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Virus Genotype Distribution and Virus Burden in Children and Adults Hospitalized for Norovirus Gastroenteritis, 2012-2014, Hong Kong.

Chan MC, Leung TF, Chung TW, Kwok AK, Nelson EA, Lee N, Chan PK - Sci Rep (2015)

Bottom Line: In young children, the median noroviral load of GII.4 and non-GII.4 cases was indistinguishably high (cycle threshold value, median [interquartile range]: 16.6 [15.2-19.3] versus 16.6 [14.9-21.6]; p = 0.45).Two age-specific non-GII.4 genotypes (GII.3 and GII.6) were identified among young children.These findings may have implications in norovirus vaccination strategy.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiology, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong Special Administrative Region, People's Republic of China.

ABSTRACT
We conducted a 2-year hospital-based study on norovirus gastroenteritis among children and adults between August 2012 and September 2014. A total of 1,146 norovirus cases were identified. Young children (aged ≤ 5 years) accounted for a majority (53.3%) of cases. Hospitalization incidence exhibited a U-shaped pattern with the highest rate in young children (1,475 per 100,000 person-years), followed by the elderly aged > 84 years (581 per 100,000 person-years). A subset (n = 395, 34.5%) of cases were selected for norovirus genotyping and noroviral load measurement. Non-GII.4 infections were more commonly observed in young children than in older adults (aged > 65 years) (20.5% versus 9.2%; p < 0.05). In young children, the median noroviral load of GII.4 and non-GII.4 cases was indistinguishably high (cycle threshold value, median [interquartile range]: 16.6 [15.2-19.3] versus 16.6 [14.9-21.6]; p = 0.45). Two age-specific non-GII.4 genotypes (GII.3 and GII.6) were identified among young children. These findings may have implications in norovirus vaccination strategy.

No MeSH data available.


Related in: MedlinePlus

Fecal viral load of norovirus genogroup II genotype 4 (GII.4) and non-GII.4 gastroenteritis on case presentation by(A) age and (B) age group. Cycle threshold (Ct) value of reverse transcription–polymerase chain reaction (RT-qPCR) assay was determined for each case to represent noroviral load. Higher Ct values indicate lower noroviral loads. Blue dotted lines indicate best-fit lines. In panel B, for clarity only p-values (Mann-Whitney U test) of comparisons between GII.4 and non-GII.4 cases were shown. Other comparisons were described in the main text where appropriate. Red horizontal lines denote medians. NS, not significant; r, Spearman’s rank correlation coefficient; *, p < 0.05.
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f2: Fecal viral load of norovirus genogroup II genotype 4 (GII.4) and non-GII.4 gastroenteritis on case presentation by(A) age and (B) age group. Cycle threshold (Ct) value of reverse transcription–polymerase chain reaction (RT-qPCR) assay was determined for each case to represent noroviral load. Higher Ct values indicate lower noroviral loads. Blue dotted lines indicate best-fit lines. In panel B, for clarity only p-values (Mann-Whitney U test) of comparisons between GII.4 and non-GII.4 cases were shown. Other comparisons were described in the main text where appropriate. Red horizontal lines denote medians. NS, not significant; r, Spearman’s rank correlation coefficient; *, p < 0.05.

Mentions: The distribution of noroviral load on presentation with age in GII.4 and non-GII.4 cases was shown in Fig. 2A. In general, noroviral load decreased with increasing age (GII.4: r = 0.17, p < 0.01; non-GII.4: r = 0.34, p < 0.01; Spearman correlation). The slope of the best-fit line of non-GII.4 cases (0.057) was greater than that of GII.4 cases (0.025), indicating the decline in noroviral load with age was more pronounced in non-GII.4 cases. The median noroviral load of GI cases was over 1,000-fold lower than that of other non-GII.4 cases (Ct value, median [IQR]: 28.0 [25.0–30.7] versus 17.4 [15.0–21.8]; p < 0.001, Mann-Whitney U test).


