Rafik Harrath

Sudden unexpected death related to enterovirus myocarditis: histopathology, immunohistochemistry and molecular pathology diagnosis at post-mortem

BackgroundViral myocarditis is a major cause of sudden unexpected death in children and young adults. Until recently, coxsackievirus B3 (CVB3) has been the most commonly implicated virus in myocarditis. At present, no standard diagnosis is generally accepted due to the insensitivity of traditional diagnostic tests. This has prompted health professionals to seek new diagnostic approaches, which resulted in the emergence of new molecular pathological tests and a more detailed immunohistochemical and histopathological analysis. When supplemented with immunohistochemistry and molecular pathology, conventional histopathology may provide important clues regarding myocarditis underlying etiology.MethodsThis study is based on post-mortem samples from sudden unexpected death victims and controls who were investigated prospectively. Immunohistochemical investigations for the detection of the enteroviral capsid protein VP1 and the characterization and quantification of myocardial inflammatory reactions as well as molecular pathological methods for enteroviral genome detection were performed.ResultsOverall, 48 sudden unexpected death victims were enrolled. As for controls, 37 cases of unnatural traffic accident victims were studied. Enterovirus was detected in 6 sudden unexpected death cases (12.5 %). The control samples were completely enterovirus negative. Furthermore, the enteroviral capsid protein VP1 in the myocardium was detected in enterovirus-positive cases revealed by means of reverse transcriptase-polymerase chain reaction (RT-PCR). Unlike control samples, immunohistochemical investigations showed a significant presence of T and B lymphocytes in sudden unexpected death victims.ConclusionsOur findings demonstrate clearly a higher prevalence of viral myocarditis in cases of sudden unexpected death compared to control subjects, suggesting that coxsackie B enterovirus may contribute to myocarditis pathogenesis significantly.

Coxsackievirus B detection in cases of myocarditis, myopericarditis, pericarditis and dilated cardiomyopathy in hospitalized patients

Coxsackieviruses B (CV-B) are known as the most common viral cause of human heart infections. The aim of the present study was to assess the potential role of CV-B in the etiology of infectious heart disease in hospitalized patients. The present study is based on blood, pericardial fluid and heart biopsies from 102 patients and 100 control subjects. All of the samples were examined for the detection of specific enteroviral genome using the reverse transcription polymerase chain reaction (RT-PCR) and sequence analysis. Immunohistochemical investigations for the detection of the enteroviral capsid protein, VP1, from the biopsies were performed. The samples were cultured on confluent KB monolayer cell line for possible virus isolation. The epidemiological data were also collected. CV-B was detected in 28 of the 102 patients. The sequence analysis demonstrated that 27 strains were identical to CV-B3 and only one strain was identical to CV-B1. Furthermore, VP1 in the heart biopsies was detected in enterovirus-positive cases, as revealed by RT-PCR. Pericarditis infection was more frequent than myocarditis (P<0.05) or myopericarditis (P=0.05). The epidemiological data demonstrate that CV-B heart infections occur mainly during autumn and winter, and young male adults are more susceptible than adolescents or adults (P<0.5). The present findings demonstrate a higher prevalence of viral heart infections, suggesting that CV-B may significantly contribute to heart infections.

Prevalence of IgG antibodies against West Nile virus in blood donors during the 2003 outbreak in Tunisia

This study aimed to evaluate the prevalence of anti-West Nile virus (WNV) IgG among two populations of Tunisian blood donors living in areas where human outbreaks of WNV have occurred. Cohorts A (Monastir) and B (Mahdia) included 742 and 102 blood donors respectively. Sera were tested by IgG ELISA test and results were confirmed by PRNT test. WNV neutralizing antibodies were detected in 32 (4.3%) and in 14 (13.7%) sera in cohorts A and B respectively. The prevalence of anti-WNV IgG was significantly higher in cohort B than in cohort A (P<0.001) and was significantly lower in females than in males (P<0.001).

