Status of global virologic surveillance for rubella viruses.

The suspected measles case definition captures rubella cases. Therefore, measles surveillance will be improved in the course of the control and eventual elimination of rubella transmission. One aspect of rubella control, virologic surveillance, is reviewed here. A systematic nomenclature for rubella viruses (RVs) based on 13 genotypes has been established and is updated when warranted by increases in information about RVs. From 2005 through 2010, the genotypes of RVs most frequently reported were 1E, 1G, and 2B, and genotypes 1a, 1B, 1C, 1h, 1j, and 2C were less frequently reported. Virologic surveillance can support rubella control and elimination. Synopses of rubella virologic surveillance in various countries, regions, and globally are given, including characterization of viruses from imported cases in a country that has eliminated rubella and studies of endemic viruses circulating in countries without rubella control objectives. Current challenges are discussed.

Update on molecular characterization of coxsackievirus B5 strains.

Among Coxsackie B viruses, Coxsckievirus B5 is one of the most predominant serotypes in human, it is frequently associated with cases of neurological diseases, epidemics of meningitis and is a common cause of cardiomyopathy and diabetes. In the present study 27 isolates of Coxsackievirus B5 from North Africa, obtained from cerebrospinal fluid and stool samples of healthy individuals, patients with acute flaccid paralysis or aseptic meningitis were investigated by partial sequencing in the 5' half of the VP1 region and compared to the up-to-date published Coxsackievirus B5 sequences in the same genomic region. Four distinct genomic groups and ten different clusters were individualized. Most of the isolates from Algeria and Tunisia belonged to two clusters. For both, the sequences from North Africa clustered mainly with sequences from European countries, the majority isolated recently during the 2000s. The analysis of the alignment of amino-acids sequences in the VP1 gene revealed four major substitutions in strains from different clusters, we also noticed changes in the BC-loop region; this region is associated with viral antigenicity. This study permit to better identify circulating Coxsackievirus B5 strains throughout the world and their genetic relationship. The protein analysis showed changes that could imply some antigenic significance. J. Med. Virol. 83:1247-1254, 2011. © 2011 Wiley-Liss, Inc.

First multicenter study for risk factors for hepatocellular carcinoma development in North Africa.

AIM: To assess the role of the major risk factors for hepatocellular carcinoma (HCC) development in the western part of North Africa. METHODS: A multicenter case control study was conducted in Tunisia, Morocco and Algeria in collaboration with Pasteur Institutes in these countries. A total of 164 patients with HCC and 250 control subjects without hepatic diseases were included. Prevalences of HBsAg, anti-hepatitis C virus (HCV) and diabetes were assessed. HCV and HBV genotyping were performed for anti-HCV and HBsAg positive patients. RESULTS: The mean age of patients was 62 ± 10 years old for a 1.5 M:F sex ratio. Sixty percent of HCC patients were positive for anti-HCV and 17.9% for HBsAg. Diabetes was detected in 18% of cases. Odd ratio (OR) and 95% confidence intervals (CI) were 32.0 (15.8 - 65.0), 7.2 (3.2 - 16.1) and 8.0 (3.1 - 20.0) for anti-HCV, HBsAg and diabetes respectively. Multivariate analysis indicated that the three studied factors were independent. 1b HCV genotype and D HBV genotype were predominant in HCC patients. HCV was the only risk factor significantly associated with an excess of cirrhosis (90% vs 68% for all other risk factors collectively, P = 0.00168). Excessive alcohol consumption was reliably established for 19 (17.6%) cases among the 108 HCC patients for whom data is available. CONCLUSION: HCV and HBV infections and diabetes are the main determinants of HCC development in North Africa. An active surveillance and secondary prevention programs for patients with chronic hepatitis and nutrition-associated metabolic liver diseases are the most important steps to reduce the risk of HCC in the region.

Genetic characterization of clade B measles viruses isolated in Tunisia and Libya 2002-2009 and a proposed new subtype within the B3 genotype.

Genetic characterization was conducted on 18 wild-type measles viruses, detected in Tunisia and Libya from 2002 to 2009. Sequence analysis of the 456 nucleotides in the carboxy terminus of the nucleoprotein (N) gene and the entire hemagglutinin (H) gene indicated that all isolates were in genotype B3. All of the viruses from 2002 to 2007 and some of the isolates from 2009 belonged to subtype B3.1. In contrast, 7 of the viruses isolated during 2008 and 2009 were quite divergent from all B3 isolates. The nucleotide sequences of the N gene of these 7 isolates differed from the sequences of the Ibadan and New York reference strain by an average of 3.1 and 4.4%, respectively. The H gene sequences differed by 1.1 and 2.6% with the same reference strains. This is the first report describing the genetic characteristics of measles viruses from clade B isolated in North Africa; the results suggest that these viruses represent a new subtype of genotype B3.

