Infection dynamics of subtype H9N2 low pathogenic avian influenza a virus in turkeys.

While mammals can be infected by influenza A virus either sporadically or with well adapted lineages, aquatic birds are the natural reservoir of the pathogen. So far most of the knowledge on influenza virus dynamics was however gained on mammalian models. In this study, we infected turkeys using a low pathogenic avian influenza virus and determined the infection dynamics with a target-cell limited model.

Phylogeographic Dynamics of H9N2 Avian Influenza Viruses in Tunisia.

Avian influenza virus subtype H9N2 is endemic in commercial poultry in Tunisia. This subtype affects poultry and wild birds in Tunisia and poses a potential zoonotic risk. Tunisian H9N2 strains carry, in their hemagglutinins, the human-like marker 226 L that is most influential in avian-to-human viral transmission.

BotCl, the First Chlorotoxin-like Peptide Inhibiting Newcastle Disease Virus: The Emergence of a New Scorpion Venom AMPs Family.

Newcastle disease virus (NDV) is one of the most serious contagions affecting domestic poultry and other avian species. It causes high morbidity and mortality, resulting in huge economic losses to the poultry industry worldwide. Despite vaccination, NDV outbreaks increase the need for alternative prevention and control means.

Synthesis of Novel 1,3,4-Oxadiazole-Derived -Aminophosphonates/-Aminophosphonic Acids and Evaluation of Their In Vitro Antiviral Activity against the Avian Coronavirus Infectious Bronchitis Virus.

An efficient and simple approach has been developed for the synthesis of eight dialkyl/aryl[(5-phenyl-1,3,4-oxadiazol-2-ylamino)(aryl)methyl]phosphonates through the Pudovik-type reaction of dialkyl/arylphosphite with imines, obtained from 5-phenyl-1,3,4-oxadiazol-2-amine and aromatic aldehydes, under microwave irradiation. Five of them were hydrolyzed to lead to the corresponding phosphonic acids. Selected synthesized compounds were screened for their in vitro antiviral activity against the avian bronchitis virus (IBV).

Aptamer-Assisted Proximity Ligation Assay for Sensitive Detection of Infectious Bronchitis Coronavirus.

Infectious bronchitis virus (IBV) is a coronavirus responsible for major health problems in the poultry industry. New virus strains continue to appear, causing large economic losses. To develop a rapid and accurate new quantitative assay for diagnosis of the virus without DNA extraction, we selected highly specific single-stranded DNA (ssDNA) aptamers with a high affinity to IBV, using the systematic evolution of ligands by exponential enrichment (SELEX) technology for aptamer screening, followed by high-throughput sequencing technology.

Phylogenetic and phylodynamic analyses of subtype-B metapneumovirus from chickens in Tunisia.

Swollen Head Syndrome (SHS) is an economically important viral disease of chickens caused by avian metapneumovirus (aMPV). The virus comprises 6 different subtypes (A,B,C,D, New-1 and New-2). To date, no information was available on the presence of the virus in Tunisian poultry.

Epidemiological and Phylogeographic Study of Equid Herpesviruses in Tunisia.

Equid herpesvirus (EHV) is a contagious viral disease affecting horses, causing illness characterized by respiratory symptoms, abortion and neurological disorders. It is common worldwide and causes severe economic losses to the equine industry. The present study was aimed at investigating the incidence of EHVs, the genetic characterization of Tunisian isolates and a spatiotemporal study, using 298 collected samples from diseased and clinically healthy horses.

Phylogenetic analysis and assessment of the pathogenic potential of the first H9N2 avian influenza viruses isolated from wild birds and Lagoon water in Tunisia.

H9N2 avian influenza virus (AIV) has been isolated from various species of wild birds and domestic poultry worldwide. It has been reported since the late 1990s, that H9N2 AIV has infected humans as reported in some Asian and North African countries. This subtype has already been circulating and constituting a serious threat to the poultry industry in Tunisia back in 2009.

Lineages, Virulence Gene Associated and Integrons among Extended Spectrum β-Lactamase (ESBL) and CMY-2 Producing from Bovine Mastitis, in Tunisia.

Extended Spectrum Beta-Lactamase (ESBL) Enterobacteriaceae are becoming widespread enzymes in food-producing animals worldwide. Escherichia coli and Klebseilla pneumoniae are two of the most significant pathogens causing mastitis. Our study focused on the characterization of the genetic support of ESBL/pAmpC and antibiotic resistance mechanisms in cefotaxime-resistant (CTXR) and susceptible (CTXS) Enterobacteriaceae isolates, recovered from bovine mastitis in Tunisia, as well as the analyses of their clonal lineage and virulence-associated genes.

