Histopathological and molecular perspectives of major parasitic diseases in ruminants: Current challenges and integrated control strategies

Background: Parasitic diseases remain one of the major causes of economic losses in ruminant livestock production worldwide, particularly in tropical and subtropical regions. Gastrointestinal helminths, blood protozoa, and ectoparasites significantly reduce animal productivity through anemia, impaired growth, decreased milk production, reproductive disorders, and mortality. In recent years, advances in veterinary pathology and molecular biology have improved understanding of host–parasite interactions, disease pathogenesis, and diagnostic approaches.
Objective: This review aimed to summarize the major parasitic diseases affecting ruminants from histopathological and molecular perspectives, focusing on pathogenesis, clinical manifestations, diagnostic methods, and integrated control strategies.
Methods: This article was conducted as a narrative literature review using scientific articles, textbooks, and international publications obtained from databases including PubMed, ScienceDirect, Google Scholar, and Scopus. Literature published between 2010 and 2025 was prioritized. Keywords used included “ruminant parasites”, “histopathology”, “molecular diagnosis”, “helminths”, “protozoa”, and “ectoparasites”. Relevant studies discussing pathology, molecular detection, epidemiology, and parasite control strategies were critically analyzed and synthesized.
Results: The review identified major parasitic diseases in ruminants, including haemonchosis, babesiosis, theileriosis, trypanosomiasis, coccidiosis, mange, and myiasis. Histopathological findings commonly included inflammatory infiltration, necrosis, hemorrhage, hyperkeratosis, and tissue degeneration. Molecular diagnostic approaches such as PCR and qPCR demonstrated higher sensitivity and specificity compared with conventional methods. Increasing antiparasitic resistance and climate-associated changes in parasite distribution were identified as emerging challenges.
Conclusion: Histopathological and molecular approaches provide valuable insights into parasite-induced lesions and disease mechanisms in ruminants. Integrated parasite management combining conventional therapy, molecular diagnostics, environmental control, and improved farm management is essential for sustainable livestock production and effective parasite prevention.