A research on rotaviral diarrhea outbreak in Guangxi Province / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>To analyze epidemiological characters of an outbreak of rotavirus diarrhea in Daxing County, Guangxi Province.</p><p><b>METHODS</b>Rotavirus-positive specimens were identified by ELISA kit. G/P typing assays were confirmed with multiplex seminested RT-PCR. Full-length VP7 genes of 4 positive specimens were amplified and analyzed.</p><p><b>RESULTS</b>30 cases of Rotavirus-positive were identified from 64 specimens. The attack rate was 46.9%, and G/P typing was G1P[8]. A change of VP7 amino acid residue is at positions 68.</p><p><b>CONCLUSION</b>G1P[8] rotavirus is the etiologic agents of this diarrhea outbreak. In addition, adults were included in this outbreak.</p>

Genetic variation in VP7 gene of rotavirus serotype G3 predominated in Changchun, China / 病毒学报

Group A rotavirus (RV) is the most important etiologic agent of severe gastroenteritis among children and the development of an effective vaccine becomes the top public health priority. Since survey of RV serotypes circulating in local community is important for introduction or development of RV vaccine, RV serotype G3 had proved as the predominant strain in Changchun from 2001 to 2005. Stool specimens collected from children with acute diarrhea were tested for group A rotavirus by enzyme-linked immunosorbent assay (ELISA) and RV isolates were typed by reverse transcription-polymerase chain reaction (RT-PCR) using serotype-specific primers. The complete VP7 gene segments of 31 rotavirus strains selected in Changchun from 1999 to 2005 were amplified with RT-PCR. Amplicons were cloned and sequenced. Comparative analysis of the VP7 sequences showed that there were no obvious differences among 31 RV strains. There was similar genetic variation among VP7 genes during the same RV season. The nucleotide sequence of VP7 gene of six G3 RV strains had one base deletion at nt1038 in 2003 RV season. The nucleotide mutations in regions A, B and C of VP7 gene took place at the same position or position near-by. Increase of nucleotide mutation in non- high variation region may benefit maintenance of serotype G3 as pre dominant strain after 2002. Increase of non continuous variation in non-high variation regions was notable.

Characteristics analysis on major genes and the encoded proteins of human G9P8 rotaviruses LL52696 and LL52727 / 病毒学报

Two Rotavirus G9P[8] strains (LL52696 and LL52727) were recognized during a sentinel-based survey in Lulong, China. Phylogenetic analysis of the VP7 gene showed that both strains isolated constituted a divergent genetic cluster distinct from the other G9 strains isolated in China. Analysis of VP4, VP6, and NSP4 genes revealed that these strains were closely related to Lulong strains. We hold that two strains were reassortant between G9 and Lulong predominant strains.

Relationship between severity of rotavirus diarrhea and serotype G and genotype / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>To learn the relationship between severity of rotavirus diarrhea and serotype G and genotype P.</p><p><b>METHOD</b>The clinical information and fecal specimens of hospitalized children less than 5 years of age with acute diarrhea in four sentinel hospitals were collected from Aug 2001 to July 2003. Specimens were tested and typed for rotavirus. Each child with rotavirus infection was assessed for severity of diarrhea according to the 20-points scoring system of Vesikari.</p><p><b>RESULTS</b>When combined with P[8], the severity scores for rotavirus diarrhea of P[8]G1 and P[8]G3 were 13 and 12 points, respectively, and the durations of diarrhea were 6 days and 5 days, respectively. The percentage of fever in patients with diarrhea caused by P[8]G1 was higher than that in those with diarrheas caused by P[8]G3 (97 percent vs. 73 percent). And the highest temperature in the cases with diarrheas caused by G1 and G3 was 39 degrees C and 38.6 degrees C, respectively. When combined with G3, the difference of diarrhea severity scores between P[4]G3 and P[8]G3 was not significant. But duration of diarrhea caused by P[4] was longer than that of diarrheas caused by P[8] (6.5 days vs. 5 days) and the maximum times of vomiting in P[8] cases was higher than in p[4] cases (4 times vs. 3 times per day). There was no significant difference in other clinical features between P[8] and P[4] infected cases.</p><p><b>CONCLUSION</b>When combined with P[8], RV diarrhea caused by G1 was associated with higher severity scores than diarrhea caused by G3. When combined with G3, there was no significant difference in severity scores between P[4] and P[8] infected cases.</p>

Rotavirus diarrhea among children in three hospitals under sentinel surveillance, from August 2001 to July 2004 / 中华流行病学杂志

