Rotavirus vaccines in developed countries

Surveillance Study of Acute Gastroenteritis Etiologies in Hospitalized Children in South Lebanon (SAGE study)

PURPOSE

Acute gastroenteritis (AGE) is a major cause of morbidity and remains a major cause of hospitalization. Following the Syrian refugee crisis and insufficient clean water in the region, this study reviews the etiological and epidemiological data in Lebanon.

METHODS

We prospectively analyzed demographic, clinical and routine laboratory data of 198 children from the age of 1 month to 10 years old who were admitted with the diagnosis of AGE to a private tertiary care hospital located in the district of Nabatieh in south Lebanon.

RESULTS

Males had a higher incidence of AGE (57.1%). Pathogens were detected in 57.6% (n=114) of admitted patients, among them single pathogens were found in 51.0% (n=101) of cases that consisted of: Entamoeba histolytica 26.3% (n=52), rotavirus 18.7% (n=37), adenovirus 6.1% (n=12) and mixed co-pathogens found in 6.6% (n=13). Breast-fed children were significantly less prone to rotavirus (p=0.041). Moreover, children who had received the rotavirus vaccine were significantly less prone to rotavirus (p=0.032).

CONCLUSION

Our findings highlight the high prevalence of E. histolytica infection as the major cause of pediatric gastroenteritis in hospitalized children, during the summer period likely reflecting the insanitary water supplies and lack of hygiene. Moreover the 42.4% of unidentified causative pathogens should prompt us to widen our diagnostic laboratory arsenal by adopting new diagnostic technologies.

Rotavirus gastroenteritis in children less than five years of age in primary care settings in Bulgaria: an observational study

BACKGROUND

Rotavirus (RV) causes a high proportion of acute gastroenteritis (AGE) cases, especially among children under the age of five years old. This surveillance study was undertaken to study the incidence and severity of rotavirus gastroenteritis (RVGE) in primary care settings in Bulgaria over a one-year period.

METHODS

In this prospective, observational study of AGE cases in children under five years of age presenting in the primary care setting over a one year period, stool samples were collected and tested for RV using a rapid visual immunochromatographic test kit. After the first visit, parents monitored their child for about two weeks and reported the symptoms experienced by the child during the follow-up period to the physician in a follow-up phone call. The percentage of RVGE cases among AGE was calculated and the severity of AGE (according to the 20-point Vesikari scale) was assessed by the physician based on the symptoms reported by the parents. The seasonality of RVGE was also studied.

RESULTS

The proportion of RVGE among the 624 AGE cases examined was 25.5%. Severe AGE was experienced by 81.8% RV-positive and 54.6% RV-negative children (p-value <0.001) and a third of all severe AGE cases occurred in RV-positive patients. A multivariate logistic regression analysis of the determinants of hospitalization indicated that severity of disease and RV-positivity were the statistically significant variables explaining hospitalization of AGE cases; even controlling for severity, RV-positive patients were more often hospitalized than RV-negative ones. RVGE cases occurred throughout the year, with peaks during August and September.

CONCLUSION

Our study emphasizes that RV is an important cause of AGE in children under five presenting in primary care settings in Bulgaria and a disproportionately high proportion of severe AGE cases may be attributed to RV infections.

TRIAL REGISTRATION NUMBER

NCT01733849.

Investigation of Rotavirus with Various Methods in Children with Acute Gastroenteritis and Determination of Its Molecular Epidemiology in Kayseri Province, Turkey

BACKGROUND

In this study, the fresh stool samples from 254 children under 5 years of age with acute gastroenteritis which were delivered between October 2012 and December 2013 were collected.

METHODS

In the stool samples, rotavirus antigens were investigated using two different immunochromatographic methods which are routinely used at different times, namely the RIDA^® QUICK Rotavirus/Adenovirus Combi Test (R-Biopharm AG, Germany) and the Genx^® Rotavirus Test (Diamed-Lab, Turkey), in addition to the Rotavirus Ag (Stool) ELISA (DRG, Germany) kit. The results were compared with reverse transcriptase PCR (RT-PCR).

RESULTS

When the Genx^® Rotavirus Test and RIDA^® QUICK Rotavirus/Adenovirus Combi Test immunochromatographic methods were compared with RT-PCR, their sensitivity and specificity were found as 97.1%, 100%, and 80.4%, 72%, respectively. As to the Rotavirus Ag (Stool) ELISA method, on the other hand, its sensitivity was found to be 95.1% and its specificity was 86.5%. The most common genotype was G9P[8] (40%), which was followed by the G1P[8] (18.7%) and G3P[8] (9.6%) genotypes.

