Distribution and titres of rotavirus antibodies in different age groups

Prevalence and diversity of human rotavirus among Thai adults

Rotavirus infections have become one of the most common causes of infectious gastroenteritis in children. Although rotavirus infections have been intensively studied in infants and young children, the study in adults has been limited. As such, this study assessed the prevalence of rotaviruses and performed the molecular characterization of rotaviruses circulating in Thai adults experiencing acute gastroenteritis between January 2018 and December 2018. Group A human rotaviruses were detected in 100 feces samples by rapid immunochromatography. The peak incidence of infection occurred in February and began to decline in the summer months. From January 2018 to December 2018, there were 1344 acute gastroenteritis adult cases in the Hospital for Tropical Diseases, Bangkok, Thailand. Among these, 310 cases were rotavirus-suspected cases. Only 100 samples tested positive for rotavirus via an immunochromatography test. Twentynine out of the 100 rotavirus-positive samples were further characterized by real-time polymerase chain reaction. The G3[P8] strain was identified as the most prevalent (31.0%) followed by G1P[8], G8P[8] and G9P[8], and G2P[8], which accounted for 20.8%, 17.2%, and 13.8%, respectively. Because of the detection of rare rotavirus genotypes, such as G8, the surveillance of rotavirus epidemiology is crucial in monitoring new emergences of rotavirus strains, leading to a better understanding of the effects of strain variation for further vaccine development.

Unexpectedly high burden of rotavirus gastroenteritis in very young infants

BACKGROUND

The highest incidence of rotavirus gastroenteritis has generally been reported in children 6-24 months of age. Young infants are thought to be partially protected by maternal antibodies acquired transplacentally or via breast milk. The purpose of our study was to assess the age distribution of children with confirmed community-acquired rotavirus gastroenteritis presenting to an urban referral hospital.

METHODS

Children presenting to The Children's Hospital of Philadelphia with acute gastroenteritis have been monitored for the presence of rotavirus antigen in the stool by ELISA (followed by genotyping if ELISA-positive) since the 1994-95 epidemic season.

RESULTS

Over the last 12 rotavirus seasons prior to the introduction of the pentavalent rotavirus vaccine in 2006, stool specimens from 1646 patients tested positive for community-acquired rotavirus infection. Gender or age was not recorded in 6 and 5 cases, respectively. Overall, 58% of the cases occurred in boys. G1 was the predominant VP7 serotype, accounting for 72% of cases. The median (IQR) age was 11 (5-21) months. A total of 790 (48%) cases occurred in children outside the commonly quoted peak age range, with 27% in infants <6 months of age and 21% in children >24 months of age. A total of 220 (13%) cases occurred during the first 3 months of life, and the highest number of episodes per month of age [97 (6%)] was observed during the second month of life.

CONCLUSIONS

The incidence of community-acquired rotavirus gastroenteritis monitored over 12 seasons in the prevaccine era at a major university hospital was nearly constant for each month of age during the first year of life, revealing an unexpectedly high incidence of symptomatic rotavirus disease in infants <3 months old. A sizeable fraction of cases occurred in children too young to have been vaccinated according to current recommendations.

Rotavirus infection in adults

Rotavirus has been recognised for 30 years as the most common cause of infectious gastroenteritis in infants and young children. By contrast, the role of rotavirus as a pathogen in adults has long been underappreciated. Spread by faecal-oral transmission, rotavirus infection in adults typically manifests with nausea, malaise, headache, abdominal cramping, diarrhoea, and fever. Infection can also be symptomless. Rotavirus infection in immunocompromised adults can have a variable course from symptomless to severe and sustained infection. Common epidemiological settings for rotavirus infection among adults include endemic disease, epidemic outbreak, travel-related infection, and disease resulting from child-to-adult transmission. Limited diagnostic and therapeutic alternatives are available for adults with suspected rotavirus infection. Because symptoms are generally self-limiting, supportive care is the rule. Clinicians caring for adults with gastroenteritis should consider rotavirus in the differential diagnosis. In this review we intend to familiarise clinicians who primarily provide care for adult patients with the salient features of rotavirus pathophysiology, clinical presentation, epidemiology, treatment, and prevention.

