Question:hard
A 24 years old cook in a hostel mess suffered from enteric fever 2 years back. The chronic carrier state in this patient can be diagnosed by:
A 24 years old cook in a hostel mess suffered from enteric fever 2 years back. The chronic carrier state in this patient can be diagnosed by:
Show Hint
Chronic typhoid carriers keep shedding Vi antigen, so Vi antibody stays high long after the fever is gone.
Updated On: Jul 8, 2026
- Vi agglutination test
- Blood culture in Brain Heart Infusion broth
- Widal test
- C-Reactive protein
Show Solution
The Correct Option is A
Solution and Explanation
Step 1: Think about where the bacteria actually live in a carrier.
After the fever settles, a small number of people keep Salmonella typhi living quietly in their gallbladder, often alongside gallstones. From there, bacteria are shed on and off into the stool, but they are not usually floating in the bloodstream anymore.
Step 2: Work out why blood tests of acute infection fail here.
Blood culture and the Widal test both depend on things that are strongest during active fever, live bacteria in the blood for culture, and rising O and H antibodies for Widal. Two years after the illness, neither of these is expected to still be positive or high, so both are poor choices for carrier detection.
Step 3: Bring in the Vi antigen angle.
The Vi capsular antigen is shed continuously by bacteria sitting in the gallbladder of a carrier. This constant low-level exposure keeps the Vi antibody level up in the blood long after acute illness, unlike O and H antibodies which fade.
Step 4: Confirm the logic with the test's actual use.
Because of this, the Vi agglutination test is used as a screening test to flag likely carriers, especially food handlers like cooks, so they can be confirmed later with stool and bile culture.
Step 5: Set aside CRP.
C-Reactive protein just shows that inflammation is happening somewhere in the body, it cannot point to typhoid or to carriage.
Step 6: Conclude.
The test built to catch a chronic carrier here is the Vi agglutination test.
\[ \boxed{\text{Vi agglutination test}} \]
After the fever settles, a small number of people keep Salmonella typhi living quietly in their gallbladder, often alongside gallstones. From there, bacteria are shed on and off into the stool, but they are not usually floating in the bloodstream anymore.
Step 2: Work out why blood tests of acute infection fail here.
Blood culture and the Widal test both depend on things that are strongest during active fever, live bacteria in the blood for culture, and rising O and H antibodies for Widal. Two years after the illness, neither of these is expected to still be positive or high, so both are poor choices for carrier detection.
Step 3: Bring in the Vi antigen angle.
The Vi capsular antigen is shed continuously by bacteria sitting in the gallbladder of a carrier. This constant low-level exposure keeps the Vi antibody level up in the blood long after acute illness, unlike O and H antibodies which fade.
Step 4: Confirm the logic with the test's actual use.
Because of this, the Vi agglutination test is used as a screening test to flag likely carriers, especially food handlers like cooks, so they can be confirmed later with stool and bile culture.
Step 5: Set aside CRP.
C-Reactive protein just shows that inflammation is happening somewhere in the body, it cannot point to typhoid or to carriage.
Step 6: Conclude.
The test built to catch a chronic carrier here is the Vi agglutination test.
\[ \boxed{\text{Vi agglutination test}} \]
Was this answer helpful?
0
