Detection of rotaviruses in the day care environment by reverse transcriptase polymerase chain reaction

Rotavirus in developing countries: molecular diversity, epidemiological insights, and strategies for effective vaccination

Rotavirus (RV) causes the loss of numerous children's lives worldwide each year, and this burden is particularly heavy in low- and lower-middle-income countries where access to healthcare is limited. RV epidemiology exhibits a diverse range of genotypes, which can vary in prevalence and impact across different regions. The human genotypes that are most commonly recognized are G1P[8], G2P[4], G3P[8], G4P[8], G8P[8], G9P[8], and G12P[8]. The diversity of rotavirus genotypes presents a challenge in understanding its global distribution and developing effective vaccines. Oral, live-attenuated rotavirus vaccines have undergone evaluation in various contexts, encompassing both low-income and high-income populations, demonstrating their safety and effectiveness. Rotavirus vaccines have been introduced and implemented in over 120 countries, offering an opportunity to assess their effectiveness in diverse settings. However, these vaccines were less effective in areas with more rotavirus-related deaths and lower economic status compared to wealthier regions with fewer rotavirus-related deaths. Despite their lower efficacy, rotavirus vaccines significantly decrease the occurrence of diarrheal diseases and related mortality. They also prove to be cost-effective in regions with a high burden of such diseases. Regularly evaluating the impact, influence, and cost-effectiveness of rotavirus vaccines, especially the newly approved ones for worldwide use, is essential for deciding if these vaccines should be introduced in countries. This is especially important in places with limited resources to determine if a switch to a different vaccine is necessary. Future research in rotavirus epidemiology should focus on a comprehensive understanding of genotype diversity and its implications for vaccine effectiveness. It is crucial to monitor shifts in genotype prevalence and their association with disease severity, especially in high-risk populations. Policymakers should invest in robust surveillance systems to monitor rotavirus genotypes. This data can guide vaccine development and public health interventions. International collaboration and data sharing are vital to understand genotype diversity on a global scale and facilitate the development of more effective vaccines.

Occurrence of Human Viruses on Fomites in the Environment: A Systematic Review and Meta-analysis

Documenting the occurrence of viruses on fomites is crucial in determining the significance of fomite-mediated transmission and the potential use of fomites for environmental disease surveillance. We conducted a systematic review and meta-analysis to compile information on the occurrence of human viruses on fomites in the environment; we identified 134 peer-reviewed papers. We compiled sampling and measurement methods, results, quality control information, and whether virus data were compared with community health data from the papers. We conducted univariate and multivariate analyses to investigate if presence of virus on fomites was associated with virus type (enveloped, nonenveloped), sampling location (healthcare setting, nonhealthcare temporary setting, nonhealthcare nontemporary setting), and area of fomite swabbed (<50, 50-100, >100 cm2). Across 275 data sets from the 134 papers, there was the most data available for Coronaviridae and from fomites at hospitals. Positivity rates, defined as the percent positive fomite samples, were low (median = 6%). Data were available on viruses from 16 different viral families, but data on viruses from 9 families had few (n < 5) data sets. Many human virus families were not identified in this review (11 families). Less than 15% of the data sets reported virus concentrations in externally valid units (viruses per area of surface), and 16% provided a quantitative comparison between virus and health data. Virus type and area swabbed were significant predictors of virus presence on fomites, and the positivity rate of data sets collected from healthcare settings and nonhealthcare nontemporary settings (e.g., individual housing) were significantly higher than those collected in nonhealthcare temporary settings (e.g., restaurants). Data from this review indicates that viruses may be present on fomites, that fomite-mediated virus transmission may occur, and that fomites may provide information on circulation of infectious diseases in the community. However, more quantitative data on diverse viruses are needed, and method reporting needs significant improvements.

Rotaviruses: From Pathogenesis to Disease Control-A Critical Review

Since their first recognition in human cases about four decades ago, rotaviruses have remained the leading cause of acute severe dehydrating diarrhea among infants and young children worldwide. The WHO prequalification of oral rotavirus vaccines (ORV) a decade ago and its introduction in many countries have yielded a significant decline in the global burden of the disease, although not without challenges to achieving global effectiveness. Poised by the unending malady of rotavirus diarrhea and the attributable death cases in developing countries, we provide detailed insights into rotavirus biology, exposure pathways, cellular receptors and pathogenesis, host immune response, epidemiology, and vaccination. Additionally, recent developments on the various host, viral and environmental associated factors impacting ORV performance in low-and middle-income countries (LMIC) are reviewed and their significance assessed. In addition, we review the advances in nonvaccine strategies (probiotics, candidate anti-rotaviral drugs, breastfeeding) to disease prevention and management.

Evaluation of different genomic regions of Rotavirus A for development of real time PCR

The nucleotide alignment of all 11 genes of human Rotavirus A (RVA) strains revealed suitability of NSP2, NSP3 and VP6 genes for the development of real time PCR (qRT-PCR). Evaluation of qRT-PCR assays using known rotavirus ELISA positive and negative fecal specimens showed non-overlapping ranges of Mean ±3SD cycle threshold (Ct) values for NSP3 and VP6 based assays. Using serial dilutions of purified RVA, high sensitivity of VP6 qRT-PCR assay (1.95 × 10^-5 pg/μL of RNA) was recorded as compared to NSP2 and NSP3 qRT-PCR assays (1.95 × 10^-4 pg/μL of RNA). Further, evaluation of the VP6 qRT-PCR assay involving 266 fecal specimens and frequency polygon analysis of the data indicated cut-off value of 35 for Ct with high sensitivity (126/131, 96%) and specificity (12/12, 100%). This VP6 qRT-PCR assay will be a useful diagnostic tool to evaluate clinical presentations in rotaviral gastroenteritis under different conditions such as breast feeding and administration of rotavirus vaccines.

