Rotavirus enteritis in the West Midlands during 1974

Implications of recent virological researches

Rotaviruses (duoviruses) can be found in more than half the cases of acute diarrhoea in children up to the age of six or seven. About that age almost everyone has antibodies to them. Second infections occur and may not be as rare as laboratory findings so far suggest. Very young infants sometimes get subclinical disease-the effect of maternal antibody transmitted across the placenta? Very similar viruses, all possessing a common antigen detectable by immunofluorescence, are known to infect and/or cause diarrhoea in children, calves, piglets, mice, foals and monkeys. The calf virus and the human virus both infect piglets; piglet virus infects calves; we don't know whether any of these can infect children. Other mammals probably have similar diarrhoea viruses. An antigen common to all these viruses is probably in the inner capsid layer, and "species-specific" antigens are probably in the outer capsid layer. A precise test for comparing different strains is bably needed. Adenoviruses possibly cause a smaller proportion of cases of diarrhoea. Coronaviruses, well-known as enteric pathogens of pigs and calves, appear also to infect adults and children. 27 nm particles and 22-23 nm particles of density 1.4 (and other particles) can be found in faeces of children with natural diarrhoea and adults with experimental diarrhoea, sometimes in enormous numbers. It is not yet established whether they cause disease. Rotaviruses, animal coronaviruses and "Norwalk" virus attack the disaccharidase-producing epithelium of the small bowel; adenovirus pathology is unknown.A safe attenuated live vaccine strain of the human rotavirus urgently needs to be developed.

Viral gastroenteritis: recent progress, remaining problems

Infants and young children are particularly susceptible to a recently identified viral enteritis which is highly contagious and seems both common and universal. In this disease, virus invades the upper intestinal epithelium, causing acute diarrhoea with early fever and vomiting. We studied a similar disease in pigs, infecting three-week-old animals with transmissible gastroenteritis virus (TGE), which also invades the upper intestinal epithelium. In this model, diarrhoea is massive 16-40 hours after infection, when stools contain increased electrolytes but no excess of sugar. In the jejunum of intact pigs at the 40-hour stage we found altered Na+ and water flux, decreased mucosal activities of disaccharidases and Na+, K+-ATPase, but normal adenylate cyclase activity. At the same stage the response of Na+ flux to glucose was blunted in jejunal epithelium studied in Ussing short-circuit chambers and in suspensions of villous cells; Cl- flux responded normally to theophylline, and thymidine kinase and sucrase activities of cells isolated from jejunal villi were similar to those found in crypt cells. Probably by 40 hours after infection most virus has been shed from the mucosa. Viral diarrhoea clearly differs from enterotoxigenic diarrhoea. Consideration of its pathogenesis must take into account the dynamic nature of the mucosal epithelium and the factors governing differentiation of enterocytes as they migrate from crypt to villus. Sufficient information is available now to characterize one specific and apparently prevalent viral enteritis in man and to identify additional viral enteritides. There is hope that preventative therapy can be developed. Our understanding of the mechanisms of viral diarrhoea is limited, but the availability of an animal model and the promise of others makes us optimistic that these deficiencies can be remedied. Greater understanding of the pathogenesis of viral diarrhoea should better the active therapy of affected infants and children.

Inactivation of human and simian rotaviruses by chlorine dioxide

The inactivation of single-particle stocks of human (type 2, Wa) and simian (SA-11) rotaviruses by chlorine dioxide was investigated. Experiments were conducted at 4 degrees C in a standard phosphate-carbonate buffer. Both virus types were rapidly inactivated, within 20 s under alkaline conditions, when chlorine dioxide concentrations ranging from 0.05 to 0.2 mg/liter were used. Similar reductions of 10(5)-fold in infectivity required additional exposure time of 120 s at 0.2 mg/liter for Wa and at 0.5 mg/liter for SA-11, respectively, at pH 6.0. The inactivation of both virus types was moderate at neutral pH, and the sensitivities to chlorine dioxide were similar. The observed enhancement of virucidal efficiency with increasing pH was contrary to earlier findings with chlorine- and ozone-treated rotavirus particles, where efficiencies decreased with increasing alkalinity. Comparison of 99.9% virus inactivation times revealed ozone to be the most effective virucidal agent among these three disinfectants.

