Rapid anthrax confirmation: Ascoli’s thermoprecipitation (thermoprecipitin) test is classically used to confirm the laboratory diagnosis of which infectious disease by detecting thermostable antigens?

Introduction / Context:
Historical but still instructive, Ascoli’s thermoprecipitation test detects thermostable antigens from Bacillus anthracis in contaminated animal products. Recognizing its application helps anchor classical diagnostic methods in medical microbiology.

Given Data / Assumptions:

• The test relies on antigen–antibody precipitation at elevated temperature.
• Samples may include hides, hair, bone meal, or tissues suspected of anthrax contamination.
• Target pathogen: B. anthracis, the agent of anthrax.

Concept / Approach:
When an extract of the suspect material is layered over anthrax antiserum and heated, a visible precipitin line forms at the interface if anthrax antigens are present. The thermostability of anthrax antigens underpins the test’s robustness. Modern diagnostics (culture, PCR, immunoassays) have superseded Ascoli’s method but the association remains a common exam point.

Step-by-Step Solution:
Identify the eponymous test and its principle: heat-aided precipitin reaction. Recall the specific pathogen targeted historically: Bacillus anthracis. Exclude other diseases that lack this classic thermoprecipitin application. Select “anthrax.”

Verification / Alternative check:
Reference descriptions consistently cite Ascoli’s test for screening animal by-products for anthrax contamination, confirming the association.

Why Other Options Are Wrong:

• Tetanus (Clostridium tetani): diagnosed clinically and by wound culture/toxin assays, not by thermoprecipitin.
• Typhoid (Salmonella Typhi) and cholera (Vibrio cholerae): use culture and serology, not Ascoli’s test.

Common Pitfalls:
Assuming all precipitin tests are interchangeable; Ascoli’s is historically specific for anthrax antigens in animal products.

Final Answer:
anthrax