engleski

Evaluation of different diagnostic techniques for the diagnosis of fascioloidosis in red deer

Fasciolodes magna is a liver trematode, commonly found in several areas in North America and Europe. The presence of F. magna in Croatia was confirmed in 2000, although the fluke was probably present in that area years before. F. magna enter uninfected habitats by natural migration of cervids and by translocation of animals. As was recently confirmed genetically, records of fluke presence in deer populations followed the path of the Danube River, which offer suitable conditions for sustaining large deer populations and for completing of parasite life cycle. High prevalence of fascioloidosis in Croatia makes it an economically important disease in wild ruminant and different diagnostic methods are being investigated in order to control the disease. The objective of the present study was to evaluate and compare following available diagnostic techniques for detection of F. magna infection in red deer: 1 coprological test (sedimentation-flotation technique on 5g of faeces-SF), 2. serological test (indirect serum ELISA technique with excretory-secretory antigens obtained from adult flukes-E/S ELISA) and 3. serum biochemistry (aspartate aminotransferase-AST, lactate dehydrogenase-LDH, glutamate dehydrogenase-GDH, glucose and globulin value and albumine/globuline ratio). The presence of F. magna was confirmed at necropsy. Samples of serum, faeces and liver of 38 red deer from the F. magna-endemic area, were used to estimate sensitivity of tests. Similar samples collected from 10 red deer outside the F. magna-endemic area were used to estimate specificity. To evaluate diagnostic value of each test, Receiver Operating Characteristic (ROC) curve analysis was performed. Sensitivity, specificity and likelihood ratio (positive and negative) were used as indices of test accuracy. Summary statistic of overall diagnostic accuracy of each test was displayed like area under the ROC curve (AUC) index with 95% confidence intervals (95% CI). According to reference test, the true prevalence was estimated at 66.7 %. Coprological test showed an AUC index of 0.894 (95% CI 0.781-0.961), E/S ELISA 0.960 (95% CI 0.858 – 0.994), AST 0.889 (95% CI 0.580 – 0.994), LDH 0.792 (95% CI 0.637 – 0.903), GDH 0.742 (95% CI 0.586 – 0.863), glucose 0, 900 (95% CI 0.771 – 0.969), globulin 0.700 (95% CI 0.549 – 0.825) and albumine/globuline ratio 0.839 (95% CI 0.697 – 0.932). These results demonstrate that the E/S ELISA technique showed higher accuracy in diagnostics of fascioloidosis with clear discrimination between negative and positive populations. Also, E/S ELISA were highly sensitive and specific when compared to diagnosing F. magna by coprological means and serum biochemistry values and might be useful diagnostic test for epidemiological studies.

Fascioloides magna; red deer; ELISA; sedimentation-flotation; serum biochemistry; ROC analysis

nije evidentirano