Doctorat (PRODUCTIONS ANIMALES)

Enquête épidémiologique et prévalence des entérobactéries pathogènes dans la chaîne alimentaire a l’est algérien.

Tue, 28 Mar 2023 00:00:00 GMT

Enquête épidémiologique et prévalence des entérobactéries pathogènes dans la chaîne alimentaire a l’est algérien. Ghougal, khireddine; Dib, Amira Leila; Kürekci, Cemil This study determined the prevalence of pathogenic enterobacteria and identified the main risk factors, in farms, slaughterhouses and butcheries in eastern Algeria, during a twoyear period. Thus, a crosssectional study was conducted, using a simple random sampling method to target 20 farms, 10 slaughterhouses and 5 butcheries. A structured questionnaire was used to assess the hygienic status of the farms, slaughterhouses and butcheries. In addition, 265 samples were collected from walls, soil, litter, feed, water and animal samples consisting mainly of white and red meat, neck skin and liver. aerobic microbial count, Enterobacteriaceae, fecal coliforms and Salmonella were enumerated and selected colonies were identified on the basis of biochemical characteristics and confirmed by MALDI TOF. On the other hand, in order to investigate the use of antibiotics by veterinarians in Algeria, a prospective survey was conducted through a questionnaire. In addition, fifteen antibiotics (15) were used to evaluate the sensitivity of the identified bacteria (n=82). Multiresistant strains (MDR) were tested for resistance genes to betalactams, sulfonamides and quinolones by PCR. The results showed that the prevalence of Enterobacteriaceae is 68.68%. While the prevalence of Escherichia coli and Salmonella spp. is 57.69% and 19.23% respectively. The highest contamination rate was in poultry farms (30.77%), red meat slaughterhouses (18.13%), white meat slaughterhouses (15.38%) and butcher shops (14.84%), followed by beef (13.19%) and sheep (7.69%), farms. The results of the questionnaire showed that the antibiotics often used in cattle and sheep farms are ß lactams, sulfonamides and tetracyclines. In contrast, in poultry farms, sulfonamides, quinolones and colistin are the most prescribed antibiotics. While the results of the antibiogram recorded an overall resistance rate of enterobacteria strains of 77.92% (60/77). The observed resistance rates showed high levels for amoxicillinclavulanic acid, oxytetracycline and trimethoprimsulfonamides. Low levels of resistance were noted for fosfomycin, colistin and gentamicin. Furthermore, for betalactams, our results showed that 3.03% of multiresistant enterobacteria carry the CMY-2 gene. On the other hand, for sulfonamides, 50% carry the Sul1 gene, 75% the Sul2 gene, and 25% the Sul3 gene. Moreover, for quinolones, no strain was positive. This study highlighted the multifactorial effects of pathogenic enterobacteria contamination on farms such as animal density, hygiene and litter scraping, manure storage, water, pest control, contact with other animals, and the decontamination process. Overall, these results indicate a high rate of contamination and antibiotic resistance by enterobacteria in the food chain. Further studies are needed to determine all potential risk factors associated with contamination and transmission of antibiotic resistance in order to assess the remedial effects of these factors. Thus, the establishment of surveillance and control systems could also help to improve the quality of products intended for human consumption and to preserve public health.

Approches innovantes dans la prévention et le traitement de la leishmaniose canine à Leishmania infantum en Algérie.

