key: cord-0040434-ptupqfuu authors: BRESEE, JOSEPH S.; GLASS, ROGER I. title: Astroviruses, Enteric Adenoviruses, and Other Gastroenteritis Viruses date: 2009-05-15 journal: Tropical Infectious Diseases DOI: 10.1016/b978-0-443-06668-9.50068-5 sha: e95c50a9fa08cbe817f1487055f171705dbdf67a doc_id: 40434 cord_uid: ptupqfuu nan Diarrheal disease remains one of the most common causes of morbidity and mortality in developing countries. The problem is particularly acute among young children, who will have an estimated 15 episodes of diarrhea in the first five years of life 1 and among whom 2.5 million deaths will occur each year. 2 For up to half of all episodes, an etiologic agent cannot be found. The importance of viral agents as causes of diarrheal disease has been increasingly appreciated, beginning with the discovery of rotavirus 3 and caliciviruses 4 in the 1970s. More recently, advances in detection methods for some other viruses, such as astroviruses and enteric adenoviruses, have led us to appreciate their role as causes of diarrheal disease. In addition, a variety of other viruses, such as picobirnaviruses, coronaviruses, and toroviruses, have been associated with gastroenteritis, but their clinical and public health importance remains unclear (Table 63-1) . Many of these viruses may be responsible for the fraction of illness for which a pathogen cannot be found and a better understanding of their epidemiology will have implications for programs to decrease morbidity and mortality in developing countries. Astroviruses were first identified in 1975 5, 6 and named based on a characteristic 5-or 6-pointed appearance noted by electron microscopy (EM). Since 1990, improvements in diagnostic methods, including the adaptation of astrovirus to grow in continuous cell lines 7 ; sequencing and elucidation of the structure of the genome [8] [9] [10] ; and development of improved methods of detection, including enzyme immumoassays and reverse-transcription polymerase chain reaction, [11] [12] [13] [14] have led to new insights into the role of astrovirus in human disease. It is now clear that astroviruses are a common cause of sporadic gastroenteritis among children, possibly second only to rotavirus, and may be associated with large-scale outbreaks of diarrhea as well. Astroviruses are 28-to 30-nm, spherical, nonenveloped viruses with a positive sense ssRNA genome and have been classified in their own family, Astroviridae. 15 Eight serotypes of human astroviruses have been identified. 16, 17 Of these, type 1 is predominant in most studies, accounting for more than half of strains isolated 16, 18, 19 ; types 2, 3, and 4 each account for 10% to 16% of astrovirus detections; and types 5, 6, 7, and 8 are less uncommonly detected. 16, 17 The relative distribution of types seems to vary by geographic location and by year, 20 and more variability may be found in developing countries. 21, 22 EPIDEMIOLOGY Gastroenteritis associated with astroviruses has been reported worldwide, both as sporadic disease and as outbreaks. Cases of astrovirus-associated gastroenteritis are most common among children less than 2 years of age, 19, [23] [24] [25] [26] [27] [28] [29] [30] [31] [32] and are less frequent among older children and adults. 33, 34 In volunteer studies, most adults neither became infected nor developed diarrhea. 33, 35 However, in a large outbreak among schoolchildren, 36,37 teachers became ill as well, perhaps as a result of a large dose of virus in this type of setting or a different mechanism of spread. In addition, outbreaks have been reported among the elderly, probably due to waning immunity with increasing age. [38] [39] [40] Gastroenteritis associated with astrovirus, like rotavirus, occurs in both developed 19, 23, 24, [27] [28] [29] [30] [41] [42] [43] and developing countries, 32, [44] [45] [46] [47] [48] suggesting that improvements in water and sanitation are unlikely to decrease disease incidence. In temperate climates, astrovirus diarrhea cases peak in winter, 17, 19, 24, 29, 31 whereas the seasonality is less clear in tropical settings. 32, 44, 46 With improvements in detection methods, astrovirus represents an important cause of community-acquired and nosocomial illness and may be the most common viral cause of gastroenteritis in children after rotavirus and possibly Norwalk-like viruses. 