Julie Brassard

Chronic hepatitis E infection in children with liver transplantation

Objective Chronic hepatitis E virus (HEV) infection has been described in immunosuppressed adult patients. A study was undertaken to establish the presence of HEV infection in children after orthotopic liver transplantation (OLT). Methods Children undergoing liver transplantation between 1992 and 2010 with available serum were classified into two groups: group 1 (control group, n=66) with normal serum aminotransferases and group 2 (n=14) with persistently increased serum aminotransferases and histological features of chronic hepatitis. Patients were tested for HEV RNA by reverse transcription-polymerase chain reaction (RT-PCR). HEV amplicons were sequenced and compared with published sequences. Antibody titres (IgG and IgM) to 12 HEV immunodominant regions were measured by enzyme-linked immunosorbent assays. Results In group 1 (control group), 15% of children were anti-HEV IgG-positive during follow-up. No anti-HEV IgM antibodies were detected in any of these children. After OLT, 86% of patients in group 2 had anti-HEV IgG compared with 36% pre-OLT. Thus, two-thirds of children acquired anti-HEV IgG after OLT. Seven anti-HEV IgG-positive patients (58%) were also anti-HEV IgM-positive more than once during follow-up after OLT. Eight years post-OLT, one girl presented with anti-HEV IgG and IgM that remained positive afterwards. In this patient, HEV RNA was found in five different annual samples from 10 years post-OLT, concomitantly with increased serum aminotransferases and cirrhosis development during that period. Phylogenetic analysis revealed two different HEV strains (detected 3 years apart) that were highly similar to swine genotype 3, suggesting a possible case of zoonotic re-infection. Conclusion The diagnosis of HEV infection is technically challenging and should be made simultaneously with RT-PCR methods, viral load quantification and serological markers. In immunosuppressed children who develop chronic hepatitis, the prevalence of HEV is high and could explain the chronic liver inflammation potentially leading to cirrhosis. Re-infection by different HEV strains from zoonotic transmission can result in progressive liver disease in immunocompromised children.

Detection of Human Food-Borne and Zoonotic Viruses on Irrigated, Field-Grown Strawberries

ABSTRACT This study evaluated the presence of pathogenic human and zoonotic viruses on irrigated, field-grown strawberries. Norovirus genogroup I, rotavirus, and swine hepatitis E virus genogroup 3 were detected on strawberries, and irrigation water is suspected as the contamination origin.

The feline calicivirus as a sample process control for the detection of food and waterborne RNA viruses.

Many food and waterborne outbreaks of infectious disease are caused by viruses. While numerous methods exist and are being developed to test food and water for the presence of enteric viruses, there is no standard control for the comparison of different methods. Potential control viruses should be well characterized, share the physical characteristics of the enterically infecting viruses and not normally be associated with foods. Here, the feline calicivirus (FCV) is proposed as a sample process control for methods aimed at the extraction and detection of RNA viruses in food and water. FCV is shown to be useful as a control for the extraction of hepatitis A virus (HAV) from water using filtration technology and from strawberries using the Pathatrix system. The FCV standard provides a valuable quality control tool when testing potentially contaminated food samples.

Cirrhosis due to Chronic Hepatitis E Infection in a Child Post-Bone Marrow Transplant

Chronic hepatitis E virus (HEV) infection occurs in immunosuppressed adults. We detected HEV ribonucleic acid in serum of an adolescent patient who had undergone bone marrow transplantation and subsequently presented with persistently increased aminotransferases and histologic chronic hepatitis, and eventually developed cirrhosis. Phylogenetic analysis revealed these HEV strains were similar to swine genotype 3a, suggesting a possible zoonosis.

Comparative analysis of different TaqMan real‐time RT‐PCR assays for the detection of swine Hepatitis E virus and integration of Feline calicivirus as internal control

Aims:  The aim of this study was to compare the performance of four TaqMan RT‐PCR assays with a commonly used nested RT‐PCR and to include the Feline calicivirus (FCV) as an internal control.

Acquisition of host plasmin activity by the Swine pathogen Streptococcus suis serotype 2.

ABSTRACT In this study, the plasminogen-binding activity of Streptococcus suis serotype 2 was investigated. Bound human plasminogen was activated by purified streptokinase, urokinase, or Streptococcus dysgalactiae subsp. equisimilis culture supernatant. Both human and porcine plasminogen were bound by S. suis. Binding was inhibited by ε-aminocaproic acid, and the plasminogen receptor was heat and sodium dodecyl sulfate resistant. One of the receptors was identified as glyceraldehyde-3-phosphate dehydrogenase. S. suis-associated plasmin activity was capable of activating free plasminogen, which in turn could contribute to degradation of fibronectin. This is the first report on the plasminogen-binding activity of S. suis. Further studies may reveal a contribution of this activity to the virulence of S. suis.

