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At least 19 recordsLinked to original sources

Importance of a new virus in acute sporadic enteritis in children.

In a year-long survey of children admitted with acute enteritis to hospital in Melbourne, Australia, an aetiological agent was found in approximately 75% of patients. During most months of the year a newly described virus belonging to the family Reoviridae was detected by electron microscopy of faecal extracts from more than 50% of patients. Recovery of this virus reached a peak (73%) during the winter. All age-group up to five years of age were susceptible to infection, which was occasionally fatal. Duration of infection was brief, with a probable incubation period of less than two days. Infections acquired in hospital were not uncommon. The name of this new virus is not decided. The name "duovirus" is proposed rather than "rotavirus" as previously suggested. There is already convincing evidence that this new virus will prove to be the most important aetiological agent of sporadic acute enteritis in young children.

Acute Disease

Response of Erythrocebus patas monkeys to experimental infection with the orbivirus Orungo virus.

The response of Erythrocebus patas monkeys experimentally inoculated by the intravenous and subcutaneous routes with Orungo virus (family Reoviridae, genus Orbivirus) was studied with reference to development of clinical signs, circulation of virus and antibody response. None of the animals showed clinical disease nor did they circulate virus. However, all the animals developed complement fixing (CF), neutralizing (N) and agar gel (AG) precipitating antibodies between day seven and day 14 post infection (p.i.). The CF antibodies appeared earlier and lasted for a longer period than did the N antibodies. The presence of transient 2-mercaptoethanol (2-ME) sensitive CF antibodies was demonstrated in sera collected between day seven and day 14 p.i. The significance of these findings in the interpretation of serological surveys in man for Orungo virus antibody is discussed.

Animals

Isolation of reovirus-like agents from patients with Crohn's disease.

220 nm filtrates of intestinal resections from 6 of 10 patients with Crohn's disease produced a cytopathic effect in WI-38 tissue-culture monolayers, whereas controls had no effect. Characterisation of the virus responsible has been completed in 3 of the 6 positive isolates and indicates that it is an R.N.A. virus, 55-60 nm in diameter, heat, ether, and acid stable, and antigenically related to Nebraska calf-diarrhoea virus. It therefore belongs to the Reoviridae family.

Antigens, Viral

[Physicochemical properties of the Okhotsky virus].

Purified concentrated Okhotsky virus was prepared. The buoyant densities of its virions were determined in sucrose and cesium chloride gradients and found to be 1.16--1.18 and 1.36 g/cm3, respectively. The experimental evidence indicated the double-stranded nature of Okhotsky virus genome RNA. The study of the above physico-chemical properties confirmed the appurtenance of Okhotsky virus to the genus Orbivirus of the Reoviridae family.

Animals

Molecular Pathogenesis, Global Epidemiological Trends, and Treatment Strategies for Pteropine Orthoreoviruses: A Narrative Review.

Pteropine orthoreoviruses are emerging bat-borne zoonotic viruses of the genus Orthoreovirus (family Reoviridae), increasingly recognized as causes of acute respiratory disease in humans. Originally grouped with the largely non-pathogenic mammalian orthoreoviruses, they have challenged that view through their association with severe influenza-like illness, evidence of human-to-human transmission, and a broad geographic range across the Old World. Maintained primarily in fruit bats of the family Pteropodidae, they are now linked to neurological as well as respiratory disease. This narrative review synthesizes current knowledge of their molecular pathogenesis, zoonotic ecology, and global epidemiology, integrating recent advances in phylogeography, reassortment-driven evolution, spillover dynamics, and translational biomedical applications within a unified One Health framework. Genomic diversity, reassortment potential, and the unique fusion-associated small transmembrane proteins together underpin viral adaptability and pathogenicity. Major gaps nonetheless remain in transmission dynamics, host adaptation, shedding ecology, and pandemic potential. Future priorities should include integrated genomic surveillance, improved diagnostic strategies, validated experimental models, and interdisciplinary One Health approaches to strengthen outbreak preparedness and prevention.

