Publications by authors named "Siham Fellahi"

18 Publications

  • Page 1 of 1

Biological and molecular characterization of a sheep pathogen isolate of and leukotoxin production kinetics.

Vet World 2021 Aug 7;14(8):2031-2040. Epub 2021 Aug 7.

Department of Microbiology, Immunology and Contagious Diseases, Institute of Agronomy and Veterinary Medicine Hassan II, Rabat, Morocco.

Background And Aim: (Mha) is a common agent of pneumonia in ruminants globally, causing economic losses by morbidity, mortality, and treatment costs. Infection by Mha is often associated with or promoted by respiratory viral pathogens and environmental conditions. Infections due to Mha have rarely been described in small ruminants. This study reports the biological and molecular characteristics of a new Moroccan Mha isolate from small ruminants presenting typical respiratory symptoms. We also studied the cultural parameters, growth kinetics, and Lkt excretion of the isolate and its pathogenicity on laboratory animals and small ruminants.

Materials And Methods: Suspected pasteurellosis cases in sheep and goat flocks in Morocco were investigated. A local strain of Mha was isolated and identified using biochemical and molecular methods. Polymerase chain reaction-targeting specific genes were used for serotyping and phylogenetic analyses; further, leukotoxin production, cytotoxicity, and pathogenicity of the isolate in mice, goats, and sheep were investigated.

Results: Phylogeny analysis revealed 98.76% sequence identity with the USA isolate of 2013; the strain growth with a cycle of 9-10 h with leukotoxin secretion was detected by NETosis and quantified by cytotoxicity and mortality of mice. Goat and sheep infections cause hyperthermia, with characteristic postmortem lesions in the trachea and lung.

Conclusion: A local isolate of Mha from sheep that died of pneumonia was characterized for the 1 time in North Africa using biological and molecular methods. Although growth on appropriate culture media is accompanied by intense leukotoxin secretion, experimental infections of sheep and goats cause hyperthermia and typical lesions of pneumonia.
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http://dx.doi.org/10.14202/vetworld.2021.2031-2040DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8448628PMC
August 2021

Protective Efficacy Evaluation of Four Inactivated Commercial Vaccines Against Low Pathogenic Avian Influenza H9N2 Virus Under Experimental Conditions in Broiler Chickens.

Avian Dis 2021 09;65(3):351-357

Unité de Pathologie Aviaire, Département de Pathologie et Santé Publique Vétérinaire, Institut Agronomique et Vétérinaire Hassan II, Rabat, Morocco (10000),

Avian influenza vaccines are commonly used in the poultry industry. The objective of this study was to compare, under experimental conditions, the protective efficacy of four imported commercial inactivated H9N2 vaccines (A, B, C, and D) in broiler chickens. A total of 150 one-day-old chicks were divided into six groups: four experimental groups, each containing 30 chicks, received one of the vaccines (A, B, C, or D) delivered in a 0.3-ml dose subcutaneously at 1 day of age, whereas the control, Group T, was not vaccinated but challenged and Group E was kept unvaccinated and unchallenged. At 21 days postvaccination, Groups A, B, C, D, and T were challenged with 10 embryo infective dose 50% of A/Chicken/Morocco/01/2016 (H9N2). All chicks were observed daily for clinical signs during the 12 days postchallenge (dpc). At 5 and 12 dpc, chicks were euthanatized for necropsy examination. Blood samples were collected weekly for serologic analysis and oropharyngeal swabs were collected for virus detection by real-time RT-PCR. Respiratory signs started at 48 hr pc and maximum severity was observed on 9 dpc. Chiefly, the birds vaccinated with vaccine B showed significantly more respiratory signs than did their counterparts. Serologic analysis revealed that the sera of Groups A and D birds showed a decrease in antibody (Ab) levels up to day 26; then a slight increase of Ab level was observed until day 31, while Group B and C birds showed a stabilization of the titers from day 21 until the end of the experiment. The viral shedding rate was significantly lower in Groups C and A (40%-50% of the birds shed virus for <7 days) compared with other challenged groups (60%-75% of the birds shed virus for ≥9 days). This experiment illustrated that vaccination applied on the first day in the hatchery with the four vaccines tested did not provide an acceptable protection against H9N2 in comparison with the controls that did not receive any vaccine. However, at first glance, we might favor vaccines A and C for their ability to reduce and shorten viral shedding as compared with vaccines B and D.
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http://dx.doi.org/10.1637/aviandiseases-D-21-00015DOI Listing
September 2021

Pathogenesis of Avian Influenza Virus Subtype H9N2 in Turkeys and Evaluation of Inactivated Vaccine Efficacy.