Development of a real‐time TaqMan PCR assay for the detection of porcine and bovine Torque teno virus

Aims:  The goal of this study was to develop and to optimize molecular tools to detect the presence of Torque teno virus (TTV) in swine and cattle. A novel real‐time polymerase chain reaction (PCR) using a TaqMan probe was developed to detect both genogroups of TTV strains.

Torque Teno Virus in Children Who Underwent Orthotopic Liver Transplantation: New Insights About a Common Pathogen

BACKGROUND  Torque Teno virus (TTV) is a ubiquitous infectious agent. Transplant recipients are at risk of hepatitis E virus (HEV) infection and could be vulnerable to TTV-associated adverse effects. The aim of this study was to evaluate the influence of immunosuppression and HEV infection on TTV replication and liver injury in pediatric patients after orthotopic liver transplantation (OLT). METHODS  Pediatric recipients of liver transplants were classified into the following 2 groups: (1) those with normal serum aminotransferases levels and (2) those with persistently increased serum aminotransferases levels and histological features of chronic hepatitis of unknown etiology. The TTV load was assessed in 342 serum samples by use of TaqMan real-time polymerase chain reaction, along with TTV genogroups and coinfection with HEV. RESULTS  TTV DNA was detected in 96% of tested serum samples. Viral load was significantly lower in patients with features of chronic hepatitis, of whom 78% had liver fibrosis scores of ≥2. Viral load decreased during posttransplantation follow-up. Viral load and genogroups were influenced by immunosuppression. Lower viral load was observed in patients coinfected with HEV. CONCLUSIONS  TTV infection is widespread, and its replication is closely related to immune status and viral coinfection. High TTV viremia is not associated with hepatitis after OLT, but, conversely, liver inflammatory activity impairs TTV replication.

Coherence among Different Microbial Source Tracking Markers in a Small Agricultural Stream with or without Livestock Exclusion Practices

ABSTRACT Over 1,400 water samples were collected biweekly over 6 years from an intermittent stream protected and unprotected from pasturing cattle. The samples were monitored for host-specific Bacteroidales markers, Cryptosporidium species/genotypes, viruses and coliphages associated with humans or animals, and bacterial zoonotic pathogens. Ruminant Bacteroidales markers did not increase within the restricted cattle access reach of the stream, whereas the ruminant Bacteroidales marker increased significantly in the unrestricted cattle access reach. Human Bacteroidales markers significantly increased downstream of homes where septic issues were documented. Wildlife Bacteroidales markers were detected downstream of the cattle exclusion practice where stream and riparian habitat was protected, but detections decreased after the unrestricted pasture, where the stream and riparian zone was unprotected from livestock. Detection of a large number of human viruses was shown to increase downstream of homes, and similar trends were observed for the human Bacteroidales marker. There was considerable interplay among biomarkers with stream flow, season, and the cattle exclusion practices. There were no to very weak associations with Bacteroidales markers and bacterial, viral, and parasitic pathogens. Overall, discrete sample-by-sample coherence among the different microbial source tracking markers that expressed a similar microbial source was minimal, but spatial trends were physically meaningful in terms of land use (e.g., beneficial management practice) effects on sources of fecal pollution.

Long-term monitoring of waterborne pathogens and microbial source tracking markers in paired agricultural watersheds under controlled and conventional tile drainage management.

ABSTRACT Surface waters from paired agricultural watersheds under controlled tile drainage (CTD) and uncontrolled tile drainage (UCTD) were monitored over 7 years in order to determine if there was an effect of CTD (imposed during the growing season) on occurrences and loadings of bacterial and viral pathogens, coliphages, and microbial source tracking markers. There were significantly lower occurrences of human, ruminant, and livestock (ruminant plus pig) Bacteroidales markers in the CTD watershed in relation to the UCTD watershed. As for pathogens, there were significantly lower occurrences of Salmonella spp. and Arcobacter spp. in the CTD watershed. There were no instances where there were significantly higher quantitative loadings of any microbial target in the CTD watershed, except for F-specific DNA (F-DNA) and F-RNA coliphages, perhaps as a result of fecal inputs from a hobby farm independent of the drainage practice treatments. There was lower loading of the ruminant marker in the CTD watershed in relation to the UCTD system, and results were significant at the level P = 0.06. The odds of Salmonella spp. occurring increased when a ruminant marker was present relative to when the ruminant marker was absent, yet for Arcobacter spp., the odds of this pathogen occurring significantly decreased when a ruminant marker was present relative to when the ruminant marker was absent (but increased when a wildlife marker was present relative to when the wildlife marker was absent). Interestingly, the odds of norovirus GII (associated with human and swine) occurring in water increased significantly when a ruminant marker was present relative to when a ruminant marker was absent. Overall, this study suggests that fecal pollution from tile-drained fields to stream could be reduced by CTD utilization.