Emergence of human caliciviruses among diarrhea cases in southwest China.
BACKGROUND
Acute diarrhea is one of the most serious problems in global public health that causes considerable morbidity and mortality worldwide. Human caliciviruses (HuCV) including norovirus (NoV, genogroup GI and GII) and sapovirus (SaV), is a leading cause of acute sporadic diarrhea in individuals across all age groups. However, few studies had been conducted clarifying the characteristics of HuCV in diarrhea cases across all age groups in China. Our study was aimed at assessing the HuCV-related diarrhea burden and NoV genotypes distribution in southwest China.


METHODS
The study was conducted in four hospitals in Kunming city, Yunnan province, from June 2014 to July 2015. Stool specimens were collected from 1,121 diarrhea cases and 319 healthy controls in outpatient departments. Reverse transcription polymerase chain reaction (RT-PCR) was used to detect NoV (GI, GII) and SaV. Sequencing was applied to confirm the three viral infections and phylogenetic analysis was performed to determine their genotypes. A structured questionnaire was used to record the demographic information and clinical symptoms of subjects.


RESULTS
HuCV was detected at an 11.0 % infection rate in 1,121 diarrhea cases and at 3.4 % rate in 319 non-diarrhea subjects (p < 0.0001, OR = 3.5, 95 % CI 1.8-6.5). The prevalence of the NoV genogroup GII and genotype GII.4 in diarrhea cases was significantly higher than that found in healthy controls (p < 0.0001, p = 0.018, respectively). NoV GII (n = 118, 10.5 %) was the most common HuCV subtype in diarrhea cases, followed by SaV (n = 3, 0.3 %) and NoV GI (n = 2, 0.2 %). Of 118 NoV GII strains isolated from diarrhea patients. GII.4 (n = 55, 46.6 %) was the predominant strain, followed by GII.3 (n = 28, 23.7 %), GII.12 (n = 25, 21.2 %), GII.17 (n = 8, 6.8 %), and GII.5 (n = 2, 1.7 %). Of the 55 GII.4 strains, the GII.4 Sydney 2012 variant had absolutely predominant prevalence (n = 52, 94.5 %), followed by the NoV GII.4-2006b variant (n = 3, 5.5 %). The GII.4 Orleans 2009 variant was not found in diarrhea cases of the study.


