ABSTRACT
Objective To identify the pathogen of an acute epidemic gastroenteritis outbreak in newborn room. Methods Forty five samples were collected from 38 newborn patients at the peak of a diarrhea outbreak, which happened in a newborn room in Inner Mongolia Autonomous Region during December 2008 to February 2009. The presence of rotavirus antigen, Adeno-like virus antigen and Astrovirus antigen were detected by enzyme-linked immunosorbent assay (ELISA). The presence of Astrovirus RNA were detected by reverse transcriptase polymerase chain reaction (RT-PCR) with universal primer of Astrovirus. Thirteen samples positive for Astrovirus nucleic acid were analyzed by sequencing and phylogenetic tree. Four samples positive for both Astrovirus antigen and Astrovirus nucleic acid were observed by immune electron microscopy. Results Both rotavirus antigen and Adeno-like virus antigen were negative in 45 faecal samples. Thirty samples were positive for Astrovirus antigen when checked by ELISA, which resulted in a positive rate of 66.7%. Thirty-one samples were positive for Astrovirus RNA when check by RT-PCR, which resulted in a positive rate of 68.9%. The genotype results confirmed all patients were infected with genotype 1 Astrovirus. The gene sequences of thirteen samples were compared with reference strains of Astrovirus type 1 in GeneBank and the homology rate of nucleotide sequence was 90.9 %- 96.3 %. The homology rate of intra these thirteen sample was 94.7%-100.0%. Four positive samples were randomly selected and observed by immune electron microscopy and a large amount of Astrovirus particles were found in two of these samples. Conclusion Genotype 1 Astrovirus is the pathogen of this diarrhea outbreak in newborn.