Ligula intestinalis in aquatic systems: taxonomy, epidemiology, pathology, and control — a concise narrative review

Ahmadiara, Emad; Hajimohammadi, Bahador; Raeisi, Mojtaba

doi:10.22034/cjvs.2025.538735.1042

Ligula intestinalis in aquatic systems: taxonomy, epidemiology, pathology, and control — a concise narrative review

Document Type : Review article

Authors

Emad Ahmadiara ¹

Bahador Hajimohammadi ²

Mojtaba Raeisi ³

¹ Department of Pathobiology, Faculty of Veterinary Medicine, Amol University of Special Modern Technologies, Amol, Iran.

² Department of Nutritional Sciences, School of Health, Golestan University of Medical Sciences, Gorgan, Iran.

³ Food, Drug and Natural Products Health Research Center, Golestan University of Medical Sciences, Gorgan, Iran.

10.22034/cjvs.2025.538735.1042

Abstract

Ligula intestinalis (Cestoda: Diphyllobothriidae) is a cosmopolitan tapeworm with a three‑host life cycle involving copepods, cyprinid fishes, and piscivorous birds. Its plerocercoid stage grows extensively within the fish's body cavity, compressing the viscera and causing profound reproductive impairment. Here we synthesize taxonomy and morphology, life cycle, epidemiology (with emphasis on Iran), pathology, zoonotic considerations, and control options. Molecular data increasingly support the synonym of Digramma with Ligula and indicate low interspecific divergence within the complex. Regionally, prevalence varies widely (≈3–60% in Iran, depending on host, season, and locality) and can reach double‑digit levels in African lakes. Gross lesions include abdominal distension and gonadal atrophy; histopathology commonly reveals ovarian/testicular degeneration and hepatic vacuolation. Despite sporadic claims, confirmed human infection by L. intestinalis has not been documented; risk is minimized by proper cooking and avoidance of raw freshwater fish. Effective control requires interrupting the life cycle (reducing copepods, excluding piscivorous birds from aquaculture), routine monitoring, biosecurity in semi‑closed systems, and public education.

Keywords

Control strategies

Epidemiology

Freshwater fish

Ligula intestinalis

Pathology

Subjects