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Biomedical subjects

Raymond Tellier

Publications and source records attributed to Raymond Tellier.

28 records · Page 2Linked to original sources

Molecular characterization of rotavirus strains from children in Toronto, Canada.

BACKGROUND: Rotaviruses are the most common agents of diarrheal illness of infants and young children. Gastroenteritis caused by rotaviruses is also more likely to be associated with severe dehydration compared to other viral gastroenteritis. OBJECTIVES: We determined the G-serotype of rotaviruses circulating in the Metro Toronto-Peel County region, during the 1997-1998 winter. STUDY DESIGN: Stool samples were collected in Metro Toronto-Peel county region from November 1, 1997 to June 30, 1998. Rotavirus presence was demonstrated by electron microscopy and ELISA. A reverse transcription-polymerase chain reaction (RT-PCR) assay for the amplification of the near-complete RHA segment 9 of rotavirus was developed and used to determine the G-serotype by sequencing and phylogenetic analysis. RESULTS: A total of 135 rotavirus isolates were used as templates for RT-PCR. Of these, four could not be amplified and one revealed a mixed infection. The G-serotypes could be unambiguously determined for the other isolates. Of these, 85 were of G-serotype 1, 41 of G2, 1 of G3, 1 of G4, and 2 of G9. CONCLUSION: Our RT-PCR assay enables unambiguous determination of the G-serotype. The overall relative incidence of G-serotypes in Toronto is similar to that of other developed countries. Serotype G9 was present at low levels in Toronto.

Antigens, Viral↗

Severe Acute Respiratory Syndrome (SARS) in a liver transplant recipient and guidelines for donor SARS screening.

Severe acute respiratory syndrome (SARS) is a recently described infectious entity with salient features of fever, headache and malaise, with rapid progression to pneumonitis. The etiology of SARS is likely a novel coronavirus. During the winter of 2003, an outbreak of SARS involving several hospitals occurred in Toronto, Canada. We describe a patient post liver transplant who contracted SARS and died during the outbreak, with subsequent infection of family and several health-care workers. A novel coronavirus was detected in respiratory specimens by PCR. Due to the potential severity of SARS in transplant recipients and the large number of cases of SARS in the community, in order to avoid transmission of SARS from a donor, we developed guidelines for SARS screening of organ donors. A screening tool based on potential hospital SARS exposure, clinical symptoms, and epidemiological exposure was used to stratify donors as high, intermediate or low risk for SARS. As SARS spreads throughout the world, it may become an increasingly significant problem for transplant patients and programs.

Aged↗

Detection and species-level identification of primate herpesviruses with a comprehensive PCR test for human herpesviruses.

A comprehensive assay for the identification of all eight human herpesviruses has been previously reported. This assay was extended to the detection and species-level identification of herpes B virus (Cercopithecine herpesvirus 1) and African green monkey cytomegalovirus (Cercopithecine herpesvirus 5), two herpesviruses of relevance to the clinical virology laboratory.

Animals↗

Children hospitalized with severe acute respiratory syndrome-related illness in Toronto.