Resistance of Enteric Viruses on Fomites

Human enteric viruses are associated with several clinical features, especially gastroenteritis. Large amounts of these viruses can be released in the environment and spread to people. Enteric viruses are nonenveloped viruses and have displayed good survival in the environment. They can be significantly resistant in food and water but also on fomites, and this is thought to play a role in transmission, leading to sporadic cases or outbreaks. The survival of enteric viruses on fomites relies on many factors including the virus itself, fomite properties, and extrinsic environmental factors such as temperature or relative humidity. Several reports in the literature have found an association with gastroenteritis cases or outbreaks and fomites naturally contaminated by enteric viruses. However, the study of virus survival following natural contamination is challenging, and most published studies are laboratory based, using experimental contamination. In addition, recent and detailed data on the resistance of each of the main enteric viruses on fomites are scarce. Many approaches, both physical and chemical, can be used to inactivate enteric viruses, the efficacy of which depends on the virus and the disinfection conditions.

Sensitive and specific nested PCR assay for detection of rotavirus A in samples with a low viral load

Techniques such as the real-time reverse transcription-polymerase chain reaction (qRT-PCR) can detect RNA in samples with a low viral load. However, these amplicons typically are either too short or at insufficient concentrations for use in subsequent sequencing reactions for genotyping and detection confirmation. The assay developed in this study detects rotavirus G genotypes and P genotypes with viral loads as low as 6.2 and 8.2 copies per reaction, respectively. The assay was validated using a panel of 91 stool samples, 32 reference rotavirus strains, and 6 non-target enteric virus samples.

Microbiological analysis of environmental samples collected from child care facilities in North and South Carolina

BACKGROUND

Children cared for outside the home are at an increased risk of enteric disease. Microbiological analyses were performed on environmental samples collected from child care facilities in North and South Carolina.

METHODS

There were 326 samples collected from 40 facilities corresponding to common surfaces (77% of samples) and the hands of care providers (23% of samples). Samples were analyzed for total aerobic plate counts (APCs), total coliforms, biotype I Escherichia coli, and pathogens Shigella spp, Salmonella enterica, E coli O157, Campylobacter jejuni, and human norovirus.

RESULTS

Median APCs and coliform counts for hands were 4.6 and 1.0 log10 colony-forming units (CFU) per hand, respectively. Median APCs for surfaces were 2.0 and 2.6 log10 CFU for flat and irregular surfaces, respectively. Coliforms were detected in 16% of samples, with counts ranging from 1.0 log10 to > 4.3 log10 CFU, with higher counts most often observed for hand rinse samples. Biotype I E coli counts were below assay detection limits (< 1 log10 CFU) for all but 1 sample. No samples were positive for any of the 4 bacterial pathogens, whereas 4 samples showed evidence of human norovirus RNA.

CONCLUSION

The relative absence of pathogens and biotype I E coli in environmental samples suggests the child care facilities sampled in this study managed fecal contamination well.

Hygienic conditions in child-care facilities in North Carolina and South Carolina: an integrated microbial and observational study

BACKGROUND

In the United States almost one-quarter (23%) of children younger than age 5 years participate in some form of out-of-home child care; these children are 2.3-3.5 times more likely to contract acute gastrointestinal illness.

METHODS

Observational investigations were done to understand the hygienic conditions and practices of 40 child-care facilities in North Carolina and South Carolina. These data were compared with microbiological indicator data (aerobic plate counts and coliform counts) collected from selected surfaces in each facility. Results from the two data sets were analyzed using nonparametric statistical methods to reveal potential risk factors for enteric disease transmission.

RESULTS

Statistically significant differences (P ≤ .05) in surface microbial counts were observed when comparing family child-care homes versus centers and between facilities participating in the Child and Adult Care Food Program and those that do not participate. Facilities without written surface cleaning or food preparation policies had statistically significantly higher microbial counts on surfaces.

CONCLUSIONS

Our unique study, which combined observational and microbiological data, provided revealing information about the relationship between hygiene indicators and sanitary practices in child-care facilities in the southeastern United States.

Waterborne Viral Gastroenteritis: An Introduction to Common Agents

Acute gastroenteritis is among the most common illnesses of human beings, and its associated morbidity and mortality are greatest among those at the extremes of age; children and elderly. During the 1970s, several viruses were associated with this syndrome, which are now known to be caused mainly by viruses belonging to four distinct families—rotaviruses, caliciviruses, astroviruses, and adenoviruses. Other viruses, such as the toroviruses, picobirnaviruses, coronavirus, and enterovirus 22, may play a role as well. Transmission by food or water has been documented for astroviruses, caliciviruses, rotaviruses, and norovirus. In developing countries, gastroenteritis is a common cause of death in children <5 years, while deaths from diarrhea are less common, much illness leads to hospitalization or doctor visits. Laboratory confirmation of waterborne illness is based on demonstration of virus particles or antigen in stool, detection of viral nucleic acid in stool, or demonstration of a rise in specific antibody to the virus. Newer methods for syndrome surveillance of acute viral gastroenteritis are being developed like multiplex real-time reverse transcriptase PCRs. Application of these more sensitive methods to detect and characterize individual agents is just beginning, but has already opened up new avenues to reassess their disease burden, examine their molecular epidemiology, and consider new directions for their prevention and control through vaccination, improvements in water quality, and sanitary practices.

