Interactions between lungworms and gastrointestinal worms in calves.

Area of Science:

• Veterinary Parasitology
• Immunology
• Animal Health

Background:

• Bovine parasitic infections involve complex interactions between gastrointestinal nematodes and lungworms.
• Understanding cross-protective immunity is crucial for effective parasite control strategies in calves.

Purpose of the Study:

• To investigate the interactions between gastrointestinal worms (Ostertagia ostertagi, Cooperia oncophora) and lungworms (Dictyocaulus viviparus) in calves.
• To assess the impact of primary infections on homologous and heterologous challenge infections.

Main Methods:

• Calves were subjected to primary infections with either gastrointestinal or lungworms.
• Subsequent challenge infections (homologous or heterologous) were administered to assess acquired resistance.
• Physiological markers like serum pepsinogen and circulating eosinophils were monitored.
• Weight gain was measured to evaluate the impact of infections.

Main Results:

• Primary lungworm infections conferred partial resistance to gastrointestinal worm challenge, less than homologous lungworm challenge.
• Primary gastrointestinal worm infections did not induce resistance to lungworm challenge; they may enhance lungworm establishment.
• Lungworm infections elevated serum pepsinogen, while gastrointestinal worms caused a delayed eosinophil rise.
• Lungworm larvae had a greater negative impact on calf weight gain than gastrointestinal nematodes.

Conclusions:

• Lungworm immunity in calves is not fully reciprocal with gastrointestinal nematode immunity.
• Gastrointestinal nematode infections may predispose calves to more severe lungworm disease.
• Lungworms pose a significant threat to calf growth, necessitating targeted control measures.