Gastrointestinal nematode immunization trials in cattle

Area of Science:

• Veterinary immunology
• Parasitology
• Animal health

Background:

• Bovine parasitic infections caused by Ostertagia ostertagi, Trichostrongylus axei, and T. colubriformis pose significant challenges to cattle health and productivity.
• Developing effective vaccines against these gastrointestinal nematodes is crucial for sustainable livestock farming.

Purpose of the Study:

• To evaluate the efficacy of immunization strategies against key gastrointestinal nematodes in calves.
• To assess the potential of using in vitro-grown parasitic larvae and exoantigens for inducing protective immunity.

Main Methods:

• Three experiments were performed involving calves.
• Immunization involved intraperitoneal injections of in vitro-grown larvae of O. ostertagi, T. axei, and T. colubriformis.
• Additional immunization groups received intravenous and intraperitoneal injections of O. ostertagi exoantigens.

Main Results:

• Calves immunized with parasitic larvae did not develop immunity.
• Calves immunized with O. ostertagi exoantigens did not develop immunity.
• None of the tested immunization protocols conferred protection against oral challenge with infective larvae.

Conclusions:

• Current immunization strategies using in vitro-grown larvae and exoantigens are ineffective for protecting calves against O. ostertagi, T. axei, and T. colubriformis.
• Further research is needed to develop viable vaccines against these economically important bovine parasites.