Publications by authors named "Khalid Omari Tadlaoui"

14 Publications

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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

Capripoxvirus Infections in Ruminants: A Review.

Microorganisms 2021 Apr 23;9(5). Epub 2021 Apr 23.

Department of Microbiology, Immunology and Contagious Diseases, Agronomic and Veterinary Institute Hassan II, Madinat Al Irfane, Rabat 6202, Morocco.

Lumpy skin disease, sheeppox, and goatpox are notifiable diseases of cattle, sheep, and goats, respectively, caused by viruses of the Capripoxvirus genus. They are responsible for both direct and indirect financial losses. These losses arise through animal mortality, morbidity cost of vaccinations, and constraints to animals and animal products' trade. Control and eradication of capripoxviruses depend on early detection of outbreaks, vector control, strict animal movement, and vaccination which remains the most effective means of control. To date, live attenuated vaccines are widely used; however, conferred protection remains controversial. Many vaccines have been associated with adverse reactions and incomplete protection in sheep, goats, and cattle. Many combination- and recombinant-based vaccines have also been developed. Here, we review capripoxvirus infections and the immunity conferred against capripoxviruses by their respective vaccines for each ruminant species. We also review their related cross protection to heterologous infections.
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http://dx.doi.org/10.3390/microorganisms9050902DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8145859PMC
April 2021

Comparative sensitivity study of primary cells, vero, OA3.Ts and ESH-L cell lines to lumpy skin disease, sheeppox, and goatpox viruses detection and growth.

J Virol Methods 2021 07 14;293:114164. Epub 2021 Apr 14.

Laboratory of Research and Development virology, MCI Animal Health, Lot. 157, Zone Industrielle Sud-Ouest (ERAC) B.P: 278, 28810 Mohammedia, Morocco.

Lumpy skin disease virus (LSDV), sheeppox virus (SPPV) and goatpox (GTPV) virus have been usually grown on primary cells for diagnosis, production and titration purposes. The use of primary cells present several inconvenient, heavy preparation, heterogeneous cell population, non-reproducible viral titration and presence of potential endogenous contaminants. Therefore investigating sensitivity of candidate continuous cell lines is needed. In this study, we compared the above Capripox viruses (CaPVs) sensitivity of primary cells of four origin (heart, skin, testis and kidney), with three cell lines (Vero, OA3.Ts and ESH-L). We tested sensitivity for virus isolation, replication cycle and titration, revealed by cytopathic effect (CPE), immunoenzymatic staining and immunofluorescence. Our results show that ESH-L cells and primary fetal heart cells present the highest sensitivity for CaPVs growth and detection. Vero cells can replicate those viruses but without showing any CPE while the titer obtained on OA3.Ts is lower than primary and ESH-L cells. ESH-L cells are an effective alternative to primary cells use for growing Capripoxviruses and their diagnosis.
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http://dx.doi.org/10.1016/j.jviromet.2021.114164DOI Listing
July 2021

Development of an inactivated combined vaccine for protection of cattle against lumpy skin disease and bluetongue viruses.

Vet Microbiol 2021 May 23;256:109046. Epub 2021 Mar 23.

Research and Development, MCI Santé Animale, ZI Sud-Ouest B.P: 278, Mohammedia, 28810, Morocco.

Lumpy Skin Disease (LSD) and Bluetongue (BT) are the main ruminants viral vector-borne diseases. LSD is endemic in Africa and has recently emerged in Europe and central Asia as a major threat to cattle industry. BT caused great economic damage in Europe during the last decade with a continuous spread to other countries. To control these diseases, vaccination is the only economically viable tool. For LSD, only live-attenuated vaccines (LAVs) are commercially available, whilst for BT both LAVs and inactivated vaccines are available with a limited number of serotypes. In this study, we developed an inactivated, oil adjuvanted bivalent vaccine against both diseases based on LSDV Neethling strain and BTV4. The vaccine was tested for safety and immunogenicity on cattle during a one-year period. Post-vaccination monitoring was carried out by VNT and ELISA. The vaccine was completely safe and elicited high neutralizing antibodies starting from the first week following the second injection up to one year. Furthermore, a significant correlation (R = 0.9040) was observed when comparing VNT and competitive ELISA in BTV4 serological response. Following BTV4 challenge, none of vaccinated and unvaccinated cattle were registered clinical signs, however vaccinated cattle showed full protection from viraemia. In summary, this study highlights the effectiveness of this combined vaccine as a promising solution for both LSD and BT control. It also puts an emphasis on the need for the development of other multivalent inactivated vaccines, which could be greatly beneficial for improving vaccination coverage in endemic countries and prophylaxis of vector-borne diseases.
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http://dx.doi.org/10.1016/j.vetmic.2021.109046DOI Listing
May 2021

Experimental infection of indigenous North African goats with goatpox virus.

