Parascariasis (P. equorum)

Infectious DiseaseParasiteEquineNew

Key Points

Parascariasis is a parasitic infection of Parascaris equorum nematodes which most commonly occurs in horses <2 years old
Larval migration through the liver and lungs cause respiratory signs like coughing and nasal discharge
Adult worms inhabit the small intestine and may cause intestinal obstruction, malnutrition and disrupted motility
Clinical signs typically include poor growth and colic
Faecal egg counts and clinical presentation are key to diagnosis
Anthelmintics are used to treat infected horses but protocols must be carefully considered, as mass worm death can cause intestinal obstruction
Anthelmintic resistance is becoming a major concern so treatments must be targeted and used alongside environmental management

Differential Diagnoses

Educational content only. This factsheet is for general veterinary education and is not a substitute for professional veterinary advice, diagnosis, or treatment. Not for use in an emergency — contact a veterinarian or emergency service. Full disclaimer →