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.

Experimental group A rotaviral infection in cynomolgus monkeys raised on formula diet

Rotaviral infections in cynomolgus monkeys (Macaca fasicularis) were studied to ascertain its suitability as a model of infection and diarrhea caused by group A human rotaviruses. Formula-fed monkeys were used as they could be observed closely. Experimental rotaviral infection of cynomolgus monkeys was age-dependent; only young monkeys were readily infected. Formula-fed newborns were readily infected with cell-culture-adapted human (WA) and simian (SA11) viruses and with a rotavirus from a human fecal specimen. However, diarrhea was detected only in very young animals. A number of rotaviral shedding patterns as a function of time were observed. Although there was no typical viral shedding pattern which represented exclusive association of viral infection with diarrhea, the initial level of viral excretion and the maximum level of viral shedding attained were much higher in animals with diarrhea. Seroconversion occurred in less than half of the inoculated animals. The presence of maternal rotaviral antibodies did not prevent infection or diarrhea.

Global seasonality of rotavirus infections

Data from 34 studies of the etiology of childhood diarrhoea were compiled in order to investigate the seasonal patterns of rotavirus gastroenteritis and consider their implications for transmission of the virus. Rotavirus was detected in 11-71% of children with diarrhoea, and the median rate of detection (33%) was independent of the level of economic development or geographical region of the study area, as well as of the method of detection used. While rotavirus infections have been called a winter disease in the temperate zones, we found that their incidence peaked in winter primarily in the Americas and that peaks in the autumn or spring are common in other parts of the world. In the tropics, the seasonality of such infections is less distinct and within 10 degrees latitude (north or south) of the equator, eight of the ten locations exhibited no seasonal trend. Throughout most of the world, rotavirus is present all the year round, which suggests that low-level transmission could maintain the chain of infection. The virus is spread by the faecal-oral route but airborne or droplet transmission has also been postulated. The epidemiology of rotavirus--its seasonality in the cooler months, its universal spread in temperate and tropical zones in developed and less developed settings--more closely resembles that of childhood viruses that are spread by the respiratory route (such as measles) than that of common enteric pathogens that are spread predominantly by the faecal-oral route.

Human viral gastroenteritis

During the last 15 years, several different groups of fastidious viruses that are responsible for a large proportion of acute viral gastroenteritis cases have been discovered by the electron microscopic examination of stool specimens. This disease is one of the most prevalent and serious clinical syndromes seen around the world, especially in children. Rotaviruses, in the family Reoviridae, and fastidious fecal adenoviruses account for much of the viral gastroenteritis in infants and young children, whereas the small caliciviruses and unclassified astroviruses, and possibly enteric coronaviruses, are responsible for significantly fewer cases overall. In addition to electron microscopy, enzyme immunoassays and other rapid antigen detection systems have been developed to detect rotaviruses and fastidious fecal adenoviruses in the stool specimens of both nonhospitalized patients and those hospitalized for dehydration and electrolyte imbalance. Experimental rotavirus vaccines have also been developed, due to the prevalence and seriousness of rotavirus infection. The small, unclassified Norwalk virus and morphologically similar viruses are responsible for large and small outbreaks of acute gastroenteritis in older children, adolescents, and adults. Hospitalization of older patients infected with these viruses is usually not required, and their laboratory diagnoses have been limited primarily to research laboratories.

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

Rotavirus infection was demonstrated in 168 (29.3%) of 573 children hospitalized for acute diarrhoea in Rome between January 1982 and December 1984. Laboratory diagnosis of these infections was made by transmission electron microscopy and enzyme immunoassay techniques with an overall agreement of 91.3%. Astroviruses, adenoviruses and small round viruses were detected in the faeces of 36 patients (6.4%). Whereas in 1982 rotavirus positive patients were clustered in the winter and following spring, in the following years cases were recorded all year round. The median age of patients with rotavirus infections was 17, 10 and 11.5 months in 1982, 1983 and 1984, respectively. In addition, a smaller number of rotavirus positive cases were admitted in 1983 when compared to those admitted during the previous as well as the subsequent years. It is suggested that a herd immunity was induced in the population by epidemic spread of rotavirus in the first half of 1982.