Acta Vet Scand 2021 Mar 4;63(1). Epub 2021 Mar 4.

Department of Research and Development, Multi-Chemical Industry Santé Animale, Lot. 157, Z I, Sud-Ouest (ERAC) B.P.: 278, 28810, Mohammedia, Morocco.

Background: Goatpox is a viral disease caused by infection with goatpox virus (GTPV) of the genus Capripoxvirus, Poxviridae family. Capripoxviruses cause serious disease to livestock and contribute to huge economic losses. Goatpox and sheeppox are endemic to Africa, particularly north of the Equator, the Middle East and many parts of Asia. GTPV and sheeppox virus are considered host-specific; however, both strains can cause clinical disease in either goats or sheep with more severe disease in the homologous species and mild or sub-clinical infection in the other. Goatpox has never been reported in Morocco, Algeria or Tunisia despite the huge population of goats living in proximity with sheep in those countries. To evaluate the susceptibility and pathogenicity of indigenous North African goats to GTPV infection, we experimentally inoculated eight locally bred goats with a virulent Vietnamese isolate of GTPV. Two uninfected goats were kept as controls. Clinical examination was carried out daily and blood was sampled for virology and for investigating the antibody response. After necropsy, tissues were collected and assessed for viral DNA using real-time PCR.

Results: Following the experimental infection, all inoculated goats displayed clinical signs characteristic of goatpox including varying degrees of hyperthermia, loss of appetite, inactivity and cutaneous lesions. The infection severely affected three of the infected animals while moderate to mild disease was noticed in the remaining goats. A high antibody response was developed. High viral DNA loads were detected in skin crusts and nodules, and subcutaneous tissue at the injection site with cycle threshold (Ct) values ranging from 14.6 to 22.9, while lower viral loads were found in liver and lung (Ct = 35.7 and 35.1). The results confirmed subcutaneous tropism of the virus.

Conclusion: Clinical signs of goatpox were reproduced in indigenous North African goats and confirmed a high susceptibility of the North African goat breed to GTPV infection. A clinical scoring system is proposed that can be applied in GTPV vaccine efficacy studies.
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http://dx.doi.org/10.1186/s13028-021-00574-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7931584PMC
March 2021

Production of small ruminant morbillivirus, rift valley fever virus and lumpy skin disease virus in CelCradle™ -500A bioreactors.

BMC Vet Res 2021 Feb 27;17(1):93. Epub 2021 Feb 27.

Laboratory of Research and Development virology, MCI Animal Health, Lot. 157, Zone Industrielle Sud-Ouest (ERAC) B.P: 278, 28810, Mohammedia, Morocco.

Background: Animal vaccination is an important way to stop the spread of diseases causing immense damage to livestock and economic losses and the potential transmission to humans. Therefore effective method for vaccine production using simple and inexpensive bioprocessing solutions is very essential. Conventional culture systems currently in use, tend to be uneconomic in terms of labor and time involved. Besides, they offer a limited surface area for growth of cells. In this study, the CelCradle™-500A was evaluated as an alternative to replace conventional culture systems in use such as Cell factories for the production of viral vaccines against small ruminant morbillivirus (PPR), rift valley fever virus (RVF) and lumpy skin disease virus (LSD).

Results: Two types of cells Vero and primary Lamb Testis cells were used to produce these viruses. The study was done in 2 phases as a) optimization of cell growth and b) virus cultivation. Vero cells could be grown to significantly higher cell densities of 3.04 × 10 using the CelCradle™-500A with a shorter doubling time as compared to 9.45 × 10 cells in Cell factories. This represents a 19 fold increase in cell numbers as compared to seeding vs only 3.7 fold in Cell factories. LT cells achieved modestly higher cell densities of 6.7 × 10 as compared to 6.3 × 10 in Cell factories. The fold change in densities for these cells was 3 fold in the CelCradle™-500A vs 2.5 fold in Cell factories. The titers in the conventional system and the bioreactor were not significantly different. However, the Cell-specific virus yield for rift valley fever virus and lumpy skin disease virus are higher (25 virions/cell for rift valley fever virus, and 21.9 virions/cell for lumpy skin disease virus versus 19.9 virions/cell for rift valley fever virus and 10 virions/cell for lumpy skin disease virus).

Conclusions: This work represents a novel study for primary lamb testis cell culture in CellCradle™-500A bioreactors. In addition, on account of the high cell densities obtained and the linear scalability the titers could be further optimized using other culture process such us perfusion.
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http://dx.doi.org/10.1186/s12917-021-02801-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7913422PMC
February 2021

Experimental evaluation of the cross-protection between Sheeppox and bovine Lumpy skin vaccines.