Heterogeneity of hepatitis B transmission in Tunisia: risk factors for infection and chronic carriage before the introduction of a universal vaccine program.

UNLABELLED: A population-based sero-epidemiological study enrolled 9486 volunteers in two governorates, Béja in the north and Tataouine in the south of Tunisia, in order to assess the magnitude of HBV transmission heterogeneity between the north and the south and within the same governorate, as well as the risk factors associated with infection and chronic carriage. RESULTS: The overall prevalence of anti-HBc, HBsAg and chronic carriage was 28.5, 5.3 and 2.9%, respectively. Significant differences were observed between the two governorates according to anti-HBc (32.1% in Béja and 27.8% in Tataouine; p=0.005) and HBsAg prevalence (4.2% in Béja and 5.6% in Tataouine; p=0.001). Significant differences were noticed between districts revealing important heterogeneity in HBV transmission within the same governorate (HBsAg ranged from 12 to <2% within the same governorate). At the individual level, the presence of a family member infected with HBV, scarification practices, needle practices in the Primary Care Center and gender (male) significantly increased the risk of anti-Hbc, HBsAg positivity and chronic carriage of infection while existence of sanitation in the house was found to be protective. The basic reproductive number and the force of infection confirmed the heterogeneity of transmission. Horizontal transmission within the family explains hyperendemic clusters in Tunisia.

Multiple diverse circoviruses infect farm animals and are commonly found in human and chimpanzee feces.

Circoviruses are known to infect birds and pigs and can cause a wide range of severe symptoms with significant economic impact. Using viral metagenomics, we identified circovirus-like DNA sequences and characterized 15 circular viral DNA genomes in stool samples from humans in Pakistan, Nigeria, Tunisia, and the United States and from wild chimpanzees. Distinct genomic features and phylogenetic analysis indicate that some viral genomes were part of a previously unrecognized genus in the Circoviridae family we tentatively named "Cyclovirus" whose genetic diversity is comparable to that of all the known species in the Circovirus genus. Circoviridae detection in the stools of U.S. adults was limited to porcine circoviruses which were also found in most U.S. pork products. To determine whether the divergent cycloviruses found in non-U.S. human stools were of dietary origin, we genetically compared them to the cycloviruses in muscle tissue samples of commonly eaten farm animals in Pakistan and Nigeria. Limited genetic overlap between cycloviruses in human stool samples and local cow, goat, sheep, camel, and chicken meat samples indicated that the majority of the 25 Cyclovirus species identified might be human viruses. We show that the genetic diversity of small circular DNA viral genomes in various mammals, including humans, is significantly larger than previously recognized, and frequent exposure through meat consumption and contact with animal or human feces provides ample opportunities for cyclovirus transmission. Determining the role of cycloviruses, found in 7 to 17% of non-U.S. human stools and 3 to 55% of non-U.S. meat samples tested, in both human and animal diseases is now facilitated by knowledge of their genomes.

A novel picornavirus associated with gastroenteritis.

A novel picornavirus genome was sequenced, showing 42.6%, 35.2%, and 44.6% of deduced amino acid identities corresponding to the P1, P2, and P3 regions, respectively, of the Aichi virus. Divergent strains of this new virus, which we named salivirus, were detected in 18 stool samples from Nigeria, Tunisia, Nepal, and the United States. A statistical association was seen between virus shedding and unexplained cases of gastroenteritis in Nepal (P = 0.0056). Viruses with approximately 90% nucleotide similarity, named klassevirus, were also recently reported in three cases of unexplained diarrhea from the United States and Australia and in sewage from Spain, reflecting a global distribution and supporting a pathogenic role for this new group of picornaviruses.

Phylogenetic analysis of echovirus 11 in the 3' end of the VP1.

OBJECTIVE: Echovirus 11 is one of the most frequently isolated enterovirus serotypes, causing a wide range of clinical diseases. We studied the genetic diversity in the 3' end of the VP1 gene of strains from different geographical origin in the world. METHODS: The sequences in the 3' end of the VP1 of 11 Tunisian isolates were determined and aligned with the published sequences to establish a phylogenetic profile. RESULTS: The grouping of the sequences was similar to what was previously reported by analyzing the whole VP1 gene with 4 genogroups, designated A-D, and 5 lineages in genogroup D. All Tunisian strains belonged to genogroup D, together with other sequences mainly from the USA and Europe. Contrary to the sequences from the USA isolated during the last 3 decades, which mostly belonged to the D4 lineage, those from Tunisia belonged to different lineages within genogroup D according to their isolation date: isolates from the early 1990s belonged to D3, those of the mid 1990s to D4 and the most recent ones to D5. CONCLUSION: Our findings further widen the interest of partial sequencing in the VP1 to study the molecular epidemiology of echovirus 11 and indicate that the genetic evolution of circulating strains may differ from one country to another according to the region's epidemiological specificities.

Identification of measles virus genotypes from recent outbreaks in countries from the Eastern Mediterranean Region.

