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Polci A.,Istituto G. Caporale | Cosseddu G.M.,Istituto G. Caporale | Ancora M.,Istituto G. Caporale | Pinoni C.,Istituto 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.

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.

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.

Mardulyn P.,Roosevelt University | Mardulyn P.,INRS - Institute National de la Recherche Scientifique | Goffredo M.,Istituto Zooprofilattico Sperimentale dellAbruzzo e Del Molise G. Caporale | Conte A.,Istituto 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.

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.

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