Sensitive and specific quantitative detection of rotavirus A by one-step real-time reverse transcription-PCR assay without antecedent double-stranded-RNA denaturation

A real-time quantitative reverse transcription-PCR (qRT-PCR) assay using the recombinant thermostable Thermus thermophilus (rTth) enzyme was developed to detect and quantify rotavirus A (RVA). By using rTth polymerase, significant improvement was achieved over the existing real-time RT-PCR assays, which require denaturation of the RVA double-stranded RNA (dsRNA) prior to assay setup. Using a dsRNA transcript for segment 7, which encodes the assay target NSP3 gene, the limit of detection for the improved assay was calculated to be approximately 1 genome copy per reaction. The NSP3 qRT-PCR assay was validated using a panel of 1,906 stool samples, 23 reference RVA strains, and 14 nontarget enteric virus samples. The assay detected a diverse number of RVA genotypes and did not detect other enteric viruses, demonstrating analytical sensitivity and specificity for RVA in testing stool samples. A XenoRNA internal process control was introduced and detected in a multiplexed qRT-PCR format. Because it does not require an antecedent dsRNA denaturation step, this assay reduces the possibility of sample cross-contamination and requires less hands-on time than other published qRT-PCR protocols for RVA detection.

Nosocomial rotavirus infections: a meta-analysis

BACKGROUND AND OBJECTIVES

Nosocomial rotavirus (nRV) infections represent an important part of rotavirus (RV)-associated morbidity. The incidence of nRV influences the estimated total RV disease burden, an important determinant of cost-effectiveness of RV vaccination programs. Our aim is to summarize the existing evidence and produce reliable estimates of nRV incidence, in pediatric settings in Europe and North America.

METHODS

We searched electronic databases for studies on nRV incidence among pediatric inpatients. To ascertain complete case reporting, only studies describing active nRV surveillance in their methodology were included. Random effects meta-analysis was performed. Meta-regression was used to obtain results adjusted for important study characteristics.

RESULTS

Twenty surveillance studies met the quality criteria for inclusion. The pooled unadjusted nRV incidence was 2.9 per 100 hospitalizations (95% confidence interval [CI]: 1.6-4.4). Incidence was significantly influenced by studies' seasonality-months (RV epidemic season only or year-round) and the age range of included patients. Highest nRV incidence was found for children <2 years of age, hospitalized during the epidemic months (8.1/100 hospitalizations; 95% CI: 6.4-9.9). The adjusted year-round nRV incidence estimate without age restriction was 0.4/100 hospitalizations (95% CI: 0.1-2.1) and 0.7 (95% CI: 0.0-1.8) for children <5 years of age.

CONCLUSIONS

This is the first meta-analysis to summarize results of surveillance studies on nRV incidence. nRV is an important problem among hospitalized infants during the winter months. The lower season and age-adjusted nRV incidence estimate seems more appropriate for application in population-based burden of disease analysis.

Comparison of surface sampling methods for virus recovery from fomites

The role of fomites in infectious disease transmission relative to other exposure routes is difficult to discern due, in part, to the lack of information on the level and distribution of virus contamination on surfaces. Comparisons of studies intending to fill this gap are difficult because multiple different sampling methods are employed and authors rarely report their method's lower limit of detection. In the present study, we compare a subset of sampling methods identified from a literature review to demonstrate that sampling method significantly influences study outcomes. We then compare a subset of methods identified from the review to determine the most efficient methods for recovering virus from surfaces in a laboratory trial using MS2 bacteriophage as a model virus. Recoveries of infective MS2 and MS2 RNA are determined using both a plaque assay and quantitative reverse transcription-PCR, respectively. We conclude that the method that most effectively recovers virus from nonporous fomites uses polyester-tipped swabs prewetted in either one-quarter-strength Ringer's solution or saline solution. This method recovers a median fraction for infective MS2 of 0.40 and for MS2 RNA of 0.07. Use of the proposed method for virus recovery in future fomite sampling studies would provide opportunities to compare findings across multiple studies.

Occurrence of bacteria and viruses on elementary classroom surfaces and the potential role of classroom hygiene in the spread of infectious diseases

The presence of microorganisms on common classroom contact surfaces (fomites) was determined to identify the areas most likely to become contaminated. Six elementary classrooms were divided into control and intervention groups (cleaned daily with a quaternary ammonium wipe) and tested for heterotrophic bacteria. Three classrooms were also tested for norovirus and influenza A virus. Frequently used fomites were the most contaminated; water fountain toggles, pencil sharpeners, keyboards, and faucet handles were the most bacterially contaminated; desktops, faucet handles, and paper towel dispensers were the most contaminated with viruses. Influenza A virus was detected on up to 50% and norovirus on up to 22% of surfaces throughout the day. Children in the control classrooms were 2.32 times more likely to report absenteeism due to illness than children in the intervention classrooms and were absent longer (on average). Improved classroom hygiene may reduce the incidence of infection and thus student absenteeism.

A model of exposure to rotavirus from nondietary ingestion iterated by simulated intermittent contacts

Existing microbial risk assessment models rarely incorporate detailed descriptions of human interaction with fomites. We develop a stochastic-mechanistic model of exposure to rotavirus from nondietary ingestion iterated by simulated intermittent fomes-mouth, hand-mouth, and hand-fomes contacts typical of a child under six years of age. This exposure is subsequently translated to risk using a simple static dose-response relationship. Through laboratory experiments, we quantified the mean rate of inactivation for MS2 phage on glass (0.0052/hr) and mean transfer between fingertips and glass (36%). Simulations using these parameters demonstrated that a child's ingested dose from a rotavirus-contaminated ball ranges from 2 to 1,000 virus over a period of one hour, with a median value of 42 virus. These results were heavily influenced by selected values of model parameters, most notably the concentration of rotavirus on fomes, frequency of fomes-mouth contacts, frequency of hand-mouth contacts, and virus transferred from fomes to mouth. The model demonstrated that mouthing of fomes is the primary exposure route, with hand mouthing contributions accounting for less than one-fifth of the child's dose over the first 10 minutes of interaction.