Avian Dis 2021 03;65(1):46-51

Unité de Pathologie Aviaire, Département de Pathologie et Santé Publique Vétérinaire, Institut Agronomique et Vétérinaire Hassan II, Rabat, Morocco.

Avian influenza H9N2 viruses circulate in all types of poultry species, including turkeys, and cause significant losses for the poultry industry in many parts of the word. The aim of this study was to assess the pathogenesis of the Moroccan avian influenza virus (AIV) H9N2 under experimental conditions in turkeys and the protection efficacy of an inactivated commercial vaccine against AIV H9N2. Unvaccinated turkeys showed marked depression sinusitis, respiratory distress characterized by bronchiolar and tracheal rales of moderate severity, and a mortality rate of 50%. Postmortem examinations of dead and euthanatized birds revealed the presence of fibrinous tracheitis and airsacculitis lesions. Vaccination reduced the mortality rate to 20%. Vaccinated birds recovered at day 10 postchallenge, and only 12.5% (1/8) and 37.5% of birds still displayed fibrinous and nonfibrinous airsacculitis lesions, respectively, at day 15 postinoculation. Viral shedding in cloacal and tracheal swabs was lower in vaccinated than in control birds. Although viral RNA was detected in the cloacal swabs of all unvaccinated turkeys at day 3 postinoculation, only 50% of the vaccinated turkeys were positive for virus detection. At day 11 postinoculation, no viral RNA was detected in oropharyngeal swabs of vaccinated turkeys, whereas 40% of the unvaccinated turkeys were still shedding virus.
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http://dx.doi.org/10.1637/aviandiseases-D-20-00067DOI Listing
March 2021

Draft Genome Sequence of the Capripoxvirus Vaccine Strain KSGP 0240, Reisolated from Cattle.

Microbiol Resour Announc 2021 Jul 29;10(30):e0044021. Epub 2021 Jul 29.

Research and Development Department, Multi-Chemical Industry, Mohammedia, Morocco.

Control of lumpy skin disease in cattle is based on vaccination with live attenuated vaccines. The Kenyan strain KSGP 0240 is commonly used to vaccinate ruminants against capripox infections, but the conferred protection is still controversial. In this study, we report the draft genome sequence of the vaccine strain KSGP 0240, reisolated from cattle.
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http://dx.doi.org/10.1128/MRA.00440-21DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8320456PMC
July 2021

Investigation of Post Vaccination Reactions of Two Live Attenuated Vaccines against Lumpy Skin Disease of Cattle.

Vaccines (Basel) 2021 Jun 8;9(6). Epub 2021 Jun 8.

MCI Santé Animale, Mohammedia 28810, Morocco.

Lumpy skin disease virus (LSDV) causes an economically important disease in cattle. The only method for successful control is early diagnosis and efficient vaccination. Adverse effects of vaccination such as local inflammation at the injection site and localized or generalized skin lesions in some vaccinated animals have been reported with live vaccines. The aim of this work was to compare the safety of two lumpy skin disease (LSD) vaccine strains, Kenyan (Kn) Sheep and Goat Pox (KSGP O-240) and LSDV Neethling (Nt) strain, and to determine the etiology of the post-vaccination (pv) reactions observed in cattle. Experimental cattle were vaccinated under controlled conditions with Nt- and KSGP O-240-based vaccines, using two different doses, and animals were observed for 3 months for any adverse reactions. Three out of 45 cattle vaccinated with LSDV Nt strain (6.7%) and three out of 24 cattle vaccinated with Kn strain (12.5%) presented LSD-like skin nodules, providing evidence that the post-vaccination lesions may not be strain-dependent. Lesions appeared 1-3 weeks after vaccination and were localized in the neck or covering the whole body. Animals recovered after 3 weeks. There is a positive correlation between the vaccine dose and the appearance of skin lesions in vaccinated animals; at the 105 dose, 12% of the animals reacted versus 3.7% at the 104 dose. Both strains induced solid immunity when protection was measured by neutralizing antibody seroconversion.
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http://dx.doi.org/10.3390/vaccines9060621DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8226854PMC
June 2021

Genome Sequence of MHA.Sh.MOR19 Serotype 1, a Moroccan Sheep Isolate.