19 In developing countries, astroviruses have generally been detected in less than 10% of young children treated for gastroenteritis in outpatient clinics or in hospitals, and the lower proportions reported from some studies (<1%-3%) may reflect insensitive detection methods rather than true prevalence. 19, 21, 42, 45, [47] [48] [49] [50] Even so, one study in rural Mexico has found astrovirus to be the most common cause of diarrhea in the first three years of life, causing 26% of diarrheal episodes in a prospectively followed cohort. 32 Outbreaks of astrovirus gastroenteritis have been reported in schools, 36, 37 day-care centers, 25,51,52 hospitals, 26, 29, 39, 53, 54 nursing homes, 38, 40 and households. 32, 55 Nosocomial spread of astroviruses may be common. 56 While the modes of transmission are still unknown, the primary mode of spread of virus is likely to be through fecal-oral contamination via person-to-person contact, 33, 35, 36, 53 although the stability of the virus in water may indicate that waterborne spread is possible. 57 Astroviruses cause a syndrome characterized by 2 to 5 days of watery diarrhea, often accompanied by vomiting and less often by high fever, abdominal pain, and other constitutional symptoms. 23, 29, 44, 46 It is generally milder than rotavirus, less commonly resulting in dehydration, 19, 23, 26, 39, 44 and rarely associated with death. 45 Lactose intolerance 43, 58 and poor weight gain 46 have been reported following astrovirus infection, and children with poor nutritional status may develop more severe disease 46 or chronic diarrhea. 50 Illness among adults is generally mild and of short duration. 33, 35, 39 However, in studies of immunocompromised persons, astrovirus is often the most common virus detected in persons with diarrhea and associated with prolonged shedding of virus. [59] [60] [61] HIV infection was associated with more severe astrovirus disease in children with HIV in Malawi. 21 Indirect evidence suggests that immunity to astrovirus develops early in life. 25, 33, 35 Astrovirus infects intestinal epithelial cells. The incubation period is 3 to 4 days, 33, 35 but may be shorter in outbreak settings. 37 Children may shed virus 1 to 2 days prior to illness and for 4 to 5 days following illness, 25,29,51 but shedding for 3 weeks has been reported when more sensitive detection methods have been used. Since most illness with astroviruses is found in young children and elderly persons, it is assumed that protection from illness is conferred by infection, and that the protection is relatively durable. Like many other enteric viruses, the immunologic correlates of protection are poorly understood for astroviruses. Until recently, electron microscopy was the only method to detect astrovirus in fecal specimens, but was relatively insensitive. 9, 24, 26, 31, 36, 37, 40, 47, 53, 58, 62, 63 Enzyme immunoassays have been developed, 11, 42 which were more sensitive, easier, and less expensive to use. 23, 25, 30, 36, 42, 44, 46, 64 Molecular diagnostic methods including reverse transcriptase-polymerase chain reaction and probes, as well as virus cultivation, are available in research laboratories. 65 Therapy for astrovirus diarrhea includes rehydration with oral or intravenous fluids. Illness is generally mild and selflimited, but malabsorption and lactose intolerance have been reported following infection. Death associated with astroviruses is rare. 43, 45, 58 In outbreaks, identification of the source of infection, such as food or contact with ill persons, may be helpful in preventing further illness. Sporadic cases are common in children and no methods of prevention have been identified. Since the infection may be spread though close personal contact, enteric precautions including appropriate hand-washing practices and isolation of ill persons may be advisable. When adenoviruses were first identified in fecal specimens of children with diarrhea, their etiologic role was questioned because adenoviruses are common causes of other illnesses (e.g., URIs) in children and are excreted in the stool. But unlike the common respiratory adenoviruses, enteric adenoviruses were difficult to grow and