Sat, 01 Jan 2022 00:00:00 GMT

Approches innovantes dans la prévention et le traitement de la leishmaniose canine à Leishmania infantum en Algérie. Medkour, Hacène; Soltani, Faouzi Leishmaniasis is among the world’s most neglected diseases. Dogs are the main reservoirs/ hosts of Leishmania infantum, causative agent of both canine and human visceral leishmaniosis. Canine leishmaniasis (CanL) represents a public health problem as one of the most prevalent zoonotic diseases worldwide. In addition, dogs are competent reservoirs/hosts of several protozoan pathogens transmitted by blood-feeding arthropods. Throughout their long history of domestication, they have served as a link for the exchange of parasites among livestock, wildlife, and humans and therefore remain an important source of emerging and re-emerging diseases. In Algeria, while CanL is well known to be endemic, no data are available on other vectorborne protozoans. First, we investigated the occurrence and diversity of trypanosomes, piroplasms and Hepatozoon spp. and update the epidemiological status of CanL in dogs from Kabylia, northern Algeria. A total of 227 dogs from three regions of Kabylia were enrolled, including 77 dogs with clinical signs. Dogs were clinically examined and were tested for L. infantum antibodies using a Rapid Immuno-Migration (RIM™) and a quantitative indirect Immunofluorescence Antibody Test (IFAT). PCR screening and sequencing were performed for vectorborne protozoa. Sixty two percent (141/227) of dogs presented at least one infection, whereas 26% (59/227) were co-infected. L. infantum antibodies were detected in 35.7% (81/227) of dogs including 88.7% (68/77) of sick dogs. Molecular investigation revealed prevalence of: 6.6% (15/227), 13.2% (30/227), 41% (93/227) for Trypanosoma spp., B. vogeli and H. canis, respectively. T. evansi (3.1%) and potential new subspecies of T. congolense had been identified. Dog’s clinical status correlates positively with L. infantum antibody titers and the presence of co-infections. Susceptibility to CanL varied according to the dog's aptitude and guard dogs were more infected (51%) (P-value = 0.001). B. vogeli infection was more frequent in juveniles than adults (32% versus 9%, Pvalue <0 .001) and in females than males (21% versus 10%, P-value = 0.02). To our knowledge, this is the first report on vector-borne protozoa infected dogs in Algeria. Current results are important not only for animal health, but also to avoid serious public health and livestock problems. Rigorous surveillance and control plans for these canine diseases are required in this area to contain them, or at least reduce their spread. In addition, current CanL therapeutics present various drawbacks. They are toxic, expensive or ineffective, thus, there is a need for more effective, safer, and cheaper drugs. Second, we evaluated and to compared the efficacy of oral administration of artesunate or meglumine antimoniate/ allopurinol in dogs with clinical leishmaniasis. Forty-two dogs with naturally occurring clinical leishmaniasis were included in this open-label, simple randomized positive control clinical field trial with 6 months of follow-up. Dogs received meglumine antimoniate 100 mg/kg/day and allopurinol 30 mg/kg/day for 28 days (control group, n = 26) or artesunate 25 mg/kg/day for 6 days (test group, n = 16). The dogs were evaluated for their clinical evolution, parasite load (by qPCR) and humoral response at different time points: 0, 30, 90, and 180 days after treatment. Data analyses showed a significant improvement in both groups in clinical scores, parasitemia and antibody titers after treatment. Compared to the control group, the artesunate group showed significantly lower clinical score (P-value = 0.0001), lower parasitemia (P-value = 0.0001) and antibody titers after 6 months of follow-up. Compared to baseline values, a rapid, significant reduction (P-value < 0.012) in antibody levels, 2.28- versus 3.04-fold for the control versus artesunate groups, respectively, was observed 30 days after treatment. Antibody levels continued to decrease further in the artesunate group, where 58% of cases became seronegative at the 6-month follow-up. All qPCR-positive dogs were negative after treatment with artesunate, while 14.3% remained positive with the appearance of two new cases in the control group. Artesunate was well tolerated, and no side effects were recorded. Treatment failures were similar in both groups with 27.27% (6/22), including 18.18% (4/22) mortality in the control group, versus 26.66% (4/15), including 13.33% (2/15) mortality in the artesunate group. This is the first report showing the potential of artesunate in the treatment of dogs with clinical leishmaniasis. Artesunate showed higher efficacy than the current first-line treatment for CanL without any adverse effects. It could be a good alternative chemotherapy for CanL, and may be considered for further studies in human leishmaniases. Further clinical trials are needed to confirm these findings, to determine if there are relapses after treatment and if dogs remain infective to sandflies, to define the ideal therapeutic dosage and duration of treatment with artesunate. We recommend the use of artesunate in the treatment of CanL, until the risk of Plasmodium spp. resistance to artesunate related to this use is assessed, in malaria-free regions such as Algeria or even the entire Mediterranean basin.

Mathematical modeling and control of brucellosis in El Oued province, Algeria.

