Genetic Characterization Of Human Parainfluenza Viruses Associated Severe Acute Respiratory Infections In Luohe,Henan Province,China,2017?2019

Object The genetic characteristics and prevalence of human parainfluenza viruses were preliminary studied in Luohe City,Henan Province,China,to provide important basic scientific data for surveillance,prevention,and control of HPIVs associated diseases in China,as well as vaccine developmentMethod One thousand and nineteen throat swab specimens from patients who met the definition of severe acute respiratory infectious(SARI)disease at the Luohe Central Hospital in Henan Province from October 2017 to June 2019 were collected.The real-time quantitative polymerase chain reaction(qPCR)was used to screen 19 common respiratory pathogens,and gender,age and season of HPIVs patients with SARI were analyzed.The full length of the Hemagglutinin-neuraminidase(HN)protein gene was amplified and sequenced by nested polymerase chain reaction(nested PCR).The HN sequences of HPIVs of China and other countries in the GenBank database were downloaded.A gene database was constructed to analyze the nucleotide and amino acid homology.The HPIVs HN gene phylogenetic tree was established by using the Maximum Likelihood MethodResult Among 1019 throat swabs 71.3%(727/1019)were positive for viruses.The positive rate of HPIVs was 10.4%(106/1019),which was the third virus with the highest detection rate.Out of the 106 HPIVs positive samples,30(3.0%,30/1019)were positive for HPIV 1,9(0.9%,9/1019)were positive for HPIV 2,52(5.1%,52/1019)were positive for HPIV 3,15(1.5%,15/1019)were positive for HPIV 4.Simultaneous infections by different viruses were observed in our study with 57.5%(61/106)HPIVs positive cases with co-infections.The positive rate of HPIVs infection was highest in the age group of 1?3 years,accounting for 51.9%(55/106)of HPIVs positive patients,and the lowest positive rate was greater than 18 years,accounting for 2.8%(3/106).The difference between the total positive rate of HPIVs in each age group was statistically significant(?2=24.276,P=0.000).HPIVs infection in this area has a clear seasonal distribution.The positive rate of summer(35.1%)is higher than that of spring(11.0%),autumn(11.1%),and winter(6.94%).There was a statistically significant difference in the positive rate of HPIVs infection between the four seasons(?2=43.768,P=0.000).Through the nested RT-PCR method,67 HPIVs HN gene full-length sequences were obtained,of which 18 HPIV 1 strains,5 HPIV 2 strains,35 HPIV 3 strains,and 9 HPIV 4 strains.The nucleotide and amino acid homology of the full length(1728 nt)of 18 HPIV 1 HN genes was 95.2%to 100%and 94.1%to 100%.Among them,17 strains have belonged to the B3 genotype,and 1 strain was B1 genotype.Compared with other countries,Henan Luohe strains have the highest homology with Thailand strains(both nucleotide and amino acid homology are 98.8%).The nucleotide and amino acid homology of the full length(1716 nt)of the five HPIV 2 HN genes was 91.4%?99.8%and 94.2%?99.8%.Four strains belong to group A and one strain belongs to group B.HPIV 2 HN genes had the highest homology with the Vietnamese strain in terms of nucleotides and amino acids,96.8%and 98.2%,respectively.35 HPIV 3 HN genes full-length sequences(1719 nt),nucleotide and amino acid homology was 96.3%to 100.0%and 98.4%to 100.0%,respectively.It has the highest homology with Spanish strains with 98.4%and 99.7%in nucleotide and amino acid homology,respectively.Among the Luohe strains in Henan,20 HPIV 3 strains belonged to the C3a subtype,14 strains belonged to the C3b subtype,and 1 strain was classified into the C5 genotype.9 HPIV 4 HN gene sequences were full-length(1740 nt),of which 7 were HPIV 4A and 2 were HPIV 4B.The nucleotide and amino acid homology of 7 HPIV 4A HN genes were 97.7%?99.8%and 97.4%?99.5%.The nucleotide and amino acid homology of the two HPIV 4B HN genes were 99.6%and 99.5%.7 HPIV 4A strains were belonged to type ? c,and two HPIV 4B strains have belonged to type ?.Compared with the HN gene(1725nt)of the prototype strain,the HPIV 4 HN gene sequence of Henan strains inserted 15 nucleotides(5 amino acids)at the C-terminusConclusions From October 2017 to June 2019,HPIVs was one of the important pathogens detected in severe acute respiratory infectious diseases in Luohe City,Henan Province,and were mainly HPIV 3 with at least three genotypes of C3a,C3b,and C5.Followed by HPIV 1,B3 was mainly genotype.The less popular HPIV 4 in Luohe City,Henan Province,mainly HPIV 4A.HPIV 2 has sporadic cases in Luohe City,mostly belonging to group A.