How long do nosocomial pathogens persist on inanimate surfaces? A systematic review

BACKGROUND

Inanimate surfaces have often been described as the source for outbreaks of nosocomial infections. The aim of this review is to summarize data on the persistence of different nosocomial pathogens on inanimate surfaces.

METHODS

The literature was systematically reviewed in MedLine without language restrictions. In addition, cited articles in a report were assessed and standard textbooks on the topic were reviewed. All reports with experimental evidence on the duration of persistence of a nosocomial pathogen on any type of surface were included.

RESULTS

Most gram-positive bacteria, such as Enterococcus spp. (including VRE), Staphylococcus aureus (including MRSA), or Streptococcus pyogenes, survive for months on dry surfaces. Many gram-negative species, such as Acinetobacter spp., Escherichia coli, Klebsiella spp., Pseudomonas aeruginosa, Serratia marcescens, or Shigella spp., can also survive for months. A few others, such as Bordetella pertussis, Haemophilus influenzae, Proteus vulgaris, or Vibrio cholerae, however, persist only for days. Mycobacteria, including Mycobacterium tuberculosis, and spore-forming bacteria, including Clostridium difficile, can also survive for months on surfaces. Candida albicans as the most important nosocomial fungal pathogen can survive up to 4 months on surfaces. Persistence of other yeasts, such as Torulopsis glabrata, was described to be similar (5 months) or shorter (Candida parapsilosis, 14 days). Most viruses from the respiratory tract, such as corona, coxsackie, influenza, SARS or rhino virus, can persist on surfaces for a few days. Viruses from the gastrointestinal tract, such as astrovirus, HAV, polio- or rota virus, persist for approximately 2 months. Blood-borne viruses, such as HBV or HIV, can persist for more than one week. Herpes viruses, such as CMV or HSV type 1 and 2, have been shown to persist from only a few hours up to 7 days.

CONCLUSION

The most common nosocomial pathogens may well survive or persist on surfaces for months and can thereby be a continuous source of transmission if no regular preventive surface disinfection is performed.

Acute diarrheal disease in children: epidemiology, prevention, and treatment

Diarrhea is one of the most common causes of morbidity and mortality in children worldwide. The causes of acute diarrhea in children vary with the location, time of year, and population studied. There is increasing recognition of a widening array of enteric pathogens associated with diarrheal diseases. Adequate fluid and electrolyte replacement and maintenance are key to managing diarrheal illnesses. Thorough clinical and epidemiologic evaluation is needed to define the severity and type of illness, exposures, and whether the patient in is immunocompromised to direct the performance of selective diagnosis cultures, toxin testing, parasite studies, and the administration of antimicrobial therapy.

Nosocomial rotavirus infection in European countries: a review of the epidemiology, severity and economic burden of hospital-acquired rotavirus disease

The data currently available on the epidemiology, severity and economic burden of nosocomial rotavirus (RV) infections in children younger than 5 years of age in the major European countries are reviewed. In most studies, RV was found to be the major etiologic agent of pediatric nosocomial diarrhea (31-87%), although the number of diarrhea cases associated with other virus infections (eg, noroviruses, astroviruses, adenoviruses) is increasing quickly and almost equals that caused by RVs. Nosocomial RV (NRV) infections are mainly associated with infants 0-5 months of age, whereas community-acquired RV disease is more prevalent in children 6-23 months of age. NRV infections are seasonal in most countries, occurring in winter; this coincides with the winter seasonal peak of other childhood virus infections (eg, respiratory syncytial virus and influenza viruses), thus placing a heavy burden on health infrastructures. A significant proportion (20-40%) of infections are asymptomatic, which contributes to the spread of the virus and might reduce the efficiency of prevention measures given as they are implemented too late. The absence of effective surveillance and of reporting of NRV infections in any of the 6 countries studied (France, Germany, Italy, Poland, Spain and the United Kingdom) results in severe underreporting of NRV cases in hospital databases and therefore in limited awareness of the importance of NRV disease at country level. The burden reported in the medical literature is potentially significant and includes temporary reduction in the quality of children's lives, increased costs associated with the additional consumption of medical resources (increased length of hospital stay) and constraints on parents'/hospital staff's professional lives. The limited robustness and comparability of studies, together with an evolving baseline caused by national changes in health care systems, do not presently allow a complete and accurate overview of NRV disease at country level to be obtained. RV is highly contagious, and the efficiency of existing prevention measures (such as handwashing, isolation and cohorting) is variable, but low at the global level because of the existence of numerous barriers to implementation (eg, lack of staff, high staff turnover, inadequate hospital infrastructure). Prevention of RV infection by mass vaccination could have a positive impact on the incidence of NRV by reducing the number of children hospitalized for gastroenteritis, therefore reducing the number of hospital cross-infections and associated costs.

Infectious diarrhea in developed and developing countries

Diarrhea from gastrointestinal infection remains a common problem. In industrialized countries, management is aimed at reducing morbidity and defining groups that may benefit from further investigation. Most infectious diarrhea is self-limiting and only requires supportive management. Viral agents are increasingly recognized as causative agents of epidemic and sporadic diarrhea. In developing countries, diarrhea is a major cause of mortality in children. Oral rehydration therapy, guided by a clinical assessment of the degree of dehydration, is cheap, simple, and effective and remains the mainstay of management of infant diarrhea. Controversies focus on the optimal formulation of oral rehydration solution. A vaccine against rotavirus has the potential to save millions of lives worldwide.