Virulence Profiling, Multidrug Resistance and Molecular Mechanisms of Strains from Chicken Carcasses in Tunisia.

Antibiotic resistance in foodborne pathogens is an emergent global health concern. The objectives of this study were to assess antimicrobial resistance (AMR) in isolates from chicken carcasses and to investigate the AMR molecular mechanisms as well as the presence of virulence determinants. The study was performed on 257 samples collected from abattoirs and retail shops in northeastern Tunisia.

Thymus capitatus flavonoids inhibit infection of Kaposi's sarcoma-associated herpesvirus.

Kaposi's sarcoma-associated herpesvirus (KSHV), also known as human herpes virus 8 (HHV-8), causes primary effusion lymphoma, multicentric Castleman's disease, and Kaposi's sarcoma. Few antiviral drugs are available to efficiently control KSHV infection, and therefore, the development of novel, effective anti-KSHV treatments is needed. The aim of this study was to determine the antiviral activity of ethanolic and aqueous extracts, essential oils, and certain flavonoids (hesperidin, eupafolin, and vicenin) derived from Thymus capitatus (commonly known as thyme).

spp. in Eggs and Laying Hens in the North-East of Tunisia: High Prevalence and Multidrug-Resistance Phenotypes.

Despite the importance of eggs in the human diet, and unlike other products, for which food safety risks are widely investigated, information on the occurrence of and antimicrobial resistance in eggs and layer hen flocks is lacking in Tunisia. This study was conducted to determine the occurrence of and the antimicrobial resistance in layer hens and on eggshells. Thus, 366 cloacal swabs and 86 eggshell smear samples were collected from five layer hen farms in the North-East of Tunisia.

Distribution of virulence and antibiotic resistance genes in Campylobacter jejuni and Campylobacter coli isolated from broiler chickens in Tunisia.

Background: Thermo-tolerant Campylobacter species are the major cause of foodborne diseases worldwide. This study aimed to evaluate the prevalence of virulence genes and antibiotic resistance determinants in Campylobacter jejuni and Campylobacter coli isolates, and to investigate the relationship between these two traits.

Methods: A total of 132 Campylobacter isolates from poultry were tested for the presence of 13 virulence genes; flaA, cadF, racR, virB11, pldA, dnaJ, cdtA, cdtB, cdtC, ciaB, wlaN, cgtB and ceuE.

First Detection of Human ST131-CTX-M-15-O25-B2 Clone and High-Risk Clonal Lineages of ESBL/pAmpC-Producing Isolates from Diarrheic Poultry in Tunisia.

Circulation of a multi-resistance clone of bacteria associated with genetic elements in diseased animals constitutes a global public health problem. Our study focused on the characterization of the support of ESBL in cefotaxime resistant (CTX) isolates recovered from poultry with diarrhea, analysis of their clonal lineage, and virulence-associated genes. The study was carried out on 130 samples of chickens with diarrhea, collected in 2015 from poultry farms in Tunisia.

Accurate detection of Newcastle disease virus using proximity-dependent DNA aptamer ligation assays.

Detecting viral antigens at low concentrations in field samples can be crucial for early veterinary diagnostics. Proximity ligation assays (PLAs) in both solution and solid-phase formats are widely used for high-performance protein detection in medical research. However, the affinity reagents used, which are mainly poly- and monoclonal antibodies, play an important role in the performance of PLAs.

Full-length genome sequencing of a very virulent infectious bursal disease virus isolated in Tunisia.

Infectious bursal disease (IBD), an acute, highly contagious, and immunosuppressive avian disease, is caused by infectious bursal disease virus (IBDV) and constitutes one of the main threats to the poultry industry, worldwide. This study was performed to isolate and characterize IBDV isolates circulating in Tunisia. Eleven collected bird samples were identified using an SYBR Green-based one-step real-time reverse transcriptase polymerase chain reaction.

Newly detected mutations in the Meq oncogene and molecular pathotyping of very virulent Marek's disease herpesvirus in Tunisia.