were therefore distinguished as the fastidious enteric adenoviruses (FEAs). Eventually, these FEAs were placed in their own group and found to belong to two predominant serotypes, 40 and 41. Besides these serotypes, only serotype 31 has occasionally been causally associated with gastroenteritis. Like astroviruses, the development of rapid, sensitive diagnostic assays for the detection of EAs has increased our appreciation of their role as causes of diarrhea in children. Adenoviruses are members of the family Adenoviridae and of the genus Mastadenovirus. The 47 defined serotypes are divided into 6 subgroups (A-F); serotypes 40 and 41 are the only members of subgroup F (called enteric adenoviruses because they have been associated with gastroenteritis in humans). 66, 67 Enteric adenoviruses are nonenveloped, icosahedral, double-stranded DNA viruses, and are 70 to 80 nm in size. Like rotavirus and astrovirus diarrhea, diarrhea associated with enteric adenoviruses occurs primarily among children less than 2 years of age. Infection is probably universal, and the age-specific incidence does not appear to differ between temperate and tropical countries, suggesting that improvements in water and sanitation will not decrease the incidence of disease. Compared to other viral agents in developing countries, EAs appear to account for a smaller proportion of diarrheal disease than in developed countries. Enteric adenoviruses generally have been detected in 1% to 4% of children with diarrhea in many studies, 19,49 although they have been detected commonly in some studies. Enteric adenoviruses were more common than rotavirus in a rural outpatient setting in Guatemala (14% of children with diarrhea had EA detected in stool compared to 5% with rotavirus), and were associated with 31% of hospital admissions for diarrhea. 68 In two South African studies, 6.5% to 13.2% of hospital admissions for diarrhea were associated with EAs 69,70 ; in one study, 70 EAs were detected as often as rotaviruses. In the few studies that have examined the role of EAs in an adult population, they appear to be less important causes of gastroenteritis than in children. No seasonality of EA infections was apparent in studies in temperate 31,71-73 or tropical countries, 68 ,74 but few studies have reviewed multiple seasons. Infections with EA can range from being mild or asymptomatic to producing profuse, nonbloody, watery diarrhea and vomiting. 71, 72, [75] [76] [77] [78] [79] Children often have 6 to 10 stools per day, and the mean duration of illness is 5 to 9 days. 68, 71, 72, [75] [76] [77] [78] Abdominal pain 71,76 and 2 to 3 days of low-grade fever (<38.5 o C) are also frequently present, whereas temperatures greater than or equal to 39 o C occur in less than 10% to 25% of children. 71, 75 Mild isotonic dehydration may occur in 15% to 50% of children, 71, 72, 76 and only severe cases require hospitalization. Respiratory symptoms, including pneumonia, have been associated with EA infections but are present less commonly than with other adenoviruses. 72, 75, 77 Asymptomatic infections have been documented in 8% and 17% of children in day-care center studies. 23, 68, 71, 72 Serum electrolytes are usually normal, and a slight leukocytosis may be present in a minority of children. 71 Gastroenteritis associated with EAs has a similar presentation among patients in developed and developing countries. However, enteric adenoviruses may be associated with chronic diarrhea and less common serotypes in HIV-infected subjects. 59, [80] [81] [82] [83] [84] Deaths from EA gastroenteritis are uncommon, but have been reported, particularly among immunocompromised children. 75, 85, 86 Long-term complications appear to be rare, but lactose intolerance 71 and malabsorption 87 have been reported and may exacerbate disease among children in developing countries where malnutrition is prevalent. Differentation of EA-associated gastroenteritis from other causes of viral gastroenteritis is difficult. EA-associated diarrhea may be more severe and prolonged than viral gastroenteritis caused by other agents 71, 72, 88 and is commonly associated with a high fever and dehydration similar to rotavirus. 