A three-year diagnostic and epidemiological study on viral infantile diarrhoea in Rome

Weather variability and paediatric infectious gastroenteritis

Investigations of the relationship between weather variability and infectious gastroenteritis (IG) are becoming increasingly important in light of international interest in the potential health effects of climate change. However, few studies have examined the impact on children, despite the fact that children are considered particularly vulnerable to climate change. We acquired data about cases of IG in children aged <15 years and about weather variability in Fukuoka, Japan from 2000 to 2008 and used time-series analyses to assess how weather variability affected IG cases, adjusting for confounding factors. The temperature-IG relationship had an inverted V shape, with fewer cases at temperatures lower and higher than ~13°C. Every 1°C increase in temperature below the threshold (13°C) was associated with a 23·2% [95% confidence interval (CI) 16·6-30·2] increase, while every 1°C increase in temperature above the threshold (13°C) was associated with an 11·8% (95% CI 6·6-17·3) decrease in incidence. The increase in cases per 1% drop in relative humidity was 3·9% (95% CI 2·8-5·0). The percentage increase of IG cases was greatest in the 0-4 years age group and tended to decrease with increasing age. We found a progressive reduction in weather-related IG cases in children aged >4 years. Our results suggest that public health interventions aimed at controlling weather-related IG may be most effective when focused on young children.

The burden of hospitalised rotavirus infections in Fiji

Rotavirus is the most common cause of acute severe dehydrating diarrhoea in young children worldwide. We describe the burden of rotavirus disease and the rotavirus types causing it in the largest city in Fiji. During 2006 and 2007, 592 children under 5 years of age were admitted to hospital in Suva, Fiji with acute diarrhoea. Of the 454 children for whom a stool specimen was tested, 39% were positive for rotavirus and the predominant strain found was the serotype G3[P8]. There is a significant burden of disease due to rotavirus in Fiji and the introduction of rotavirus vaccines into the national immunization schedule may drastically reduce inpatient diarrhoeal disease.

The epidemiology of human rotavirus associated with diarrhoea in Kenyan children: a review

Rotavirus gastroenteritis still remains a major cause of morbidity and mortality among young children in developing countries, with approximately 150,000-200,000 deaths occurring annually in sub-Saharan Africa. We reviewed papers published over the last 30 years on the epidemiology of rotavirus diarrhoea among the hospitalized and out-patient children in Kenya. The analysis shows rotavirus prevalence of 6-56% with diarrhoea occurring throughout the year and generally exhibiting distinct peaks during the dry months. Among the common genotype, G1 was the most predominant up to the year 2002 but more recently there has been an emergence of genotype G9 as the most predominant genotype and to a less extent G8. It is important to continue rotavirus surveillance in Kenya to determine accurately the burden of rotavirus disease and the emerging new genotypes. This will assist policy makers in decision making on rotavirus vaccine introduction and determining the impact of the vaccine.

[Viral gastroenteritis. Application of a protocol for astrovirus detection in childhood gastroenteritis]

BACKGROUND AND OBJECTIVE

Diagnosis of viral gastroenteritis is an important subject in clinical virology which is mainly determined by the availability of reagents in laboratories, such as in the case of astrovirus. The aim of this study was to estimate the increase in the diagnostic performance achieved after the incorporation of astrovirus search in the diagnosis protocol of acute viral gastroenteritis. We also analyzed the trend of infections in other more commonly searched virus, such as rotavirus and enteric adenovirus.

MATERIAL AND METHODS

Retrospective study during 20 years that included 12,980 stool samples processed for gastroenteritis virus diagnosis. Since 1997 an enzyme immunoassay for astrovirus has been applied to those samples that are negative for rotavirus and adenovirus. The study was divided in two periods (1986-1996 and 1997-2005, without and with astrovirus diagnosis) and the percentage of patients diagnosed in each period was compared. The trend of positive results as well as the percentage of positive results over all patients studied was modelled using the least squares method.