Bat-borne viruses

Biochemical and biophysical characteristics of diarrhea viruses of human and calf origin.

Polyacrylamide gel electrophoretic analysis of purified preparations of human and calf diarrhea viruses indicated eight polypeptide components, or possibly nine in the case of the calf diarrhea virus. Thermal denaturation and analytical studies of the calf diarrhea virus genome showed it to consist of 11 double-stranded segments of RNA. The placing of the human and calf diarrhea viruses together with other similar viruses into a genus separate from reovirus and orbivirus, but within the family Reoviridae, is discussed.

Animals

Biophysical and biochemical characterization of five animal viruses with bisegmented double-stranded RNA genomes.

Infectious pancreatic necrosis virus of fish, infectious bursal disease virus of chickens, Tellina virus and oyster virus of bivalve molluscs, and drosophila X virus of Drosophila melanogaster are naked icosahedral viruses with an electron microscopic diameter of 58 to 60 nm. The genome of each of these viruses consists of two segments of double-stranded RNA (molecular weight range between 2.6 x 10(6) and 2.2 x 10(6), and the virion, capsid proteins fall into three size class categories (large, medium, and small; ranging from 100,000 to 27,000) as determined by polyacrylamide slab gel electrophoresis. The hydrodynamic properties of the five viruses are similar as determined by analytical ultracentrifugation and laser quasi-elastic, light-scattering spectroscopy. The calculated particle weights range between 55 x 10(6) and 81 x 10(6). Tryptic peptide comparisons of 125I-labeled virion proteins showed that five viruses are different from each other, although there was considerable overlap in the peptide maps of the three aquatic viruses, indicting a degree of relatedness. Cross-neutralization tests indicated that drosophila X, infectious pancreatic necrosis, and infectious bursal disease viruses were different from each other and from oyster and Tellina viruses. The same test showed oyster and Tellina viruses to be related. The biochemical and biophysical properties of the five viruses cannt be included in the family Reoviridae or in any of the present virus genera.

Animals

[Detection of an agent similar to rotavirus in infantile gastroenteritis].

The etiology of nonbacterial enterovirus infections in children was studied in autumn and winter under conditions of focal outbreaks in Moscow hospitals. Electron microscopy revealed a reovirus-like agent in concentrated suspensions of feces collected in the acute period of the disease from children suffering from diarrhea. Examinations of paired sera from the patients by the CF test with the antigen of Nebraska calf disease virus established significant rises in antibody titers in 68.3% of cases. The results permit a conclusion that in this country a virus of acute gastroenteritis of children (viral gastroenteritis A) is circulating, causing outbreaks of the disease. The virus belongs to the genus Rotavirus of the Reoviridae family.

Antibodies, Viral

Viruses and diarrhea--a review.

A critical analysis of the literature shows that only a few viral agents have been proved by accepted criteria to cause acute gastroenteritis. Rotavirus, of the RNA family reoviridae, is the cause of most childhood gastroenteritis. The parvovirus-like agents (Norwalk, Hawaii, MC, and W) are proved agents of epidemic gastroenteritis. There is good evidence that the Marcy, FS, and Niigata agents were the causes of gastroenteritis outbreaks. Thirty percent of all acute gastroenteritis episodes in large investigations are still etiologically unaccounted for. Much work remains to be done on define the pathogenesis and immunology of viral gastroenteritides.

Diarrhea

The Ornithodoros (Alectorobius) capensis group (Acarina: Ixodoidea: Argasidae) of the palearctic and oriental regions. O. (A.) coniceps identity, bird and mammal hosts, virus infections, and distribution in Europe, Africa, and Asia.