71, 88 Like other viral agents of gastroenteritis, the exact mode of transmission is unknown. EAs are probably transmitted by fecal-oral spread, by person-to-person contact, or by respiratory droplets. No foodborne or waterborne outbreaks have been described. 89 The incubation period of the disease is 7 to 10 days, 77,78,90 and viral shedding may persist for 10 to 14 days. 90 Mechanisms of diarrhea and immunity associated with EA are poorly understood. Type 40-and 41-specific antibodies develop following infection 71, 91, 92 and can be detected in the absence of recent diarrheal illness. 69, 92 Children can become ill when reinfected with EA. 93 However, illness among adults is uncommon, even in outbreak settings where they have a high likelihood of exposure. Electron microscopy (EM) was first used to detect enteric adenoviruses in fecal specimens when they are shed in large amounts (as many as 10 11 particles/gram of feces). Since EM cannot distinguish EAs from nonenteric serotypes, 94 immune electron microscopy (IEM) can enhance sensitivity and specificity of EA detection. [95] [96] [97] [98] Enzyme immunoassays using monoclonal antibodies to types 40 and 41 and to the adenovirus hexon common to all serotypes have been developed. [98] [99] [100] [101] [102] These are the easiest, most rapid methods for detection 103 and have proven to be highly sensitive and specific compared to IEM. 98 There are currently no commercial kits using DNA detection methods. Enteric adenoviruses grow in Graham 293 cells, a cell line transformed by adenovirus type 5. 104 Viruses can then be identified using one of the preceding methods or by use of restriction enzyme analysis. No specific therapy is available for EA gastroenteritis, so treatment is directed toward prevention and treatment of dehydration. Oral rehydration solutions are effective in treating diarrhea with mild and moderate dehydration, and severe dehydration may require use of intravenous fluids. Prevention of illness is currently not possible due to lack of understanding of risk factors for transmission. Attention to good hand washing when caring for ill persons seems reasonable. First identified in 1985, 105 picobirnaviruses (PBVs) have since been detected in a variety of animals. [106] [107] [108] [109] [110] [111] The virus has since been detected in human fecal specimens from patients with and without diarrhea, 59, [112] [113] [114] [115] but has been associated with disease only in a study of HIV-infected adults in the United States 59 and Argentina. 116 Picobirnaviruses are small (pico), bisegmented (bi-RNA) viruses that are members of the family Birnaviridae. Atypical picobirnaviruses have been detected with three segments of RNA. 112 On electron miscroscopy, the virus is a 35-nm, discreet virus with no distinctive surface structure. Little is known about the distribution or incidence of picobirnaviruses. In two studies, PBVs have been detected from diarrheic stools of adults with coexistent Cryptosporidium infection, and in one study, HIV-infected patients with chronic diarrhea excreted the virus for seven months. 59, 113 The geographic or temporal distribution of picobirnaviruses is unknown, although viruses have been isolated from humans in several countries. No serologic immune response, measured by IEM, was detected in a group of adults with HIV, 59 although serum antibody has been detected by solid-phase IEM in infected rabbits. 110 Although PBVs may be seen by EM, the most sensitive and specific methods of detection involves identification of two segments of RNA by polyacrylamide electrophoresis from a stool specimen. 59 Coronaviruses were first reported in association with diarrhea in adults 117 and tropical sprue among children and adults in India in 1975. 118 While subsequent reports documented detection of coronavirus-like particles (CVLPs) in stools of persons with diarrhea, they could not associate CVLPs with diarrhea. 