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Mardulyn P.,Roosevelt University | Mardulyn P.,INRS - Institute National de la Recherche Scientifique | Goffredo M.,Instituto Zooprofilattico Sperimentale Dellabruzzo E Del Molise G Caporale | Conte A.,Instituto Zooprofilattico Sperimentale Dellabruzzo E Del Molise G Caporale | And 6 more authors.
Molecular Ecology | Year: 2013

Bluetongue (BT) is a commonly cited example of a disease with a distribution believed to have recently expanded in response to global warming. The BT virus is transmitted to ruminants by biting midges of the genus Culicoides, and it has been hypothesized that the emergence of BT in Mediterranean Europe during the last two decades is a consequence of the recent colonization of the region by Culicoides imicola and linked to climate change. To better understand the mechanism responsible for the northward spread of BT, we tested the hypothesis of a recent colonization of Italy by C. imicola, by obtaining samples from more than 60 localities across Italy, Corsica, Southern France, and Northern Africa (the hypothesized source point for the recent invasion of C. imicola), and by genotyping them with 10 newly identified microsatellite loci. The patterns of genetic variation within and among the sampled populations were characterized and used in a rigorous approximate Bayesian computation framework to compare three competing historical hypotheses related to the arrival and establishment of C. imicola in Italy. The hypothesis of an ancient presence of the insect vector was strongly favoured by this analysis, with an associated P ≥ 99%, suggesting that causes other than the northward range expansion of C. imicola may have supported the emergence of BT in southern Europe. Overall, this study illustrates the potential of molecular genetic markers for exploring the assumed link between climate change and the spread of diseases. © 2013 Blackwell Publishing Ltd.


Mejri S.,Institute Pasteur Of Tunisie | Mejri S.,Institute Of La Recherche Veterinaire Of Tunisie | Mhalla S.,Institute Pasteur Of Tunisie | Ben Yahia A.,Institute Pasteur Of Tunisie | Triki H.,Institute Pasteur Of Tunisie
Annales de Biologie Clinique | Year: 2012

Hepatitis C virus (HCV) is an important causative agent of chronic liver disease worldwide distributed. In Tunisia, reported HCV seroprevalence is about 0.7%, with higher infection rate in the North-East region (Béjà). Subtype 1b is the largely predominant genotype. As it was suggested in a previous study, a specific HCV variant, subtype 1b was circulating in Tunisia, especially in urban areas of the North-Nest region. The aim of this work was to assess phylogenetic relatedness between viruses circulating in different other parts of Tunisia, and to compare them with those from the North-West region, and with those from other countries. Phylogenetic analyses were carried out on two viral regions: the NS5B and the E1. Phylogenetic analyses identified a group of sequences forming a cluster including almost exclusively Tunisian strains. This phylogenetic cluster comprises more than the half of all investigated Tunisian strains, especially those from urban parts of Béjà (North-West). Such results were observed not only after investigations in the NS5B region, but also after analyses in the E1 viral region. All these observations confirm the hypothesis about the specific local variant of HCV subtype 1b in the country, particularly in the North-West. This local variant could be related to a common HCV transmission route, as it was suggested in a previous publication.


Cherif N.,Institute Of La Recherche Veterinaire Of Tunisie | Lopez-Jimena B.,University of Malaga | Garcia-Rosado E.,University of Malaga | Cano I.,Institute Ciencias Marinas Of Andalucia | And 4 more authors.
Journal of Applied Ichthyology | Year: 2011

Viral Encephalopathy and Retinopathy (VER), is caused by a nodavirus included within the Betanodavirus genus of the Nodaviridae family. This disease affects more than 30 marine fish species worldwide and has been a major obstacle in the aquaculture industry; control of the disease is based on virus detection, essentially in carrier specimens. This study describes a real time PCR procedure for viral nervous necrosis virus detection from several organs of sea bass, Senegalese sole, and gilt-head sea bream, from fish displaying either clinical symptoms or asymptomatic cases. The sensitivity of this technique was about 106-fold higher than that of the conventional RT-PCR. The newly designed primers detected nodavirus isolates belonging to the RGNNV and SJNNV genotypes. © 2010 Blackwell Verlag, Berlin.