CONCLUSION

Consequently, it was revealed that the sensitivity of ELISA and immunochromatographic methods, which provide results in a short time and are used in the investigation of rotavirus antigen, was high and their specificity was low; further studies to determine the distribution of G and P genotypes will contribute to establishing strategies for vaccine development for rotavirus in the world.

Gastroenteritis attributable to rotavirus in hospitalized Saudi Arabian children in the period 2007-2008

Purpose

Rotavirus (RV) is a leading cause of severe gastroenteritis (GE) in children across the world. As there is a lack of epidemiological data for RV gastroenteritis (RVGE) in Saudi Arabia, this hospital-based study was designed to estimate the disease burden of RVGE and assess the prevalent RV types in Saudi children younger than 5 years of age.

Patients and methods

Children hospitalized for acute GE were enrolled at four pediatric referral hospitals in Saudi Arabia. The study was conducted from February 2007 to March 2008 and used the World Health Organization’s generic protocol for RVGE surveillance. The Vesikari severity scale was used to assess the severity of RVGE. Stool samples were tested for RV using an enzyme-linked immunosorbent assay. Samples were further typed by reverse transcriptase–polymerase chain reaction and hybridization assay for determining the G and P types.

Results

A total of 1,007 children were enrolled; the final analysis included 970 children, of whom 395 were RV positive, 568 were RV negative, and seven had unknown RV status. The proportion of RVGE among GE hospitalizations was 40.7% (95% confidence interval: 37.6–43.9). The highest percentage of RVGE hospitalizations (83.1%) was seen in children younger than 2 years of age. The highest proportion of RV among GE hospitalizations was in June 2007 with 57.1%. The most common RV types detected were G1P[8] (49.3%), G1G9P[8] (13.2%), and G9P[8] (9.6%). Before hospitalization, severe GE episodes occurred in 88.1% RV-positive and 79.6% RV-negative children. Overall, 94% children had recovered by the time they were discharged. Two children (one RV positive and one RV negative) died due to GE complications.

Conclusion

RVGE is responsible for a high proportion of hospitalizations in Saudi children younger than 5 years of age. Routine RV vaccination has therefore been introduced into the national immunization program and may help reduce the morbidity, mortality, and disease burden associated with RVGE in Saudi Arabia.

Anoctamin 1 in secretory epithelia

Fluid and electrolyte releasing from secretory epithelia are elaborately regulated by orchestrated activity of ion channels. The activity of chloride channel at the apical membrane decides on the direction and the rate of secretory fluid and electrolyte. Chloride-dependent secretion is conventionally associated with intracellular increases in two second messengers, cAMP and Ca(2+), responding to luminal purinergic and basolateral adrenergic or cholinergic stimulation. While it is broadly regarded that cAMP-dependent Cl(-) secretion is regulated by cystic fibrosis transmembrane conductance regulator (CFTR), Ca(2+)-activated Cl(-) channel (CaCC) had been veiled for quite some time. Now, Anoctamin 1 (ANO1 or TMEM16A) confers Ca(2+)-activated Cl(-) currents. Ano 1 and its paralogs have been actively investigated for multiple functions underlying Ca(2+)-activated Cl(-) efflux and fluid secretion in a variety of secretory epithelial cells. In this review, we will discuss recent advances in the secretory function and signaling of ANO1 in the secretory epithelia, such as airways, intestines, and salivary glands.

A hospital-based surveillance of rotavirus gastroenteritis in children <5 years of age in Singapore

BACKGROUND

In Singapore, 2 rotavirus vaccines were licensed in October 2005 and July 2007, respectively, for vaccinating infants aged ≥ 6 weeks against rotavirus gastroenteritis. These vaccines are optional and are not included in the National Childhood Immunization Program. This study aimed to determine the incidence of rotavirus gastroenteritis-associated hospitalizations among children <5 years of age.

METHODS

Children <5 years, who were hospitalized for acute gastro enteritis, were enrolled between September 2005 and April 2008. Stool samples were tested for the presence and serotyping of rotavirus. Incidence and proportion of gastroenteritis and rotavirus gastroenteritis cases were calculated with 95% confidence intervals.