Virus Genotype Distribution and Virus Burden in Children and Adults Hospitalized for Norovirus Gastroenteritis, 2012-2014, Hong Kong.

Chan MC, Leung TF, Chung TW, Kwok AK, Nelson EA, Lee N, Chan PK - Sci Rep (2015)

Fecal viral load of norovirus genogroup II genotype 4 (GII.4) and non-GII.4 gastroenteritis on case presentation by(A) age and (B) age group. Cycle threshold (Ct) value of reverse transcription–polymerase chain reaction (RT-qPCR) assay was determined for each case to represent noroviral load. Higher Ct values indicate lower noroviral loads. Blue dotted lines indicate best-fit lines. In panel B, for clarity only p-values (Mann-Whitney U test) of comparisons between GII.4 and non-GII.4 cases were shown. Other comparisons were described in the main text where appropriate. Red horizontal lines denote medians. NS, not significant; r, Spearman’s rank correlation coefficient; *, p < 0.05.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4469980&req=5

f2: Fecal viral load of norovirus genogroup II genotype 4 (GII.4) and non-GII.4 gastroenteritis on case presentation by(A) age and (B) age group. Cycle threshold (Ct) value of reverse transcription–polymerase chain reaction (RT-qPCR) assay was determined for each case to represent noroviral load. Higher Ct values indicate lower noroviral loads. Blue dotted lines indicate best-fit lines. In panel B, for clarity only p-values (Mann-Whitney U test) of comparisons between GII.4 and non-GII.4 cases were shown. Other comparisons were described in the main text where appropriate. Red horizontal lines denote medians. NS, not significant; r, Spearman’s rank correlation coefficient; *, p < 0.05.
Mentions: The distribution of noroviral load on presentation with age in GII.4 and non-GII.4 cases was shown in Fig. 2A. In general, noroviral load decreased with increasing age (GII.4: r = 0.17, p < 0.01; non-GII.4: r = 0.34, p < 0.01; Spearman correlation). The slope of the best-fit line of non-GII.4 cases (0.057) was greater than that of GII.4 cases (0.025), indicating the decline in noroviral load with age was more pronounced in non-GII.4 cases. The median noroviral load of GI cases was over 1,000-fold lower than that of other non-GII.4 cases (Ct value, median [IQR]: 28.0 [25.0–30.7] versus 17.4 [15.0–21.8]; p < 0.001, Mann-Whitney U test).

Bottom Line: In young children, the median noroviral load of GII.4 and non-GII.4 cases was indistinguishably high (cycle threshold value, median [interquartile range]: 16.6 [15.2-19.3] versus 16.6 [14.9-21.6]; p = 0.45).Two age-specific non-GII.4 genotypes (GII.3 and GII.6) were identified among young children.These findings may have implications in norovirus vaccination strategy.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiology, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong Special Administrative Region, People's Republic of China.

ABSTRACT
We conducted a 2-year hospital-based study on norovirus gastroenteritis among children and adults between August 2012 and September 2014. A total of 1,146 norovirus cases were identified. Young children (aged ≤ 5 years) accounted for a majority (53.3%) of cases. Hospitalization incidence exhibited a U-shaped pattern with the highest rate in young children (1,475 per 100,000 person-years), followed by the elderly aged > 84 years (581 per 100,000 person-years). A subset (n = 395, 34.5%) of cases were selected for norovirus genotyping and noroviral load measurement. Non-GII.4 infections were more commonly observed in young children than in older adults (aged > 65 years) (20.5% versus 9.2%; p < 0.05). In young children, the median noroviral load of GII.4 and non-GII.4 cases was indistinguishably high (cycle threshold value, median [interquartile range]: 16.6 [15.2-19.3] versus 16.6 [14.9-21.6]; p = 0.45). Two age-specific non-GII.4 genotypes (GII.3 and GII.6) were identified among young children. These findings may have implications in norovirus vaccination strategy.

No MeSH data available.


Related in: MedlinePlus