<p><b>OBJECTIVE</b>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.</p><p><b>METHODS</b>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.</p><p><b>RESULTS</b>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.</p><p><b>CONCLUSION</b>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.</p>

Investigation of human calicivirus (HuCV) diarrhea among infantile and young children in China, 1999--2005 / 病毒学报

Human calicivirus (HuCV) has been well known as an important pathogen of outbreak and sporadic acute nonbacterial gastroenteritis worldwide. To investigate epidemiological feature and genetic diversity of HuCV among children in China, fecal specimens were collected from children under 5 years of age with acute diarrhea at 13 hospitals in different provinces across China. The study was performed year-round from January 1999 to June 2005. Fecal specimens were tested for bacteria and rotavirus first and the negative specimens then were tested for HuCV using ELISA and RT-PCR. PCR amplicons were cloned and sequenced for strain characterization. A total of 4426 rotavirus- negative fecal samples were screened. From these, 840 (19%) were positive for HuCV by either or both ELISA (14%) and RT-PCR (9.6%). HuCV infection occurred year-round with an epidemic in each winter (October-January) and mainly in children at 6 -- 17 months of age. Of 151 HuCV strains characterized, 146 belong to norovirus (NV, 96.7%) and 5 were sapoviruses (SV). Among norovirus strains, genotype GG II/4 was most common (99/146), followed by GG II/3 (22/146), GG II/5 (8/146), and 2 strains of each of GG II/6, GG II/7, GG II/8, and GG I/2, the other 9 strains of NV GG II were unique, potentially belonging to new genotypes. These results plus the epidemiology data suggested that HuCVs are an important cause of severe diarrhea in Chinese children that were under reported due to a lack of a simple diagnostic assay. The finding of the potential new genotypes indicates that the current assays need to be improved for broader detection and besides, a continual surveillance for better understanding the epidemiology the disease burden and the searching for new strains of HuCVs is necessary.

Sequence analysis of norovirus CHN02/LZ35666 from Lanzhou city of China based on RdRp and VP1 genes / 病毒学报

Sequence analysis of a new norovirus (NV) isolated from Lanzou city of China was performed based on partial sequence of RNA dependent RNA polymerase (RdRp) and complete capsid protein (VP1) gene. The isolated strain CHN02/LZ35666 shared high sequence homology with GII-4 NVs. Nucleotide homologies of RdRp region and encoded capsid protein region were 90.4% -- 98.6% and 89.8% -- 95.7% , respectively, while amino acid homology of capsid protein region was 94.4% -- 97.4%. The analysis of GDD motif in RdRp region indicated this GDD motif of Lanzhou strain differed from those of the GII-4 predominant epidemic strains. Lanzhou strain formed an independent branch in GII-4 cluster in the phylogenetic tree based on nucleotide sequence of RdRp region and amino acid sequence of capsid protein. Sequence alignment revealed a mutation at the fourth key site of the receptor-binding interface in the strains isolated after 2002 compared with those of previous strains suggesting a possible change of binding pattern to HBGAs receptors.

Epidemiological investigation of an outbreak of acute gastroenteritis caused by human calicivirus in Lulong County / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>To survey an outbreak of acute gastroenteritis in Lulong County and analyze the cause of the disease.</p><p><b>METHODS</b>Epidemiological methods were applied to investigate an outbreak of acute gastroenteritis occurred in June 2000 in Lulong County. Stool specimens were collected from diarrhea patients and were tested for human calicivirus by ELISA and RT-PCR. The products of RT-PCR were cloned and sequenced, then phylogenetic analysis was carried out.</p><p><b>RESULTS</b>In total, 736 farmers were surveyed, among them 134 had acute gastroenteritis, the attack rate was 18.20%, and one elderly patient died. The age of patients was from 1 to 77 years and the incidence of the disease among young people was higher with a peak in June 25 through 30. Six stool specimens were tested for caliciviruses by ELISA and 3 were positives, one of them was confirmed by RT-PCR and belonged to norovirus genotype GI/2. No other pathogens were detected.</p><p><b>CONCLUSION</b>Human calicivirus was confirmed to be the cause of the outbreak of acute gastroenteritis.</p>

Astrovirus infection among hospitalized children with acute diarrhea in seven regions of China, 1998-2005 / 中华流行病学杂志

