Resistance to Echinococcus granulosus infection in lambs

Area of Science:

• Veterinary Parasitology
• Immunology
• Infectious Diseases

Background:

• Echinococcus granulosus causes cystic echinococcosis, a significant zoonotic disease.
• Developing effective vaccination strategies against Echinococcus granulosus is crucial for livestock health.

Purpose of the Study:

• To evaluate the efficacy of multiple subcutaneous oncosphere injections in stimulating resistance against Echinococcus granulosus infection in lambs.
• To investigate the developmental stage of Echinococcus granulosus responsible for inducing protective immunity.

Main Methods:

• Lambs received two or more subcutaneous injections of Echinococcus granulosus oncospheres, with injections spaced 14 days apart.
• In vitro studies cultured oncospheres in serum from immunized or challenged animals to assess cyst viability.
• Serum's lethal effects on cultured oncospheres were measured over time.

Main Results:

• Multiple oncosphere injections induced significantly higher resistance compared to a single injection.
• In vitro cultures showed that most oncospheres were killed before 7 days, indicating early cyst stages trigger resistance.
• Serum from animals receiving two injections exhibited increased lethal effects on oncospheres, which diminished over time.

Conclusions:

• Subcutaneous immunization with Echinococcus granulosus oncospheres effectively primes lambs for resistance against oral infection.
• Immunity appears to be mediated by early developmental stages of the parasite.
• The high level of resistance induced by multiple injections might be transient, suggesting the need for further research on long-term immunity.