Microbiol Resour Announc 2021 May 27;10(21):e0035921. Epub 2021 May 27.

Research and Development Department, Multi-Chemical Industry, Mohammedia, Morocco.

Mannheimia haemolytica is the principle bacterial pathogen in ruminants associated with respiratory disease. Here, we report the draft genome sequence of the Mannheimia haemolytica MHA.Sh.MOR19 strain that was recently isolated in the northwest of Morocco from the lung of a lamb that died from pneumonia. The genome size is 2,434,458 bp.
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http://dx.doi.org/10.1128/MRA.00359-21DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8201628PMC
May 2021

The expression in plants of an engineered VP2 protein of Infectious Bursal Disease Virus induces formation of structurally heterogeneous particles that protect from a very virulent viral strain.

PLoS One 2021 16;16(2):e0247134. Epub 2021 Feb 16.

Laboratory of Biotechnology, ENEA Casaccia Research Center, Rome, Italy.

Infectious Bursal Disease Virus (IBDV), the etiological agent of Gumboro disease, causes mortality and immunosuppression in chickens and major losses to poultry industry worldwide. The IBDV major capsid protein VP2 is considered the best candidate for the production of novel subunit vaccines. This structural protein contains the major conformational epitopes responsible for the induction of IBDV neutralizing antibodies in chickens and has been demonstrated able to form supramolecular structures in yeast and insect cells. The aim of this study was to express an engineered version of the VP2 protein (His-pVP2) to verify its ability to self-assemble into virus-like particles in plants. The recombinant VP2 was transiently expressed by agroinfiltration in Nicotiana benthamiana and transmission electron microscopy of sucrose density gradient fractions revealed the presence of a mixed population of differently shaped particles ranging from spherical capsids, with a diameter between ~25 and ~70 nm, to tubular structures, with variable length (from 100 to 400 nm). The recombinant VP2-based particles when used for the intramuscular immunization of specific-pathogen-free chicks resulted able to induce the production of anti-IBDV specific antibodies at titers comparable to those induced by a commercial vaccine. Moreover, all the immunized birds survived to the challenge with a Moroccan very virulent IBDV strain with no major histomorphological alterations of the Bursa of Fabricius, similarly to what obtained with the commercial inactivated vaccine.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0247134PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7886152PMC
September 2021

Complete genome analysis and time scale evolution of very virulent infectious bursal disease viruses isolated from recent outbreaks in Morocco.

Infect Genet Evol 2020 01 31;77:104097. Epub 2019 Oct 31.

Université de Toulouse, INRA, ENVT, IHAP, F- 31076 Toulouse, France. Electronic address:

Emerging of very virulent infectious bursal disease virus (vvIBDV) genotype in poultry flocks in Morocco were characterized. VP2 sequence analysis showed that the strains of Moroccan vvIBDV genotypes clustered separately from classic and vaccine strains reference of IBDV. The full-length genome of four Moroccan vvIBDV strains was determined, in order to get a more exhaustive molecular characterization allowing to conduct the evolution time scale and speculations on their origin. In a phylogenetic tree, nucleotide sequences of segment A and B formed a common branch with those vvIBDV references strains published in GenBank, but they clearly grouped into a distinct subcluster. An alignment of deduced amino acid sequences segment B, confirmed the presence of the conserved TDN tripeptide found in all of the vvIBDV genotype and revealed the presence of 2 substitutions I472L and E688D specific for the vvIBDV Moroccan isolates. The deduced amino acid sequences of segment A genes showed the presence of the "signature" typical of the vvIBDV genotype and revealed the presence of 7 aa substitutions specific for the vvIBDV Moroccan strains. The evolution rate for IBDV VP2 gene was estimated at 5.875 × 10 substitutions/site/year. The estimation of the time to most common recent ancestor of Moroccan vvIBDV based on the VP2 sequences available was 31 years, corresponding to 3 years earlier than the first vvIBDV case detection in layers in the country.
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http://dx.doi.org/10.1016/j.meegid.2019.104097DOI Listing
January 2020

Co-infections of chickens with avian influenza virus H9N2 and Moroccan Italy 02 infectious bronchitis virus: effect on pathogenesis and protection conferred by different vaccination programmes.