RESULTS

The percentages of positive patients for rotavirus, adenovirus and astrovirus were 10.3%, 2.3% and 6.0% respectively, and there were uncommon co-infections by rotavirus and adenovirus (0.2%). The protocol applied to the astrovirus diagnosis increased the diagnosis rate up to 16.8% of the studied cases. Significant statistical differences were observed between the 2 study periods. A quadratic growth was observed in the results of positive diagnosis of viral gastroenteritis during the study period.

CONCLUSIONS

The search of astrovirus in gastroenteritis cases by a selective protocol increased the diagnostic performance of gastrointestinal virus by 6%. In view of these results, it would be useful to implement astrovirus diagnosis in faeces with liquid or semi-liquid consistency when rotavirus and adenovirus detection is negative.

Climatic factors associated with hospitalizations for rotavirus diarrhoea in children under 5 years of age

This study compares the seasonality of rotavirus diarrhoeal hospital admissions and its relationship to climatic factors across three Australian cities. Weekly admission of rotavirus diarrhoea (1993-2003) in children aged <5 years and weekly average temperature and relative humidity for each city were modelled using a log-linear model with a cubic trend and season. Interactions were included to test for differences in the effect of temperature and humidity between seasons and between cities. Admissions of rotavirus diarrhoea peaked in winter and spring and were lowest in summer. Higher temperature and humidity in the previous week were associated with a decrease in rotavirus diarrhoeal admissions in three cities. The effects of both temperature and humidity on rotavirus admissions in Brisbane differed across seasons. Strategies to combat outbreaks of rotavirus diarrhoea should take climatic factors and seasonal effects into consideration to plan for the excess seasonal hospital admissions.

Reverse transcriptase-PCR for the detection of Astrovirus in children with nosocomial acute diarrhoea in Naples, Italy

OBJECTIVE

This study was made to determine the incidence of nosocomial viral gastroenteritis in all children aged 0-4 years, admitted in the Pediatric Hospital over a 3-year period.

METHODS

Astrovirus was detected by reverse transcriptase-PCR; routine diagnostic tests for Rotavirus, Adenovirus, and common bacterial pathogens were carried out on all samples.

RESULTS

Of the 460 children with nosocomial diarrhea, 23 harbored Astrovirus (5%). Most cases occurred during the coldest months of the year. Children under 1 year of age were the most susceptible population.

CONCLUSION

The collected data confirms the importance of viral etiology in nosocomial gastroenteritis. The reported rate of detection stresses the importance of Astrovirus in pediatric diarrhea. The authors recommend screening for this virus on a routine basis.

Prevalence and characterization of astroviruses in Argentinean children with acute gastroenteritis

Among viral agents causing gastroenteritis, human astroviruses (HAstVs) take second or third place, after rotaviruses and caliciviruses, as the most frequent cause of illness. The aims of this study were to determine the prevalence of HAstV infection and to characterize the circulating HAstV strains in children with diarrhea under 3 years of age treated between 1995 and 1998 at out- or in-patient facilities of the children's hospital in Mendoza, Argentina. Reverse transcription-polymerase chain reaction (RT-PCR) and enzyme immunoassay (EIA) were used to detect HAstVs in stool specimens. Positive specimens were tested further by EIA and/or sequenced to type detected HAstV strains. HAstVs were detected in 40 (3.7%) of 1,070 samples that were rotavirus and calicivirus-negative: 14 (3.5%) of 402 from outpatients and 26 (3.9%) of 668 from inpatients. HAstV infection tended to be more severe in children during their first year of life: 18 (4.7%) of 383 HAstV-positive children 0-11 months old were hospitalized versus 8 (2.8%) of 285 children 1 year of age or older (P = 0.29). Type 1 (HAstV-1) was the most common type (41%), followed by HAstV-4 (25%), HAstV-2 (13%), HAstV-3 (13%), and HAstV-5 (8%). In this first epidemiological study of HAstV infection in this region, we confirmed HAstV to be a cause of severe gastroenteritis in children, more often among children younger than 12 months of age. HastV-4 caused 25% of HastV infections in Mendoza, although it has been detected commonly elsewhere. Distinct genetic lineages were apparent but their epidemiological significance remains to be demonstrated.