Lopez-Jimena B.,IFAPA Centro El Toruno | Cherif N.,Institute Of La Recherche Veterinaire Of Tunisie | Garcia-Rosado E.,University of Malaga | Infante C.,IFAPA Centro El Toruno | And 5 more authors.
Journal of Applied Microbiology | Year: 2010

Aims: To detect the possible coexistence of striped jack nervous necrosis virus (SJNNV) and red-spotted grouper nervous necrosis virus (RGNNV) genotypes in a single fish, a methodology based on the combination of PCR amplification and blot hybridization has been developed and applied in this study. Methods and Results: The degenerate primers designed for the PCR procedure target the T4 region within the capsid gene, resulting in the amplification of both genotypes. The subsequent hybridization of these amplification products with two different specific digoxigenin-labelled probes resulted in the identification of both genotypes separately. The application of the RT-PCR protocol to analyse blood samples from asymptomatic wild meagre (Argyrosomus regius) specimens has shown a 46·87% of viral nervous necrosis virus carriers. The combination of RT-PCR and blot hybridization increases the detection rate up to 90·62%, and, in addition, it has shown the coexistence of both genotypes in 18 out of the 32 specimens analysed (56·25%). Conclusions: This study reports the coexistence of betanodaviruses belonging to two different genotypes (SJNNV and RGNNV) in wild fish specimens. Significance and Impact of the Study: This is the first report demonstrating the presence of SJNNV and RGNNV genotypes in the same specimen. This study also demonstrates a carrier state in this fish species for the first time. © 2010 The Society for Applied Microbiology.


Al-Gallas N.,Institute Pasteur Of Tunis | Abbassi M.S.,Institute Of La Recherche Veterinaire Of Tunisie | Gharbi B.,Institute Pasteur Of Tunis | Manai M.,Institute Pasteur Of Tunis | And 4 more authors.
Foodborne Pathogens and Disease | Year: 2013

Four hundred and thirty Salmonella isolates, recovered from various food-animal products, were tested for nalidixic acid resistance, plasmid-mediated quinolone resistance, and genetic relationship. One hundred fifteen isolates (113 Salmonella serovar Enteritidis and two Salmonella serovar Typhimurium isolates) of 430 (26.7%) Salmonella isolates exhibited nalidixic acid resistance. Polymerase chain reaction screening for qnrA, qnrB, qnrS, qepA (encoding fluoroquinolones resistance) and rmtB (encoding aminoglycosides resistance) showed that 5 (1.16%) isolates were positive for qnr-and qepA-type genes, and the aac(6′)-Ib-cr gene was observed in two (1.7%) Enteritidis isolates concomitantly with qnrA or qnrB. The co-occurrence of qepA and rmtB in one Typhimurium isolate is noteworthy. Pulsed-field gel electrophoresis revealed a high genetic homogeneity of nalidixic-resistant isolates and the persistence of clonal clusters over 4 years in different regions in Tunisia and from various food-animal products. To the best of our knowledge, this is the first report of co-occurrence of qepA and rmtB in a Salmonella strain. © 2013, Mary Ann Liebert, Inc.


Polci A.,Instituto G Caporale | Cosseddu G.M.,Instituto G Caporale | Ancora M.,Instituto G Caporale | Pinoni C.,Instituto G Caporale | And 6 more authors.
Transboundary and Emerging Diseases | Year: 2015

A duplex real-time reverse transcription-polymerase chain reaction (qRT-PCR) assay was developed for a simple and rapid diagnosis of Peste des petits ruminants (PPR). qRT-PCR primers and TaqMan probe were designed on a conserved region of nucleocapsid protein (Np) of PPR virus (PPRV) genome. An in vitro transcript of the target region was constructed and tested to determine analytical sensitivity. Commercial heterologous Armored RNA® was used as an internal positive control (IPC) for either RNA isolation or RT-PCR steps. The detection limit of the newly designed duplex real-time RT-PCR (qRT-PCR PPR_Np) was approximately 20 copies/μl with a 95% probability. No amplification signals were recorded when the qRT-PCR PPR_Np was applied to viruses closely related or clinically similar to PPRV- or to PPR-negative blood samples. A preliminary evaluation of the diagnostic performance was carried out by testing a group of 43 clinical specimens collected from distinct geographic areas of Africa and Middle East. qRT-PCR PPR_Np showed higher sensitivity than the conventional gel-based RT-PCR assays, which have been used as reference standards. Internal positive control made it possible to identify the occurrence of 5 false-negative results caused by the amplification failure, thus improving the accuracy of PPRV detection. © 2013 Blackwell Verlag GmbH.