119, 120 Coronoviruses are pleomorphic, 60 to 200 nm, ssRNA viruses that belong to the family Coronaviridae. Because of their pleomorphic appearance, misdiagnosis is problematic and no confirmatory test is available. Consequently, the prevalence of human enteric coronaviruses (HECVs) is unknown, and while they have been detected in studies in several countries, 16, 24, 45, 62, [121] [122] [123] [124] [125] [126] [127] [128] [129] they are not clearly associated with disease. In studies that have compared rates of HECV detection in stools from patients with diarrhea versus controls, the results are mixed. Because of the long duration of shedding and the possibility for asymptomatic infection, the pathogenicity of HECVs may be difficult to prove by comparing rates of detection between well and ill persons. Many studies have reported the majority of viral detections among young children and infants, 24, 121, [126] [127] [128] 130 but detections among adults are common. 24, 84, 119, 127, 131 With some exceptions, 45, 126, 130 most studies have reported no differences in detection by time of year. 127 Mode of spread of HECVs is unknown. Illness descriptions from outbreaks thought to be associated with coronaviruses have included the occurrence of vomiting and diarrhea of short duration, often accompanied by fever. 117, 130 Besides gastroenteritis, HECVs have been reported in association with other gastrointestinal diseases including necrotizing enterocolitis, 132, 133 and neonatal diarrhea 122 in infants, and tropical sprue. 118, 134 In several reports of clinical signs and symptoms associated with the new severe acute respiratory syndrome (SARS)-associated coronavirus, diarrhea has been a common symptom, reported in around a quarter of patients 135, 136 It is not clear whether patients with the SARS coronavirus can have diarrhea without respiratory symptoms. HECVs may be identified with EM by their distinctive 20-nm, clublike projections. 137 Enteric coronaviruses are distinct from respiratory coronaviruses and do not cross-react by enzyme-linked immunosorbent assay (ELISA) or immunoblots, although there is cross-reactivity on IEM. 129 Toroviruses are members of the family Coronaviridae and the genus Torovirus. They are pleomorphic, 100-to 150-nm, ssRNA viruses with 20-nm, clublike projections extending from the capsid. [138] [139] [140] The epidemiology of these infections remains unclear. Toroviruses have been detected in stools of children and adults with diarrhea in developed countries. 49, [140] [141] [142] However, in these studies there was no epidemiologic association with illness, and the detections could not be confirmed using additional tests. In an EM survey of diarrhea among children in Toronto, torovirus-like particles were detected in 224 (8%) of 3800 stool specimens. The particles in some of these stools were later confirmed as torovirus by an ELISA incorporating bovine and human antibodies. 143 A serum response to infection can be measured in infected cows, which develop IgM and IgG following gastrointestinal infection, 144 but no serum immune response has been reported in humans. Electron microscopists can identify torovirus-like particles in human specimens but cannot confirm the detection. 145 Several additional methods including ELISA, 144, 146 cDNA probes for hybridization, 142 and RT-PCR 143 have been used successfully in animals and hold promise for detection of human disease. A variety of other viruses have been implicated in gastroenteritis to some degree including parvoviruses, enteroviruses, reoviruses, and pestiviruses, and have been reviewed in detail elsewhere. Parvoviruses, reoviruses, and pestiviruses may cause diarrhea in nonhumans, and there are reports of human cases of gastrointestinal illnesses. [147] [148] [149] [150] [151] [152] [153] However, the data are inconclusive, and they are not currently thought to be causes of gastroenteritis in humans. The global burden of dehydrating disease The global burden of diarrhoeal disease Virus particles in epithelial cells of duodenal mucosa from children with viral gastroenteritis Visualization by immune electron microscopy of a 27 nm particle associated with acute infectious nonbacterial gastroenteritis Virus-like particles in winter vomiting disease Growth and characterisation of human faecal astrovirus in a continuous cell line RNA sequence of astrovirus: Distinctive genomic organization and a putative retrovirus-like ribosomal frameshifting signal that directs the viral replicase synthesis Analysis of astrovirus serotype 1 RNA, identification of the viral RNA-dependent RNA polymerase motif, and expression of a viral structural