Sci Rep 2020 06 1;10(1):8888. Epub 2020 Jun 1.

Research and Development Virology, Multi-Chemical Industry, Lot. 157, Z I, Sud-Ouest (ERAC) B.P.: 278, Mohammedia, 28810, Morocco.

The Capripoxvirus genus includes three agents: Sheeppox virus, Goatpox virus and Lumpy skin disease virus. Related diseases are of economic importance and present a major constraint to animals and animal products trade in addition to mortality and morbidity. Attenuated vaccines against these diseases are available, but afforded cross-protection is controversial in each specie. In this study, groups of sheep, goats and cattle were vaccinated with Romania SPPV vaccine and challenged with corresponding virulent strains. Sheep and cattle were also vaccinated with Neethling LSDV vaccine and challenged with both virulent SPPV and LSDV strains. Animals were monitored by clinical observation, rectal temperature as well as serological response. The study showed that sheep and goats vaccinated with Romania SPPV vaccine were fully protected against challenge with virulent SPPV and GTPV strains, respectively. However, small ruminants vaccinated with LSDV Neethling vaccine showed only partial protection against challenge with virulent SPPV strain. Cattle showed also only partial protection when vaccinated with Romania SPPV and were fully protected with Neethling LSDV vaccine. This study showed that SPPV and GTPV vaccines are closely related with cross-protection, while LSDV protects only cattle against the corresponding disease, which suggests that vaccination against LSDV should be carried out with homologous strain.
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http://dx.doi.org/10.1038/s41598-020-65856-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7264126PMC
June 2020

Development and Evaluation of an Inactivated Lumpy Skin Disease Vaccine for Cattle.

Vet Microbiol 2020 Jun 18;245:108689. Epub 2020 Apr 18.

Research and development Virology, Multi-Chemical Industry, Lot. 157, ZI Sud-Ouest (ERAC) B.P: 278, Mohammedia 28810, Morocco.

Lumpy skin disease (LSD) of cattle is caused by a virus within Capripoxvirus genus. It leads to huge economic losses in addition to trade and animal movement limitation. Vaccination is the only economically feasible way to control this vector-borne disease. Only live attenuated vaccines have been used so far and no inactivated vaccine has been developed nor tested in cattle. In this study, we developed an inactivated oily adjuvanted vaccine based on Neethling strain and tested it on cattle. Selected criteria of appreciation were safety, antibody response by Virus Neutralization and protection through challenge. A field trial was also performed in Bulgaria. The vaccine was safe and did not cause any adverse reaction, high level of specific antibodies was obtained starting from day 7 post-vaccination and protection against virulent challenge strain that caused typical disease in control animals was total. Induced protection was similar to that obtained with live vaccine, without any adverse effect. In addition, the field study confirmed safety and efficacy of the vaccine, which did not show any adverse reaction and induced a high level of antibodies for up to one year. General prophylaxis based on inactivated vaccine could be of great benefit in endemic countries or at risk regions.
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http://dx.doi.org/10.1016/j.vetmic.2020.108689DOI Listing
June 2020

Experimental infection of dromedary camels with virulent virus of Peste des Petits Ruminants.

Vet Microbiol 2019 Aug 8;235:195-198. Epub 2019 Jul 8.

Research and Development, MCI Santé Animale, Lot. 157, Z. I., Sud-Ouest (ERAC) B.P: 278, Mohammedia, 28810, Morocco. Electronic address:

Peste des Petits Ruminants Virus (PPRV) causes a severe contagious disease of sheep and goats and has spread extensively in last years through Asia and Africa. PPRV, known to infect exclusively small ruminants, has been recently reported in camels in Iran and Sudan. Reported clinical symptoms are similar to those observed in small ruminants, fatality rate still unknown. However most of the authors reported seropositive camels without clinical signs. Camel sensitivity to PPRV is still controversial and more investigation need to be performed. In this study, we tested camel susceptibility by an experimental infection using a virulent PPRV strain belonging to lineage IV. Young dromedary camels were infected intravenously and observed one month for clinical symptoms. Viraemia and virus secretion charge in swabs were evaluated by PCR. Seroconversion was assessed by ELISA and virus neutralisation test. Infected animals did not manifest any clinical symptoms of the disease and no virus was detected in secretions. Seroconversion was observed from day 14 post infection.
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http://dx.doi.org/10.1016/j.vetmic.2019.07.004DOI Listing
August 2019

Pathogenicity and Full Genome Sequencing of the Avian Influenza H9N2 Moroccan Isolate 2016.

Avian Dis 2019 03;63(1):24-30

Research and Development Department, Multi-Chemical Industry, Lot 157, Z I, Sud-Ouest (ERAC) B. P. 278, Mohammedia 28810, Morocco.

