Sero-prevalence of Middle East respiratory syndrome coronavirus (MERS-CoV) specific antibodies in dromedary camels in Tabuk, Saudi Arabia.

The Middle East Respiratory Syndrome Coronavirus (MERS-CoV) is a novel Coronavirus which was responsible of the first case of human acute respiratory syndrome in the Kingdom of Saudi Arabia (KSA), 2012. Dromedary camels are considered as potential reservoirs for the virus and seem to be the only animal host which may transmit the infection to human. Further studies are required to better understand the animal sources of zoonotic transmission route and the risks of this infection. A primary sero-prevalence study of MERS-CoV preexisting neutralizing antibodies in Dromedary camel serum was conducted in Tabuk, western north region of KSA, in order to assess the seopositivity of these animals and to explain their possible role in the transmission of the infection to Human. One hundred seventy one (171) serum samples were collected from healthy dromedary camels with different ages and genders in Tabuk city and tested for specific serum IgG by ELISA using the receptor-binding S1 subunits of spike proteins of MERS-CoV. 144 (84,21%) of the total camel sera shown the presence of protein-specific antibodies against MERS-CoV. These results may provide evidence that MERS-CoV has previously infected dromedary camels in Tabuk and may support the possible role of camels in the human infection.

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

BACKGROUND: Decay 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. RESULTS: Infectivity 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. CONCLUSION: Within 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.

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

BACKGROUND: Viral 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. METHODS: This 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. RESULTS: Overall, 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. CONCLUSIONS: Our 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.

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 virus's strains detected previously in Tunisia. Further studies need to be conducted to evaluate the emergence of the virus's strains in clinical and water samples and more epidemiological data need to be collected about the risk factors which may contribute to acute hepatitis.

Hepatitis A in Tunisia: phylogenetic analysis of hepatitis A virus from 2001 to 2004.

Tunisia is a highly endemic area for hepatitis A virus (HAV) infection. In the present study, the phylogenetic characterization of the VP1 gene (882 nucleotides) and of the VP1/2A junction (336 nucleotides) of Tunisian strains were examined. One hundred strains isolated from patient with anti-HAV IgM from 2001 to 2004 were amplified by RT-PCR, sequenced at the VP1 and at the VP1/2A junction and aligned with the published sequences to establish phylogenetic analysis. All Tunisian strains belong to genotype I with a greater presence of sub-genotype IA (98%) originate from most of Tunisian regions and 2% of sub-genotype IB. In addition, sub-genotype IA and IB strains formed 25 different clusters. Genetically similar strains were also identified between 2001 and 2004 isolated from the southern and the central part of Tunisia, suggesting that an indigenous strain has been circulating in the Tunisia. The genetic profile of the VP1 region showed that Tun159-02 and Tun40-03 clustered respectively in the IB and IA sub-genotype, however, analysis of VP1/2A junction revealed in contrast that Tun159-02 and Tun40-03 clustered respectively in IA and IB. This is the first report to identify sub-genotype IA in Tunisia and provides new data on the genetic relatedness of HAV from Tunisia and the distribution of sub-genotype IA in this part of the world.

Direct typing of human enteroviruses from wastewater samples.

A RT-PCR approach for the direct detection and typing of human enteroviruses in the environment is described in this study. A semi-nested RT-PCR using COnsensus-DEgenerated Hybrid Oligonucleotide Primers (CODEHOP) designed from the VP2 genome region has been developed for the direct typing of enteroviruses in clinical samples (Ibrahim et al., 2013). This CODEHOP/VP2 PCR strategy as well as the CODEHOP/VP1 technique described by Nix et al. (2006), were tested for the detection and typing of enteroviruses in wastewater samples. Virus particles were first extracted and concentrated from wastewater samples by using respectively beef extract and polyethylene glycol 6000, and the presence of enteroviruses was screened by a RT-PCR method using primers from the 5'-end non-coding region (5'NCR). Fifty-two of 172 samples (30.2%) were revealed positive by the 5'NCR method. From these 52 samples, only 19 samples (36.5%) were found positive by at least one of the two CODEHOP techniques, with the following distribution: VP1(+)/VP2(+)=4 (7.7%), VP1(-)/VP2(+)=13 (25%) and VP1(+)/VP2(-)=2 (3.8%). These results illustrate that the direct typing of enteroviruses in environmental samples is insensitive, possibly due to the presence of large amounts of amplification inhibitors; however, the VP2 method was found able to allow the direct detection and typing of c. one-third of the positive environmental samples.