protein The complete sequence of a human astrovirus Diagnosis of astrovirus gastroenteritis by antigen detection with monoclonal antibodies Antigenic characterization of cell-cultivated serotypes and development of astrovirusspecific monoclonal antibodies Direct serotyping of human rotavirus in stools using serotype 1-, 2-, 3-, and 4-specific monoclonal antibodies to VP7 Detection of human astrovirus serotype 1 by the polymerase chain reaction Subgenomic RNA sequence of human astrovirus supports classification of Astroviridae as a new family of RNA viruses Typing of human astroviruses from clinical isolates by enzyme immunoassay and nucleotide sequencing Prevalence of human astrovirus serotypes in the Oxford region 1976-1992, with evidence for two new serotypes Identification of adenoviruses in faeces from patients with diarrhoea at the Hospitals for Sick Children A prospective casecontrol study of the role of astrovirus in acute diarrhea among hospitalized young children Prevalence of human astrovirus serotype 4: Capsid protein sequence and comparison with other strains Detection and characterization of human astroviruses in children with acute gastroenteritis in Blantyre, Malawai A prospective study of astrovirus diarrhea of infancy in Mexico City Astrovirus and adenovirus associated with diarrhea in children in day care settings Electron microscopic reporting of gastrointestinal viruses in the United Kingdom, 1985-87 Outbreaks of astrovirus gastroenteritis in day care centers Astrovirus associated gastroenteritis in a children' s ward Stool viruses in babies in Glasgow: 1. Hospital admissions with diarrhoea Potential spectrum of etiological agents of viral enteritis in hospitalized infants Astroviruses as a cause of nosocomial outbreaks of infant diarrhea The frequency of astrovirus as a cause of diarrhea in Baltimore children Comparative epidemiology of rotavirus, subgenus F (Types 40 and 41) adenovirus, and astrovirus gastroenteritis in children Population-based prevalence of symptomatic and asmptomatic astrovirus infection in rural Mayan infants Characterization and seroepidemiology of a type 5 astrovirus associated with an outbreak of gastroenteritis in Marin County, California Astrovirus-associated diarreha in South African Adults Astrovirus infection in volunteers A large outbreak of acute gastroenteritis associated with astrovirus among students and teachers in Osaka Astrovirus-associated epidemic gastroenteritis in Japan An outbreak of gastroenteritis in a home for the elderly associated with astrovirus type 1 and human calicivirus Outbreaks of astrovirus type 1 and rotavirus gastroenteritis in a geriatric in-patient population A 27-nm virus isolated during an outbreak of acute infectious nonbacterial gastroenteritis in a convalescent hospital: A possible new serotype Astroviruses as a cause of nosocomial outbreaks of infant diarrhea Detection of astrovirus in pediatric stool samples by immunoassay and RNA probe A three-year diagnostic and epidemiological study on viral infantile diarrhoea in Rome Astroviruses as a cause of gastroenteritis in children Viruses in acute gastroenteritis in children in Pune Astrovirus-associated diarrhea among Guatemalan ambulatory rural children Viral gastro-enteritis in children in Malawi Viral agents associated with infantile gastroenteritis in Nigeria: Relative prevalence of adenovirus serotypes 40 and 41, astrovirus, and rotavirus serotypes 1 to 4 Etiology of communityacquired pediatric viral diarrhea: a prospective longitudinal study in hospitals, emergency departments, pediatric practices and child care centers during the winter rotavirus outbreak Astrovirus infection in association with acute persistent and nosocomial diarrhea in Bangladesh Virologic features of an astrovirus diarrhea outbreak in a day care center revealed by reverse transcription-polymerase chain reaction An outbreak of gastroenteritis associated with astrovirus serotype 1 in a day care center in Rio de Janeiro Astrovirus-associated gastroenteritis in children The incidence of viralassociated diarrhea after admission to a pediatric hospital Intrafamilial outbreak of astrovirus gastroenteritis in Sao Paulo, Brazil Astrovirus, adenovirus, and rotavirus in hospitalized children: prevalence