المستودع الرقمي لـكلية الطب البيطري

Aims: To determine the seroprevalence of Toxoplasma gondii (T. gondii) in women from Aljalla Maternity and Gynaecology Hospital (AMGH) and to evaluate the association between the infection and potential risk factors. Methods: A cross-sectional study was conducted at AMGH in Tripoli during the year 2012. Data on potential risk factors were collected by a structured questionnaire and results of the test. The output data of questionnaire were used to assess potential risk factors for positive outcome. All sera (n = 500) was screened against ToxoG, by using the Vidas machine automated enzyme-linked florescent immunoassay. The association between the outcome variables and its potential risk factors were screened in a multivariate analysis. A p-value < 0.05 was considered to be significant. Results: The overall seroprevalence was estimated to be 50.8% with 95% confidence interval (CI) (46.42%–55.18%). The results revealed that T. gondii infection is highly prevalent, and eating habits (consuming raw meat and/or raw vegetables or fruits) were highly significant associated in multivariable analysis. Expectedly, a significantly [odds ratio (OR):1.712; p =
Abdusalam Sharef Abdusalam Mahmoud(1-2019)

The epidemiological patterns of Bluetongue (BT) in North Africa and Mediterranean Basin (MB) dramatically changed by emergence of subsequent episodes of novel bluetongue virus (BTV) serotypes with highly pathogenic indexes and socio-economic impacts. The objective of the study was to investigate the sero-prevalence and serotype distribution of BTV in Libya. During 2015-2016, a total of 826 serum samples were collected from domestic ruminants in Libya. All sera were assayed by competitive enzyme-linked immunosorbent assays (c-ELISA). C-Elisa-positive samples (43.3%; 173/400) were further analyzed by virus neutralization assay to identify BTV serotypes and determine the antibody titre of positive samples. An overall BTV sero-prevalence was 48.4% (95% CI: 45.0%-51.8%). Neutralizing antibodies were detected against the following BTV serotypes namely: BTV-1, BTV-2, BTV-3, BTV-4, BTV-9 and BTV-26. While BTV-1, BTV-2, BTV-4 and BTV-9 circulation was unsurprising as they have been responsible of the last year outbreaks in Northern African Countries, the detection of BTV-3 and BTV-26 was definitely new and concerning for the animal health of the countries facing the Mediterranean Basin. It is crucial that European and Northern African authorities collaborate in organizing common surveillance programmes to early detect novel strains or emerging serotypes in order to set up proper preventive measures, and, in case, develop specific vaccines and plan coordinated vaccination campaigns. arabic 13 English 96
Abdusalam Sharef Abdusalam Mahmoud(1-2018)

A serological survey was carried out in Libya to investigate the circulation of Rift Valley fever virus (RVFV) among domestic ruminants. A total of 857 serum samples were collected from year 2015 to 2016 in eleven provinces of Libya belonging to five branches of the country. Samples were tested for RVFV antibodies using a competitive EnzymeLinked Immunosorbent Assay (c-ELISA). Antibodies specific for RVFV were not detected in any of the 857 samples. However, a statistical analysis was carried out to assess the maximum expected number of infected animals and the maximum expected prevalence of RVFV among Libyan ruminants’ populations according to the sampled population. The overall maximum expected prevalence was estimated to be 1.8% for cattle and 0.4% for small ruminants. Results seem to exclude the circulation of RVFV, however, a surveillance plan should be implemented in areas at risk of RVFV introduction. arabic 10 English 55
Abdusalam Sharef Abdusalam Mahmoud, (6-2018)

Since 1998, southern Europe has experienced multiple incursions of different serotypes and topotypes of Bluetongue virus, a vector-borne transmitted virus, the causative agent of Bluetongue (BT), a major disease of ruminants. Some of these incursions originated from northern Africa, likely because of wind-blown dissemination of infected midges. In this report, we describe the detection and whole genome characterization of a novel BTV-3 strain identified in a symptomatic sheep in Tunisia. Sequences were immediately deposited with the GenBank Database under Accession Nos KY432369-KY432378. Alert and preparedness are requested to face the next vector seasons in northern Africa and the potential incursion of this novel strain in southern Europe arabic 11 English 57
Abdusalam Sharef Abdusalam Mahmoud(1-2021)