Laboratory investigations on rotavirus in infantile gastroenteritis in Jamaica

Between March 1982 and March 1983 rotaviruses were detected in faecal specimens from 193 (19%) of 1020 Jamaican children under 5 years old with acute gastroenteritis. The excretion of rotaviruses in a control group of non-diarrhoeal children was only 1.4%. Rotaviruses were detected more frequently in the cooler months of the year; the prevalence ranged from 1.7% in August to 46% in January. In a comparison of the ELISA technique and electron microscopy for investigating rotavirus infections, the ELISA was demonstrated to be more sensitive especially for weakly positive cases. Because of its relative simplicity, low cost and rapidity the ELISA appears to be more suitable for use in developing countries.

Rotavirus-associated gastroenteritis in black infants in South Africa

From March 1983 to February 1985, rectal swabs were collected from the black infants admitted to the gastroenteritis unit at Ga-Rankuwa Hospital, Pretoria, Republic of South Africa, to investigate the prevalence of rotavirus-associated gastroenteritis. Overall, 23.1% of the patients tested were found to be positive for rotaviral illness; a definite seasonal pattern emerged, showing a marked increase in the number positive during the autumn. Other factors of importance in terms of rotaviral illness included the age distribution of the patients, the presence of vomiting, and duration of illness.

Molecular epidemiology of human rotavirus

The epidemiology of human rotavirus (HRV) in north-east Scotland was investigated between 1982 and 1984. During this period 708 HRV infections were recorded. The majority (83%) of the infections were in children less than 5 years of age although some were recorded in adults. The peak incidence occurred in the winter months although a high number of HRV infections was reported during the summer of 1983. A total of 840 faecal specimens containing rotavirus were screened for HRV genome RNA by polyacrylamide gel electrophoresis. Seven hundred (83%) specimens gave RNA profiles suitable for establishing the HRV electrophoretype. Twenty-five different electrophoretypes were identified, of which 21 had 'long' RNA profiles and four had 'short' RNA profiles. There was extensive co-circulation of distinct electrophoretypes although during any one epidemic period the majority of viruses belonged to a relatively small number of types. Comparison of viruses collected from hospitalized and non-hospitalized patients showed no differences in electrophoretype distribution. HRV was identified in faecal specimens from a wide age group and no correlation was demonstrated between age of patient and electrophoretype of the infecting virus.

Inactivation of human and simian rotaviruses by chlorine

The inactivation of simian rotavirus SA-11 and human rotavirus type 2 (Wa) by chlorine was compared at 4 degrees C by using single-particle virus stocks. Both virus types were usually more readily inactivated at pH 6.0 than at pH 8.0 when low chlorine concentrations (0.05 to 0.2 mg/liter) were used. A complete (5 log) reduction of both was obtained within 20 s at all pH levels when chlorine concentrations were increased to 0.3 mg/liter. Slight differences in the chlorine sensitivities of SA-11 and human rotavirus type 2 were noted but were not considered to be significant.

Detection of rotavirus-specific IgG antibodies by immunoperoxidase assay and enzyme-linked immunosorbent assay

An indirect immunoperoxidase assay (IPA) has been developed for determination of IgG antibodies to rotavirus. The technique employed as antigen, SA-11 infected MA 104 cells, which were air-dried on glass slides and acetone-fixed. In parallel, rota-specific IgG antibodies were determined by enzyme-linked immunosorbent assay (ELISA). Specific IgG antibodies to rotavirus were determined in sera of healthy children and in sera of patients suffering from gastroenteritis. A good correlation (r = 0.92) and (r = 0.98) for healthy children and patients, respectively, was found between IPA and ELISA techniques. The IPA technique is rapid and simple and positive results, because of the intensive staining, are easily read by low-power light microscope. The potential application of IPA and ELISA methods in serodiagnosis of rotavirus infections is discussed.