Marek's disease (MD) is a contagious avian viral disease that is responsible for large economic losses to farmers. The disease is caused by Marek's disease virus (species Gallid alphaherpesvirus 2), which causes neurological lesions, immune suppression, and tumor proliferation of lymphoid cells that invade a large number of organs and tissues. Despite widespread vaccination, Marek's disease virus (MDV), has shown a continuous increase in its virulence and has acquired the ability to overcome immune responses induced by vaccines.

Generation of ssDNA aptamers as diagnostic tool for Newcastle avian virus.

Aptamers are short single-stranded DNA (ssDNA), RNA or synthetic XNA molecules, which are used as a class of affinity binders recognizing target molecules with a very high affinity and specificity. The aim of this study was to generate and characterize ssDNA aptamers for the detection of Newcastle disease virus (NDV). These aptamers were selected using systematic evolution of ligands by exponential enrichment (SELEX) in combination with quantitative high-throughput DNA sequencing.

Full-length genome sequences of the first H9N2 avian influenza viruses isolated in the Northeast of Algeria.

Background: H9N2 avian influenza viruses (AIV) has a worldwide geographic distribution and affects poultry of different types of production. H9N2 AIV was first reported in the Northeast of Algeria in April 2017, following an outbreak associated with high mortality, in broiler flocks. In the present study, we report full-length genome sequences of AIV H9N2, and the detailed phylogeny and molecular genetic analyses.

Historical origins and zoonotic potential of avian influenza virus H9N2 in Tunisia revealed by Bayesian analysis and molecular characterization.

During 2009-2012, several outbreaks of avian influenza virus H9N2 were reported in Tunisian poultry. The circulating strains carried in their hemagglutinins the human-like marker 226L, which is known to be important for avian-to-human viral transmission. To investigate the origins and zoonotic potential of the Tunisian H9N2 viruses, five new isolates were identified during 2012-2016 and their whole genomes were sequenced.

Viral interference between H9N2-low pathogenic avian influenza virus and avian infectious bronchitis virus vaccine strain H120 in vivo.

The interaction between a low pathogenic avian influenza virus (A/CK/TUN/145/2012), a H9N2 Tunisian isolate, and a vaccine strain (H120) of avian infectious bronchitis, administered simultaneously or sequentially three days apart to chicks during 20 days, was evaluated using ELISA antibody levels, quantitative reverse transcription-polymerase chain reaction (qRT-PCR) analyses and histopathology examination. First, the in vivo replication interference of avian influenza virus (AIV) and infectious bronchitis virus (IBV) was evaluated using qRT-PCR to detect accurately either AIV or IBV genomes or viral copy numbers during dual infections. Second, we have determined the amount of specific antibodies in sera of chick's infected with AIV alone, IBV alone, mixed AIV + IBV, IBV then AIV or AIV IBV 3 days later using an ELISA test.

Molecular characterization of a unique variant of avian infectious bronchitis virus in Tunisia.

Avian infectious bronchitis virus (IBV) is responsible of significant economic losses for poultry industry around the world, through evolution of its pathogenicity, inadequacy of vaccines, and virus evasion. Such evasion is related to the unstable nature of its RNA, in particular the S glycoprotein encoding gene, which raises great challenges with regard to the control of the disease, along with the lack of proof reading mechanisms of the RNA polymerase. The emergence of new variants might be a reason for the endemic outbreaks that are being reported in Tunisia, in addition to poor vaccination techniques and ineffective prophylactic programs.

Prevalence and Antibiotic Resistance Patterns of spp. Isolated from Broiler Chickens in the North of Tunisia.

The aim of the current study is to assess the prevalence of infection in broiler chickens, raised in intensive production conditions, and to evaluate the antimicrobial susceptibility of recovered isolates. A total of 590 cloacal swab samples were taken from 13 broiler chicken flocks in the North East of Tunisia. All samples were tested for the presence of thermophilic by culture and PCR, targeting the and genes, respectively.

Viral interference between low pathogenic avian influenza H9N2 and avian infectious bronchitis viruses in vitro and in ovo.

Background: Low pathogenic avian influenza (LPAI) H9N2 and infectious bronchitis virus (IBV) are important pathogens of poultry, causing important economic losses for the sector. Replication interference between these two viruses was described using cell cultures (CC) and embryonated chicken eggs (ECE). Chicken embryo lung (CEL) and ECE were simultaneously or sequentially infected with IBV vaccine strain (H120) and LPAIV-H9N2 (A/Ck/TUN/145/2012) to evaluate viral interactionsin vitro and in ovo, respectively.