CONCLUSIONS
NoV GII was the major genogroup and GII.4 was the most predominant strain detected in diarrhea patients. The GII.17 is an emergent variant in sporadic diarrhea and might become the predominant strain in diarrhea cases in the near future. Rapid, accurate detection kits need to be developed to help us find and treat NoV-associated diarrhea in clinical settings in a timely manner.
National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Shanghai, 200025, People's Republic of China.|Key Laboratory of Parasite and Vector Biology, Ministry of Health of China, WHO Collaborating Center for Tropical Diseases, National Center for International Research on Tropical Diseases, Shanghai, 200025, People's Republic of China.
Shun-Xian
SX
Zhang
The First People's Hospital of Yunnan Province, Kunming, 650000, People's Republic of China.
Li
L
Li
Yunnan Provincial Center for Disease Control and Prevention, Kunming, 650000, People's Republic of China.
Jian-Wen
JW
Yin
National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, 102206, People's Republic of China.
Miao
M
Jin
National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, 102206, People's Republic of China.
Xiang-Yu
XY
Kong
National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, 102206, People's Republic of China.
Li-Li
LL
Pang
The First Clinical Medical College of Lanzhou University, Lanzhou, 730000, People's Republic of China.
Yong-Kang
YK
Zhou
National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Shanghai, 200025, People's Republic of China.|Key Laboratory of Parasite and Vector Biology, Ministry of Health of China, WHO Collaborating Center for Tropical Diseases, National Center for International Research on Tropical Diseases, Shanghai, 200025, People's Republic of China.
Li-Guang
LG
Tian
National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Shanghai, 200025, People's Republic of China.|Key Laboratory of Parasite and Vector Biology, Ministry of Health of China, WHO Collaborating Center for Tropical Diseases, National Center for International Research on Tropical Diseases, Shanghai, 200025, People's Republic of China.
Jia-Xu
JX
Chen
National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention, Shanghai, 200025, People's Republic of China. ipdzhouxn@sh163.net.|Key Laboratory of Parasite and Vector Biology, Ministry of Health of China, WHO Collaborating Center for Tropical Diseases, National Center for International Research on Tropical Diseases, Shanghai, 200025, People's Republic of China. ipdzhouxn@sh163.net.
Xiao-Nong
XN
Zhou
Acute diarrhea; Calicivirus; Epidemiology; Norovirus; Novel genotype; Sporadic cases
Appl Environ Microbiol. 2014 Jun;80(12):3552-61
24705321
J Clin Microbiol. 2008 Apr;46(4):1474-7
18272704
J Infect. 2015 Jul;71(1):19-27
25753104
Epidemiol Infect. 2012 Jul;140(7):1161-72
22444943
Clin Infect Dis. 2012 Dec;55 Suppl 4:S303-11
23169942
Front Immunol. 2013 Nov 28;4:402
24348474
Emerg Infect Dis. 2015 Jul;21(7):1240-2
26080037
Infect Dis Poverty. 2016 May 14;5(1):49
27179509
BMC Infect Dis. 2013 Jul 22;13:338
23875971
Epidemiol Infect. 2009 May;137(5):617-25
18430264
Am J Epidemiol. 2014 Feb 15;179(4):507-12
24305574
Clin Infect Dis. 2011 Feb 15;52(4):466-74
21258098
Lancet. 2013 Jul 20;382(9888):209-22
23680352
Emerg Infect Dis. 2011 Jan;17(1):7-15
21192848
Emerg Infect Dis. 2013 Aug;19(8):1337-9
23880450
N Engl J Med. 2009 Oct 29;361(18):1776-85
19864676
Lancet Infect Dis. 2014 Aug;14(8):664-5
24981040
Clin Microbiol Rev. 2001 Jan;14(1):15-37
11148001
Arch Virol. 2014 Aug;159(8):1995-2002
24610551
Euro Surveill. 2011 Jul 28;16(30):null
21813081
Emerg Infect Dis. 2008 Aug;14(8):1224-31
18680645
PLoS Negl Trop Dis. 2015 Mar 04;9(3):e0003568
25738935
BMC Infect Dis. 2015 Apr 15;15:183
25884557
J Clin Microbiol. 2006 Apr;44(4):1262-7
16597849
Lancet Infect Dis. 2014 Aug;14(8):725-30
24981041
Euro Surveill. 2015 Jul 02;20(26):null
26159307
Am J Trop Med Hyg. 2010 Apr;82(4):717-22
20348525
Infect Dis Poverty. 2016 Jun 27;5(1):64
27349521
Euro Surveill. 2015 Jun 18;20(24):null
26111236
J Med Virol. 2015 Dec;87(12):2040-7
25982899
Epidemiol Infect. 2000 Aug;125(1):93-8
11057964
Lancet. 2013 Apr 20;381(9875):1405-16
23582727
Infect Dis Poverty. 2013 Dec 20;2(1):31
24359669
Emerg Infect Dis. 2015 Aug;21(8):1477-9
26196235
J Infect Dis. 2013 Apr;207(7):1058-65
23300161
Infect Dis Poverty. 2015 Nov 04;4:49
26530964
J Virol Methods. 1999 Dec;83(1-2):145-54
10598092
BMC Infect Dis. 2013 Sep 03;13:412
24004442
J Clin Virol. 2013 Mar;56(3):185-93
23218993
BMC Infect Dis. 2015 Dec 18;15:574
26678989
J Med Virol. 2014 Jul;86(7):1235-42
24523136
N Engl J Med. 2013 Mar 7;368(10):971
23465122
Clin Infect Dis. 2012 Oct;55(7):897-904
22700832
Curr Opin Infect Dis. 2008 Oct;21(5):544-52
18725806
N Engl J Med. 2013 Mar 21;368(12):1121-30
23514289
J Clin Virol. 2008 Sep;43(1):42-8
18602864
J Clin Microbiol. 2006 Apr;44(4):1405-12
16597869
Clin Lab. 2007;53(3-4):125-8
17447646
BMC Infect Dis. 2015 Oct 14;15:425
26467099
J Clin Virol. 2009 Jan;44(1):1-8
19084472