Role of rotavirus as the cause of acute paediatric diarrhoea in Calcutta

Of the 245 acute paediatric diarrhoea cases admitted to the Infectious Diseases Hospital, Calcutta between July, 1979 and June, 1981, rotavirus was detected in the faeces of 55 (22.4%) patients either as the sole aetiological agent or in association with other enteropathogens. Children aged six months to two years were most commonly infected. The virus was detected throughout the year with higher incidence during the winter months of both years. The frequency of detection of major enteropathogens other than rotavirus was Vibrio cholerae biotype El Tor (31.0%), enteropathogenic Escherichia coli (8.2%) and enterotoxigenic E. coli (6.5%).

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.

The effects of relative humidity and temperature on the survival of human rotavirus in faeces

The effects of relative humidity and temperature on the survival of human rotavirus in a thin layer of faeces on an impervious surface and on absorbent material was investigated using the indirect immunofluorescence technique in LLC-MK2 cells to titrate infectivity. Rotavirus was found to be very stable at low and high relative humidities but not in the medium range of relative humidity. Rotavirus infectivity was lost more rapidly under all humidities at 37 degrees C than at 4 degrees or 20 degrees C.

Faecal adenoviruses from Glasgow babies. Studies on culture and identity

Attempts were made to isolate viruses from babies' stools that contained adenoviruses detected by electron microscopy. One hundred and fifty-nine specimens from 71 children were studied and adenoviruses of established serotypes were isolated from 81 stools. Serial stool samples containing adenovirus particles were obtained from 35 children, and prolonged shedding of recognized serotypes was common. Simultaneous and sequential infections by different serotypes were also observed. Thirty-six children shed adenoviruses that could not be isolated using cell cultures normally used to detect adenoviruses, and nine of these children also shed adenoviruses of established serotypes. Passage in Chang conjunctival cell culture allowed characterization of fastidious adenoviruses from 14 children as members of a previously unrecognized serotype.

Influence of humidity on rotavirus prevalence among Nigerian infants and young children with gastroenteritis

Rotaviruses were detected by counterimmunoelectro-osmophoresis in the feces of 16 (13.8%) of 116 infants and young children with gastroenteritis during a 5-month period (September 1979 through January 1980) in Ife, Nigeria. The rate of rotavirus detection varied inversely with relative humidity and was highest in December (38.5% positive) when the humidity was lower. There was not such a distinct relationship with temperature or vapor pressure; and although the rate of rotavirus detection was higher in the drier months (November to January; 19.3% positive) than in the rainy season months (September and October; 8.5% positive), the average humidity was lower in the drier months than in the rainy months. Low relative humidity (49 to 78%) is apparently the most important environmental factor for rotavirus survival and spread in this area.

Rotavirus and acute diarrhoeal disease in children in a southern Indian coastal town

Rotavirus was found by electron microscopy in the stools of 70.7% of a representative sample (368) of the 3355 children with acute diarrhoea admitted to hospital over a period of 16 months in Calicut on the west coast of India. The prevalence of the virus was high (nearly 100% of cases examined) in the period from November to January and lowest in May just before the onset of the monsoon. Prevalence was high (75.1%) in infants aged from 6 to 23 months, but was considerably lower in those under 6 months of age (34.8%). The management of cases and the planning of control measures for this disease are discussed in the light of knowledge of the high prevalence of rotavirus.

Diagnostic virology using electron microscopic techniques

This chapter illustrates the development of the use of electron microscopy in viral diagnosis. The field covered is confined to medical viral diagnosis, but parallel developments have taken place in both veterinary and botanical fields and techniques derived from both these sources are also included where relevant. It is reported that the scanning transmission mode of operation, which can induce image contrast changes electronically, may enhance studies with unstained sections and perhaps facilitate thin section immune electron microscopy (IEM). The application of negative stain IEM has been particularly useful for the study of the antigenic nature of some of the newly discovered noncultivable viruses. Viral antigens can also be detected in thin sections of infected cells by IEM with suitably labeled specific antibodies. Confirmation of viral infection by electron microscopy on tissues originally processed for light microscopy is also frequently useful.