<p><b>OBJECTIVE</b>To study the epidemiology and strain variations of astrovirus infection among children under 5 years of age, hospitalized for acute diarrhea in China.</p><p><b>METHODS</b>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.</p><p><b>RESULTS</b>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.</p><p><b>CONCLUSION</b>Astrovirus seemed an important etiologic agent in young children with acute diarrhea in China and Serotype 1 was the most prevalent one.</p>

Etiological study on viral diarrhea among children in Lanzhou, Gansu, from July 2004 through June 2005 / 中华流行病学杂志

<p><b>OBJECTIVE</b>To study molecular epidemiology of four major etiological viruses among children with acute diarrhea in Lanzhou, Gansu province.</p><p><b>METHODS</b>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.</p><p><b>RESULTS</b>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.</p><p><b>CONCLUSION</b>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.</p>

Molecular epidemiology of human caliciviruses diarrhea among infants and young children in Lanzhou from December 2001 to June 2004 / 中华儿科杂志

<p><b>OBJECTIVE</b>To investigate the characteristics of human caliciviruses (HuCV) diarrhea among infants and young children with acute diarrhea in Lanzhou, Gansu Province, China by using molecular epidemiologic techniques.</p><p><b>METHODS</b>Stool specimens were collected from both outpatients and inpatients with acute diarrhea in Lanzhou. Enzyme-linked immunosorbant assay (ELISA) was used to detect rotavirus antigen (RVA). Reverse transcription-polymerase chain reactions (RT-PCR) were used to detect HuCV in stool specimens of RV ELISA (-).</p><p><b>RESULTS</b>Of the stool specimens collected from 515 cases in Lanzhou from December 2001 to June 2004, 264 were RVA ELISA (+) and 251 were RVA ELISA (-). Among all cases who were RVA ELISA (-), 25 (9.96%) were found positive for HuCV. HuCV was detected in 12 of 133 cases (9.02%) from December 2001 to November 2002, no genotyping was performed for these cases. From July 2003 to June 2004 13 of 118 cases (11.02%) were found positive for HuCV, of whom 11 cases had Norwalk-like virus GII (NLV GII) infection and 2 cases had Sapporo-like virus infection (one case had combined infection with astrovirus) and no NLV GI was found. HuCV infection mainly occurred in children under 2 years of age and no seasonal cluster was found.</p><p><b>CONCLUSION</b>HuCV is one of the major etiological agents of viral diarrhea among infants and young children in Lanzhou. NLV GII maybe the predominant genotype.</p>

Rotavirus surveillance data from Kunming Children's Hospital, 1998 - 2001 / 中华流行病学杂志

<p><b>OBJECTIVE</b>To study the epidemiological status on rotavirus diarrhea in Kunming to improve the rotavirus vaccine immunization program.</p><p><b>METHODS</b>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.</p><p><b>RESULTS</b>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.</p><p><b>CONCLUSION</b>Rotavirus was the major cause of acute diarrhea in Kunming. An effective rotavirus vaccine for prevention and control of rotavirus diarrhea should be developed.</p>

Phylogenetic analysis of enterovirus 71 isolated from patients with hand, foot and mouth disease in Guangdong and Fujian provinces, 2000-2001 / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>To identify enterovirus 71 (EV71) strains isolated from patients with hand, foot and mouth disease (HFMD) in Guangdong and Fujian provinces from 2000 to 2001 by using phylogenetic analysis.</p><p><b>METHODS</b>All 25 samples were first tested for enteric viruses by RT-PCR using enterovirus specific primers EV-1 and EV-2, and then were identified for EV71 by RT-PCR using EV71 specific primers 159S and 162A. The amplicons of 485bp segment (part of the VP1 gene) were cloned into pGEM-T and sequenced. A phylogenetic tree was constructed by comparison of the sequences with other 12 EV71 strains isolated from China, Japan, Hungary, and the United States including the prototype BrCr.</p><p><b>RESULTS</b>The positive rate of EV71 was about 20%. The sequence analysis showed that the new isolate (GZH2000) shared 94%-96% nucleotide identity with three strains isolated in 1998 and 2000, and 91% with a strain isolated in 1987 from Chinese mainland, but shared only 82%-84% homology with EV71 isolates studied abroad.</p><p><b>CONCLUSIONS</b>EV71 is one of the important pathogens of HFMD in south China. The strains isolated from mainland were closely related with most isolates from Taiwan, but different from most EV71 strains reported abroad. The symptoms of EV71 infection in mainland were not as intensive as those described in Taiwan's outbreak.</p>

Genotype of human calicivirus from infants with diarrhea in Guangzhou city in 2001 / 中华儿科杂志