Avian Pathol 2020 Feb 3;49(1):21-28. Epub 2019 Oct 3.

Université de Toulouse, ENVT, INRA, UMR IHAP, Toulouse, France.

Since the emergence of low pathogenic avian influenza (LPAI) H9N2 viruses in Morocco in 2016, severe respiratory problems have been encountered in the field. Infectious bronchitis virus (IBV) is often detected together with H9N2, suggesting disease exacerbation in cases of co-infections. This hypothesis was therefore tested and confirmed in laboratory conditions using specific-pathogen-free chickens. Most common field vaccine programmes were then tested to compare their efficacies against these two co-infecting agents. IBV γCoV/chicken/Morocco/I38/2014 (Mor-IT02) and LPAI virus A/chicken/Morocco/SF1/2016 (Mor-H9N2) were thus inoculated to commercial chickens. We showed that vaccination with two heterologous IBV vaccines (H120 at day one and 4/91 at day 14 of age) reduced the severity of clinical signs as well as macroscopic lesions after simultaneous experimental challenge. In addition, LPAI H9N2 vaccination was more efficient at day 7 than at day 1 in limiting disease post simultaneous challenge. Simultaneous challenge with IBV and AIV H9N2 induced higher pathogenicity in SPF birds than inoculation with IBV or AIV H9N2 alone.Recommended vaccination programme in commercial broilers to counter Mor-IT02 IBV and LPAIV H9N2 simultaneous infections: IB live vaccine H120 (d1), AIV H9N2 inactivated vaccine (d7), IB live vaccine 4-91 (d14).
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http://dx.doi.org/10.1080/03079457.2019.1656328DOI Listing
February 2020

Functional characterization of a plant-produced infectious bursal disease virus antigen fused to the constant region of avian IgY immunoglobulins.

Appl Microbiol Biotechnol 2019 Sep 22;103(18):7491-7504. Epub 2019 Jul 22.

Laboratory of Biotechnology, ENEA Casaccia Research Center, Rome, Italy.

Infectious bursal disease virus (IBDV) is the cause of an economically important highly contagious disease of poultry, and vaccines are regarded as the most beneficial interventions for its prevention. In this study, plants were used to produce a recombinant chimeric IBDV antigen for the formulation of an innovative subunit vaccine. The fusion protein (PD-FcY) was designed to combine the immunodominant projection domain (PD) of the viral structural protein VP2 with the constant region of avian IgY (FcY), which was selected to enhance antigen uptake by avian immune cells. The gene construct encoding the fusion protein was transiently expressed in Nicotiana benthamiana plants and an extraction/purification protocol was set up, allowing to reduce the contamination by undesired plant compounds/proteins. Mass spectrometry analysis of the purified protein revealed that the glycosylation pattern of the FcY portion was similar to that observed in native IgY, while in vitro assays demonstrated the ability of PD-FcY to bind to the avian immunoglobulin receptor CHIR-AB1. Preliminary immunization studies proved that PD-FcY was able to induce the production of protective anti-IBDV-VP2 antibodies in chickens. In conclusion, the proposed fusion strategy holds promises for the development of innovative low-cost subunit vaccines for the prevention of avian viral diseases.
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http://dx.doi.org/10.1007/s00253-019-09992-9DOI Listing
September 2019

Molecular characterization and phylogenetic analysis of very virulent infectious bursal disease virus circulating in Morocco during 2016-2017.

Arch Virol 2019 Feb 26;164(2):381-390. Epub 2018 Oct 26.

Unité de Pathologie Aviaire, Département de Pathologie et Santé Publique Vétérinaire, IAV Hassan II, BP 6202, Rabat-Instituts, 10000, Rabat, Morocco.