Acute diarrhea and rotavirus infection in newborn babies and children in Yogyakarta, Indonesia, from June 1978 to June 1979

A longitudinal study of acute diarrhea in children in Yogyakarta, Indonesia (June 1978 to June 1979), showed little variation throughout most months of the year in numbers of children admitted to hospital and in numbers infected with rotaviruses. Both decreased during November and December coincidentally with seasonal change from dry to wet conditions. Rotavirus particles were identified by electron microscopy in fecal specimens from 126 of 334 (38%) infants and children with acute diarrhea. Nosocomial rotavirus infections occurred in 11% of control children admitted to hospital for other reasons. Socioeconomic level and preexisting nutritional status did not influence the incidence of rotavirus excretion. Rotavirus infections were most common in children aged 6 to 24 months. There was a low incidence of infection in infants less than 6 months old. Rotavirus infection was seldom observed in newborn babies delivered in an urban hospital nursery, in a rural health center, or at home. One of 72 newborn babies with diarrhea excreted rotavirus. One of 53 healthy newborn babies excreted rotavirus. It is concluded that, in Indonesia, rotavirus infection is a major cause of childhood diarrhea throughout the year, but is an uncommon cause of diarrhea in newborn babies.

Rotavirus, adenovirus, and non-viral enteropathogens in diarrhoea

The aetiology of rotavirus and adenovirus in acute gastroenteritis was studied in a prospective series that comprised 283 children admitted consecutively with diarrhoea during a 1-year period. Rotavirus was associated in 49% of the cases by solid-phase radioimmunoassay and electron microscopical examination of stool specimens, or by serology. Adenovirus was detected by radioimmunoassay in the stool specimens of 29 (11%) patients, including 8 cases of possible dual infection with rotavirus. Rotavirus infections showed a typical age distribution and seasonal clustering between January and June, whereas the adenovirus-associated cases did not form a distinctive subgroup. Enteropathogenic bacteria were found in 10% of cases, and were nearly as common in association with rotavirus infection as not. Respiratory symptoms accompanied diarrhoea in 34% of the patients with rotavirus and in 25% of those with neither rotavirus nor adenovirus. Therefore we could not confirm the existence of a 'rotavirus syndrome', nor could we confirm an association of respiratory symptoms with rotavirus infection. Use of antibiotics before the onset of diarrhoea was more common among those with non-viral diarrhoea (23%) than in the rotavirus group (13%). Rotavirus infections appeared to be common among cases of 'antibiotic-induced' diarrhoea.

A prospective clinical study of rotavirus diarrhoea in young children

The clinical and laboratory features of 96 children aged 6 to 36 months with acute rotavirus diarrhoea were compared to findings on 63 children of the same age with acute non-rotavirus diarrhoea. Of the rotavirus-associated cases 80% occurred between January and June. In general, the diarrhoea was more severe in these patients than in the others, but no difference was seen in duration of symptoms. Clinical features characteristic of rotavirus-associated cases included: dehydration and acidosis upon admission, vomiting, fever, neutropenia and sugar in the stools (Clinitest greater than or equal to 0.5%). In contrast, no difference was seen in the occurrence of respiratory symptoms (53% in the rotavirus, 62% in the non-rotavirus group), or in the presence of mucus strands, occult blood or leucocytes in stools. A combination of the above criteria may be helpful in the presumptive diagnosis of rotavirus diarrhoea.

The 30- to 54-nm rotavirus-like particles in gastroenteritis: incidence and antigenic relationship to rotavirus

The 30- to 54-nm rotavirus-like particles were observed in the stool specimens of 17 children with gastroenteritis. These small rotavirus-like particles were shown to be antigenically related to the commonly described 68-nm rotavirus using the techniques of immune electron microscopy and ELISA (enzyme-linked immunosorbent assay). Four specimens containing the small rotavirus-like particles were shown to contain an antigen of a common human rotavirus serotype (type 2). The findings of small rotavirus-like particles of different diameters sharing a common antigen with rotavirus type 2 cautions against the naming of new candidate viruses based on morphology alone. In addition, the shedding of pure populations of single-shelled rotaviruses, herein described, could be an unusual phenomenon which may occur only sporadically. The relationship of the smaller rotavirus-like particles to rotavirus morphogenesis is discussed.

