Multivariate spatially-structured variability of ovine helminth infections

Area of Science:

• Veterinary Parasitology
• Spatial Epidemiology
• Helminthology

Background:

• Sheep farming is economically significant in southern Italy.
• Parasitic helminths pose a substantial threat to sheep health and productivity.
• Understanding helminth distribution is crucial for effective control strategies.

Purpose of the Study:

• To investigate the multivariate geographical distribution of four key sheep helminths in the Campania region.
• To analyze spatial associations and ecological factors influencing helminth prevalence.
• To quantify the impact of shared intermediate hosts on parasite distribution.

Main Methods:

• A cross-sectional survey conducted in 2004-2005.
• Utilized multivariate Bayesian hierarchical models.
• Analyzed faecal egg counts transformed by square root.

Main Results:

• Demonstrated distinct geographical patterns for Fasciola hepatica, Calicophoron daubneyi, Dicrocoelium dendriticum, and Haemonchus contortus.
• Quantified the influence of common intermediate hosts, particularly for F. hepatica and C. daubneyi.
• Identified spatial correlation between D. dendriticum and F. hepatica.
• Found H. contortus was not spatially associated with the other studied helminths.

Conclusions:

• The study provides evidence of previously unrecognized ecological components influencing helminth distribution in sheep.
• Findings support the biological and epidemiological knowledge of these parasites.
• Results can inform targeted parasite control programs in sheep populations.