Effect of age on concentrations of serum antibodies to viral, bacterial, and food antigens in elderly Swiss people

Serum antibody concentrations to two viral, five bacterial, and two food antigens were investigated in 307 elderly Swiss subjects, and the hypothesis of whether serum antibody titers decreased with age was tested. The cross-sectional part of the study consisted of 216 unselected consecutive patients hospitalized in one geriatric hospital. The patients were divided into two age groups (65 to 84 and 85 to 102 years old), and their antibody titers were compared. No age-related decreases in antibody titers were observed. The members of the two age groups were well matched for medical diagnosis and nutritional and inflammatory status. The prospective part of the study consisted of 91 healthy elderly subjects living in the community; they were 71 to 76 years old when they were enrolled in the study. Their serum antibody status was measured at the beginning of the study and 4 years later. We observed a significant decrease in diphtheria antitoxin levels and a significant increase in antibody titer to the capsular polysaccharide of Streptococcus pneumoniae. No change in antibody titer to rotavirus, respiratory syncytial virus, lipopolysaccharide of Escherichia coli, C polysaccharide of S. pneumoniae, or the polyribosyl-ribitol phosphate of Haemophilus influenzae was observed. Thus, no signs of B-cell immunosenescence were seen in these two groups of elderly Swiss people.

Viruses and diarrhoea--where are we now?

Viruses are important causes of diarrhoea, with the major mortality occurring in the poor tropical overcrowded parts of the world. A successful vaccine, to rotavirus at least, may be developed, but how widely it would be used is uncertain. Even if successful, it would not remove all virus-associated diarrhoea and vomiting any more than a successful influenza vaccine would remove all viral respiratory disease. Perhaps the one aspect that needs most attention is the host. It is evident that not all infections lead to disease and that this is not simply related to the amount of virus in the faeces. This could be an indicator of the amount of damage--more virus coming from more infected cells--but there appear to be similar amounts of virus in "normal" stools as in diarrhoeal ones. Why is it then that some host, some babies, and not others have diarrhoea and vomiting? Is there an important, and as yet unrecognized, difference? If there is and it can be identified, then finding how to induce it or increase it in young babies could be as effective as a vaccine.

Prevalence of antibodies to Norwalk virus in England: detection by enzyme-linked immunosorbent assay using baculovirus-expressed Norwalk virus capsid antigen

A total of 3,250 serum specimens collected in England in 1991 and 1992 were tested by an indirect enzyme-linked immunosorbent assay for antibody to Norwalk virus using baculovirus-expressed capsid antigen, and 2,382 (73.3%) were positive. The prevalence of Norwalk virus antibody differed regionally. It was lowest (24.6%) in 6- to 11-month-old infants and increased to 89.7% in persons over 60 years old.

Circulating and breast-milk anti-rotaviral antibodies and neonatal rotavirus infections: a maternal-neonatal study

In view of the high prevalence of rotavirus (RV) diarrhoea in Indian (Asian) infants in South Africa, a hospital-based study of 124 mothers and their neonates was carried out to establish the prevalence of maternal and neonatal circulating anti-RV antibodies, RV antibodies in breast-milk, and neonatal RV infections in this population. Thirty-four per cent of the mothers and 38% of the neonates had complement-fixing (CF) serum antibodies. There was a significant correlation between maternal and cord blood antibody levels (p less than 0.001; chi-square test). Fifteen per cent of hospital-born newborns showed asymptomatic RV excretion while still in hospital, mostly at 2-6 days of age, but some even earlier, with two shedding the virus before the age of 24 h. This excretion occurred in both seronegative and seropositive babies. The breast-milk of only 3.2% of the mothers was positive for CF-anti-RV antibodies, implying that either these were not present in the breast-milk or that the CF-test employed was not sufficiently sensitive for detecting these antibodies in milk specimens. Eighteen (18.2%) of 99 infants followed up showed evidence of RV infection 1-7 months after birth; none was symptomatic; 12 excreted RV in the stools while 6 others seroconverted. Asymptomatic reinfection was documented in 4 of 14 babies who had been infected initially as neonates.

Rotavirus serology and excretion in hospitalized non-diarrhoeal patients

Despite the well-recognized association between rotavirus (RV) and infantile diarrhoeal disease, a few studies have shown that the isolation rate of RV from the faeces of non-diarrhoeal patients can be high, suggesting that the finding of RV in the stools of individual gastro-enteritis (GE) patients need not necessarily denote an aetiological relationship. A prospective study of rotavirus serology and stool excretion was carried out in a group of non-diarrhoeal paediatric patients. A positive ELISA for RV antigen was found in 13.3% children, which compared favourably with an asymptomatic RV-excretion rate of 16.2% found in normal subjects in the community, but differed significantly from the 54.6% RV-excretion rate found in hospitalized GE patients. This confirms that RV is an important enteropathogen. Furthermore, approximately half of the non-diarrhoeal infants acquired nosocomial RV infections in hospital, most of these being asymptomatic. One-sixth of asymptomatic RV excretors showed evidence of prior exposure to rotavirus.