Occurrence of bacteria and biochemical markers on public surfaces

From 1999-2003, the hygiene of 1061 environmental surfaces from shopping, daycare, and office environments, personal items, and miscellaneous activities (i.e., gymnasiums, airports, movie theaters, restaurants, etc.), in four US cities, was monitored. Samples were analyzed for fecal and total coliform bacteria, protein, and biochemical markers. Biochemical markers, i.e., hemoglobin (blood marker), amylase (mucus, saliva, sweat, and urine marker), and urea (urine and sweat marker) were detected on 3% (26/801); 15% (120/801), and 6% (48/801) of the surfaces, respectively. Protein (general hygiene marker) levels > or = 200 microg/10 cm2 were present on 26% (200/801) of the surfaces tested. Surfaces from children's playground equipment and daycare centers were the most frequently contaminated (biochemical markers on 36%; 15/42 and 46%; 25/54, respectively). Surfaces from the shopping, miscellaneous activities, and office environments were positive for biochemical markers with a frequency of 21% (69/333), 21% (66/308), and 11% (12/105), respectively). Sixty samples were analyzed for biochemical markers and bacteria. Total and fecal coliforms were detected on 20% (12/60) and 7% (4/ 60) of the surfaces, respectively. Half and one-third of the sites positive for biochemical markers were also positive for total and fecal coliforms, respectively. Artificial contamination of public surfaces with an invisible fluorescent tracer showed that contamination from outside surfaces was transferred to 86% (30/ 35) of exposed individual's hands and 82% (29/35) tracked the tracer to their home or personal belongings hours later. Results provide information on the relative hygiene of commonly encountered public surfaces and aid in the identification of priority environments where contaminant occurrence and risk of exposure may be greatest. Children's playground equipment is identified as a priority surface for additional research on the occurrence of and potential exposure to infectious disease causing agents.

Increased detection of rotavirus using a real time reverse transcription-polymerase chain reaction (RT-PCR) assay in stool specimens from children with diarrhea

Six-hundred and twenty-six stool specimens collected from children with diarrhea over a 12-month period were tested for rotavirus using a real time reverse transcription-polymerase chain reaction (RT-PCR) assay, a conventional nested PCR assay and by electron microscopy (EM). A fragment of 87 bp in a highly-conserved region of non-structural protein 3 (NSP3) in rotavirus genome was amplified by a single-step RT-PCR protocol in a closed-tube system. Rotavirus was detected in 123 samples (20%) with the real time RT-PCR assay, 113 samples (18%) with the nested-PCR assay, and 79 samples (13%) with EM. Using serial diluted nucleic acid extract, we compared the sensitivity of real time RT-PCR with conventional RT-PCR and conventional nested PCR assays. Real time RT-PCR was two to four logs more sensitive than the conventional assays. The reaction time required for the RT-PCR assay is about half the time required for the conventional nested-PCR. The real time RT-PCR assay is both simple and rapid with advantages including enhanced sensitivity and a lower risk for cross-contamination making it a useful tool for the detection of rotavirus in various situations including sporadic gastroenteritis, outbreaks, and environmental investigations. G(1) was the predominant type (89%), followed by G(2) (10%), and G(4) (1%). No rotavirus of G(3), G(8), and G(9) types were found. The peak season for rotavirus infection was January to May in northern Alberta.

Effect of oral administration of tormentil root extract (Potentilla tormentilla) on rotavirus diarrhea in children: a randomized, double blind, controlled trial

OBJECTIVES

To determine the effectiveness of tormentil root extract (TRE) for treatment of rotavirus diarrhea in children.

BACKGROUND

Rotavirus, one of the most widely spread pathogens of acute, dehydrating diarrhea in children, is estimated to cause >800 000 annual deaths of young children in developing countries. Currently no rotavirus vaccine is available. Management involves rehydration therapy. Available antiperistaltic or antisecretory drugs to reduce the severity of diarrhea can cause serious side effects in children.

METHODS

A randomized, double blinded, placebo-controlled trial was conducted at Children's Hospital for Infectious Diseases #3, St. Petersburg, Russia in 40 children ranging in age from 3 months to 7 years with rotavirus diarrhea. We constructed 2 groups for comparison: a treatment group that consisted of 20 children treated with tormentil root extract; and a control group of 20 children who received a placebo. All patients received 3 drops of tormentil root extract or placebo per year of life, three times daily until discontinuation of diarrhea, or a maximum of 5 days. An objective method was used to evaluate diarrhea, and physical examination was used to assess degree of dehydration in children.

RESULTS

The duration of diarrhea in the tormentil root extract treatment group was 3 days, compared with 5 days in the control group (P < 0.0001). In the treatment group 8 of 20 (40%) children were diarrhea-free 48 h after admission to the hospital, compared with 1 of 20 (5%) in the control group (P < 0.0001). Subjects in the treatment group received smaller volumes of parenteral fluids than subjects in the control group.

CONCLUSIONS

The administration of tormentil root extract in controlled doses shortened the duration of rotavirus diarrhea and decreased the requirement for rehydration solutions. Tormentil root extract appears to be an effective measure to treat rotavirus diarrhea in children.

Excretion of serotype G1 rotavirus strains by asymptomatic staff: a possible source of nosocomial infection

This study supports the hypothesis that feces from asymptomatic adults may provide a vehicle for the transmission of rotavirus, in addition to aerosols, hands, and fomites. The observed preferential carriage of serotype G1 strains in the adult gastrointestinal tract may explain G1 predominance and persistence in epidemiologic studies worldwide.

Transmission of rotavirus and other enteric pathogens in the home

Rotavirus is the most common gastrointestinal pathogen present in day-care settings. Control and prevention of rotavirus infection are difficult because of the lack of a licensed vaccine, the absence of any effective treatment other than palliative measures and the presence of asymptomatic children shedding virus. Rotavirus is transmitted by fecal-oral contact and possibly by contaminated surfaces and hands and respiratory spread. Other gastrointestinal pathogens are also transmitted primarily by the fecal oral route, although contaminated surfaces, hands or food may also serve to transmit infection in some cases. Control and prevention measures for all enteric pathogens include isolating infected children from others, thoroughly cleaning and disinfecting environmental surfaces with effective agents and strictly following handwashing procedures before and after contact with infected persons and/or potentially contaminated surfaces.