Rjeibi M.R.,Manouba University | Ben Hamida T.,Institute Of La Recherche Veterinaire Of Tunisie | Dalgatova Z.,Institute Of La Recherche Veterinaire Of Tunisie | Mahjoub T.,Manouba University | And 3 more authors.
Parasite | Year: 2015

Trypanosoma evansi, the agent of surra, is a salivarian trypanosome, originating from Africa. Surra is a major disease in camels, equines and dogs, in which it can often be fatal in the absence of treatment. Animals exhibit nonspecific clinical signs (anaemia, loss of weight and abortion). In the present survey, a blood sample was collected in Sousse (Central Tunisia) from a dog that presented clinical signs of trypanosomiasis. Giemsa-stained blood smears and PCR were performed. ITS1 sequences from blood had 99.8 and 99.5% homology with published T. evansi sequences from cattle and camels, respectively. To our knowledge, this is the first report of T. evansi in a Tunisian dog. © M.R. Rjeibi et al., published by EDP Sciences, 2015.


PubMed | Institute Of La Recherche Veterinaire Of Tunisie and Manouba University
Type: | Journal: Parasite (Paris, France) | Year: 2015

Trypanosoma evansi, the agent of surra, is a salivarian trypanosome, originating from Africa. Surra is a major disease in camels, equines and dogs, in which it can often be fatal in the absence of treatment. Animals exhibit nonspecific clinical signs (anaemia, loss of weight and abortion). In the present survey, a blood sample was collected in Sousse (Central Tunisia) from a dog that presented clinical signs of trypanosomiasis. Giemsa-stained blood smears and PCR were performed. ITS1 sequences from blood had 99.8 and 99.5% homology with published T. evansi sequences from cattle and camels, respectively. To our knowledge, this is the first report of T. evansi in a Tunisian dog.


Cherif N.,Institute Of La Recherche Veterinaire Of Tunisie | Gagne N.,Gulf | Groman D.,University of Prince Edward Island | Kibenge F.,University of Prince Edward Island | And 3 more authors.
Journal of Fish Diseases | Year: 2010

Finfish nodaviruses (betanodaviruses) can cause highly destructive infections in numerous species of farmed marine fish larvae and juveniles worldwide. The betanodavirus genome consists of two single-stranded positive-sense RNA molecules (RNA1 and RNA2). The virus can be classified into four genotypes based on the partial sequences of the coat protein (CP) gene (T2 and T4 regions). Currently, genomic sequence information for RNA1 regions of RNA2 outside of T2 and T4 is less well documented. This study reports on the characterization of the full RNA2 sequence of a Tunisian betanodavirus with a length of 1433 nt, containing a 339 amino acid open-reading frame encoding the CP, and typing to the redspotted grouper nervous necrosis virus Ia genotype following phylogenetic analysis. The homology of the capsid protein to other betanodaviruses or alphanodaviruses was compared. In addition, a full length RNA1 sequence of 3104 nt encoding a 982 amino acid RNA-dependent RNA polymerase was obtained. © 2009 Blackwell Publishing Ltd.


PubMed | Institute Of La Recherche Veterinaire Of Tunisie
Type: Journal Article | Journal: Journal of fish diseases | Year: 2010

Finfish nodaviruses (betanodaviruses) can cause highly destructive infections in numerous species of farmed marine fish larvae and juveniles worldwide. The betanodavirus genome consists of two single-stranded positive-sense RNA molecules (RNA1 and RNA2). The virus can be classified into four genotypes based on the partial sequences of the coat protein (CP) gene (T2 and T4 regions). Currently, genomic sequence information for RNA1 regions of RNA2 outside of T2 and T4 is less well documented. This study reports on the characterization of the full RNA2 sequence of a Tunisian betanodavirus with a length of 1433 nt, containing a 339 amino acid open-reading frame encoding the CP, and typing to the redspotted grouper nervous necrosis virus Ia genotype following phylogenetic analysis. The homology of the capsid protein to other betanodaviruses or alphanodaviruses was compared. In addition, a full length RNA1 sequence of 3104 nt encoding a 982 amino acid RNA-dependent RNA polymerase was obtained.

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