Rotavirus infection in young children in the highlands of Papua New Guinea

Rotavirus infections were detected by electron microscopy examinations in 54 of 66 children (82%) with acute gastroenteritis which necessitated admission to hospital during April to July, 1979, in the Highlands of Papua New Guinea. Longitudinal epidemiological studies may confirm rotavirus infections to be more important aetiolgical agents of childhood gastroenteritis in this region than in many other countries studied to date.

Gastroenteritis in Auckland: An aetiological and clinical study

Faecal specimens from 60 patients (under six years old), most of whom were Maoris and Pacific Islanders admitted to Auckland Hospital with gastroenteritis during the months of June and July 1977, were examined for the presence of faecal viruses, bacterial pathogens and parasites. Faecal specimens from 18 non-diarrhoeal control patients were also examined, of which three contained rotavirus. Forty-three (72 per cent) gastroenteritis patients had rotavirus detectable in stools by electron microscopy or immune electron microscopy. Of the remainder, 17 patients were regarded as having non-rotavirus diarrhoea. Enterotoxigenic Esch. coli. was isolated from seven patients of whom six yielded stable toxin producers (ST+), four labile toxin producers (LT+) and two dual toxigenic strains (ST+/LT+). All ST+ isolates appeared to be of low enterotoxigenicity as indicated by low gut weight/carcass weight ratios in the infant mouse assay. Rotavirus was the commonest aetiological agent (72 per cent), bacterial pathogens (alone) accounted for only five per cent and no enteric pathogens were found in 15 per cent of cases. Non-agglutinable rotavirus, presumably a different serotype, was seen in both gastroenteritis and control patients. Rotavirus ‘satellite’ particles previously undescribed were demonstrated in a number of stool samples.

An outbreak of gastroenteritis in young children caused by adenoviruses

During October and November, 1978, gastroenteritis developed in 17 of 24 young children aged between eight months and two years from an R.A.F. station in the U.K. The illness, in which diarrhoea was always the predominant symptom, had an incubation period of eight to ten days and lasted about a week. It seemed to be transmitted from child to child, and in all but one instance parents and older siblings remained well. Stool specimens from 14 of the affected children were examined bacteriologically and virologically, and a highly significant association was found between the presence of adenovirus particles in stools, identified by electron microscopy, and the acute stage of the illness. This evidence suggests that an adenovirus was the cause of this outbreak of gastroenteritis.

Recurrent attack of rotavirus gastroenteritis after adenovirus-induced diarrhoea

A 14-month-old baby boy suffered a second attack of rotavirus gastroenteritis within one month of the initial one. The second attack followed a diarrhoeal episode associated with adenovirus. Gastrointestinal symptoms in the second attack were more severe than those of the first. The adenovirus-associated enteritis was mild compared with the illness in both episodes of rotavirus infection.

Role of rotavirus (reo-like) in weanling diarrhea of pigs

Piglets weaned abruptly and precociously at 3 weeks of age and placed in a crowded nursery commenced diarrhea 3 to 5 days later. Death losses were low (approximately 6%), but weight gain ceased for 2 weeks. Large numbers of rotavirus (reo-like) particles were seen by electron microscopy in diarrhetic fluids. Sections of intestines showed a loss of adsorptive surface in that villi were shortened and fused with adjacent villi. Immunofluorescence revealed rotaviral antigens within damaged enterocytes. Rotavirus-containing gut fluid was harvested from sick, weaned piglets. This fluid, filtered free of bacteria, was used to inoculate per os colostrum-deprived piglets. These infected piglets developed diarrhea and dehydration, and large numbers of rotaviral particles were seen in their diarrhetic fluid. Also, rotaviral antigens were present in aberrant enterocytes, and the intestinal villi were shortened. Since the weaned piglets (3 weeks old) came from sows that were providing their piglet's intestine with passive antibody protection via milk, we concluded that the abrupt removal of the piglet from the gut-bathing antibody combined with the stress of weaning produced a neonate vulnerable to the ubiquitous rotavirus. Similar circumstances may prevail and operate in exacerbating rotaviral diarrhea in neonates of other species of mammals.