A serological investigation of rotavirus infections in a shanty town population in Rio de Janeiro

The presence of antibodies against rotavirus was investigated by enzyme immunosorbent assay (ELISA) in two distinct groups of children living in a shanty town in Rio de Janeiro. One hundred and thirty six plasma samples were randomly collected from children of 0 to 33 months (first group) and 255 serum samples were collected from other 85 children at ages of 2, 6 and 9 months (second group). A high percentage of antibodies were found in the newborn children and this rate decreased progressively until the age of 11 months, after which it increased again. At the age of 7 months, geometric mean antibody titers increased indicating that infection had occurred.

Rotavirus serology and breast-feeding in young children in rural Guinea-Bissau

One hundred and forty-four children aged 9-20 months living in 14 villages in a rural area of Guinea-Bissau were examined for circulating rotavirus antibodies twice in a 15-month period. An immunofluorescence technique was used. About 3/4 of the children seroconverted, independent of age on entering the study. The age-specific proportion of seropositivity increased from 4/40 (10%) at 9-11 months to 26/29 (90%) at 33-35 months of age. All the initially seropositive children retained detectable antibodies to rotavirus. The relative risk of seroconversion was 1.4 times (95% confidence interval 1.0-2.0) more common among children living in villages by the mainroad as compared to those living off the road. Contact rate is probably dependent on population density and mobility but not on age. Breast-feeding, decreasing sharply through the age interval covered by the follow-up (9-35 months), had no apparent influence on seroconversion at the ages concerned.

Pattern of acquisition of rotavirus antibody in children followed up from birth to the age of three years

Nine hundred and forty-eight serum samples from 83 children living in Belem, Brazil, collected within their first three years of life, were tested for the presence of group-specific rotavirus-antibody by an enzyme-linked immunosorbent assay (ELISA) blocking-test. Passively transferred maternal antibody lasted about two and half months; subsequently, low levels of rotavirus antibody started to appear at seven months, reaching a peak at eleven months of age. From one year onwards positivity gradually increased, reaching highest values at 34 months of life. Individual responses were examined in sera from 61 children who were followed up since birth to three years of age: 38 (62.3%) of them developed a long-term immunity following first infection; eleven (18.0%) children developed a short-term immunity after first infection by rotavirus; seven (11.5%) had no antibody response within their first three years of life; and 5 (8.2%) showed positive antibody response from birth to three years old.

The antigenic diversity of rotaviruses: significance to epidemiology and vaccine strategies

Rotaviruses are the major cause of infantile gastroenteritis world-wide. Much antigenic diversity exist amongst them. This has important implications to diagnosis, epidemiology and vaccination strategies. The nature of this diversity is now well understood. This review outlines and discussed our current knowledge of the subject from a historical perspective.

Prevalence of antibody to human calicivirus in Japan and Southeast Asia determined by radioimmunoassay

Three hundred ninety single sera from adults in Japan, Indonesia, Singapore, and Papua New Guinea were tested for antibodies to human calicivirus (HCV) by a radioimmunoassay blocking test. A high prevalence of antibodies was observed in samples collected in Japan and Southeast Asia. Of 240 serum specimens collected from five districts in Japan, 209 (87.1%) were positive for HCV antibodies. No striking difference in the prevalence of the antibody was seen among those districts. In sera collected in Southeast Asia, 84.0% (126 of 150) had antibodies to HCV (70% [35 of 50] in Singapore, 88% [44 of 50] in Indonesia, and 94% [47 of 50] in Papua New Guinea). These results indicate that HCV is a common infectious agent in Japan and Southeast Asia.

Rotavirus infection in a small community

Serial titres of rotavirus specific IgG and IgM have been measured in children and adults living in a small community over a 2 1/4-year period. In all age groups the mean titres of rotavirus specific IgG and IgM rose and fell in parallel with the changes in frequency of gastroenteritis symptoms in the community but after the time when respiratory symptoms reached their peak. Gastroenteritis symptoms were seen most commonly in the children but were also frequent in adults, especially the women. Titres of rotavirus specific IgG changed with age, increasing through childhood into early adult life, but decreased thereafter only to increase again in those over the age of 50 years. Females had higher levels of IgG in all age groups but especially among the children and 30-49-year-old women. The high levels of IgG did not protect the young adults from symptomatic gastroenteritis. Detectable levels of rotavirus specific IgM occurred in all age groups but more commonly in children aged under 10 years and in young adults. Raised levels of IgM were uncommon in the elderly, who rarely suffered gastroenteritis symptoms. An epidemiological model is proposed in which the older members of the community act as a reservoir of rotavirus, passing the infection to the children, who then infect the young adults.

