Infection Characterization Of Human Rhinovirus In Children With Acute Respiratory Infections In Gansu Province During2011

BackgroundHuman rhinoviruses (HRVs) are the predominant cause of the commoncold. They have been reportedly found in some patients with lower respiratorytract infections, such as pneumonia. They are also the major cause of asthmaexacerbations in children and adults. So we study the epidemic characteristics ofHRV in children with acute respiratory infections in Gansu province forproviding reference for HRV prevention and cure.Objective1. To study the epidemic characteristics of HRV in children with acuterespiratory infections in Gansu province.2. To investigate the relationship between clinical severity of HRVinfection and distribution of group A, B or C in children with acute respiratoryinfections in Gansu province.3. To complete the epidemiological data of HRV in China and providereference for prevention and cure of acute respiratory infections in children inGansu province.Methods286throat swabs were collected from children with acute respiratoryinfections in Gansu province during2011. Multiplex reverse transcription-PCRwere used to screen those specimens for detection of common respiratory tractpathogen. For HRV-positive samples, we use nested reverse transcriptionpolymerase chain reaction （nested RT-PCR） to amplify VP1and VP4/VP2 gene fragments of HRV. PCR products were identified by capillaryelectrophoresis. The VP4/VP2and VP1regions of HRV-positive samples weresequenced. If the sequencing results had too much impure peaks, we did geneticcloning to get the correct sequence. Nucleotide and amino acid homologyanalysis were taken according to the sequencing results. At last, we constructphylogenetic trees with Neighbor-Joining method.Results30of286specimens were positive for HRV by multiplex RT-PCR and3were excluded by nested RT-PCR, as they had proven to be Echovirus. Thenumber of HRV positive sample was27and the positive rate was9.44%（27/286）.2were mixed infections with HRV and respiratory syncytial virus（RSV）,2were mixed infections with HRV and parainfluenza virus（PIV）,1was mixed infection with HRV and influenza viruses（FLU）,1was mixedinfection with HRV and human bocavirus （HBOV） and1was mixed infectionwith HRV and adenovirus（ADV） out of27. The mean age of HRV-positivechildren is3years in our research, children less than one year old has thehighest proportion44.4%（12/27）. There were16male（16/185，8.64%）and11female （11/101，10.89%） in27HRV-positive cases and no significantdifferences between them. The highest HRV positive rate fell in May of2011（6/27，22.2％）. Common cold has the highest proportion,12.24%（12/98）followed by pneumonia,8.50%（13/153）. The remaining2cases were bronchitis.All HRV infections were cured with goodprognosis.Sequence analysis showed HRV A was the predominant genotype inGansu province in2011. It accounted for84.62%（22/26） of positive cases, followed by HRV C （11.54%，3/26）and only one HRV B was detected（3.85%,1/26）. The homology analysisresults and phylogenetic tree showed that27strains of HRV which weredetected from specimens in Gansu province in children with acute respiratoryinfections in2011belonged to different genotypes of HRV.Conclusions1. HRV was an important pathogen in children with acute respiratoryinfections in Gansu province during2011.2. HRV could be detected throughout the year in Gansu province and primarily infected children under one year old.3. Children with acute respiratory infections caused by HRV were curedwith good prognosis.4. The group A-type was the epidemic genotype of HRV in Gansu provinceduring2011.5. More than one genotype existed and they had co-epidemic in childrenwith acute respiratory infections in Gansu province in2011.