The current status of the rotavirus vaccine

The US just licensed of an oral tetravalent rhesus reassortant vaccine for routine immunization of infants against rotavirus. The virus was first identified 25 years ago and is now recognized to be the most common single cause of severe diarrhea throughout the world. Most children suffer at least one infection and reinfection is common. Studies of natural immunity show that breastfeeding may merely delay onset of primary infection and that maternal immunity has little effect-especially in developing countries where onset in early infancy is common. Immunity, furthermore, appears to be serotype-specific. Early attempts to develop a vaccine focused on animal forms of rotavirus. More recent efforts have created human-animal reassortants that have been far more successful.

Rotavirus infection and rates of hospitalisation for acute gastroenteritis in young children in Australia, 1993-1996

OBJECTIVE

To determine rates of hospitalisation of young children for acute gastroenteritis in Australia, and to estimate the proportion of these admissions caused by rotavirus infection.

DESIGN

Analysis of hospital admission records, and parallel, prospectively collected data on rotavirus-positive admissions.

SETTING

Hospitals admitting young children in all Australian States and Territories in 1993-1996.

PATIENTS

All children under five years admitted to hospital for acute gastroenteritis (International Classification of Diseases, ninth revision principal diagnosis codes 003.0, 004.0-009.3 and 558.9).

MAIN OUTCOME MEASURES

Rate of hospital admission per 1000 children per year by State, and the proportion of admissions caused by rotavirus infection.

RESULTS

There were almost 20,000 hospital admissions annually in Australia for acute gastroenteritis in children under five years, at an average rate of 15/1000. An estimated 50% of these were attributable to rotavirus infection, implying a rate of hospitalisation for rotavirus-related gastroenteritis of 7.5/1000/year. Among children under two years this rate was 11.6/1000. Rotavirus incidence rates generally followed a typical seasonal pattern in temperate regions of the country, with sharp peaks in mid to late winter. Rates of hospitalisation varied markedly, even between States with apparently similar patterns of disease, while the incidence in the Northern Territory was 3-5 times higher than other States.

CONCLUSIONS

Rotavirus-related gastroenteritis is a major cause of hospital admissions in young children, and large savings to the healthcare system are possible if it can be prevented at reasonable cost. Variation in treatment practices between States may be worth studying in greater detail as another source of potential savings.

Rotavirus infection among children with diarrhoea in Italy

Despite the absence of a nationwide surveillance system for rotavirus infection, relevant information concerning the epidemiology of this pathogen in Italy can be obtained from hospital-based studies carried out since the early 1980s on patients with acute diarrhoea. A review of more than 50 papers and congress proceedings published in both international and national literature indicates that rotavirus is the most important cause of diarrhoea in Italy among young children requiring hospitalization, with a prevalence ranging from approximately 20% to 40% in different studies. Infection is predominant among children aged 6-24 months, although cases are also common in younger children and in children 2-3 y of age. Despite differences among studies in geographical area, years and age group under investigation, an increase in rotavirus cases is consistently reported in the winter months, with a peak in February through April. Although a few studies have been conducted in non-hospitalized patients, rotavirus infection is significantly less frequent among outpatients with enteritis than among inpatients. Most circulating rotavirus strains typed from 1981 to 1992 belong to serotype 1 and, to a lesser extent, 4. However, untypable rotavirus strains have been found in these years, with prevalences up to 27%, suggesting a possible spread of non-serotype 1 through 4 strains.