RESULTS

Among 1976 children included in the according-to-protocol cohort, 781 were rotavirus positive with a median age of 24 months (range: 0-59 months). The overall incidence of rotavirus gastroenteritis hospitalizations during the entire study period in children <5 years of age was 4.6 (95% confidence interval: 4.3-4.9) per 1000 person-years with the highest number of cases observed in children 13-24 months of age (26.5%). G1P[8] (18.3%) and G9P[8] (9.9%) were the most common rotavirus types. Rotavirus gastroenteritis hospitalizations peaked between January and March.

CONCLUSION

Rotavirus infection was the primary cause of acute gastro enteritis hospitalizations among children <5 years of age, constituting nearly one-third of gastroenteritis hospitalizations in Singapore. The predominant strain observed in Singapore was G1P[8]. Results of this study suggest the need for implementation of rotavirus vaccination into National Childhood Immunization Program in Singapore.

Seasonality of rotavirus in South Asia: a meta-analysis approach assessing associations with temperature, precipitation, and vegetation index

BACKGROUND

Rotavirus infection causes a significant proportion of diarrhea in infants and young children worldwide leading to dehydration, hospitalization, and in some cases death. Rotavirus infection represents a significant burden of disease in developing countries, such as those in South Asia.

METHODS

We conducted a meta-analysis to examine how patterns of rotavirus infection relate to temperature and precipitation in South Asia. Monthly rotavirus data were abstracted from 39 published epidemiological studies and related to monthly aggregated ambient temperature and cumulative precipitation for each study location using linear mixed-effects models. We also considered associations with vegetation index, gathered from remote sensing data. Finally, we assessed whether the relationship varied in tropical climates and humid mid-latitude climates.

RESULTS

Overall, as well as in tropical and humid mid-latitude climates, low temperature and precipitation levels are significant predictors of an increased rate of rotaviral diarrhea. A 1°C decrease in monthly ambient temperature and a decrease of 10 mm in precipitation are associated with 1.3% and 0.3% increase above the annual level in rotavirus infections, respectively. When assessing lagged relationships, temperature and precipitation in the previous month remained significant predictors and the association with temperature was stronger in the tropical climate. The same association was seen for vegetation index; a seasonal decline of 0.1 units results in a 3.8% increase in rate of rotavirus.

CONCLUSIONS

In South Asia the highest rate of rotavirus was seen in the colder, drier months. Meteorological characteristics can be used to better focus and target public health prevention programs.

Rotavirus toxin NSP4 induces diarrhea by activation of TMEM16A and inhibition of Na+ absorption

Rotavirus infection is the most frequent cause for severe diarrhea in infants, killing more than 600,000 every year. The nonstructural protein NSP4 acts as a rotavirus enterotoxin, inducing secretory diarrhea without any structural organ damage. Electrolyte transport was assessed in the colonic epithelium from pups and adult mice using Ussing chamber recordings. Western blots and immunocytochemistry was performed in intestinal tissues from wild-type and TMEM16A knockout mice. Ion channel currents were recorded using patch clamp techniques. We show that the synthetic NSP4(114-135) peptide uses multiple pro-secretory pathways to induce diarrhea, by activating the recently identified Ca2+ -activated Cl- channel TMEM16A, and by inhibiting Na+ absorption by the epithelial Na+ channel ENaC and the Na+ /glucose cotransporter SGLT1. Activation of secretion and inhibition of Na+ absorption by NSP4(114-135), respectively, could be potently suppressed by wheat germ agglutinin which probably competes with NSP4(114-135) for binding to an unknown glycolipid receptor. The present paper gives a clue as to mechanisms of rotavirus-induced diarrhea and suggests wheat germ agglutinin as a simple and effective therapy.

Epidemiology of rotavirus infections in children less than 5 years of age: Germany, 2001-2008

BACKGROUND

rotavirus (RV) infection is the leading cause of acute gastroenteritis in young children worldwide. In 2006, 2 live-attenuated RV-vaccines became available for use in infants ≤ 6 months of age. In Germany, a statutory notification system for RV infection has been in place since 2001 to monitor RV epidemiology. Our objective was to assess RV disease burden in German children <5 years of age.

METHODS

Detailed descriptive analysis of national RV surveillance data in children <5 years of age collected in Germany between January 2001 and December 2008.

RESULTS

between 2001 and 2008, 72% of all notified RV patients were children <5 years of age. The highest annual incidence (approximately, 200/10,000) was in children <2 years of age. In the <5 years age-group, approximately 50% of reported patients were hospitalized and of those, 9% acquired the infection nosocomially. Since 2004, a total of 8 children <5 years of age were reported as RV-associated deaths, and case fatality due to RV infection was <0.01/10,000.