Ornithodoros (Alectorobius) coniceps (Canestrini 1890), which was briefly described from adult specimens from St. Mark's Cathedral, Venice, Italy, has been a confusing taxon. We redescribe and illustrate the adult and immature stages from St. Mark's Cathedral (topotypes) and elsewhere, list criteria to distinguish this species from others in the O. (A.) capensis complex, and provide data for 36 collections, chiefly from nest sites of wild and domestic pigeons in humid, rocky situations, and from a nest of the pallid swift, in Italy, France, Egypt, Kenya, Israel, Jordan, Afghanistan, Ukrainia, and Turkmenia. Other collections of small-sized adults and nymphs, lacking larvae, from pigeon, swallow, and swift nest in Nepal, India, and Sri Lanka, are tentatively assigned to this taxon. This is the only member of the O. (A.) capensis group not associated with marine or wading birds. Humans bitten by O. (A.) coniceps in buildings or caves may suffer from pain, edema, chills, and fever. BAku virus (Reoviridae) has been isolated from this tick in Uzbekistan, but most reports of other viruses and infectious agents are clouded by probable misidentification of O. (A.) maritimus as O. (A. coniceps. Published data on the life cycle and dynamics are reviewed briefly. Previously, this tick has not been reported from the Ethiopian Faunal Region (Kenya).

Africa

Classification of rotaviruses: report from the World Health Organization/Food and Agriculture Organization Comparative Virology Program.

The Reoviridae working team was established under the World Health Organization/Food and Agriculture Organization Comparative Virology Program in 1975. The generic name rotavirus has been adopted for the reovirus-like agents associated with diarrhea in man and animals, and the Nebraska calf diarrheal virus strain of bovine rotavirus has been selected as a candidate reference virus. Stocks of this virus and of gnotobiotic calf antiserum have been prepared. Antigenic differences among rotaviruses isolated from different species were recognized on the basis of virus-neutralization tests; a possible association between antigen specificity and variation in the RNA segments and structural proteins of rotaviruses was noticed.

Antigens, Viral

[Morphological virus diagnosis--electron microscopy study of animal viruses with negative contrast procedure].

Reported in this paper are results obtained in morphological virus diagnosis by using the negative contrast technique on the basis of electron microscopy. The availability of high-efficiency electron microscopy as well as of perfectly improved techniques of preparation, knowledge of the latest virus model concepts, and indivudual skills in diagnosis are essential conditions for the above approach. Parvoviridae, picornaviridae, and togaviridae are identifiable only in high particle concentrations and by group representation. Papovaviridae, adenoviridae, herpetoviridae, poxviridae, and reoviridae, on the other hand, can be safely identified even as single particles. The diagnosis of orthomyxoviridae, paramyxoviridae, rhabdoviridae, and retroviridae is facilitated by their own dimensions and their characteristic helico-symmmetrical nucleocapside. Coronaviridae are of highly conspicuous morphology but, nevertheless, pose problems in differential diagnosis. Substantive improvement of morphological virus diagnosis, in terms of minute details, may be achieved by means of the negative contrast method on the basis of immune electron microscopy. Advantages implied in that morphological method include less time-consuming and quite uninvolved practicability and good dependability of diagnosis for more efficient decision-making in research and practice.

Animals

Viruses associated with acute gastroenteritis in young children.

Conventional virologic investigations generally failed to implicate viruses as a cause of acute gastroenteritis in young children. When negative-contrast stain electron microscopy was used for the examination of stool samples from affected patients, several candidate etiologic agents were discovered. Rotavirus (otherwise known as orbivirus, reo-like agent, and infantile gastroenteritis virus) emerged as an important causative agent. In a considerable number of patients, however, no causative agent was identified. Several other candidate etiologic viruses now "stand in the wings" awaiting additional evidence as to their role in the pathogenesis of acute gastroenteritis. In a study period of 12 months, 669 patients were found to be shedding virus in association with symptoms of diarrhea, vomiting, and temperature elevation. Approximately one third of these patients acquired their infection in hospital.

Acute Disease

Human reovirus-like agent infection. Occurrence in adult contacts of pediatric patients with gastroenteritis.