Very virulent infectious bursal disease virus (vvIBDV), the cause of significant economic losses in many poultry-producing areas, has been present in Morocco since 1991. In spite of the introduction of vaccination, disease outbreaks are frequently observed. To ascertain if vaccines failure may be due to the emergence of new strains, the aim of this study was to perform for the first time the molecular characterization of vvIBDV strains circulating in Morocco by focusing on the hypervariable region (HVR) of the VP2 protein, which is frequently used for molecular epidemiology and phylogenetic studies. Field samples of haemorrhagic bursae of Fabricius were collected for molecular characterization in different parts of the country during 2016-2017 from 48 chicken flocks showing symptoms of disease. In a phylogenetic tree, nucleotide sequences containing the VP2 HVR of 13 samples that were positive for vvIBDV formed a common branch with those of vvIBDV references strains published in GenBank, but they clearly grouped into a distinct subcluster. An alignment of the deduced amino acid sequences, in addition to confirming the presence of the "signature" typical of the vvIBDV HVR, also revealed the presence of substitutions in hydrophilic loops that are known to be involved in the elicitation of neutralizing antibodies. One of these substitutions is unique to the Moroccan isolates. These results represent the first molecular characterization of vvIBDV isolates in Morocco and may indicate that one of the causes of vaccine ineffectiveness is antigenic drift.
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http://dx.doi.org/10.1007/s00705-018-4076-3DOI Listing
February 2019

Efficacy of Massachusetts and 793B Vaccines Against Infectious Bronchitis Moroccan-Italy 02 Virus in Specific-Pathogen-Free Chickens and Commercial Broilers.

Avian Dis 2017 12;61(4):466-471

A Unité de Pathologie Aviaire, Département de Pathologie et Santé Publique Vétérinaire, Institut Agronomique et Vétérinaire Hassan II, BP 6202, Rabat- Instituts, Rabat, Morocco 10000.

The ability of commercial vaccines H120 and 4/91 to protect against Moroccan-Italy 02 infectious bronchitis virus (Mor-It02) was investigated in specific-pathogen-free (SPF) chickens and commercial broiler chickens. Commercial broiler chicks (Experiment 1) were vaccinated at the hatchery with H120 vaccine at Day 1, and challenged at Day 21 with 10 50% egg-infective dose (EID) of Mor-It02. All chicks were observed daily for clinical signs attributable to Mor-It02 infection during the 10 days postchallenge (pc). At 5 and 10 days pc, chicks were humanely sacrificed for necropsy examination, and tissues were collected for histopathology evaluation. To better understand the findings on commercial broilers, day-old SPF chicks were divided into five groups in a second experiment: Group Mass/4-91, vaccinated with H120 and 4/91 respectively at Days 1 and 15 of age; Group Mass/Mass, vaccinated by H120 at Days 1 and 15; Group Mass, vaccinated with H120 at Day 1; Group NV, kept unvaccinated; and Group NC, kept as a negative control (unchallenged). At Day 24 of age, Groups Mass/4-91, Mass/Mass, Mass, and NV were challenged with 10 EID of Mor-It02. In both experiments, blood samples were collected at different periods for serologic analyses. Oropharyngeal swabs were collected for virus detection by reverse-transcription PCR. In Experiments 1 and 2, respiratory signs started as early as 24 hr pc and maximum severity was observed on Days 3 and 4 pc. The viral shedding rate was significantly lower in Group Mass/4-91 compared to other challenged groups. Serologic analysis in both experiments showed that the sera of challenged group exhibited significantly higher antibody titers than sera collected before challenge. Histopathologic investigations in SPF birds showed deciliation and hyperplasia in Group NV and less-pronounced lesions in Groups Mass/Mass and Mass. In commercial broilers vaccinated with H120 alone, hyperplasia and deciliation were observed in 90% of the tracheas. These experiments illustrated that Mor-It02 is pathogenic for chickens and a combination of live H120 and 4/91 vaccines given respectively at Day 1 and Day 15 of age confer a good protection against Mor-It02.
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http://dx.doi.org/10.1637/11686-060817-Reg.1DOI Listing
December 2017

Phylogenetic analysis of avian infectious bronchitis virus isolates from Morocco: a retrospective study (1983 to 2014).

