Step 1: Understanding the Concept:
Vaccine strains are specific, characterized lineages of microorganisms (either live-attenuated or inactivated) used to stimulate protective immunity against diseases in livestock and poultry.
Step 2: Detailed Explanation:
Let us correlate each disease with its respective immunizing strain:
- A. Bovine brucellosis: The live-attenuated Brucella abortus Strain 19 (S19) is a widely used vaccine globally to prevent brucellosis in female calves.
Thus, A matches with IV.
- B. Anthrax: The Sterne strain is a live, non-encapsulated (toxin-producing but safe) spore vaccine developed by Max Sterne, used extensively to immunize livestock against Bacillus anthracis.
Thus, B matches with III.
- C. Tuberculosis: The BCG strain (Bacille Calmette-Guérin) is an attenuated strain of Mycobacterium bovis used as a vaccine against tuberculosis.
Thus, C matches with I.
- D. NCD (Newcastle Disease): The R2B strain is a mesogenic, live-attenuated strain used for booster vaccination in poultry against Newcastle Disease (Ranikhet disease).
Thus, D matches with II.
Step 3: Final Answer:
Matching these pairs gives A-IV, B-III, C-I, D-II, which corresponds to option (A).