The human 11p15 region is divided into two independent imprinted domains, the H19/IGF2 and CDKN1C/KCNQ1 domains. Each domain is regulated by its own imprinting control regions, ICR1 and ICR2, which carry opposite germline imprints. The expression of 11p15 imprinted genes is regulated by two major mechanisms. ICR1 binds a zinc finger protein (CTCF) on the unmethylated maternal allele and acts as a chromatin insulator, whereas ICR2 is unmethylated on the paternal allele and serves as a promoter for a regulatory non-coding RNA (KCNQ1OT1). Dysregulation of 11p15 genomic imprinting results in two human foetal growth disorders: the Beckwith-Wiedemann (BWS) and the Silver-Russell (SRS) syndromes, which display opposite growth phenotypes. Various 11p15 epigenetic and genetic defects result in BWS and SRS. Gain or loss of DNA methylation account for 60% of BWS and SRS and, in most cases, the mechanism of the DNA methylation defect is unknown. The overall aim of this thesis was to decipher the mechanisms resulting in loss or gain of DNA methylation at ICR1 or ICR2 by investigating large cohorts of BWS and SRS patients displaying a “primary” DNA methylation defect. We aimed at establishing what was the incidence of copy number variations (CNVs) (duplications, deletions and segmental uniparental isodisomies) confined to one or one part of the H19/IGF2 or CDKN1C/KCNQ1 domains. We also screened extensively the ICR1 imprinting control region in BWS and SRS patients to identify new genetic defects. We show in this work that genetic defects in cis account for a significant proportion (approximately 30%) of BWS patients with ICR1 gain of DNA methylation but are rare in SRS and BWS patients with loss of DNA methylation at ICR1 and ICR2, respectively. We describe novel small gain and loss CNVs involving only part of the two domains in BWS and SRS. We also describe, for the first time, mutations and small deletions involving binding sites for the OCT4 and SOX2 pluripotency factors. Those defects account for approximately 14% of BWS cases and result in a BWS phenotype upon maternal transmission. We further characterize the role of OCT4/SOX2 pluripotency factors in the maintenance of genomic imprinting at the H19/IGF2 domain in mouse embryonic stem cells. By screening the whole 11p15 region for susceptibility alleles for loss or gain of DNA methylation, our group identified a novel 4.5 kb cis-regulatory region within the CDKN1C/KCNQ1 domain. A specific 4.5 kb haplotype confers, upon maternal transmission, a risk of ICR2 loss of DNA methylation in BWS patients. This study investigated the mechanism involved in the risk of ICR2 loss of DNA methylation in BWS and showed that within this 4.5 kb region, two SNPs (rs11823023 and rs179436) affect CTCF occupancy at DNA motifs flanking the CTCF 20 bp core motifs. This study identifies a new cis-regulatory region and highlights the crucial role of CTCF for the regulation of genomic imprinting at the CDKN1C/KCNQ1 domain. These recent findings bring new insights in the regulation of genomic imprinting at both the IGF2/H19 and CDKN1C/KCNQ1 domains. arabic 8 English 50
Mansur Ennuri Moftah Shmela(9-2014)

Background: During the last three decades there are many viral infections emerging and re-emerge with high socio-economic and public health impacts worldwide. The Coronavirus Severe Acute Respiratory Syndrome (SARS-CoV-2) emerged in China in late December 2019. Later, on 30th Jan 2020, the World Health Organization (WHO) has constituted the COVID-19 as a public health emergency of international concern (PHEIC). arabic 15 English 86
Abdusalam Sharef Mahmoud, Abdulgader Dhawi Alfitouri Dhawi, Aziza Sulieman Mayouf , Ahlam Masaud Ellafi(3-2021)

The imprinted expression of the IGF2 and H19 genes is controlled by the imprinting control region 1 (ICR1) located at chromosome 11p15.5. This methylation-sensitive chromatin insulator works by binding the zincfinger protein CTCF in a parent-specific manner. DNA methylation defects involving the ICR1 H19/IGF2 domain result in two growth disorders with opposite phenotypes: an overgrowth disorder, the Beckwith– Wiedemann syndrome (maternal ICR1 gain of methylation in 10% of BWS cases) and a growth retardation disorder, the Silver–Russell syndrome (paternal ICR1 loss of methylation in 60% of SRS cases). Although a few deletions removing part of ICR1 have been described in some familial BWS cases, little information is available regarding the mechanism of ICR1 DNA methylation defects. We investigated the CTCF gene and the ICR1 domain in 21 BWS patients with ICR1 gain of methylation and 16 SRS patients with ICR1 loss of methylation. We identified four constitutional ICR1 genetic defects in BWS patients, including a familial case. Three of those defects are newly identified imprinting defects consisting of small deletions and a single mutation, which do not involve one of the CTCF binding sites. Moreover, two of those defects affect OCT-binding sequences which are suggested to maintain the unmethylated state of the maternal allele. A single-nucleotide variation was identified in a SRS patient. Our data extends the spectrum of constitutive genetic ICR1 abnormalities and suggests that extensive and accurate analysis of ICR1 is required for appropriate genetic counseling in BWS patients with ICR1 gain of methylation.
Demars, J., Mansur Ennuri Moftah Shmela, S. Rossignol, J. Okabe, I. Netchine, S. Azzi, S. Cabrol, C. Le Caignec, A. David , Y. Le Bouc, A. El-Osta , C. Gicquel(9-2010)

The imprinted 11p15 region is organized in two domains, each of them under the control of its own imprinting control region (ICR1 for the IGF2/H19 domain and ICR2 for the KCNQ1OT1/CDKN1C domain). Disruption of 11p15 imprinting results in two fetal growth disorders with opposite phenotypes: the Beckwith-Wiedemann (BWS) and the Silver-Russell (SRS) syndromes. Various 11p15 genetic and epigenetic defects have been demonstrated in BWS and SRS. Among them, isolated DNA methylation defects account for approximately 60% of patients. To investigate whether cryptic copy number variations (CNVs) involving only part of one of the two imprinted domains account for 11p15 isolated DNA methylation defects, we designed a single nucleotide polymorphism array covering the whole 11p15 imprinted region and genotyped 185 SRS or BWS cases with loss or gain of DNA methylation at either ICR1 or ICR2. We describe herein novel small gain and loss CNVs in six BWS or SRS patients, including maternally inherited cis-duplications involving only part of one of the two imprinted domains. We also show that ICR2 deletions do not account for BWS with ICR2 loss of methylation and that uniparental isodisomy involving only one of the two imprinted domains is not a mechanism for SRS or BWS. arabic 22 English 137
- Demars, J., S. Rossignol, I. Netchine, K. S. Lee, Mansur Ennuri Moftah Shmela, L. Faivre, J. Weill, S. Odent, S. Azzi, P. Callier, J. Lucas, C. Dubourg, J. Andrieux, Y. Le Bouc, A. El-Osta , C. Gicquel(10-2011)