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Objective: To learn the epidemiologic characteristics of rotavirus diarrhea in three hospitals under sentinel surveillance from August 2001 to July 2004 and to provide background information for developing and implementing rotavirus vaccine., Methods: Data from hospital-based rotavirus surveillance among children < 5 years old hospitalized with acute diarrhea was used. Patients' clinic information and feces specimens were collected. Specimens were tested and typed for rotavirus., Results: Totally, 3121 specimens were tested and the detection rate of rotavirus was 51%. Among all the children with rotavirus diarrhea, 94% were < 2 years old. G3 (69.9%) was the most prevalent serotype followed by G1 (6.6%) and G2 (2.9%). P[8] was the most common genotype of rotavirus. The most common G-P combination identified in this study was P[8] G3 (64.0%). Seveal other combinations of minor frequency were also identified., Conclusion: Rotavirus infection was most commonly seen among children < 5 years old hospitalized with acute diarrhea in the three hospitals. It is important to develop and implement rotavirus vaccine to prevent and control severe rotavirus infection. Because of the diversity of rotavirus strains, it is necessary to perform rotavirus strain surveillance to understand the dynamic nature of viral transmission.

Objective: To study the epidemiology and strain variations of astrovirus infection among children under 5 years of age, hospitalized for acute diarrhea in China., Methods: Inpatients under 5 years of age with acute diarrhea in hospitals of seven provinces between 1998 and 2005 were enrolled in the study Stool specimens were collected and tested for astrovirus using the Dako Amplified IDEIA Astrovirus kits or reverse-transcription polymerase chain reaction (RT-PCR). Genetic identities of the strains were determined using RT-PCR with serotype-specific primers and confirmed by sequencing of the RT-PCR products., Results: A total of 1668 diarrheal stool samples tested for both rotavirus and calicivirus negative were examined. The detection rate of astrovirus infection was 5.5% (91/1668) and the diarrhea cases caused by astrovirus infection could be found in any season of the year but mainly occurred in cold season from October to next January. Astrovirus detection-rates were: 7.4% among infants aged 9-11 months followed by 6.1% in 12-17 month-olds, and 6-8 months 5.6% & 0-2 months 5.6% before 8 months. Over 95% of astrovirus infections occurred in children before 2 years of age. Among 49 strains, typed, serotype 1(45/91) was most commonly seen while serotype 5 was in two cases and serotype 3 and 8 were detected in only one case respectively., Conclusion: Astrovirus seemed an important etiologic agent in young children with acute diarrhea in China and Serotype 1 was the most prevalent one.

Objective: To study molecular epidemiology of four major etiological viruses among children with acute diarrhea in Lanzhou, Gansu province., Methods: Stool specimens were collected from all 400 inpatients less than 5 years old with acute diarrhea admitted in Department of Pediatrics, the First Hospital, Lanzhou University from Jul. 2004 through Jun. 2005. Dako IDEIA kits were used for detection of rotavirus, adenovirus and astrovirus. Calicivirus detection was done by both reverse transcription-polymerase chain reactions (RT-PCR) and ELISA. Further strain characterization of rotavirus and astrovirus was carried out with RT-PCR., Results: A total of 400 stool samples were collected and tested. Rotavirus was present in 47.3% of the cases: calicivirus in 15.5%, astrovirus in 9.5% and adenoviruses in 7.5%. Mixed infections with multiple enteric viruses were present in 13.5% of all samples. Among 189 rotavirus positive samples, serotype G2 (34.4%) was the predominant strain followed by G3 (32.8%), G1 (1.1%) and mixed-G infection (5.8%). 25.9% of strains remained to be non-typeable. P genotyping showed P [4] (45%) was most common followed by P [8] (22.1%), and non-typeable (32.9%). Strain P [4] G2 (43.6%) was the most common combination followed by P [8] G3 (25.6%), P [4] G3 (13.8%), and P [8] G2, P [4] G1 and P [8] G1. Among 38 astrovirus strains, serotypes 1 (57.8%) was the predominant. Serotype 3 and 8 were found only in one case respectively, 14 strains remained to be non-typeable. A peak admission of rotavirus diarrhea was observed from October through December. More than 95.0% of viral diarrhea patients under hospitalization occurred among children younger than 2 years. The incidence rates of rotavirus were highest in infants aged 6 - 23 months., Conclusion: Rotavirus was the most important pathogen for viral diarrhea among children hospitalized in Lanzhou followed by calicivirus, astrovirus, and adenovirus. The predominant rotavirus strain circulated was P [4] G2, which was different from the finding in the previous years. The high rate of mixed infection with different viral agents was notable.