<p><b>OBJECTIVE</b>To understand the characteristics of human calicivirus (HuCV) infection in infants with diarrhea in Guangzhou city and to study genotype of the virus.</p><p><b>METHODS</b>The authors collected fecal specimens from 22 children with acute nonbacterial gastroenteritis from November to December, 2001. HuCV was detected from the specimens by RT-PCR. The PCR products were cloned into the PMD18-T cloning vector and sequenced.</p><p><b>RESULTS</b>HCV was detected from the specimens of 2 cases (9%, 2/22). The nucleotide sequence analysis revealed that the virus strains belonged to genotype 2 of Norwalk-like viruses.</p><p><b>CONCLUSION</b>HuCV is one of the pathogens causing diarrhea in infants and young children in Guangzhou area. HuCV infection occurred sporadically in autumn and winter.</p>

Surveillance finding on rotavirus in Changchun children's hospital during July 1998-June 2001 / 中华流行病学杂志

<p><b>OBJECTIVE</b>To establish baseline patterns of rotavirus diarrhea and to describe its epidemiologic features in Changchun city, prior to rotavirus vaccine immunization.</p><p><b>METHODS</b>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.</p><p><b>RESULTS</b>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.</p><p><b>CONCLUSION</b>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.</p>

Epidemiological study of rotavirus diarrhea in Beijing, China - a hospital-based surveillance from 1998 - 2001 / 中华流行病学杂志

<p><b>OBJECTIVE</b>To provide information on epidemiology of rotavirus infection in Beijing, China.</p><p><b>METHODS</b>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.</p><p><b>RESULTS</b>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.</p><p><b>CONCLUSION</b>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.</p>

Epidemiological study of human caliciviruses among children with acute diarrhea in Lulong county, 1999 - 2001 / 中华流行病学杂志

<p><b>OBJECTIVE</b>To investigate the epidemiological characteristus of human caliciviruses (HuCVs) among children under 5 years of age with acute diarrhea and to estimate the disease burden in Lulong county.</p><p><b>METHODS</b>HuCVs were detected by enzyme linked immunosorbent assay (ELISA) and reverse transcription-polymerase chain reaction (RT-PCR). Some PCR amplicons were cloned and sequenced. Phylogenetic tree was constructed for strain characterization. The rate of HuCVs-attributed hospitalization was estimated according to the positive rate of HuCVs detection in fecal specimens collected from hospitalized diarrhea patients.</p><p><b>RESULTS</b>Between July 1999 and June 2001, 708 fecal specimens were collected, of which 393 rotavirus-negative and 5 rotavirus-positive specimens were detected for HuCVs. Thirty-one point six percentage of fecal specimens from patients with diarrhea was HuCVs positive. Among inpatients, HuCVs positive rate was 17.5%. HuCVs detection was mainly distributed in 3 - 17 mouth-old children, in winter. All 11 strains belonged to NLV GII in which 6 strains GII-3, 2 strains GII-4 and 3 strains GII-7, and they shared 55.1% - 100% nucleotide identity. NLV GII-4 and GII-7 were identified in 2000, while NLV GII-3 and GII-7 in 2001. The preliminary estimate of HuCVs-attributed hospitalization rate was 3.6 per thousand.</p><p><b>CONCLUSION</b>Human caliciviruses with different genotypes circulated among children in Lulong county with GII NLVs were the prevalent strains. The disease burden of HuCVs was second to rotavirus.</p>

Investigation of an outbreak of acute diarrhea caused by Human calicivirus / 中华实验和临床病毒学杂志

<p><b>BACKGROUND</b>To survey a diarrhea outbreak in Guangan city and analyze the cause of the disease.</p><p><b>METHODS</b>The population enrolled in the surveillance came from four different settings and was randomly sampled. Stool specimens collected from diarrhea patients were tested ordinarily for enteric bacteria and further examined for viral pathogens with PAGE, ELISA and RT-PCR.</p><p><b>RESULTS</b>In total, 4,567 persons were surveyed, among them 942 had acute diarrhea (prevalence 20.63%). The incidence was higher in rural area (28.6%) than in urban area (19.6%) (chi-square =22.29, P less than 0.005) with a peak in May 10 through 25 four human caliciviruses were detected from stool specimens by ELISA and RT-PCR in specimens from 4 and 1 patients, respectively.</p><p><b>CONCLUSION</b>Human calicivirus probably was the cause of this diarrhea outbreak in Guangan city.</p>