and association with gastroenteritis Astrovirus survival in drinking water Clinical associations of stool astrovirus in childhood Enteric viruses and diarrhea in HIV-infected patients Etiology and outcome of diarrhea after marrow transplantation: A prospective study Application of electronmicroscopy, enzyme immunoassay, and RT-PCR to monitor an outbreak of astrovirus type 1 in a paediatric bone marrow transplant unit Six-year retrospective surveillance of gastroenteritis viruses indentified at ten electron microscopy centers in the U.S. and Canada 28 nm particles in faeces in infantile gastroenteritis Astrovirus as a cause of gastroenteritis in Japan The changing epidemiology of astrovirus-associated gastroenteritis: a review Characteristics of noncultivable adenoviruses associated with diarrhea in infants: a new subgroup of human adenoviruses Candidate adenoviruses 40 and 41: Fastidious adenoviruses from human infant stool Adenovirus types 40 and 41 and rotaviruses associated with diarrhea in children from Guatemala Antibodies to fastidious faecal adenoviruses (species 40 and 41) sera from children Infection by enteric adenoviruses, rotaviruses, and other agents in a rural African environment Importance of enteric adenoviruses 40 and 41 in acute gastroenteritis in infants and young children Enteric adenovirus infection and childhood diarrhea: an epidemiologic study in three clinical settings Importance of rotavirus and adenovirus types 40 and 41 in acute gastroenteritis in Korean children Incidence of enteric adenoviruses among children in Thailand and the significance of these viruses in gastroenteritis Clinical features of adenovirus enteritis: A review of 127 cases Enteric adenovirus infection among infants with diarrhea in rural Bangladesh Gastroenteritis associated with enteric type adenovirus in hospitalized infants An outbreak of gastroenteritis in young children caused by adenoviruses Incidence of enteric adenovirus gastroenteritis in Iranian children Prevalence of enteric adenovirus from acute gastroenteritis: A five year study Adenovirus colitis in the acquired immunodeficiency syndrome Adenoviruses from patients with AIDS: A plethora of serotypes and a description of five new serotypes of subgenus D (types 43-47) Gastrointestinal infections in AIDS Enteric viral infections as a cause of diarrhoea in the acquired immunodeficiency syndrome Disseminated adenovirus infection with hepatic necrosis in patients with human immunodeficiency virus infection and other immunodeficiency states Infectious gastroenteritis in bone-marrow transplant recipients Intestinal damage in rotavirus and adenovirus gatroenteritis assessed by D-xylose malabsorption Patients with enteric adenovirus gastroenteritis admitted to an Australian teaching hospital from 1981 to 1992 Centers for Disease Control: Viral agents of gastroenteritis: Public health importance and outbreak management Clinical features of acute gastroenteritis associated with rotavirus, enteric adenoviruses, and bacteria Outbreak of infantile gastroenteritis due to type 40 adenovirus Antibody response to enteric adenovirus types 40 and 41 in sera from people in various age groups Previous enteric adenovirus infection does not protect against subsequent symptomatic infection: Longitudinal follow-up of eight infants Rapid presumptive recognition of diarrhea-associated adenoviruses Adenovirus in faeces of children with acute gastroenteritis in Rio de Janeiro, Brazil Detection of adenovirus types 40 and 41 in stool specimens by immune electron microscopy Solid-phase immune electron microscopy (SPIEM) by use of protein A and its application for characterization of selected adenovirus serotypes Evaluation of a commercial monoclonal antibody-based enzyme immunoassay for detection of adenovirus types 40 and 41 in stool specimens Monoclonal antibody enzyme-linked immunosorbent assay for specific identification and typing of subgroup F adenoviruses Direct identification of enteric adenovirus, a candidate new serotype, associated with infantile gastroenteritis Antigen detection with monoclonal antibodies for the diagnosis of adenovirus gastroenteritis Evaluation of a commercial monoclonal antibody for detection of adenovirus antigen Compmarison of detection methods for