal swab samples. Influenza A (H1N1) pdm09 was found in 1 nasopharyngeal swab sample. In hospital B, influenza A (H1N1) pdm09 was found in 1 aerosol sample and in 2 nasopharyngeal swab samples while influenza A (H3N2) virus was found in 3 nasopharyngeal swab samples. Influenza A (H3N2) virus in aerosol samples (A/Environment-air/Huai’an/A1/2017) showed the highest nucleotide identity (99.8%) with the strain A/Huai’an/TA1/2017 from nasopharyngeal swab samples, and Influenza A (H1N1) pdm09 in aerosol samples (A/Environment-air/Huai’an/B1/2017) was related closely to the strain A/Huai’an/TA7/2017 isolated from nasopharyngeal swab samples. Conclusions There was indoor air contamination by influenza A virus in both hospitals. It was helpful to know the prevalence of influenza virus in the population by surveying aerosol of hospital for influenza virus. As compared to influenza A (H1N1) pdm09 isolates, there was genetic diversity in HA gene of H3N2 viral isolates. Key words: Hospital; Influenza A virus; H1N1 subtype; H3N2 subtype; Genotype