[Seroepidemiology of rotavirus in a population of children, Goiânia, Goiás, Brazil]

Amostras de soro de 125 crianças, com idades entre 0 e 10 anos, da população de Goiânia, Goiás, Brasil, geraram um índice de prevalência de anticorpos para rotavirus (ensaio imunoenzimático) de 82,4%. Aparentemente, o maior risco de infecção pelo vírus se dá no grupo de 1 a 3 anos. Não existe diferença de infecção de acordo com o sexo. Informações soroepidemlológicas a nível nacional, são de grande importância para o melhor conhecimento do comportamento do vírus na população em risco, principalmente quando existe a possibilidade de uma futura imuno-profilaxia. O teste imuno-enzimático em comparação com a contraimuno-eletro-osmoforese, mostrou-se mais sensível para a detecção de anticorpos para rotavirus.

Rotavirus-specific antibodies in fetal bovine serum and commercial preparations of serum albumin

Rotavirus-specific antibodies were detected in fetal bovine serum, bovine serum albumin, and human serum albumin by radioimmunoprecipitation with the NCDV strain of bovine rotavirus as the detecting antigen. Fetal bovine sera neutralized bovine rotavirus in a plaque reduction neutralization test to titers of 1:20 or greater. Immunoglobulins purified from fetal bovine serum by protein A-agarose affinity chromatography precipitated rotavirus antigens but did not neutralize bovine rotavirus. Rotavirus antibodies in fetal bovine serum and in purified serum albumin preparations may interfere with diagnostic assays for the detection of rotavirus antigens or antibodies.

A murine model for oral infection with a primate rotavirus (simian SA11)

Simian rotavirus SA11 was shown to replicate in the gastrointestinal tracts of infant mice after oral inoculation. Clinical symptoms, histopathological changes in the small intestinal mucosa, and the type-specific humoral immune response were all characteristic of rotavirus-induced gastroenteritis. The availability of this small animal model for the study of a primate rotavirus infection should expedite analysis of the immune response necessary for protection against challenge.

Response of mice to rotaviruses of bovine or primate origin assessed by radioimmunoassay, radioimmunoprecipitation, and plaque reduction neutralization

Sera from (i) gnotobiotic BALB/c, CD-1, and CFW mice and (ii) conventional BALB/c mice were evaluated by radioimmunoassay, radioimmunoprecipitation, and plaque reduction neutralization, using the Wa, SA-11, and WC-3 (bovine) strains of rotavirus as the detecting antigens. The gnotobiotic mice had no antirotavirus antibody detectable by radioimmunoprecipitation and no neutralizing antibody at a dilution of 1:50 by plaque reduction neutralization. All sera from the conventional mice had rotavirus-specific antibodies detected by radioimmunoassay and by radioimmunoprecipitation at serum dilutions of 1:50 and 1:10,000, respectively. The antibodies were directed against viral proteins p116, p94, p88, and p84 of all three viruses, but had no neutralizing activity against heterologous rotaviruses at a dilution of 1:50. Conventional seropositive mice were parenterally immunized with the Wa, SA-11, or WC-3 strain of rotavirus. An approximate 100-fold increase in rotavirus-specific antibodies was detected by radioimmunoassay, and greater than 20-fold selective neutralization of the immunizing strain of virus was observed. Sera from the mice immunized with Wa virus had antibodies directed against inner and outer capsid proteins of all three rotaviruses. The mouse can be a useful model for studying the immune response to heterologous rotavirus infection; preexisting antibodies presumably directed towards murine rotavirus do not prevent the development of a type-specific immune response to a nonmurine rotavirus.

Improved immunofluorescence techniques with microplates for the detection of M and G immunoglobulins against rotavirus

A selection of microplates and an inverted microscope were used for the detection of immuno-fluorescence in large numbers of infected cell monolayers. The optical features of this instrument in combination with either Terasaki or Microlymp plates, simplify procedures and allow economical use of reagents, for determining fluorescent antibody levels. The techniques described were applied for estimating M and G immunoglobulins against rotavirus in elderly patients and the validity of the tests was established.

Studies on human lacteal rotavirus antibodies by immune electron microscopy

In vitro studies carried out by immune electron microscopy (IEM) indicate that rotavirus aggregation detected in the stools of newborn breast-fed infants with rotavirus infection is antibody-induced. Aggregation of rotavirus particles occurred with the IgA-containing fraction of expressed breast milk (EBM) obtained five days postpartum and with the IgA- and IgG-containing fractions of a pool of EBMs containing samples collected 2-3 days postpartum. Bovine milk fractions also demonstrated this activity in the IgG- and IgA-containing fraction. Studies on unfractionated EBMs from a mother who experienced a rotavirus infection during the 43rd week of lactation showed that following rotavirus infection all three major classes of rotavirus-specific antibodies were present in breast milk, this being confirmed by enzyme immunoassay.