adenovirus from enteric clinical specimens Propagation and in vitro studies of previously non-cultivatable enteral adenoviruses in 293 cells A virus with bisegmented double-stranded RNA genome in rat (Oryzomys nigripes) intestines A virus with bisegmented double-stranded RNA genome in guinea pig intestines Viruses with bisegmented double-stranded RNA in pig faeces Porcine picobirnavirus in UK? Veterin Record Bovine birna type virus: A new etiological agent of neonatal calf diarrhoea? Detection and characterization of a novel bisegmented double-stranded RNA virus (picobirnavirus) from rabbit faeces A novel avian virus with trisegmented double-stranded RNA and further observations on previously described similar viruses with bisegmented genome Identification of viruses with bi-and trisegmented double-stranded RNA genome in faeces of children with gastroenteritis Detection of picobirnavirus associated with Cryptosporidium positive stools from humans Novel viruses in human feces Sequence heterogeneity among human picobirnaviruses detected in a gastroenteritis outbreak Diarrhea and enteric emerging viruses in HIV-infected patients Coronavirus particles in faeces from patients with gastroenteritis (letter) Pleomorphic virus-like particles in human faeces The human enteric coronaviruses Human enteric coronaviruses Rotavirus and coronavirus-like particles in aboriginal and non-aboriginal neonates in Kalgoorlie and Alice Springs Pleomorphic, enveloped, virus-like particles associated with gastrointestinal illness in neonates A finding of coronavirus particles in feces of patients with diarrhea Coronavirus-like particles and other agents in the faeces of children in Efate, Vanuatu Fecal rotaviruses, adenoviruses, coronavirus-like particles, and small round viruses in a cohort of rural Costa Rican children Human-enteric-coronavirus-like particles (CVLP) with differnet epidemiological characteristics An eight-year study of the viral agents of acute gastroenteritis in humans: Ultrastructural observations and seasonal distribution with a major emphasis on coronavirus-like particles Shedding of coronavirus-like particles by children in Lesotho Coronaviruses and gastroenteritis: Evidence of antigenic relatedness between human enteric coronavirus strains and human coronavirus OC43 Coronavirus-like particles in human gastrointestinal disease Identification of astrovirus serotypes from children treated at the Hospitals for Sick Children, London 1981-93 Association of coronavirus-like infection with neonatal necrotizing enterocolitis Intestinal lesions containing coronavirus-like particles in neonatal necrotizing enterocolitis: an ultrastructural analysis Chronic enterocyte infection with coronavirus: One possible cause of the syndrome of tropical sprue? A major outbreak of severe acute respiratory syndrome in Hong Kong Clinical manifestations, laboratory findings and treatment outcomes of SAS patients Coronaviridae: The viruses and their replication The proposed family Toroviridae: Agents of enteric infections Toroviruses of animals and humans (a review) Association of torovirus with acute and persistent diarrhea in children An enveloped virus in stools of children and adults with gastroenteritis that resembles the Breda virus of calves cDNA probes for the detection of bovine torovirus (Breda virus) infections Enzyme-linked immunosorbent assay reactivity of torovirus-like particles in fecal specimens from humans with diarrhea Seroepidemiology of Breda virus in cattle using ELISA A morphologic study of the replication of Breda virus (proposed family Toroviridae) in bovine intestinal cells Detection of Breda virus antigen and antibody in humans and animals by enzyme immunoassay Viruses and gastroenteritis in infants (letter) Serotyping of human rotaviruses in Argentina by ELISA with monoclonal antibodies Small round viruses: Classification and role in foodborne infections Cytopathogenic enteric viruses associated with undifferentiated diarrheal syndromes in early childhood Enteropathogenic viruses and bacteria. Role in summer diarrheal diseases of infancy and early childhood An outbreak of infection with a type 1 reovirus among children in an institution Infantile gastroenteritis associated with excretion of pestivirus antigens