Virol Sin 2017 Apr;32(2):155-158

Interactions Hôtes-Agents Pathogènes, Université de Toulouse, Institut National de la Recherche Agronomique, École National Vétérinaire de Toulouse, Toulouse, 31076, France.

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http://dx.doi.org/10.1007/s12250-016-3885-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6598899PMC
April 2017

First outbreaks and phylogenetic analyses of avian influenza H9N2 viruses isolated from poultry flocks in Morocco.

Virol J 2016 08 15;13(1):140. Epub 2016 Aug 15.

IHAP, Université de Toulouse, INRA, ENVT, F-31076, Toulouse, France.

Background: H9N2 avian influenza viruses continue to spread in poultry and wild birds worldwide. Morocco just faced its first H9N2 influenza virus outbreaks early 2016 affecting different types of poultry production. After its introduction, the virus spread very rapidly throughout the country.

Methods: Samples were collected from 11 chicken flocks with high morbidity and mortality rates. Four viruses were successfully isolated from broiler chickens and one from broiler breeders and fully sequenced.

Results: Phylogenetic and molecular markers analyses showed the Moroccan viruses belonged to the G1 lineage and likely originated from the Middle East. As known for H9N2 viruses, the Moroccanisolates possess several genetic markers that enhance virulence in poultry and transmission to humans.

Conclusion: The present study demonstrated that under field conditions H9N2 could have a devastating effect on egg production and mortalities and highlighted a lack of surveillance data on the pathogen in the region.
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http://dx.doi.org/10.1186/s12985-016-0596-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4986173PMC
August 2016

Avian infectious bronchitis virus in Africa: a review.

Vet Q 2016 Jun 12;36(2):71-5. Epub 2016 Jan 12.

a Laboratory of Virology, Microbiology and Quality/Ecotoxicology & Biodiversity, Faculty of Sciences and Techniques Mohammedia , University Hassan II of Casablanca , Morocco.

Infectious bronchitis virus (IBV) is worldwide in distribution, highly infectious, and extremely difficult to control because it has extensive genetic diversity, a short generation time, and a high mutation rate. IBV is a Gammacoronavirus, single-stranded, and positive-sense RNA virus. Avian infectious bronchitis is well studied in European countries with identification of a large number of IBV variants, whereas in African countries epidemiological and scientific data are poor and not updated. However, previous studies reported that an IBV variant continues to appear regularly in Africa, as currently described in Morocco. No cross-protection between IBV strains was reported, some being unique to a particular country, others having a more general distribution. This review aims to provide a general overview on IB disease distribution in African countries and an update on the available studies of IBV variants in each country.
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http://dx.doi.org/10.1080/01652176.2015.1126869DOI Listing
June 2016

Comparison of SYBR green I real-time RT-PCR with conventional agarose gel-based RT-PCR for the diagnosis of infectious bronchitis virus infection in chickens in Morocco.

BMC Res Notes 2016 Apr 22;9:231. Epub 2016 Apr 22.

Laboratory of Virology, Microbiology and Quality/Ecotoxicology & Biodiversity, Faculty of Sciences and Techniques-University Hassan II Mohammedia, PO Box 146, Quartier Yasmina-Mohammedia, 20650, Casablanca, Morocco.

Background: A rapid, sensitive, and specific molecular method for the diagnosis of infectious bronchitis virus (IBV) infection is important in curbing infectious bronchitis outbreaks in Morocco and other countries.

Methods: In this study, an easy-to-perform SYBR green I real-time reverse transcriptase polymerase chain reaction (RT-PCR) targeting the nucleocapsid gene of IBV was developed and compared with conventional agarose gel-based RT-PCR for the detection of IBV infection.

Results: We found that the SYBR green I real-time RT-PCR was at least 10 times more sensitive than the agarose gel electrophoresis detection method. The assay exhibited high specificity for IBV infection. All negative controls, such as Newcastle disease virus, infectious bursal disease virus, and avian influenza virus, were not detected.

