Epidemiologic features of rotavirus infection in Taiwan: a review

Hospital-based surveillance of severe rotavirus gastroenteritis and rotavirus strains in young Taiwanese children

BACKGROUND/PURPOSE

Rotavirus remains a leading cause of pediatric gastroenteritis-related hospitalization. Surveillance studies have revealed that several major rotaviral genotypes are responsible for most cases of rotavirus gastroenteritis (RVGE). This study aimed to understand the characteristics of acute gastroenteritis (AGE) caused by rotavirus in young children in Taiwan.

METHODS

Ten hospitals in Taiwan were subjected to prospective hospital-based AGE surveillance during 2014-2017, and children younger than 5 years old who were hospitalized due to AGE were enrolled in the study. Medical and demographic variables were recorded and analyzed, and stool specimens were collected for rotavirus identification and genotyping via real-time RT-PCR. Non-rotavirus AGE age-matched controls were enrolled.

RESULTS

Surveillance identified 4747 young children hospitalized with AGE during this study period. The median age of these patients was 2.0 years. Rotavirus was detected in stool samples from 518 patients (10.9%). The prevalent months of RVGE in 2014, 2015, and 2017, wherein the rotavirus positivity rates exceeded 30%. The most common serotypes were G3P[8] (303/518, 58.9%) and G1P[8] (86/518, 16.6%). The percentage of G3P[8] increased from 4.9% in 2014 to 74.3% in 2016 (P < 0.0001), whereas the percentage of G1P[8] decreased from 61.0% in 2014 to 22.5% in 2015 (P < 0.0001). Compared with G3P[8], G1P[8] was associated with a significantly higher C-reactive protein level (P < 0.05).

CONCLUSION

Rotavirus remains a notable pathogenic etiology of childhood AGE and the G3P[8] serotype was dominant in Taiwan. This study highlighted the importance of rotavirus surveillance to ensure protective effectiveness against the circulating strains.

Immunogenicity, reactogenicity, and safety of a human rotavirus vaccine, Rotarix, in Taiwanese infants who received a dose of hepatitis B immunoglobulin after birth

This Phase-IV study evaluated the human rotavirus (RV) vaccine Rotarix (RIX4414) to provide additional local clinical data to the Taiwan Food and Drug Association (NCT01198769). Healthy infants aged 6-12 weeks who were given a hepatitis B immunoglobulin (HBIg) dose after birth, received two doses of RIX4414 (0, 2-month schedule). Anti-RV IgA antibody concentrations were measured using ELISA. A total of 15 infants were enrolled, and included in the according-to-protocol cohort. The anti-RV IgA antibody seroconversion rate 2 months post-Dose 2 was 100% (95% confidence interval = 78.2-100) and the geometric mean concentration was 254.7 U/ml (95% confidence interval = 145.0-447.7). Two episodes of gastroenteritis were reported, and one stool sample was tested for RV, which was negative. No fatal serious adverse events were reported during the study period between November 2010 and April 2011. The two-dose regimen of RIX4414 was highly immunogenic and safe when administered to healthy Taiwanese infants who received a HBIg dose after birth.

TRIAL REGISTRATION NUMBER

NCT01198769.

Concomitant rotavirus and Salmonella infections in children with acute diarrhea

BACKGROUND AND PURPOSE

The incidence of concomitant rotavirus and Salmonella infection has been reported to be 1.3% to 7.4%. We designed this study to compare the clinical manifestations in children infected with rotavirus, Salmonella, or both.

METHODS

The medical records of admitted children with acute rotavirus or Salmonella gastroenteritis in 2001 were reviewed. They were divided into group R (rotavirus), group S (Salmonella) and group C (concomitant infection with both). The differences of clinical manifestations and laboratory data among the three groups were analyzed via chi-squared, analysis of variance (ANOVA), Bonferroni and Kruskal-Wallis tests, and odds ratios with 95% confidence intervals (95% CI).

RESULTS

Among the 895 cases reviewed, 550 were group R, 312 group S, and 33 (3.7%) group C. Group C had more vomiting compared with group S (p = 0.0017). Comparing with group R, group C had more prolonged and high fever (> or = 39 degrees C) (p < 0.05), more percentage of green coloration, with mucus and blood contained in the stool (p < 0.001). The C-reactive protein (CRP) value was significantly higher in group C (9.70 +/- 11.05 mg/dL) than in group R (1.33 +/- 3.62mg/dL) or S (5.22 +/- 6.11 mg/dL) (p < 0.05). Hypokalemia was found most frequently in group C (C: 30.0%, S: 8.8%, R: 7.3%) (p = 0.0026).