Thu, 26 Jan 2023 00:00:00 GMT

Mathematical modeling and control of brucellosis in El Oued province, Algeria. Ramdani, Nacira; Boussena, Sabrina; Moula, Nassim Brucellosis is an endemic zoonotic disease responsible for enormous losses in animal industry and public health in Algeria. Therefore, designing a control/eradication policy adjusted to epidemiological and socioeconomic conditions appeared to be a requisite. In this context, the present PhD project aimed to simulate different control strategies over 20 years in order to predict the optimum approach to eradicate the brucellosis in small ruminant in El Oued district. Therefore, a cross sectional study was carried out among small ruminant flocks to determine the herd and individual true prevalence. Six hundred and twelve (612) sera samples were screened for anti-Brucella spp. antibodies using Rose Bengal test (RBT), and indirect enzymelinked immunosorbent assay (iELISA) in parallel and complement fixation test (CFT) for confirmation. Afterward, a deterministic mathematical model of the dynamic spread of brucellosis in small ruminant using compartmental model and a deterministic simulation agentbased-model (ABM) of different control strategies were developed. Indispensable data in relation to Brucella melitensis, characteristics of animal population in the study area, vaccination, and the performance of serological tests were collected meticulously. True herd prevalence was 27.95% (95% CI: 17.18–42.01) and true individual prevalence was 3.98% (95% CI: 2.51–6.03). Sampling of 50% of adults to be culled and slaughtered after positive reaction to RBT and CFT used in serial testing revealed to be the optimum strategy to eradicate the disease for about 18-19 years in the study area. Combining vaccination of young animals may enhance slightly the effectiveness of the eradication policy, but would not be cost-effective for a long-term program. Based on our findings, the adoption of test-and- slaughter strategy in order to eliminate the disease in El Oued district is strongly advised. However, cooperation and willingness of all stakeholders is vital for the adopted program to be effective and fruitful. Similar studies in distinct ecological areas and unified epidemiological conditions are highly recommended to draw up an optimal control/eradication plan.

L’influence des probiotiques sur le métabolisme du Lapin.

Thu, 09 Jun 2022 00:00:00 GMT

L’influence des probiotiques sur le métabolisme du Lapin. Kadja, Louiza; Dib, Amira Leila In recent years, the idea of modulating the intestinal microbiota with probiotics in order to meet breeding objectives, or to prevent certain metabolic disorders such as type 2 diabetes and metabolic syndrome, has been developed. The objective of this study consists in evaluating the influence of three probiotic strains Bifidobacterium animalis subsp. Lactis BB-12, Lactobacillus rhamnosus GG and Saccharomyces boulardii CNCM I-745, on the values of some biochemical, ionic, hematological and zootechnical parameters in healthy rabbits, as well as some biochemical and morphometric parameters in diseased rabbits resulting from the induction of diabetes type 2 and metabolic syndrome, upon 24 weeks of consumption of a diabetogenic diet rich in sucrose and lipids. The first experiment lasted 60 days and was carried out on 40 healthy rabbits from the ITELV2006 line, divided into four groups including the control (T), rabbits were fed diets supplemented in the BA group, with Bifidobacterium animalis subsp. Lactis BB-12, Lactobacillus rhamnosus GG in the LR group and Saccharomyces boulardii CNCM I-745 for the SB group. The rabbits of the 3 groups received the probiotics for 30 days and then the administration of probiotics were stopped for the last 30 days of the experiment. In the second experiment, 48 rabbits from the same line including 24 from the first experiment and 24 new rabbits, were divided into 8 batches, healthy control (TS), sick control (TM), Group1 (BAM, LRM, SBM); batches treated with the three aforementioned probiotics, from 5 weeks of age and Group 2 (BAM+, LRM+, SBM+); batches treated with the three above-mentioned probiotics from 13 weeks of age. The results showed an beneficial modifications in most of the parameters studied, including a decrease in fasting blood sugar (P˂0.001), total cholesterol (P˂0.01), triglycerides (P˂0.05), sodium (P˂0.01) and increased plasma levels of protein parameters (P˂0.001), iron (P˂0.001), calcium and potassium (P˂0.05). In addition, a significant increase in some hematological parameters of the two lines (GR, Hb, GB, NEUT) (P˂0.001), was recorded mainly during the treatment discontinuation period (from day 31 to day 60). Similarly, body weight increased significantly for the three groups of healthy rabbits supplemented by probiotics. On the other hand, the results of the second experiment showed significant alterations (P˂0.001), in most of the parameters studied after 24 weeks of induction of diabetes and metabolic syndrome, in particular in TM. In addition, a decrease in fasting blood glucose, OGTT, HbA1c, CT, TG and LDL (P˂0.05) and an increase in HDL, PT and ALB (P˂0.05) were recorded especially in group 1 of rabbits treated from 5 weeks of age. Also, these batches showed a significant improvement in certain morphometric parameters, such as body weight, CA and BMI (P˂0.05).Finally, the effect of probiotics seems to be dependent on race, sex, time and age of administration. In-depth studies on the effect of other strains or/and a mixture of several strains used with different doses, in animals or in humans involving age and sex and different races and/or species, are to be considered. In addition, metagenomic analyzes will be necessary to know how and when to intervene to meet the objectives of either breeding or medicine.