Food-related illness and death in the United States

To better quantify the impact of foodborne diseases on health in the United States, we compiled and analyzed information from multiple surveillance systems and other sources. We estimate that foodborne diseases cause approximately 76 million illnesses, 325,000 hospitalizations, and 5,000 deaths in the United States each year. Known pathogens account for an estimated 14 million illnesses, 60, 000 hospitalizations, and 1,800 deaths. Three pathogens, Salmonella, Listeria, and Toxoplasma, are responsible for 1,500 deaths each year, more than 75% of those caused by known pathogens, while unknown agents account for the remaining 62 million illnesses, 265,000 hospitalizations, and 3,200 deaths. Overall, foodborne diseases appear to cause more illnesses but fewer deaths than previously estimated.

First rotavirus vaccine licensed: is there really a need?

The first rotavirus vaccine was licensed in the United States on 31 August 1998 for the prevention of severe rotavirus diarrhea in children. Despite this landmark in new vaccines, many pediatricians and public health professionals in Europe are uncertain of the need for this vaccine for the routine immunization of infants. In Europe, ample evidence suggests that rotavirus is the most common cause of hospitalizations for severe diarrhea among children, but proper studies documenting the disease burden of rotavirus or the cost-effectiveness of a rotavirus immunization program have only been conducted in the United Kingdom following epidemiologic models used in the United States. All children are infected with rotavirus during their first few years of life, 30-50% of diarrheal hospitalizations among children <5 years are due to this agent, and, by the age of 5 years, between 1 in 40 and 1 in 77 children in Europe and the United States may be hospitalized for rotavirus. The first vaccine is a live, oral preparation combining four different serotypes of rotavirus and administered in three doses with other childhood immunizations. The good efficacy against severe rotavirus diarrhea, the low risk of adverse side effects and the positive cost-effectiveness equation have led the two major immunization advisory groups in the U.S. to recommend this vaccine for routine use in American infants. European physicians and policy-makers should re-examine the epidemiology and disease burden of rotavirus diarrhea now that an effective method of prevention is at hand.

Direct detection of Clostridium perfringens enterotoxin in patients' stools during an outbreak of food poisoning

An outbreak of diarrhoea in a hotel affected 25 time keepers attending the 1997 Mediterranean Games. Epidemiological investigation implicated a 'pasta al ragù' consumed at the hotel's restaurant and Clostridium perfringens food poisoning was identified by direct detection of C. perfringens enterotoxin in patients' stools. This report confirms that a careful evaluation of epidemiological features, together with the availability of direct and rapid laboratory methods, may lead to a prompt identification of C. perfringens food poisoning.

Astrovirus infection in South Africa: a pilot study

Astroviruses have been shown to be important aetiological agents associated with gastroenteritis in children, as have rotaviruses and the enteric adenoviruses. However, no inclusive studies have been conducted in South Africa to allow a comparison of the relative roles of these different viral agents. In this study, stool specimens were obtained between 1991 and 1993 from 225 young children with acute gastro-enteritis. These were examined for the presence of astroviruses using a monoclonal antibody-based ELISA, and for rotaviruses and enteric adenoviruses using commercially available kits. A control group of 56 infants and young children without symptoms of diarrhoeal illness was included in the study. Astroviruses were detected in 7% of the stools compared with 20% infected with rotaviruses and only 3% infected with enteric adenoviruses. In the control group, one specimen each had astrovirus or adenovirus and two shed rotaviruses. The astrovirus prevalence observed in this study is similar to that reported in other developing communities. Rotavirus and astrovirus infections were more prevalent in the autumn and early winter than in other seasons. Astrovirus and rotavirus infections predominated in children between 3 and 22 months of age.

Prevalence of astrovirus infection among Chilean children with acute gastroenteritis

The frequency of astrovirus infection in 456 Chilean children with diarrhea was determined by enzyme-linked immunosorbent assay, reverse transcriptase PCR, and cell culture. Astrovirus was detected in 16.5% of rotavirus-negative and 7% of rotavirus-positive samples obtained from emergency rooms or hospitals and in 11% of samples from day care centers. HAst-1 was the predominant serotype identified.