CONCLUSIONS

the high incidence of RV infection and RV-associated hospitalization in children <5 years of age results in a high disease burden. Routine childhood RV vaccination would be a measure to reduce the burden in this age-group. However, cost-effectiveness analyses specific to the German setting should be considered in the decision-making process. An RV-surveillance system is in place in Germany that could potentially monitor the effect of an RV-vaccination program once implemented.

Reduction in rotavirus-associated acute gastroenteritis following introduction of rotavirus vaccine into Australia's National Childhood vaccine schedule

INTRODUCTION

: Rotavirus vaccines were introduced into the funded Australian National Immunization Program (NIP) in July 2007. Due to purchasing arrangements, individual states and territories chose either a 2-dose RV1 (Rotarix, GSK) regimen or 3-dose RV5 (Rotateq, Merck/CSL) regimen. This allowed comparison of both vaccines in similar populations with high infant vaccination coverage.

METHODS

: Admission and rotavirus identification data from the major pediatric hospitals in 3 states (2 using RV5, 1 RV1), together with state-based hospitalization and vaccination data from Queensland (RV5) were analyzed for the years before, and up to 30 months following rotavirus vaccine introduction. Emergency encounters and short-stay unit admissions for gastroenteritis are also described.

RESULTS

: Rotavirus vaccine coverage in Australia is high, with 87% of infants receiving at least 1 dose. Hospital admissions for both rotavirus gastroenteritis and nonrotavirus-coded gastroenteritis were reduced following vaccine introduction in all states, not only for the age group eligible for NIP rotavirus vaccination, but also for children born prior. RV5 vaccine efficacy in Queensland has been estimated at 89.3%. Marked reductions in acute gastroenteritis emergency presentations and short-stay unit admissions have also been observed.

CONCLUSIONS

: Early evidence from the NIP in Australia has demonstrated high rotavirus coverage with both RV1 and RV5. The introduction of both vaccines has been associated with a marked reduction in gastroenteritis admissions, supportive of both direct vaccine protection, as well as with indirect herd protection.

Development of a rapid and sensitive latex agglutination-based method for detection of group A rotavirus

Considering the background of morbidity and mortality caused by human rotavirus, detection methods that use rotavirus group antigen (VP6) in either enzyme immunoassay (EIA) or latex agglutination test (LAT) has been employed routinely in clinical diagnostic and epidemiological studies. In order to develop a rapid and sensitive rotavirus group A LAT, part of segment 6 corresponding to conserved N-terminal portion of the VP6 (1-245 aa) was cloned in Escherichia coli expression pGEX vector (glutathione S-transferase-GST gene fusion system) that has been modified previously containing a histidine tail at C-terminus. The immunological propriety of the recombinant VP6 having a total molecular weight of 52 kDa was evaluated by Western blot and by the ability of inducing anti-recombinant VP6 polyclonal antibodies in rabbit. The polyclonal serum produced was conjugated to a latex support to detect rotavirus in stool specimens. The percentage values for sensitivity and specificity of the rotavirus group A LAT were 98.5% and 100%, respectively.

Advances in defining etiology and new therapeutic approaches in acute diarrhea

Defining etiology of acute diarrhea is critical to disease therapy and prevention. In this review we look at recent developments in etiologic agents of acute diarrhea and advances in therapy and prevention of the illness. Newly appreciated agents include enterotoxigenic Bacteroides fragilis, Klebsiella oxytoca and Laribacter hongkongensis. Atypical enteropathogenic E. coli (EPEC) strains lacking the gene for epithelial attachment appear to be more important as causes of diarrhea than traditional EPEC strains. Enterotoxigenic E. coli and enteroaggregative E. coli diarrhea known to be important abroad, have recently been shown to occur in the United States. Non-O157:H7 strains of Shiga toxin-producing E. coli are increasing and infrequently are being sought. There is currently a serious epidemic of nosocomial diarrhea due to a fluoroquinolone-resistant and more virulent and difficult to treat strain of C. difficile. Rotavirus vaccine development should lead to reduction of infant gastroenteritis mortality in infants living in developing regions. Noroviruses produce outbreaks of water- and food-borne disease but show broad genetic diversity. Reduced osmolarity oral rehydration treatment (ORT) and recombinant human lactoferrin/lysozyme plus rice-based ORT effectively treat acute diarrhea. Probiotics were shown to be effective in preventing antibiotic associated- and C. difficile-diarrhea. Rifaximin prevents and azithromycin effectively treats travelers' diarrhea.