Fasciolosis in Algerian livestock: Epidemiological trends and economic consequences

Fasciolosis, a parasitic disease of ruminants, poses significant economic and animal-health challenges in Algeria. This study aimed to assess spatial, temporal, and species-specific patterns of fasciolosis prevalence across diverse agro-climatic zones and to estimate associated economic losses. Between 2013 and 2023, eight wilayas El-Tarf, Skikda, Jijel (Region I), Blida, Mila (Region II), and M'Sila, Medea, Laghouat (Region III) were surveyed. Systematic postmortem inspections of 1,569,392 animals (349,176 cattle; 982,669 sheep; 235,639 goats; 1,882 camels; 26 horses) were performed by qualified veterinarians, with liver and bile-duct examination for Fasciola. Data on region, species, year, and season were analyzed in R 4.4.0 using ANOVA, Kruskal-Wallis, Tukey's post hoc tests, and principal component analysis (PCA). Economic losses were calculated from condemned liver weights in Blida, Laghouat, and Jijel, converted to USD. PCA distinguished three regional prevalence profiles, with PC1 (77.7% variance) separating overall prevalence levels. Region I exhibited the highest mean prevalence (2.47%), peaking at 3.54% in 2018 - significantly greater than Region II (1.39%) and Region III (1.96%) (p < 0.01). Cattle showed the greatest infection rate (mean 4.14%), significantly higher than sheep (1.32%; p < 0.001) and goats (0.25%; p < 0.001), while horses and camels remained uninfected. Seasonal analysis revealed highest prevalence in autumn and winter (≈2.1%) versus spring (≈1.5%). Economic losses totaled USD 10.6 million in Blida, USD 1.0 million in Laghouat, and USD 142.2 million in Jijel over the study period. Targeted control strategies, adapted to regional and seasonal risk patterns, are essential. Future work should investigate environmental and management factors driving regional differences and evaluate cost-effective interventions to mitigate fasciolosis impact in Algerian livestock.