Sixty-four adult family contacts of 61 young patients with gastroenteritis were included in a study for evidence of concurrent infection with the human reovirus-like agent (HRVLA) of infantile diarrhea. Evidence of infection was detected in 26 (41%) of the adult contacts. The HRVLA infection occurred significantly more often among adult contacts of pediatric patients infected with HRVLA (55%) than among contacts of young patients not infected with the agent (17%). Mild cases of gastroenteritis developed in only three of the contacts infected with HRVLA.

Adolescent

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.

Acute Disease

Pathogenic rotaviruses isolated from pigs and calves.

Rotavirus is commonly isolated from diarrhoeic calves and pigs. Bacterium-free faecal filtrates containing rotavirus from five different outbreaks of disease in calves all caused diarrhoea and clinical illness in gnotobiotic calves and five different isolates from pigs were inoculated into gnotobiotic pigs with similar results. The author was unsuccessful in finding an avirulent strain although one of the calf isolates was from a non-diarrhoeic calf. The laboratory strain of calf virus retained its virulence after being passaged seven times in gnotobiotic calves, which included sucrose density gradient purification on two occasions. The calf tissue culture-adapted virus retained its virulence. Rotavirus isolates from humans, calves, pigs and foals were infectious to pigs. Although sharing a common antigen the viruses were separable according to host infectivity, virulence and neutralizing antigens. In both calves and pigs the main lesion was loss of the epithelial cell of the small intestine and stunting of villi. Passive protection of the calf and pig was poor. Circulating antibody was not protective and although high levels of clolostral antibody in the gut lumen at the time of infection protected calves clinically, the antibody level secreted in milk declined 10-fold 48 hours after parturition. Frequently other viruses are found together with rotavirus in cases of diarrhoea. Their role is being investigated.

Animals

Recent advances in the aetiology of viral gastroenteritis.

Studies with the human reovirus-like (HRVL) agnet, also designated rotavirus and duovirus, have revealed that it is a major aetiological agent of diarrhoea of infants and young children in many parts of the world. In a study of patients admitted with a diarrhoeal illness to the Children's Hospital of the District of Columbia in the United States from January 1974 to June 1975, it was found that half of the patients studied by both virus shedding (by electron microscopy) and serological (complement-fixation) techniques demonstrated evidence of infection with the HRVL agent. The temporal distribution of infections with the HRVL agent followed a seasonal pattern with this agent being shed exclusively by patients admitted during the cooler months of the year. Electron microscopic examination of stools was as efficient as serological methods for detecting infection with the HRVL agent. We also initiated studies to determine the possible mode of transmission of the HRVL agent by studying contacts of hospitalized patients. We found that 35% parents of patients with HRVL infections were also infected with the HRVL agent. Serological studies revealed that the HRVL agent was antigenically related to the Nebraska Calf Diarrhoea Virus, the epizootic diarrhoea of infant mice virus, the SA-11 virus, and the "O" agent.

Animals

Ultrastructural study of avian synovium infected with an arthrotropic reovirus.

Three-week-old chicks were inoculated via the foot pad with the avian reovirus (strain WVU 2937) that has been proved to be the causative agent in avian viral arthritis. The initial stages of the avian reovirus infection in the synovium of the hock joint were studied by transmission electron microscopy to shed light on the early virus-host relationship of an arthrotropic virus and synovial tissue. At 48 hours postinoculation (PI), coated, partially coated, and uncoated virus particles were seen in a dense lysosome-like inclusion in the cytoplasm of subsynovial fibroblasts. Virus replication was demonstrated in fibroblasts of the subsynovium 4 days PI. Infiltration of leukocytes into the area of the virus replication was noted at the time of virus replication (4 days PI). By the second week of the infection (11 days PI), the subsynovium was heavily infiltrated with lymphocytes and plasma cells, and proliferative changes had occurred in the synovial lining cells.

Animals