CONCLUSION

Concomitant rotavirus and Salmonella infections accounted for 3.7% of cases in this study. They had higher CRP as well as incidence of hypokalemia [corrected] In a child with rotavirus gastroenteritis, concomitant infection with Salmonella should be considered if the child has sustained a high fever (> or = 39 degrees C) for over 4 days and a green stool with mucus and blood.

Molecular epidemiology and clinical manifestations of viral gastroenteritis in hospitalized pediatric patients in Northern Taiwan

By reverse transcription-PCR or PCR, among 257 children with nonbacterial acute gastroenteritis (AGE), rotavirus, norovirus, astrovirus, enteric adenovirus, and multiple viruses were identified in 78 (30.4%), 21 (8.2%), 7 (2.7%), 51 (19.8%), and 53 (20.6%) patients, respectively. Higher disease severity was found for AGE caused by multiple viruses and by rotavirus alone. The majority of rotaviruses isolated from 2004 to 2006 belonged to genotypes G1 (20.4%), G2 (16.5%), G3 (27.2%), and G9 (21.4%).

Genetic distribution of group A human rotavirus types isolated in Gyunggi province of Korea, 1999–2002

BACKGROUND

Human rotavirus genotypes G1-G4 and G9 are the major etiological agents of infantile gastroenteritis. G1 was the most prevalent in Korea during the 10-year period prior to 1997. However, between 1998 and 1999, G4 was the predominant type in Korea, as it was in other Asian countries.

OBJECTIVES

The circulating pattern and genetic variability of group A human rotavirus in Gyunggi, Korea, 1999-2002, were examined in 189 stool specimens.

STUDY DESIGN

Stool samples were collected from children with diarrhea, and group A human rotavirus type was determined using multiplex RT-PCR in those specimens found to be positive for rotavirus by ELISA. Each genotype was sequenced, and phylogenetic analysis was performed on the sequences.

RESULT

We found significant variability from year to year in the prevalence of different G and P types of rotavirus. We also found relatively high prevalence rates for types normally considered to be uncommon. Furthermore, we found that the most prevalent combination of G and P types changed from year to year. Although the combination of G and P types changed every year, the sequence of G genotypes showed a high level of similarity (>97%) compared to those of strains from other Asian countries.

CONCLUSION

We report the types of rotavirus circulating in Gyunggi province, Korea from 1999 to 2002. This information on rotavirus diversity has important implications for rotavirus vaccine efficacy and future vaccine development.

Disease burden and related medical costs of rotavirus infections in Taiwan

Background

The disease burden and associated medical costs of rotavirus infections in inpatient and outpatient sectors in Taiwan were examined in anticipation of the availability of new rotavirus vaccines.

Methods

The yearly national case number and medical costs for all for inpatients and outpatients with acute gastroenteritis (AGE) were extracted from the Bureau of National Health Insurance database in Taiwan according to ICD-9-CM codes. A retrospective study was also performed using records of children with AGE seen at three hospitals in Taiwan in 2001 to identify laboratory confirmed rotavirus infection cases. The annual incidence and related medical costs of AGE due to rotavirus infection were then estimated.

Results

Children <5 years old comprised 83.6% of inpatient and 62.0% of outpatient pediatric AGE cases in Taiwan in 2001. Rotavirus was the most common agent detected among AGE patients in this age group in the three hospitals, and was detected in 32.9% (221/672) of inpatient and 24% (23/96) of outpatient stool specimens tested for microbial etiologies. An estimated 277,400 to 624,892 cases of rotavirus infections sought medical care in Taiwan in 2001, equaling one in 2 to 5 children <5 years old required medical care due to rotavirus infection. The incidence of hospitalization due to rotavirus infections was 1,528–1,997/100,000 for children <5 years old. The total associated medical costs due to rotavirus infection were estimated at US $10–16 millions in Taiwan in 2001. Although the per-capita medical cost of rotavirus infection was lower in Taiwan than in the United States or Hong Kong, the personal economic burden was similar among the three places when normalized for gross national incomes per capita.

Conclusion

Infections caused by rotavirus constitute an important human and economic burden among young children in Taiwan. A safe and effective vaccine is urgently needed.