Rotavirus outbreak on a pediatric oncology floor: possible association with toys

BACKGROUND

Several outbreaks of rotavirus gastroenteritis have occurred in hospitals and day care centers. In the spring of 1997, an outbreak of rotavirus occurred on our pediatric unit. Aggressive infection control measures were instituted, and potential lapses in infection control were assessed.

METHODS

Memorial Sloan-Kettering Cancer Center is a 434-bed cancer hospital in New York City. The pediatric unit is a 42-bed ward with both bone marrow transplant patients and non-bone marrow transplant oncology patients. Nosocomially acquired rotavirus was defined as diarrhea, vomiting, or gastrointestinal upset with onset 48 hours or more after hospital admission, accompanied by a positive enzyme immunoassay for rotavirus antigen.

RESULTS

Between February 24 and April 4, 1997, 8 patients on the pediatric unit had nosocomial rotavirus. Aggressive infection control measures were instituted. Patients with rotavirus were cohorted and placed on contact precautions (strict handwashing, gloves, and gown). Investigation by the infection control team revealed that communal toys in the playroom were not being cleaned according to the weekly protocol.

CONCLUSIONS

An outbreak of nosocomial rotavirus occurred on our pediatric oncology unit. Shared toys may have served as fomites in the transmission of rotavirus.

Rotaviruses detected by reverse transcription polymerase chain reaction in acute gastroenteritis during a trial of rhesus-human reassortant rotavirus tetravalent vaccine: implications for vaccine efficacy analysis

BACKGROUND

Rotaviruses are routinely diagnosed by detection of rotavirus antigen in stools using an enzyme immunoassay (EIA). A sensitive method, like reverse transcription polymerase chain reaction (RT-PCR), may reveal more rotaviruses, but the clinical significance of such findings is not well established.

OBJECTIVES

To study whether RT-PCR can detect more episodes of rotavirus-associated gastroenteritis than EIA and to determine how rotavirus RT-PCR findings might change efficacy analysis of a rotavirus vaccine trial, in which the outcome measure was rotavirus gastroenteritis diagnosis with EIA.

STUDY DESIGN

We applied RT-PCR for detection of rotaviruses in gastroenteritis episodes encountered in an efficacy trial of rhesus-human reassortant rotavirus tetravalent (RRV-TV) vaccine, in a total of 2398 infants. During a follow-up, covering two rotavirus epidemic seasons, 256 cases of rotavirus associated gastroenteritis were detected by EIA; 226 were in the primary efficacy analysis period that included children who had received three doses of vaccine or placebo.

RESULTS

With RT-PCR, 84 (33%) more cases of rotavirus gastroenteritis were diagnosed than with EIA, 65 of these were in the primary efficacy analysis period. Clinically, cases of rotavirus gastroenteritis diagnosed by RT-PCR were much milder (median severity score 6 on a 20-point scale) than those diagnosed by EIA (median score 11), P < 0.0001. RT-PCR revealed proportionally more G2 and G4 rotaviruses than EIA. G1 rotaviruses detected by RT-PCR were almost equally divided between RRV-TV (25) vaccine and placebo (28) groups, whereas an apparent vaccine protective effect was seen in the distribution of G2 (one in the RRV-TV and eight in the placebo group) and G4 rotaviruses (six in the RRV-TV and 14 in the placebo group).

CONCLUSION

RT-PCR is a useful tool in the diagnosis of rotavirus gastroenteritis, particularly for cases associated with other than the epidemiologically dominant G-type. Application of RT-PCR contributes to the overall appraisal of performance of rotavirus vaccine.

Monitoring rotavirus environmental contamination in a pediatric unit using polymerase chain reaction

Rotavirus environmental contamination in a pediatric unit was investigated. Surfaces were swabbed, then viruses eluted, ultracentrifuged, and detected by polymerase chain reaction (PCR) amplification. Of 55 samples, 25 (46%) tested positive. Rotavirus RNA was more prevalent on surfaces in direct contact with children (thermometers and play mats) than on other environmental surfaces (washbasins, door handles, etc). PCR has proved useful for monitoring rotavirus environmental contamination.

Prevention of rotavirus disease: guidelines for use of rotavirus vaccine. American Academy of Pediatrics

Virtually all children experience rotavirus (Rv) infection before school entry. In the United States and other temperate countries, Rv disease peaks in the winter and during this time is responsible for the majority of episodes of diarrhea in infants and young children. 1-4 Data collected by the Centers for Disease Control and Prevention from 1979 through 1992 indicate that approximately 50 000 hospitalizations attributable to Rv occur annually in the United States, a number that approximates about 1 in 78 children being hospitalized with Rv diarrhea by 5 years of age.2,5 RotaShield (Wyeth-Lederle Vaccines and Pediatrics, Philadelphia, PA) was licensed by the Food and Drug Administration on August 31, 1998, for oral administration to infants at 2, 4, and 6 months of age. The rationale for using Rv immunization for prevention or modification of Rv disease is based on several considerations. First, the rate of illness attributable to Rv among children is comparable in industrialized and developing countries, which indicates that improved public sanitation is unlikely to decrease the incidence of disease.6,7 Second, although implementation of oral rehydration programs to prevent dehydration has improved in the United States, widespread use is inadequate to prevent significant morbidity.8-11 Third, trials of rhesus rotavirus-tetravalent (Rv) vaccine in the United States, Finland, and Venezuela show efficacy rates of approximately 80% for prevention of severe illness and 48% to 68% against Rv-induced diarrheal episodes.12-16 These results are similar to the protection observed after natural Rv infection, which also confers better protection against subsequent episodes of severe disease than against mild illness.17-19 This statement provides recommendations regarding the use of Rv vaccine in infants in the United States.

