[Infection status, clinical symptoms and gene type transition of group A rotavirus in children, less than five years-of-age, with diarrhea in sentinel hospitals of Henan Province, China].

Objective: To investigate the infectious status, gene type transition and epidemiological features of rotavirus A isolated from infants and children (<59 months-of-age) in sentinel hospitals from 2008 to 2015 in Henan province, China. Methods: In total, 2 541 stool samples (each 3- 5 ml) were collected from infants and children aged less than five years in two sentinel hospitals and group A rotavirus was detected by a double antibody sandwich ELISA. Viral RNA was extracted from positive samples and G/P gene typing was performed using a two-step nested multiplex RT-PCR. Epidemiological information (including demographic information such as age, sex and clinical symptoms) was also collected from the patients and analyzed. Results: Group A rotavirus was detected in 30.9% (785/2 541) of diarrhea samples from children. The detection rate was higher in October (54.8%, 345/629) and lower in July (5%, 5/101) each year from 2008 to 2015. The group A rotavirus infection rate was higher in boys (30.6%, 451/1 476) than in girls (31.4%, 334/1 065) (χ(2)=0.18, P=0.664). Infection mainly occurred in 4-12 months old patients (61.3%, 481/785) (χ(2)=196.69, P<0.001), and the infection rate was lower in cities (26%, 258/992) compared with rural areas (34.0%, 527/1 549) (χ(2)=18.19, P<0.001). G typing of 785 strains of group A rotavirus revealed the following types: G1 (13.5%, 106 strains), G2 (11.1%, 87 strains), G3 (29.7%, 233 strains), and G9 (57.5%, 451 strains); P typing revealed the predominance of P[4] (11.3%, 89 strains) and P[8] (84.7%, 665 strains); gene type combinations comprised mainly G9P[8], G2P[4], G3P[8], G1P[8], respectively accounted for 52.9% (415), 9.7% (76), 17.3% (136), 11.3% (89). Gene type combinations G1 [8] and G3P[8] have been decreasing in prevalence since 2008 and G9P[8] has become the dominant gene type of group A rotavirus in Henan province. Among the group A rotavirus infection samples, the male:female infection ratio was 1.4∶1 (451/334), with no significant difference in the infection rate (χ(2)=0.18, P=0.664); the infection rate was higher in 4- 12 months old patients (61.3%, 481/785), with a significant difference detected between age groups (χ(2)=196.69, P<0.001). The rate of detection was lower in cities (26.0%, 258/992) than in rural areas (34.0%, 527/1 549) (χ(2)=18.19, P<0.001). Clinical analysis revealed a body temperature of below 37 degrees in 75.7% of positive cases (594 patients), 37.0- 37.5 degrees in 17.2% of cases (135 patients), 37.6-38.0 degrees in 2.0% of cases (16 patients), and above 38 degrees in 5.1% of cases (40 patients), with most cases showing no fever or a mild fever. The frequency of episodes of diarrhea among the patients was 0- 3 times (21.1%, 166 cases), 4- 6 times (65.6%, 515 cases), 7- 9 times (8.0%, 63 cases), or 10- 15 times (5.2%, 41 cases), mainly showing mild and moderate diarrhea. Vomiting also varied in frequency among the patients from no vomiting (86.9%, 682 cases), 1-2 times (11.8%, 92 cases), 3 times (6.0%, 47 cases), and more than 3 times (0.4%, 3 cases). The occurrence of dehydration varied from no dehydration (86.9%, 682 cases), mild dehydration of 1%- 5% (12.1%, 95 cases), to severe dehydration of ≥5% (1.0%, 8 cases). Conclusion: A higher infection rate of group A rotavirus was detected in children younger than five years of age with acute diarrhea in sentinel hospitals in Henan province, including part-mixed infection cases. A predominance of cases was detected in the autumn, and secondly the spring of each year. Gene type G9P[8] was most frequently isolated. The majority of patients displayed no fever, vomiting or dehydration. The cases with clinical symptoms of fever, diarrhea, vomiting and dehydration often showed mild disease.