A search for faecal viruses in new-born and other infants

Faecal specimens were collected at weekly intervals over the winter months from 141 new-born infants without diarrhoea. Contrary to the findings in other studies, no viruses were detected by electron micriscopy or culture in any of these specimens. Over the same period faecal specimens were collected from 84 infants up to four years of age admitted to hospital. Rotaviruses or adenoviruses were found in 48% of infants with gastroenteritis. Enteroviruses and other small round virus-like particles were found in infants both with and without gastroenteritis. No viruses or pathogenic bacteria could be found in 34% of specimens from infants with gastroenteritis.

A survey of rotavirus associated with gastroenteritis in Aboriginal children in Western Australia

In a year-long survey which was carried out between April, 1975, and March, 1976, faecal specimens from Aboriginal and some non-Aboriginal children who suffered from gastroenteritis were examined by electron microscopy for rotavirus, and also tested for bacteria and parasites. The children were under six years of age and came from all parts of Western Australia, except Perth. Rotaviruses, "astroviruses" and adenoviruses were detected as well as the usual potentially pathogenic bacteria and parasites. Two peaks of rotavirus incidence were found during the year in specimens from Kalgoorlie, but only one peak occurred in Derby. Rotavirus was somewhat more frequently seen in non-Aboriginal than Aboriginal children.

Identificação por contraimunoeletroforese de rotavirus em casos de diarréia infantil

Os resultados obtidos na identificação de rotavirus, usando a técnica da contraimunoeletroforese, com 162 amostras de feses de crianças com quadros diarréicos agudos, mostram uma distribuição percentual de positividade de 72,7%, 77,7% e 66,6% em diferentes grupos etários de 6 a 8 meses até um ano de idade.

Comparison between adsorption of poliovirus and rotavirus by aluminum hydroxide and activated sludge flocs

Adsorption of poliovirus and rotavirus by aluminum hydroxide and activated sludge flocs was studied. Both aluminum hydroxide and activated sludge flocs adsorbed greater amounts of poliovirus than rotavirus. Aluminum hydroxide flocs reduced the titer of poliovirus in tap water by 3 log10, but they only reduced the titer of a simian rotovirus (SA-11) in tap water by 1 log10 or less and did not noticeably reduce the number of human rotavirus particles present in a dilute stool suspension. Activated sludge flocs reduced the titer of added poliovirus by 0.7 to 1.8 log10 and reduced the titer of SA-11 by 0.5 log10 or less. These studies indicate that a basic difference in the adsorptive behavior of enteroviruses and rotaviruses exists and that water and wastewater treatment processes that are highly effective in removal of enteroviruses may not be as effective in removing other viral groups such as rotaviruses.

Virions associated with acute gastroenteritis in Vancouver, 1976

Virions were identified by electron microscopic observation of unconcentrated extracts of feces obtained from 55 (33%) of 167 children aged 3 weeks to 5 years who were hospitalized with acute gastroenteritis at Children's Hospital, Vancouver between January and December 1976. Morphologic types included 30 rotavirus, 15 adenovirus, 5 astrovirus and 5 picornavirus-like particles.

Distinct reovirus-like agents associated with acute infantile gastroenteritis

Human reovirus-like particles were found by electron microscopy in the stools of 25% of 71 infants and young children hospitalized with acute gastroenteritis in Mexico between December 1976 and April 1977. The virus was also identified by the electrophoresis patterns of its ribonucleic acid upon disruption of partially purified particles. This technique is as reliable as electron microscopy but less laborious, and could become a routine diagnostic procedure. The electrophoretic patterns of viral ribonucleic acid from different cases suggest that there are at least two different reovirus-like agents associated with infantile gastroenteritis.