Extended excretion of rotavirus after severe diarrhoea in young children

BACKGROUND

Rotaviruses are the major cause of severe childhood diarrhoea. Knowledge of the natural history of infection, including duration of intestinal virus shedding, is important in the understanding of transmission, sources of infection, and immune responses.

METHODS

We carried out a study of rotavirus excretion in 37 children admitted to hospital with severe rotavirus diarrhoea. Sequential faecal specimens were collected from each child during 100 days of surveillance, and screened for rotavirus by EIA and by amplification of genome double-stranded RNA by reverse-transcription PCR. IgA coproantibody was estimated by EIA.

FINDINGS

Duration of rotavirus excretion ranged from 4 to 57 days after onset of diarrhoea. Excretion ceased within 10 days in 16 (43%) children, and within 20 days in 26 (70%) children. Extended excretion was detected for 25-57 days in the remaining 11 (30%) children owing mainly to continued excretion of the primary infecting strain. Extended excretion was significantly associated with antirotavirus IgA coproantibody boosts during 100 days of surveillance (p=0.001, log-rank test), and with recurrence of mild diarrhoea symptoms during convalescence (p=0.006, Fisher's exact test).

INTERPRETATION

Severe rotavirus disease in young children may be followed by extended excretion of rotavirus. The risk of transmission to others may be greater than previously believed. Extended excretion could also explain some cases of the postgastroenteritis syndrome.

Incidence of enteroviruses in Mamala Bay, Hawaii using cell culture and direct polymerase chain reaction methodologies

The consequence of point and nonpoint pollution sources, discharged into marine waters, on public recreational beaches in Mamala Bay, Hawaii was evaluated using virus cell culture and direct reverse transcriptase - polymerase chain reaction (RT-PCR). Twelve sites, nine marine, two freshwater (one stream and one canal), and one sewage, were assessed either quarterly or monthly for 1 year to detect the presence of human enteric viruses. Water samples were concentrated from initial volumes of 400 L to final volumes of 30 mL using Filterite electronegative cartridge filters and a modified beef extract elution procedure. Cell culture was applied using the Buffalo Green Monkey kidney cell line to analyze samples for enteroviruses. Positive samples were also evaluated by RT-PCR, using enterovirus-specific primers. Levels of RT-PCR inhibition varied with each concentrated sample. Resin column purification increased PCR detection sensitivity by at least one order of magnitude in a variety of sewage outfall and recreational marine water samples but not in the freshwater canal samples. Using cell culture, viable enteroviruses were found in 50 and 17% of all outfall and canal samples, respectively. Samples were positive at beaches 8% of the time. These data illustrate the potential public health hazard associated with recreational waters. Using direct PCR, viruses were detected at the outfall but were not found in any beach or canal samples, in part, owing to substances that inhibit PCR. Therefore, conventional cell culture is the most effective means of detecting low levels of infectious enteroviruses in environmental waters, whereas direct RT-PCR is rendered less effective by inhibitory compounds and low equivalent reaction volumes.Key words: enteroviruses, RT-PCR, cell culture, marine waters.

Epidemiological study on infectious diarrheal diseases in children in a coastal rural area of Kenya

Diarrheal diseases are major causes of morbidity and mortality among children in developing countries. We have analyzed the causative agents of diarrhea in children under five years of age who resided in rural environments but attended a hospital in Malindi, a coastal town in Kenya. Bacterial diarrhea was found in 239 (27.7%) of 862 patients with diarrhea. Diarrheagenic Escherichia coli, including enteropathogenic, enterotoxigenic, and enterohaemorrhagic strains, was isolated from 119 (13.8%) patients, followed by Salmonella spp. (63 cases, 7.3%) and Shigella spp. (56 cases, 6.5%). Intestinal parasites were found in 109 (12.6%) of the patients. Entamoeba histolytica and Giardia lamblia were found in 67 (7.8%) and 42 (4.9%) of the cases, respectively. Rotavirus was found in 69 (16.1%) of 428 cases, a part of the 862 cases. Significant differences in age distribution were seen in diarrheal cases due to Campylobacter spp., G. lamblia, and rotavirus. No significant seasonal incidence of specific pathogens was found, but the number of diarrheal patients was significantly correlated to rainfall. Drinking water was contaminated with bacteria at concentrations ranging from 10(3) to 10(6) CFU/ml in 98% of the households and by coliform bacteria at concentrations of 10(2) to 10(5) CFU/ml in 72% of the households. These results suggest that the main routes of infection may be contaminated drinking water and fecal-oral transmission of enteric pathogens. Consequently, we propose that the enhancement of hygienic practice through health education is a feasible control measure of diarrhea in the study area.

Longitudinal study of rotavirus infection in child-care centres

OBJECTIVE

To describe the epidemiology of symptomatic and asymptomatic rotavirus infection among young children attending Sydney child-care centres during the 1994 rotavirus season.

METHODS

Children aged 0-36 months in 11 child-care centres participated in the study. A weekly stool specimen was collected from each subject and tested for rotavirus antigen by commercial enzyme immunoassay.

RESULTS

One hundred and seventy-eight children (76 girls and 102 boys) with a mean age of 18.2 +/- 6.5 (SD) months were enrolled for a total of 2249 child-weeks. Of 1653 weekly faecal specimens, 59 (3.6%) were positive for rotavirus antigen. Positivity for rotavirus antigen peaked at 8.0% and 7.4% of specimens in weeks 6 and 7, respectively. The 59 positive specimens were obtained from 44 children in eight of the 11 study centres. One child appeared to suffer a second episode. Eighty-two per cent of episodes were associated with symptoms of gastroenteritis. Overall, 32% of the children in the eight affected centres were infected; 52% of those < 12 months were infected compared to 26% of older children. Secondary spread to household contacts was also documented.