Enteropathogens associated with childhood diarrhea in Italy. The Italian Study Group on Gastrointestinal Infections

BACKGROUND

Infectious diarrheal diseases remain an important cause of childhood morbidity in industrialized countries. The knowledge of the etiology and epidemiology of childhood diarrhea in a given area is needed to plan any measure designed to prevent or ameliorate diarrheal illness and to develop practice guidelines for the most appropriate stool examination procedures.

METHODS

We evaluated 618 children with diarrhea and 135 controls prospectively for viral, bacterial and parasitic enteric pathogens. Diarrheagenic Escherichia coli was identified by gene probes specific to different virulence factors. Stool filtrates were examined for the presence of free bacterial toxins by a cell culture cytotoxicity assay. Clinical and epidemiologic data were recorded and analyzed in relation to microbiologic findings.

RESULTS

Enteropathogens were identified in 59% of children with diarrhea and in 10.4% of asymptomatic controls. The agents mainly associated with disease were rotavirus (23.6%), Salmonella (19.2%) and Campylobacter (7.9%). Rotavirus was significantly more frequent among children observed as inpatients whereas Campylobacter was significantly more common in outpatients. Infections with diarrheagenic E. coli, Shigella flexneri, yersinia enterocolitica, Cryptosporidium and Giardia were observed in a limited number of patients. The clinical presentation of children was not sufficiently characteristic to permit presumptive diagnosis of a specific pathogen. conversely the presence of blood and/or leukocytes in stools had a high positive predictive value for Salmonella or Campylobacter infection.

CONCLUSION

The results of this study will be useful for planning strategies to prevent and control diarrheal diseases in our country.

Hospitalisations for rotavirus gastroenteritis among children under five years of age in New South Wales

OBJECTIVE

To estimate the number of children under five years of age hospitalised for rotavirus gastroenteritis in New South Wales.

DESIGN

Retrospective survey with comparison of patterns of hospital admissions for acute gastroenteritis in children under five with laboratory reports of rotavirus infection.

SETTING

New South Wales, January 1991-December 1993.

OUTCOME MEASURES

Laboratory reports of rotavirus infection to the Eastern Sydney Laboratory Surveillance Program (a voluntary laboratory reporting scheme) and hospital admissions of children under five with principal diagnosis classified under international classification of diseases, 9th revision, clinical modification (ICD-9-CM) codes 008.6, 008.8, 009.0-009.3 and 558.9 from NSW Inpatient Statistics Collection.

RESULTS

Rotavirus infections were reported throughout each year (mean, 57 reports per month), with incidence peaks in August or September. Admissions for gastroenteritis showed the same seasonal pattern (correlation coefficient, 0.93). About 3700 children under five were admitted for rotavirus gastroenteritis annually in NSW at an estimated annual cost of 4.6 million dollars. Annual rates were highest for children aged 12-23 months (1800 per 100000 population in age group), intermediate for those aged 0-11 and 24-35 months (810 and 1000 per 100000 in age group, respectively) and lowest for those aged 36-47 and 48-59 months (450 and 190 per 100000 population, respectively, in age group).

CONCLUSIONS

Rotavirus is a major cause of morbidity among young children in NSW. Routine infant vaccination against rotavirus could reduce this morbidity and the resulting health costs.

Nosocomial gastroenteritis in two infant wards over 26 months

We retrospectively reviewed 209 cases of nosocomial diarrhea in two infant wards at St Göran's Children's Hospital. They occurred from April 1987 to May 1989, when 3105 patients spent 26,355 hospital days. The hospital is a 250-bed tertiary center with university affiliation. Fourteen percent of patients at risk developed nosocomial diarrhea, and the relative attack rate was 1.1 episodes per 100 hospital days. A probable viral etiology was found in 47% of patients. Rotavirus was most frequent and occurred during the community rotavirus seasons. Also small, round, structured viruses were common, and two outbreaks of astrovirus gastroenteritis occurred. Failure to detect a virus was particularly common among infants younger than 4 months. However, a seasonal distribution and peaks concordant with defined clusters in older patients, suggest also that some of these detection-negative cases may have a viral etiology.