An epidemic of rotavirus-associated gastroenteritis in a nursing home for the elderly

92 cases of acute gastroenteritis were registered among 256 individuals during an outbreak in a nursing home for the elderly, the majority of patients being between 70 and 90 years of age. Most cases appeared in 4 of the 8 wards; 66% of the inmates of these wards became ill. Characteristic symptoms were initial nausea and vomiting followed by diarrhoea and low fever. A number of patients were severely ill. One patient died. Rotavirus infection was diagnosed by virus detection and/or antibody titre rise during the acute phase of the illness in 13 of 16 patients examined. At the end of the outbreak, high titres of complement-fixing antibodies against rotavirus (greater than or equal to 64) were detected in serum from 21/22 patients convalescing from the disease, as compared to only 5/45 individuals with no signs of disease. It is tentatively suggested that the outbreak became extensive and rather severe because of lowered immunity against rotavirus infection among the elderly.

Seroepidemiology of rotavirus infection in rural Bangladesh

A prospective seroepidemiological study of rotavirus infection was performed in children in a village in rural Bangladesh. Ninety-three percent of the children had detectable antibodies during the study, and there were 66 significant rises in titer occurring in 57 of the 85 children. Antibody titer rises occurred in older children and younger children with equal frequency. Nine children (11%) had evidence of multiple infections during the 16-month period. Winter infections were most frequent, although one summer (monsoon) season was also associated with a large cluster. Subjects with high titers (greater than 1:8) of antibody less frequently developed a titer rise than did subjects with lower titers.

An outbreak of rotavirus infection in a long-stay ward of a geriatric hospital

An outbreak of rotavirus infection in elderly patients in a long-stay ward of a geriatric hospital is described. Virus was detected in 7/15 (47%) symptomatic individuals. Four members of staff were among those affected. The findings emphasise the need for electron microscopy to be used in the initial investigation of outbreaks of diarrhoea in all age groups.

New concepts in viral gastroenteritis

The use of negative contrast electronmicroscopy of stool suspension in the investigation of the aetiology of childhood gastroenteritis has led to the recognition of a number of candidate viral agents. There is convincing evidence that rotavirus is the single most important cause of community acquired gastroenteritis, and is responsible for some nosocomial outbreaks. The epidemiology of rotavirus acqusition, differential clinical susceptibilities of young and older infants, pathogenesis of disease, mechanisms of immunity and breast milk protection, and the role of different viral serotypes are aspects as yet poorly understood; and attempts to propagate human rotavirus in tissue culture have met with only limited success. Moreover, the aetiologically unaccountable one third of cases of infantile diarrhoea, and the association of enteritis with up to six other virus-like particles add to the complexity of the problem. This review considers the available data from human and animal studies, and based on the experience of ourselves and others comments on the present state of knowledge and trends in continuing research.

Epidemic viral gastroenteritis

Epidemic viral gastroenteritis is a significant world wide problem. In developed countries, gastroenteritis accounts for significant morbidity and loss of time from work; in the Third World it is the leading cause of mortality among infants and children. Recent technologic advances have been associated with an explosion of research activity. Two virus groups, the Norwalk-like agents and the rotaviruses, are currently accepted as causative agents of viral gastroenteritis in man. The problem of viral gastroenteritis is reviewed both from a current and a historic perspective.

Simian rotavirus (SA 11) in serodiagnosis of human rotavirus infections

Tests were made on 169 sera from children up to 10 years of age for rotavirus antibodies by indirect immunofluorescence and complement fixation tests. The simian strain SA 11 served as a substitute antigen for the human rotavirus. Furthermore, the SA 11 complement-fixing antigen was compared with a commercial antigen of the bovine rotavirus strain NCDV. It was demonstrated that SA 11 which can be more easily propagated than most bovine strains, may be used as a substitute antigen in complement fixation and indirect immunofluorescence for serodiagnosis of human rotavirus infections.

Viruses in the stools

It has long been possible to isolate viruses from the stools by culture, though the viruses found are rarely implicated in disease of the gut. In contrast, only recently has it been possible to identify viruses in the stools of patients with diarrhoea. Initially, such identifications were made by electron microscopy but the unsuitability of the microscope for large-scale screening has led to the development of other methods. The new methods have concentrated on rotaviruses but other viruses are also implicated and an overall view of the significance of finding a virus in any stool specimen has to take into account the evidence about all viruses, old and new.