Prediction of Trypanosoma evansi infection in dromedaries using artificial neural network (ANN).

Surra is caused by Trypanosoma evansi, a flagellated parasite that affects domestic and wild animals. Surra is a neglected tropical disease causing serious problems to camels breed in Algeria. The aim of our study consists to extract the major risk factors that predict T.evansi infection in dromedaries using artificial neural networks. This investigation was conducted on 115 dromedaries from Ghardaïa district, Southern Algeria. The immune trypanolysis test was used to detect antibodies against T. evansi. Firstly, the gamma test has been used to choose optimal input parameters. The obtained results indicate that the age, gender, breed, clinical manifestations history, herd size, as well as the animal activities were the most predictors of T. evansi infection. Afterward, an artificial neural network method has been performed for modelling the proposed optimal inputs and their accuracy was assessed through seven statistical indicators. The comparative study indicates the effectiveness of the (6-9-1) model trained by the Tansig transfer function. The proposed model has demonstrated a good performance: 0.925 for training data and 0.962 for validation data. Furthermore it could be very useful for the rapid intervention of veterinarians as close as possible to the point-of-care (POC).

Assessment of Trypanosoma evansi prevalence and associated risk factors by immune trypanolysis test in camels from Ghardaïa district, southern Algeria.

Trypanosoma evansi (T. evansi) is a flagellated parasite with worldwide distribution, mainly affecting camels, horses, dogs, buffaloes and wild animals. Trypanosomosis caused by T. evansi, known as surra, is a vector borne disease that affects the health and productivity of camels. The aim of our study was to assess the prevalence of trypanosomosis due to T. evansi in camels by the immune trypanolosis test and to identify associated risk factors. Our cross-sectional study was performed on 161 camels from Ghardaïa district, southern Algeria. A structured questionnaire was used to collect data on individual characteristics (age, gender and breed) husbandry management (herd size and activity of animals) and health conditions (history of abortion and clinical symptoms). The immune trypanolysis test revealed an overall seroprevalence of 9.3% (CI 95%, 5.9-14.9). Possible factors associated with T. evansi infection were analysed by univariate and multivariate logistic regression. The results showed that risk factors for camels were history of symptoms (P = 0.002, OR = 21.91, CI95% = 3.48-169.80), racing activities (P = 0.003, OR = 0.01, CI95% = 0.001-0.18) and small herd size (P = 0.013, OR = 8.22, CI95% = 1.64-49.75). In conclusion, this study showed that T. evansi is endemic in camels of Ghardaïa district. To reduce dissemination of the disease to non-endemic areas, it is recommended to minimise risk factors associated with the infection.

Serological, clinical, and risk factors of the Newcastle disease on broilers flocks in Algeria.

AIM: The work aimed at studying the serological and clinical factors, as well as the risk factors of the Newcastle disease (ND) on broilers herds in Algeria. MATERIALS AND METHODS: A sample of 1248 birds was randomly selected from 52 broiler flocks. We took blood samples from each bird at the level of the wing vein area where an indirect enzyme-linked immunosorbent assay technique was carried out through the use of an IDvet kit. RESULTS: The flocks showed 82.69% of seroprevalence. Clinically speaking, the most common symptoms were sneezing, rale, greenish diarrhea, torticollis, and motor discords. Most commonly observed postmortem lesions were the proventriculitis, tracheitis, and enteritis. Especially, the caeca are hemorrhagic. The scores show the effect of risk factors. There was a significant effect on the mortality, the hygiene and vaccination groups on antibody titers in time 2. The antibody titers were elevated in the herd that recorded a high mortality (more than 10%) compared with those which recorded a low mortality (<10%) (p=0.002). Therefore, the antibody titers were elevated in herds with bad hygiene, compared with the ones with good hygiene (p=0.04). At last, when broiler chicken were not boosted by ND vaccine, flocks appeared to be more seropositive (p=0.02). CONCLUSION: The serological survey conducted in this study provided an important scope for ND as a dominant viral disease in broilers. Many factors are responsible for the onset of these diseases; correct biosecurity measures are needed to reduce the impact of this pathology in poultry farms.