Validation of the natural sedimentation technique in the diagnosis of chronic fasciolosis

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There are various diagnostic techniques available for chronic fasciolosis in ruminants. However, many of them exhibit low specificity and sensitivity, making them impractical for field use and in low-resource laboratories. The present study evaluates the usefulness of the Natural Sedimentation technique in diagnosing chronic fasciolosis in three domestic species conducted at the Laboratorio de Parasitología y Enfermedades Parasitarias, Facultad de Ciencias Veterinas, Universidad Nacional de Cajamarca. Fecal samples were collected from n = 323 cattle, n = 362 sheep, and n = 231 swine for Fasciola hepatica fecal egg counts. The visualization of adult parasites in animal livers post-mortem was considered the gold standard. Additionally, the sensitivity of the technique was evaluated using five different amounts of feces. In cattle, a sensitivity of 0.93 ± 0.03, specificity of 0.91 ± 0.06, positive predictive value of 0.96 ± 0.03, and negative predictive value of 0.86 ± 0.07 were obtained. In sheep, a sensitivity of 0.79 ± 0.05, specificity of 0.83 ± 0.07, positive predictive value of 0.90 ± 0.04, and negative predictive value of 0.66 ± 0.08 were observed. In swine, a sensitivity of 0.92 ± 0.06, specificity of 1.00 ± 0.00, positive predictive value of 1.00 ± 0.00, and negative predictive value of 0.96 ± 0.03 were found. There was no statistical difference in egg counts when using 1, 2, 3, 4, and 5 g of feces (p = 0.907). Furthermore, 1 to 688 fecal eggs of F. hepatica were counted in 1 g of feces. The Natural Sedimentation technique has both qualitative and quantitative applications with satisfactory results when using 1 g of feces in the diagnosis of chronic fasciolosis in domestic animals. Due to its simplicity, it can be implemented in field conditions and low-resource laboratories.