BACKGROUND: Molecular characterization of measles viruses (MV) helps to identify transmission pathways of the virus and to document persistence or interruption of endemic virus circulation. In the Eastern Mediterranean Region, measles genotypes from only few countries have been documented. OBJECTIVES: This study reports the genetic characteristics of virus strains from recent measles outbreaks in Tunisia, Libya, Syria and Iran in 2002-2003. STUDY DESIGN: Virus sequences in the nucleoprotein gene were obtained by PCR amplification of virus isolates or serum samples. The sequences were compared to the reference ones for genotype identification and to other published sequences within the same genotype. RESULTS AND CONCLUSIONS: The Tunisian and Libyan epidemic strains belonged to genotype B3, they were closely related to each other and to isolates from Western Africa. The Syrian and Iranian viruses belonged to genotype D4, and differed from each other and from the other published sequences within this genotype. Our results provide valuable baseline and new tools for improved virological measles surveillance in the future, at country, regional and global levels.

Molecular characterization of coxsackievirus B5 isolates.

Coxsackie B viruses of serotype 5 are associated frequently with sporadic cases of neurological diseases, epidemics of meningitis, and chronic diseases such as cardiomyopathy and diabetes. In this article, 15 strains of Coxsackievirus B5 isolated from patients with neurological disorders and healthy people were investigated by partial sequencing in the 5' half of the VP1 region and compared to other published sequences of Coxsackievirus B5, in the same genomic region. All Coxsackievirus B5 sequences showed less than 25% nucleotide difference between each other and a minimum of 27.8% of divergence with prototype sequences from other Coxsackievirus B serotypes. Within the Coxsackievirus B5 group of sequences, four clusters were individualized and may correspond to four genotypes: one genotype with large geographical distribution, containing most recent strains that have circulated from 1984 to 2000, another genotype represented by the prototype Faulkner strain, isolated in the early 1950s, and two intermediate genotypes, comprising strains isolated from 1970 to 1999 and closely related to swine vesicular disease virus. This study confirms the ability of partial sequencing in VP1 to determine serotype and to genetically characterize Coxsackievirus B5 field isolates. It gives a first approach on the molecular epidemiology of these viruses, which have a particular importance in human health.

Community-acquired poliovirus infection in children with primary immunodeficiencies in Tunisia.

The global polio eradication program recommends the use of massive vaccination campaigns with live vaccine through National Immunization Days (NIDs) to displace the wild virus from the community. Immunodeficient patients may be indirectly infected and become chronic excretors and potential reservoirs of polioviruses, a concern for the posteradication era. This prospective study aimed to assess the risk of community-acquired infection of immunodeficient patients following NIDs, the dynamics of viral excretion and the genetic variation of excreted viruses. Sixteen children with various primary immunodeficiencies, who did not receive the vaccine during the campaign, were investigated. Stool samples were collected weekly, shortly after the NIDs, during at least 3 months, and were processed for viral isolation. Isolates were characterized by three intratypic differentiation methods and partial sequencing of the VP1/2A region. Polioviruses were detected in 4 out of 16 patients (serotype 1 in 3 patients and serotype 3 in 1 patient). Sequencing revealed more than 99% homology with homotypic Sabin strains, suggesting recent infection. Duration of viral excretion ranged from 1 to 7 weeks. Nine out of eleven isolates from the three poliovirus serotype 1-infected patients disclosed a non-Sabin-like phenotype by enzyme-linked immunosorbent assay and had recurrent mutations within or close to the neutralizing antigenic sites. In summary, the risk of secondary infection in immunodeficient patients is within the range previously reported for the general population. Although none of the four infected patients developed prolonged viral excretion, particular viral variants were selected and may be of epidemiological significance.

Measles surveillance and control in Tunisia: 1979-2000.

BACKGROUND: The aim of this study was to analyze measles epidemiology in Tunisia after the introduction of specific vaccine in 1979 and the results of the serological investigation of suspected cases, introduced as part of the National Program for Measles Elimination recently implemented. METHODS: Available data were used to examine trends in measles epidemiology from 1979 to 2000: number of reported cases, patient's age, reporting date, epidemiological link with similar cases and laboratory confirmation. Serological investigation included the detection, by ELISA, of measles and rubella IgMs in 542 suspected measles cases sampled from 1997 to 2000. RESULTS: Measles coverage level increased gradually and was maintained to over 90% since 1992. In parallel, the annual incidence of reported cases declined and outbreaks became less frequent, the latest occurred in 1992. Measles-specific IgMs were detected in only nine patients who received measles vaccine few days before blood collection, anti-rubella IgMs were detected in 52% of cases. CONCLUSION: Vaccination strategies including routine and supplemental immunizations, implemented in Tunisia, achieved a substantial decrease in measles incidence. Virological results highlight frequent confusion, at the clinical level, with the other etiologies of rash and fever and the importance of systematic serological confirmation of cases.