OBJECTIVE: An outbreak of severe acute respiratory syndrome (SARS) occurred in the greater Toronto area between February and June 2003. We describe the clinical, laboratory, and epidemiologic features of children who were admitted to the Hospital for Sick Children, Toronto, with a presumptive diagnosis of suspect or probable SARS. METHODS: A prospective investigational study protocol was established for the management of children with a presumptive diagnosis of suspect or probable SARS. All were ultimately classified as having probable SARS, suspect SARS, or another cause on the basis of their epidemiologic exposure, clinical and radiologic features, and results of microbiologic investigations. RESULTS: Twenty-five children were included; 10 were classified as probable SARS and 5 were classified as suspect SARS, and in 10 another cause was identified. The exposure consisted of direct contact with at least 1 adult probable SARS case in 11 children, travel from a World Health Organization-designated affected area in Asia in 9 children, and presence in a Toronto area hospital in which secondary SARS spread had occurred in 5 children. The predominant clinical manifestations of probable cases were fever, cough, and rhinorrhea. With the exception of 1 teenager, none of the children developed respiratory distress or an oxygen requirement, and all made full recoveries. Mild focal alveolar infiltrates were the predominant chest radiograph abnormality. Lymphopenia; neutropenia; thrombocytopenia; and elevated alanine aminotransferase, aspartate aminotransferase, and creatine kinase were present in some cases. Nasopharyngeal swab specimens were negative for the SARS-associated coronavirus by an in-house reverse transcriptase-polymerase chain reaction in all 25 children. CONCLUSIONS: Our results indicate that SARS is a relatively mild and nonspecific respiratory illness in previously healthy young children. The presence of fever in conjunction with a SARS exposure history should prompt one to consider SARS as a possible diagnosis in children irrespective of the presence or absence of respiratory symptoms. Reverse-transcriptase polymerase chain reaction analysis of nasopharyngeal specimens seems to be of little utility for the diagnosis of SARS during the early symptomatic phase of this illness in young children.

Adolescent↗

Fulminant disseminated Varicella Zoster virus infection without skin involvement.

BACKGROUND: Varicella Zoster virus (VZV) infection is potentially very serious in bone marrow transplant recipients, and may manifest as a disseminated visceral infection. This condition is generally accompanied by a vesicular rash. OBJECTIVES: We review here a case of fulminant fatal disseminated VZV infection, not accompanied by skin involvement, and the laboratory approaches currently available to diagnose this disease. STUDY DESIGN: Post mortem tissue samples were subjected to histopathological examination, and tested for herpesviruses by electron microscopy and PCR. RESULTS: Intranuclear inclusions were noted by histological examination in the lungs, liver, kidneys and bone marrow. Particles with a herpesvirus morphology were visualized in liver tissue. VZV DNA was detected in liver and bone marrow by PCR followed by sequencing of the amplicons. Viremia was documented by retrospective testing of the serum by PCR. CONCLUSIONS: A disseminated VZV infection which proved rapidly fatal was demonstrated in a case without skin manifestations. This rare presentation of VZV infection is potentially underdiagnosed. Testing for VZV viremia by PCR can at the very least suggest the diagnosis although whether plasma-associated viremia is truly pathognomonic of visceral disseminated infection remains to be established.

Bone Marrow Transplantation↗

Characterization of hepatitis C virus quasispecies by matrix-assisted laser desorption ionization-time of flight (mass spectrometry) mutation detection.

Hepatitis C virus (HCV), the causative agent of hepatitis C, frequently causes chronic infection. The mechanisms of viral persistence continue to be the object of investigation. An important aspect of HCV chronic infection is the quasispecies nature of the viral population, which has been particularly well documented in the hypervariable region 1 of the E2 glycoprotein. Recent studies show that characterization of the quasispecies diversity at the amino acid level can help to predict the outcome of HCV infection. Currently the accurate characterization of HCV quasispecies requires the cloning of PCR products, followed by the sequencing of many clones. In this study we present a new method to characterize HCV quasispecies, based on in vitro translation of the amplicons, followed by mass spectrometry analysis of the resulting peptide mix. The assay was used on reference HCV samples and on clinical samples. In principle, this method could be applied to other chronic viral infections in which quasispecies play a role.

Child, Preschool↗

Mycoplasma pneumoniae pericarditis demonstrated by polymerase chain reaction and electron microscopy.

We report a case of pericarditis occurring in a 17-year-old girl who received a bone marrow transplant. The presence of Mycoplasma pneumoniae in the pericardial fluid was demonstrated by polymerase chain reaction, and Mycoplasma-like organisms were detected by electron microscopy. Because no other infectious agent could be found in the pericardial fluid, M. pneumoniae was presumed to be the etiologic agent of the pericarditis.

Adolescent↗