The complete genome of klassevirus - a novel picornavirus in pediatric stool.
BACKGROUND
Diarrhea kills 2 million children worldwide each year, yet an etiological agent is not found in approximately 30-50% of cases. Picornaviral genera such as enterovirus, kobuvirus, cosavirus, parechovirus, hepatovirus, teschovirus, and cardiovirus have all been found in human and animal diarrhea. Modern technologies, especially deep sequencing, allow rapid, high-throughput screening of clinical samples such as stool for new infectious agents associated with human disease.


RESULTS
A pool of 141 pediatric gastroenteritis samples that were previously found to be negative for known diarrheal viruses was subjected to pyrosequencing. From a total of 937,935 sequence reads, a collection of 849 reads distantly related to Aichi virus were assembled and found to comprise 75% of a novel picornavirus genome. The complete genome was subsequently cloned and found to share 52.3% nucleotide pairwise identity and 38.9% amino acid identity to Aichi virus. The low level of sequence identity suggests a novel picornavirus genus which we have designated klassevirus. Blinded screening of 751 stool specimens from both symptomatic and asymptomatic individuals revealed a second positive case of klassevirus infection, which was subsequently found to be from the index case's 11-month old twin.


CONCLUSIONS
We report the discovery of human klassevirus 1, a member of a novel picornavirus genus, in stool from two infants from Northern California. Further characterization and epidemiological studies will be required to establish whether klasseviruses are significant causes of human infection.
Greninger
Alexander L
AL
Howard Hughes Medical Institute, Departments of Medicine, Biochemistry, and Microbiology, University of California, San Francisco, California 94143, USA. gerbix@gmail.com
Runckel
Charles
C
Chiu
Charles Y
CY
Haggerty
Thomas
T
Parsonnet
Julie
J
Ganem
Donald
D
DeRisi
Joseph L
JL
D002140:California; D005243:Feces / Q000821:virology*; D005759:Gastroenteritis / Q000821:virology*; D016679:Genome, Viral; D006801:Humans; D008969:Molecular Sequence Data; D010849:Picornaviridae / Q000235:genetics* / Q000302:isolation & purification*; D010850:Picornaviridae Infections / Q000821:virology*; D012367:RNA, Viral / Q000235:genetics*; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid
D012367:RNA, Viral