In Morocco in early 2016, a low pathogenic avian influenza virus serotype H9N2 caused large economic losses to the poultry industry, with specific clinical symptoms and high mortality rates on infected farms. Subsequent to the H9N2 outbreak, the causal agent was successfully isolated from chicken flocks with high morbidity and mortality rates, propagated on embryonated eggs, and fully sequenced. The phylogenetic analysis suggested that the Moroccan isolate could have derived from the Middle East isolate A/chicken/Dubai/D2506.A/2015. This study was designed to assess the pathogenicity of the Moroccan isolate H9N2 in experimentally infected broiler and specific-pathogen-free (SPF) chickens. At 22 days of age, one broiler and two SPF chicken groups were inoculated by dropping 0.2 ml of the H9N2 isolate (10 EID/ml) in both nostrils and eyes. Clinically inoculated chickens with H9N2 displayed mild lesions, low mortality rates, and an absence of clinical signs. The H9N2 virus was more pathogenic in broiler chickens and produced more severe tissue lesions compared to SPF chickens. The viral shedding was detected up to 6 days postinoculation (pi) in oropharyngeal and cloacal swabs in infected birds with a maximum shedding in the oropharynges of the broiler group. All experimental chickens seroconverted and registered high hemagglutination inhibition titers as early as day 7 pi. The present study indicates that the H9N2 virus isolated from a natural outbreak was of low pathogenicity under experimental conditions. However, under field conditions infection with other pathogens might have aggravated the disease.
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http://dx.doi.org/10.1637/11941-080418-Reg.1DOI Listing
March 2019

Thermal Stability Study of Five Newcastle Disease Attenuated Vaccine Strains.

Avian Dis 2016 12;60(4):779-783

Research and Development Department, Multi-Chemical Industry, Lot. 157, Z I, Sud-Ouest (ERAC) B.P.: 278, Mohammedia 28810, Morocco.

Newcastle disease (ND) is a big concern throughout the world because of the devastating losses that can occur with commercial and backyard poultry. The major problem in many countries is the loss of the vaccine's effectiveness due to inadequate use or storage conditions, particularly in hot climates. In the present study, stability of the five, most-used NDV vaccine strains (I-2, LaSota, B1, Clone 30 [C30], and VG-GA) was tested comparatively at different storage temperatures (4 and 37 C for the freeze-dried form and 4, 24, 37, and 45 C for the freeze-dried vaccine reconstituted in diluents). The vaccine stability was evaluated by the cumulative infectious titer drop and the theoretical shelf life at particular temperatures. Results showed that I-2 and LaSota are the most stable vaccine strains compared to B1, C30, and VG-GA; they registered the lowest titer drops and the longest shelf life whether at cool, high, or room temperatures and for both freeze-dried and reconstituted vaccines.
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http://dx.doi.org/10.1637/11426-042116-Reg.1DOI Listing
December 2016

Comparative innocuity and efficacy of live and inactivated sheeppox vaccines.

BMC Vet Res 2016 Jun 29;12(1):133. Epub 2016 Jun 29.

Research and Development Virology, Multi-Chemical Industry, Lot. 157, Z I, Sud-Ouest (ERAC) B.P.: 278, Mohammedia, 28810, Morocco.

Background: Sheeppox (SPP) is one of the priorities, high-impact animal diseases in many developing countries, where live attenuated vaccines are routinely used against sheeppox virus (SPPV). In an event of an SPP outbreak, historically disease-free countries would hesitate to use of live vaccines against SPPVdue to the safety and trade reasons. Currently no killed SPPV vaccines are commercially available. In this study, we developed an inactivated Romanian SPPVvaccine and assessed its efficacy and potency in comparison with a live attenuated Romanian SPPV vaccine. Four naïve sheep were vaccinated once with the Romanian SPPV live attenuated vaccine and16 sheep were vaccinated twice with the inactivated vaccine. All sheep in the live vaccine group were included in the challenge trial, which was conducted using a highly virulent Moroccan SPPV field strain. Eight sheep of the inactivated vaccine group were challenged and the remaining sheep were monitored for seroconversion. Experimental animals were closely monitored for the appearance of clinical signs, body temperature and inflammation at the injection site. Two naïve sheep were used as unvaccinated controls.

Results: The inactivated Romanian SPPV vaccine was found to be safe and confer a good protection, similar to the live vaccine. Specific antibodies appeared from seven days post vaccination and remained up to nine months.

Conclusion: This study showed that the developed inactivated Romanian SPPV vaccine has a potential to replace attenuated vaccine to control and prevent sheep pox in disease-free or endemic countries.
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http://dx.doi.org/10.1186/s12917-016-0754-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4928353PMC
June 2016
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