Epidemiology and strain characterization of rotavirus diarrhea in Malaysia

OBJECTIVES

The objectives of the study were to describe the epidemiology and strain characterization of rotavirus (RV), to determine the proportion of hospitalizations for diarrhea attributable to RV among children under 5 years of age, and to estimate the disease burden of RV diarrhea in Malaysia.

METHODS

All children 0-59 months of age admitted for acute gastroenteritis to Kuala Lumpur Hospital (KLH) or Hospital Umum Sarawak (HUS) were surveyed. The periods of surveillance were from February 1, 2001 to April 30, 2003 in KLH and April 1, 2001 to March 31, 2003 for HUS.

RESULTS

The highest rate of RV-associated diarrhea was among children aged 6-17 months, accounting for 55% of RV-associated diarrhea. There was no seasonality observed in either hospital. P[8]G9 strains were predominant, accounting for 73% of all strains in both hospitals, 80% from KLH and 61% from HUS. There was no mortality.

CONCLUSIONS

RV was responsible for 38% of hospitalizations for diarrhea. It was most common in the 6-17 months age group. There was no seasonality observed for RV-associated diarrhea. The most prevalent strain of RV was P[8]G9. The estimated incidence of RV-associated diarrhea was 27 per 10000 population under the age of 5 years per year.

Microbial Etiology of Acute Gastroenteritis in Hospitalized Children in Taiwan

BACKGROUND/PURPOSE

Viral infections are the most common causes of acute infectious diarrhea in the pediatric population. To explore any possible microbial etiologies of acute gastroenteritis in children, we detected stool viral antigen including rotavirus, adenovirus, norovirus and astrovirus. We also studied the possible precipitating factors.

METHODS

During a period of 1 year (from October 2003 to September 2004), children from birth to 15 years old admitted to the pediatric ward were prospectively surveyed. Stool specimens were collected within 48 hours after admission and then frozen at -40 degrees C until analysis. Enzyme immunoassay was used to detect rotavirus, astrovirus, norovirus and adenovirus. Bacterial culture was performed at the same time.

RESULTS

During the study period, 82 stool samples were collected due to acute gastroenteritis and fit the definition of a diarrhea episode. Forty-two (51.2%) patients with viral infection, 11 (13.4%) with bacterial infection, and six (7.3%) with mixed viral and bacterial infection were detected. The most prevalent virus was rotavirus (35.4%), followed by norovirus (29.3%). The most prevalent cause of bacterial infection was Salmonella (19.5%). With regard to clinical severity, rotavirus resulted in longer hospital stay, higher rate of vomiting, stool occult blood, leukocytosis, lower rate in stool pus cell, and C-reactive protein elevation more than 5 mg/dL as compared with norovirus. Only the difference in hospital stay reached significant statistical difference.

CONCLUSION

Norovirus is an important cause of acute gastroenteritis in children, although rotavirus is still the leading cause of pediatric acute gastroenteritis.

Epidemiological profile of rotavirus infection in the Republic of Korea: results from prospective surveillance in the Jeongeub District, 1 July 2002 through 30 June 2004

To facilitate future decisions regarding the usefulness of rotavirus vaccines in the Republic of Korea, active surveillance was conducted in a network of clinics, emergency departments, and hospitals serving Jeongeub District, Korea. Children with diarrhea underwent standard clinical evaluations, and stool specimens were collected to test for the presence of rotavirus. Parents were interviewed to collect demographic and family information. From 1 July 2002 through 30 June 2004, a total of 4106 children, representing 1 (50%) of every 2 children <5 years old in the study population, were evaluated for rotavirus diarrhea. Of the 2232 stool specimens obtained throughout the year, 460 (20.6%) were rotavirus positive; however, the monthly prevalence of rotavirus infection peaked at 49.5% in February 2004. Of the 460 rotavirus-positive stool specimens, 366 were obtained from children who visited outpatient clinics, and 94 were obtained from children who were hospitalized. By extrapolating the proportion of rotavirus-positive patients to all children with diarrhea in the surveillance system, we calculate that 882 children in Jeongeub District had rotavirus infection (which would predict that there would be 702 associated clinic visits and 180 hospitalizations). Genotyping of rotavirus strains showed that 39% of strains were type G9P[8], 24% were type G1P[8], 17% were type G3P[8], and 13% were type G2P[4]. The incidence of rotavirus diarrhea peaked at age 13-24 months, and 94% of cases occurred during the first 3 years of life. The annual incidence of all rotavirus disease-associated outcomes was 56.9 cases/1000 children <5 years old (95% confidence interval [CI], 51.9-62.2 cases/1000 children <5 years old). The incidence of rotavirus disease-associated hospitalizations was 11.6 cases/1000 children <5 years old (95% CI, 9.5-14.2 cases/1000 children <5 years old). In Korea, diarrhea is common during childhood, and the incidence of diarrhea due to rotavirus infection suggests that improved programs for the prevention and control of both rotavirus diarrhea and diarrhea due to other causes are needed.