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

Coxsackieviruses B (CV­B) 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 CV­B 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 (RT­PCR) 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. CV­B was detected in 28 of the 102 patients. The sequence analysis demonstrated that 27 strains were identical to CV­B3 and only one strain was identical to CV­B1. Furthermore, VP1 in the heart biopsies was detected in enterovirus­positive cases, as revealed by RT­PCR. Pericarditis infection was more frequent than myocarditis (P<0.05) or myopericarditis (P=0.05). The epidemiological data demonstrate that CV­B 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 CV­B may significantly contribute to heart infections.

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.

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).

Genetic analysis of HAV strains in Tunisia reveals two new antigenic variants.

To evaluate the genetic variability of hepatitis A virus (HAV) isolates in Tunisia, serum samples were collected from 99 patients in different Tunisian areas in 2003 containing 92 cases with acute hepatitis, five with severe acute hepatitis and two with fulminant hepatitis. The entire VP1 gene was amplified and sequenced. Sequences were then aligned and a phylogenetic analysis was performed. Additionally, the amino acid (aa) sequence of the VP1 was determined. The analysis of Tunisian HAV isolates revealed that all the isolates were sub-genotype IA with 96.4%-99.8% of identity and showed the emergence of two novel antigenic variants. The Tun31-03 antigenic variant, with a 38 aa deletion containing Met156, Val171, Leu174 and Ala176 and located between 150 and 187 aa of the VP1 protein where neutralization escape mutations, was found. The second antigenic variant, Tun36-03, was isolated from a patient with fulminant hepatitis and presented a substitution of Thr by Pro at position 10 of the VP1 protein. This amino acid is located in a peptide presenting an antigenically reactive epitope of the VP1 protein. This substitution has never been described previously.

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 virus's strains detected previously in Tunisia. Further studies need to be conducted to evaluate the emergence of the virus's strains in clinical and water samples and more epidemiological data need to be collected about the risk factors which may contribute to acute hepatitis.

Coxsackievirus B3 replication and persistence in intestinal cells from mice infected orally and in the human CaCo-2 cell line.

Although the transmission of coxsackievirus B3 occurs mainly via the oral route, little is known about the primary replication and persistence of this agent in the intestine. To address this question, BALB/c mice were inoculated by gavage with coxsackievirus B3, Nancy strain. The mice were killed from 1 hr to 90 days after infection. The viral markers were detected in the small intestine using RT-PCR, cell culture and detection of VP1 protein. Coxsackievirus B3 was detected positive by the three methods from hr 2 to day 45 after infection. By using monoclonal antibodies directed towards VP1, CD40 and CD26, the virus was shown to be present in the lymphocytes of the mucosa as soon as 2 hr after infection; in contrast, no virus was detected in the epithelial cells lining the intestinal lumen. Further experiments were performed to evaluate the capacity of coxsackievirus B3 to establish a persistent infection in two intestinal cell lines. In contrast to HT29 cells, the CaCo-2 cells were shown to develop a persistent infection for up to 20 passages, as demonstrated by the detection of viral RNA and VP1 protein. This study provides further evidence that, after infection by the oral route, the viral particles are concentrated in the lymphocytes of the mucosal layer. In addition, the results suggest that coxsackievirus B3 is capable of establishing a persistent infection in the small intestine that may act as a reservoir of viral particles for the delayed spread of the virus to other target organs.

Detection of enterovirus in human skeletal muscle from patients with chronic inflammatory muscle disease or fibromyalgia and healthy subjects.

Enterovirus RNA has been found previously in specimens of muscle biopsy from patients with idiopathic dilated cardiomyopathy, chronic inflammatory muscle diseases, and fibromyalgia or chronic fatigue syndrome (fibromyalgia/chronic fatigue syndrome). These results suggest that skeletal muscle may host enteroviral persistent infection. To test this hypothesis, we investigated by reverse transcription-polymerase chain reaction (RT-PCR) assay the presence of enterovirus in skeletal muscle of patients with chronic inflammatory muscle diseases or fibromyalgia/chronic fatigue syndrome, and also of healthy subjects. Three of 15 (20%) patients with chronic inflammatory muscle diseases, 4 of 30 (13%) patients with fibromyalgia/chronic fatigue syndrome, and none of 29 healthy subjects was found positive. The presence of VP-1 enteroviral capsid protein was assessed by an immunostaining technique using the 5-D8/1 monoclonal antibody; no biopsy muscle from any patient or healthy subject was found positive. The presence of viral RNA in some muscle biopsies from patients exhibiting muscle disease, together with the absence of VP-1 protein, is in favor of a persistent infection involving defective viral replication.