The rotavirus genus

Human rotaviruses, discovered nearly 20 years ago, have been proven to be major cause of paediatric diarrhoeal disease morbidity and mortality. The clinical significance of these viruses stimulated basic studies on their biology, molecular and antigenic properties and epidemiology. General features, clinical relevance, epidemiologic pattern and laboratory diagnosis of human rotavirus infections are here reviewed.

Detection of astrovirus in pediatric stool samples by immunoassay and RNA probe

Two new astrovirus assays, a rapid biotin-avidin enzyme immunoassay (EIA) and RNA probe hybridization, were developed and compared with an established astrovirus assay, an indirect EIA, and immune electron microscopy. Sensitivity and specificity were evaluated by using a screening panel of 22 astrovirus-positive and 305 astrovirus-negative fecal specimens. The biotin-avidin assay was equivalent in performance to the reference indirect assay, and both could detect about 10 ng of viral protein. Although the probe was more sensitive than either EIA and could detect higher dilutions of virus in tissue culture and stool specimens, it did not detect more astrovirus-positive fecal specimens. Of the 22 astrovirus-positive specimens detected by the EIAs, 20 were confirmed by immune electron microscopy with hyperimmune rabbit antiserum. To determine the usefulness of EIAs for large epidemiologic studies, EIAs were used to screen 1,289 stool specimens from three studies of children with and without diarrhea. Astrovirus was detected in 3.5% of specimens from children with diarrhea and 1.9% of specimens from those without diarrhea. Our results indicate that the biotin-avidin EIA is an efficient, sensitive, and specific method for routinely screening large numbers of fecal samples and that its application in epidemiologic studies may yield higher rates of astrovirus infection than have been found previously by other methods.

HT-29 cells: a new substrate for rotavirus growth

Susceptibilities of a continuous rhesus monkey kidney cell line (MA-104) and that of a human colon carcinoma cell line (HT-29) to infection by different human and animal rotavirus strains were compared. HT-29 cells appeared to be more sensitive to human rotavirus infection than MA-104 cells, whereas the latter cell line was more susceptible to animal rotavirus replication. The greater sensitivity to human rotavirus infection of HT-29 cells was confirmed by the successful, direct isolation of these viruses from faecal specimens. Human rotavirus infection of HT-29 cells was also followed by transmission electron microscopy. In ultra-thin sections, unenveloped particles of rotaviruses, representing infectious mature virions, were observed in large number. Moreover, many "double-shelled" particles were detected in negative-stained supernatants from infected cultures. Scanning electron microscopy of uninfected HT-29 cells showed that in the presence of Ca++, required for rotavirus growth, they are able to express some of the features of mature intestinal cells. In view of these results, HT-29 cells appear to be a useful in vitro model for the study of rotavirus infection.

Infection of staff during an outbreak of viral gastroenteritis in an elderly persons' home

An outbreak of viral gastroenteritis in an elderly persons' residence is reported. Seventeen of 37 (47%) residents and 22 of 50 (44%) staff developed illness. Adenovirus was seen by direct electron microscopy in two vomitus and two faeces specimens. It is suggested that the most likely mode of transmission was environmental contamination by vomitus.

Four-year study of rotavirus electropherotypes from cases of infantile diarrhea in Rome

Rotavirus infections were detected in 210 of 675 children with acute diarrhea admitted to a major pediatric hospital in Rome from January 1982 through December 1985. Most of the patients with rotavirus infections were admitted during the winter season in both 1982 and 1985, whereas during the two intermediate years, cases occurred in all months. Among 84 rotavirus samples examined, 14 different electropherotypes were recognized, 2 of which largely predominated over the others. The two electropherotypes were particularly frequent in the 2 epidemic years, altogether accounting for 70.2% of the samples typed, and circulated in distinct periods. None of the viruses showed a short pattern of electrophoretic migration of the genome, indicating a minor involvement of subgroup I rotaviruses in hospitalization-requiring diarrheas occurring in the area surveyed.