Phylogenetic analyses of human rotavirus in central Taiwan in 1996, 2001 and 2002

BACKGROUND

Rotavirus epidemiology information is required for gastroenteritis disease control and prevention. Information gathered about the serotype distribution of rotaviruses isolated in Taiwan is of crucial significance, before a licensed rotavirus vaccine is introduced.

OBJECTIVES

The purpose of the present study is to investigate the epidemiological diversity of rotaviruses in Taiwan.

STUDY DESIGN

A total of 51 stool samples taken from cases of acute gastroenteritis were collected from three teaching hospitals in central Taiwan in 1996, 2001 and 2002. The samples were subjected to RT-PCR tests of VP7 gene of the human rotavirus group A, B, C.

RESULTS

A total of 16 stool samples were detected positive by RT-PCR and 10 were sequence analyzed and classified into G1, G3, and G9 types. Compared with other HRV strains: the sequences of CS96-40 of G1 are similar to MVD9816 (identity rate 97.15% and 96.09%, respectively, from Uruguay); the sequences of CS02-01 of G3 are similar to 98-B31 (identity rate 98.93% and 98.72%, respectively, from Japan); the sequences of CS01-05, CS01-06, CS01-07, CS01-09, CS01-13, CS02-02, CS02-03, CS02-04 are very similar to other established G9 rotaviruses sequences (identity rate 96.85-99.88%), especially between CS02-04 and SP2737 (from Japan) with an identity rate of 99.88% and 100% nucleotide and amino acid, respectively. Except for CS01-06 strain, it is VR3, but not VR5, VR7 or VR8, that found to be the most frequent mutated amino acid regions of VP7 in these strains.

CONCLUSIONS

Our findings are the first to document the high prevalence of G9 HRV strains in Taiwan, and suggest the re-emergence of G3 strains in central Taiwan since 1991. Epidemiological surveys carried out in this study suggest genotype shifts from type G1 before 1996, to G9 in 2001 and 2002 and the re-emergence of G3 type in 2002.

Global distribution of rotavirus serotypes/genotypes and its implication for the development and implementation of an effective rotavirus vaccine

A safe and effective rotavirus vaccine is urgently needed, particularly in developing countries. Critical to vaccine development and implementation is a knowledge base concerning the epidemiology of rotavirus G and P serotypes/genotypes throughout the world. The temporal and geographical distribution of human rotavirus G and P types was reviewed by analysing a total of 45571 strains collected globally from 124 studies reported from 52 countries on five continents published between 1989 and 2004. Four common G types (G1, G2, G3 and G4) in conjunction with P[8] or P[4] represented over 88% of the strains analysed worldwide. In addition, serotype G9 viruses associated with P[8] or P[6] were shown to have emerged as the fourth globally important G type with the relative frequency of 4.1%. When the global G and/or P type distributions were divided into five continents/subcontinents, several characteristic features emerged. For example, the P[8]G1 represented over 70% of rotavirus infections in North America, Europe and Australia, but only about 30% of the infections in South America and Asia, and 23% in Africa. In addition, in Africa (i) the relative frequency of G8 was as high as that of the globally common G3 or G4, (ii) P[6] represented almost one-third of all P types identified and (iii) 27% of the infections were associated with rotavirus strains bearing unusual combinations such as P[6]G8 or P[4]G8. Furthermore, in South America, uncommon G5 virus appeared to increase its epidemiological importance among children with diarrhea. Such findings have (i) confirmed the importance of continued active rotavirus strain surveillance in a variety of geographical settings and (ii) provided important considerations for the development and implementation of an effective rotavirus vaccine (e.g. a geographical P-G type adjustment in the formulation of next generation multivalent vaccines).