Conclusion: The SYBR green I real-time RT-PCR test described herein can be used to rapidly distinguish IBV from other respiratory pathogens, which is important for diagnosis and control of infectious bronchitis outbreaks in Morocco. The test is a valuable and useful method as a routine assay for diagnosis of clinical IBV infection in commercial chickens.
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http://dx.doi.org/10.1186/s13104-016-2037-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4841946PMC
April 2016

Phylogenetic analysis of avian infectious bronchitis virus S1 glycoprotein regions reveals emergence of a new genotype in Moroccan broiler chicken flocks.

Virol J 2015 Aug 4;12:116. Epub 2015 Aug 4.

Laboratoirede Virologie, Microbiologie et Qualité/ETB- Faculté des Sciences et Techniques, Mohammedia, Université Hassan II- Casablanca, Mohammedia, 20650, Morocco.

Background: Infectious bronchitis virus (IBV), a major pathogen of commercial poultry flocks, circulates in the form of several serotypes/genotypes. Only a few amino-acid changes in the S1 subunit of wild-type IBVS proteins may result in mutants unaffected by current vaccines.

Methods: Partial S1 gene sequences of 3 IBV isolates of the Moroccan Italy 02 genotype from vaccinated and unvaccinated broiler chicken flocks, located in southern and central regions of Morocco, were amplified by RT-PCR, sequenced, and aligned for phylogenetic and amino-acid similarity analyses.

Results: The three isolates were found genetically highly distant from known avian IBV based on partial sequences of their S1 genes: gammaCoV/chicken/Morocco/I01/2011(IBV/Morocco/01), gammaCoV/chicken/Morocco/I30/2010 (IBV/Morocco/30), and gammaCoV/chicken/Morocco/I38/2013 (IBV/Morocco/38), nucleotide sequence identities reached 89.5 % to 90.9 % among the three isolates. The deduced protein sequence identities ranged from 29.7 % (between IBV/Morocco/38 and Egypt SCU-14/2013-1) to 78.2 % (between IBV/Morocco/01 and Spain/05/866). Amino acid sequence comparison and phylogenetic analysis indicated the emergence of a new Moroccan genotype, clustering with regionally related isolates from Spain (Spain/05/866) and belonging to a new sub-genotype.

Conclusion: Our sequencing results demonstrate a co-circulation of wild-type infectious bronchitis viruses in broiler chickens. These results justify permanent monitoring of circulating strains in order to rationally modify vaccination strategies to make them appropriate to the evolving field situation.
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http://dx.doi.org/10.1186/s12985-015-0347-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4524495PMC
August 2015

Prevalence and molecular characterization of avian infectious bronchitis virus in poultry flocks in Morocco from 2010 to 2014 and first detection of Italy 02 in Africa.

Avian Pathol 2015 ;44(4):287-95

a Unité de Pathologie Aviaire, Département de Pathologie et Santé Publique Vétérinaire , Institut Agronomique et Vétérinaire Hassan II , Rabat , Morocco.

The aim of this study was to investigate the prevalence and diversity of infectious bronchitis virus (IBV) genotypes in poultry flocks in 16 areas of Morocco between 2010 and 2014. A total of 360 chicken flocks suspected of being infected by IBV were screened for the IBV N gene using real-time reverse transcriptase-polymerase chain reaction (RT-PCR). Flocks were classified into four groups according to their IBV vaccination programme. Group 1 contained unvaccinated birds. Group 2 received a single application of live H120 vaccine. Groups 3 and 4 birds received one or two booster vaccination(s), respectively, mostly using the H120 vaccine. The real-time RT-PCR results showed that 51.7% of the flocks were positive for the IBV genome with geographical disparities. Molecular characterization of IBV was performed on 50 RT-PCR positive samples by partially sequencing the S1 gene, including the hypervariable regions (nucleotides 705-1097). Two predominant genotypes were detected, with the Massachusetts type dominating (66%), among which 25% of the samples were identical to the H120 vaccine. The second most common genotype (present in 32% of the flocks) was surprisingly Italy 02, revealing the first detection of this genotype in Morocco and also in Africa. 793B, the predominant genotype in the late 1990s in Morocco, was only detected on one occasion and was identical to the 4/91 vaccine strain. This study highlights the high prevalence of IBV in poultry farms in Morocco and confirms its continuous dynamic changes and evolution.
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http://dx.doi.org/10.1080/03079457.2015.1044422DOI Listing
December 2016
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