CONCLUSIONS

Rotavirus infection poses a significant health problem in under-3-year-old children attending child-care centres in Sydney. We believe that these results are applicable to all Australian children of this age attending group child care.

The emergency department approach to diarrhea

Enteric disease represents a significant medical problem on a worldwide basis. The evaluation of patients with diarrhea in the emergency department should follow a stepwise methodology to identify potentially serious disorders. The evaluation of the stool for fecal leukocytes is an important differentiation point in the evaluation of the moderately to seriously ill diarrhea patient. Oral rehydration alone can treat the vast majority of diarrhea patients. Oral rehydration solution takes advantage of the sodium glucose coupled active absorption mechanism, which is largely unaffected by enteric toxins. Antimicrobial or antidiarrheal agents are rarely indicated in the treatment of diarrhea.

Evaluation of reverse transcription and polymerase chain reaction (RT/PCR) for the detection of rotaviruses: applications of the assay

Our aim was to evaluate the reverse transcription and polymerase chain reaction (RT/PCR) technique for the detection of rotavirus shedding by infected children as a routine diagnostic procedure, in comparison to the enzyme-linked immunosorbent assay (ELISA), electron microscopy (EM) and polyacrylamide gel electrophoresis (PAGE) of rotavirus double-stranded RNA. Two-hundred and twenty stool specimens were collected from infants and young children with diarrhoea, and 10-20% faecal suspensions were made. Several methods of rotavirus dsRNA extraction were assayed. Electrophoretic analysis of viral RNA was carried out on 10% polyacrylamide gels followed by silver staining. RT/PCR was performed using oligonucleotide primers specific for both 3' and 5' ends of the rotavirus gene encoding VP7 which are highly conserved among group A rotaviruses. Following RNA extraction with phenol-chloroform and ethanol precipitation, RT/PCR could detect rotaviral RNA in only 11 of 25 samples known to contain rotaviruses by conventional methods. The purification of RNA extracts by CF11 cellulose and the application of the RNAID method were equally effective in extracting RNA and/or removing inhibitory substances from the faecal samples. RT/PCR led to the detection of 66 positive samples from 220 specimens tested (30%), whilst 64 specimens were positive by ELISA (29%), 59 (26.8%) by PAGE and 56 (25.4%) by EM. In our study, RT/PCR was 100 times more sensitive than the ELISA test in detecting rotaviruses serially diluted in a faecal suspension. Although RT/PCR is theoretically much more sensitive than ELISA, PAGE and EM for detection of rotaviruses, great care must be taken to remove inhibitory substances from the enzymatic reactions. We do not consider that RT/PCR should replace immunoassays with high sensitivity and specificity for rotavirus testing in faecal samples, although this technique has other applications, like the search for rotavirus in different clinical specimens (sera, cerebrospinal fluid, respiratory secretions, etc.) and in environmental samples, as well as the typing of viral strains using serotype-specific primers.

Evaluation of the effects of disinfectants on rotavirus RNA and infectivity by the polymerase chain reaction and cell-culture methods

Rotaviruses have been linked to outbreaks of acute gastroenteritis of children in day-care centres and hospital paediatric wards. There is, therefore, the need for monitoring effective decontamination of such environments. We have evaluated the effects of seven different methods of disinfection/inactivation (four chemical and three physical) on rotavirus using the PCR and cell-culture methods. We observed that 6% H2O2, 2500 ppm chlorine, an ethano-phenolic disinfectant, u.v. irradiation and heat completely destroyed the infectivity of rotavirus as well as RNA amplifiable by PCR. On the other hand, treatment with 80% ethanol resulted in the loss of infectivity despite the fact that RNA was still amplifiable. Rotavirus subjected to drying over a 24 h period still retained amplifiable RNA but infectivity was reduced by 100-fold when compared to the control. This study demonstrated an agreement between PCR and cell-culture monitoring systems, however, PCR is a more rapid and sensitive assay.

Control of infections in child care

The control of infections in child-care centres involves vaccination of children and staff, attention to hygiene (particularly to handwashing), exclusion of children (and employees) while infectious and/or grouping of infectious children, separation of toilet-trained children from those in nappies, and judicious use of antimicrobial agents and vaccination during outbreaks. By reporting cases of infectious diseases in patients with child-care contact to public health authorities, doctors can assist in controlling such diseases in child care.

Development of a method for detection of enteroviruses in shellfish by PCR with poliovirus as a model

The application of the PCR to complex samples is hindered by amplification inhibitors. We describe a reverse transcription-PCR-based method capable of inhibitor removal for the detection of enteroviruses in shellfish. Initial virus extraction stages based on a modified polyethylene glycol precipitation technique (G.D. Lewis and T.G. Metcalf, Appl. Environ. Microbiol. 54:1983-1988, 1988) were followed by virus purification with 1,1,2-trichloro,2,2,1-trifluoroethane and concentration by ultrafiltration. A guanidine isothiocyanate-glass powder extraction system was utilized for sample lysis, RNase protection, and nucleic acid purification. Removal of PCR inhibitors and method sensitivity were quantified in shellfish (oysters and mussels) seeded with poliovirus. PCR sample tolerance exceeded 4 g for depurated shellfish; however, polluted field samples were more inhibitory. Virus recoveries of 31% for oyster extracts and 17% for mussel extracts and nucleic acid extraction reverse transcription-PCR detection limits down to 1 PFU yielded an overall sensitivity limit of < 10 PFU of poliovirus in up to 5 g of shellfish. PCR-positive results were obtained from a variety of polluted field samples naturally contaminated with human enteroviruses. The methods developed for virus recovery and PCR inhibitor removal should be equally applicable to detection of other RNA viruses such as hepatitis A virus, Norwalk virus, and other small round-structured viruses in shellfish.