Objective: To study the epidemiological status on rotavirus diarrhea in Kunming to improve the rotavirus vaccine immunization program., Methods: A hospital-based sentinel surveillance program for rotavirus was set up among children less than 5 years old with acute diarrhea in Kunming Children's Hospital. Clinical information and fecal specimens were collected and rotavirus were detected by polyacrylamide gel electrophoresis (PAGE) and/or enzyme linked immunosorbent assay (ELISA). Positive specimens were further serotyped or genotyped by ELISA and/or RT-PCR., Results: During the three years of surveillance, 466 specimens were collected. Rotavirus were detected on 246 (52.8%) specimens. 97% of the rotavirus diarrhea cases occurred among children less than 2 years old. There was a peak of admissions for rotavirus diarrhea cases between October and December which accounted for 48% of all the rotavirus hospitalizations each year. Among 204 specimens with G serotyping, the predominant strain was serotype G1 (47.5%) followed by G2 (17.6%), G3 (15.7%), G9 (4.9%) and G4 (1.0%). Mixed infection (2.5%) were rare and 22 specimens (10.8%) remained non-typeable. P genotyping showed P[4], P[8] and P[6] were the most common strains, accounting for 29.3%, 27.6% and 13.8% respectively. P[4]G2 was the most common strain which accounted for 34.1% (14/41) followed by P[8]G1 (29.3%) and P[6]G9 (12.2%). Another 7 uncommon P-G combinations were also identified., Conclusion: Rotavirus was the major cause of acute diarrhea in Kunming. An effective rotavirus vaccine for prevention and control of rotavirus diarrhea should be developed.

Objective: To provide information on epidemiology of rotavirus infection in Beijing, China., Methods: An ongoing hospital-based surveillance was conducted among children < 5yr old with acute diarrhea according to WHO generic protocol (CID-98). During a 3-year study (Apr. 1998 to Mar. 2001), a total of 484 stool samples were collected from 1 457 patients, including 275 samples from 1 048 outpatients and 209 samples from 409 inpatients., Results: The overall detection rate of rotavirus infection was 25.4%. Rotavirus was responsible for 27.3% of diarrhea inpatients on a yearly base, and 46.2% during rotavirus season. Two peaks of diarrhea were observed each year, one in the summer (June-Sep.) due to bacterial dysentery (16.7%) and another in fall winter (Oct.-Dec.) due to rotavirus infection (23.0%). The detection rate on rotavirus was the highest in age group of 6 - 11 months (38.2%), followed by 1 - 2 years old (28.5%). Ninety six point eight percentage of children were infected under 3 years of age. The number of deaths, possibly caused by rotavirus diarrhea were accounted for 40% of all diarrhea deaths and 11.1% of the total deaths. Serotyping of 123 rotavirus isolates showed that serotype G1 (55.3%) was predominant, followed by G2 (26.8%), G3 (9.8%), G4 (0.8%), and 10 isolates (8.1%) remained non-typeable. Mixed infections (0.8%) seemed to be rare., Conclusion: Rotavirus diarrhea was an important infectious disease among children in Beijing. Safe and effective rotavirus vaccines for the prevention of severe diarrheas and the reduction of treatment costs are of significant importance to China.

Objective: To establish baseline patterns of rotavirus diarrhea and to describe its epidemiologic features in Changchun city, prior to rotavirus vaccine immunization., Methods: Hospital-based surveillance was conducted among children under 5 years old with acute diarrhea in Changchun Children's Hospital. Fecal samples were determined to identify rotavirus by PAGE and/or ELISA. G serotypes of rotavirus were identified by ELISA and/or nested RT-PCR. P genotyping were carried out by RT-PCR. All data were computerized and analysed by "Generic Manual on Rotavirus Surveillance" set by CDC in the USA., Results: In total, 2 343 diarrhea cases were screened and 1 211 fecal samples were collected. Rotavirus was detected in 31.0% among outpatients and 52.9% in inpatients. During the peak of the season (November through March), 58.6% of diarrhea was caused by rotavirus among inpatients. 95.0% of rotavirus diarrhea cases occurred among children aged < 2 years. The predominant strain was serotype G1 (82.4%), followed by G2 (5.0%), G3 (3.3%), G4 (0.9%). P genotyping showed that P[8] and P[4] were the most common ones. Nine different P-G combinations were identified, four strains (P[8]G1, P[4]G2, P[8]G3, and P[8]G4) commonly seen worldwide accounted for 75.6% of the total. Taken together with uncommon strains, including the novel types P[4]G4 and P[8]G2, it highlights the extraordinary diversity of rotaviruses circulating in China., Conclusion: Rotavirus is the major cause of severe child diarrhea in Changchun. Developing a rotavirus vaccine for prevention of severe disease and reduction of treatment costs seemed to be necessary.

Group A rotaviruses are the most important etiologic agents of severe gastroenteritis in children, and as a result, the development of an effective vaccine against severe rotavirus diarrhea is a top public health priority. Previous studies indicated that G1 rotavirus are much more common in most countries around the world and development of G1--specific vaccine may be important in protection against human illness. In this report, we analyzed the VP7 gene and VP4 gene variable regions of 36 G1 rotavirus community strains collected from different geographic locations worldwide. Comparative analysis of the VP7 sequences showed that most of the amino acid substitutions of global strains occurred in and around previously identified epitope regions VR3, VR4, and VR6, suggesting that there are slight antigenic differences among these strains. Growtree phylogram using the VP7 amino acid sequences as an index grouped all strains into three clusters. The VP7 sequence of each cluster possesses distinctive amino acid residues which are peculiar to most members of the same group at a most positions. These data will be essential to achieve a much better understanding of molecular epidemiologic characteristics of G1 rotavirus around the world.