Study of Coxsackie B viruses interactions with Coxsackie Adenovirus receptor and Decay-Accelerating Factor using Human CaCo-2 cell line

BackgroundDecay Accelerating Factor (DAF) and Coxsackievirus-Adenovirus Receptor (CAR) have been identified as cellular receptors for Coxsackie B viruses (CV-B). The aim of this study is to elucidate the different binding properties of CV-B serotypes and to find out if there are any amino acid changes that could be associated to the different phenotypes.Twenty clinical CV-B isolates were tested on CaCo-2 cell line using anti-DAF (BRIC216) and anti-CAR (RmcB) antibodies. CV-B3 Nancy prototype strain and a recombinant strain (Rec, CV-B3/B4) were tested in parallel. The P1 genomic region of 12 CV-B isolates from different serotypes was sequenced and the Trans-Epithelial Electrical Resistance (TEER) along with the virus growth cycle was measured.ResultsInfectivity assays revealed clear differences between CV-B isolates with regard to their interactions with DAF and CAR. All tested CV-B isolates showed an absolute requirement for CAR but varied in their binding to DAF. We also reported that for some isolates of CV-B, DAF attachment was not adapted. Genetic analysis of the P1 region detected multiple differences in the deduced amino acid sequences.ConclusionWithin a given serotype, variations exist in the capacity of virus isolates to bind to specific receptors, and variants with different additional ligands may arise during infection in humans as well as in tissue culture.

Seroprevalence and Molecular Characterisation of Human Hepatitis A virus in Serum Samples of Tunisian Patients with Clinical Symptoms of Viral Hepatitis

The aim of the present study was to investigate the seroprevalence of Hepatitis A virus antibodies in patients with clinical symptoms of viral hepatitis and molecular characterization of the detected isolates. The present study deals with the seroprevalence and the genetic diversity of HAV in 400 Tunisian patients presenting in dispensaries (160 patients) and in University Hospitals (240 patients) with hepatitis symptoms between 2006 and 2008. The patients with acute hepatitis were mainly from rural regions. However, the total number of patients was decreased over time. The collected samples were from patients with hepatitis symptoms occurring mainly during January–March (36.7, 26, and 35.5%) and September–December (39.4, 43.4, and 35.5%) during the three years of study, respectively. However, HAV infection was established for only 110 among 400 patients. The detected isolates were clustered within sub-genotype IA. The present study constituted another report of the continued surveillance of HAV infection in the region of Monastir and the molecular characterisation of the detected strains.

Coxsackie B3 myocarditis in a case of sudden unexpected death in young athlete: Histopathological, immunohistochemical and molecularpathological for diagnosis

Virus-induced myocarditis is a common disease even in infants and young adults, but the diagnosis can be difficult according to the Dallas-criteria, which have been criticized as being too unreliable. The diagnosis has been substantially improved due to immunohistochemistry (IHC) for the detection of the VP1-capsid-protein of enterovirus as well as reversetranscriptase-polymerase chain reaction assays (RT-PCR) for viral genome detection. We report an unusual case of myocarditis in a young adult athlete whose heart disease was not clinically recognized and, thus, caused his sudden unexpected death (SUD). Histopathological investigations of heart tissue samples revealed signs of myocarditis. IHC was used to detect the VP1-capsid-protein of enterovirus. RT-PCR assays were used to detect enterovirus RNA. Enterovirus myocarditis was determined as a cause of death.

Characterization of outbreak hepatitis a isolates in five Tunisian childcare centers

In the present study, epidemiological survey and molecular characterization of hepatitis A virus during an outbreak in five Tunisian childcare centers in El-Mahres during October and November 2006 were carried out. Five well-water and five drinking water samples were included in the present study. Serological investigation and molecular characterization were carried out. All patients were IgM seropositive and the viral genome was detected in all clinical and well-water samples whereas it was not detected in drinking water from the five childcare centers. Sequence analysis showed that all Tunisian strains belong to sub-genotype IA. The genetic profile of the VP1/2A junction showed that the outbreak isolates underwent an amino acid substitution which was absent in viruss strains detected previously in Tunisia. Further studies need to be conducted to evaluate the emergence of the viruss strains in clinical and water samples and more epidemiological data need to be collected about the risk factors which may contribute to acute hepatitis.