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Question #46501
The Question
A patient exhibiting sustained high fever (39°C to 40°C), weakness, and intestinal perforation tests negative for the Widal test. Clinical history reveals severe protein-energy malnutrition and significant atrophy of Mucosa-Associated Lymphoid Tissue (MALT). Which of the following is the most scientifically accurate explanation for this 'false negative' diagnostic result?
Options
- A.
MALT atrophy prevents the pathogen from reaching the reticuloendothelial system, restricting the infection to the gut lumen.
- B.
The Widal test relies on the detection of pathogen DNA, which is not amplified due to the lack of mucosal lymphocytes.
- C.
Severe malnutrition and MALT dysfunction cause hypogammaglobulinemia, failing to produce sufficient antibody titers required for visible agglutination.
- D.
In the absence of functional MALT, Salmonella typhi fails to produce the O and H antigens necessary for the Widal test.
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Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Regulatory_Failure
Understand how NOT, EXCEPT, and logical constraints are used to manipulate exam results.
Concepts Behind This Question
Widal Test Specificity|MALT Structure|Primary vs Secondary Immune Response
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often memorize 'Widal test = Typhoid' without understanding its underlying mechanism (antigen-antibody agglutination).
This question tests the realization that serological tests depend entirely on the host's ability to mount an immune response.
If the host's lymphoid tissue (MALT) is compromised, the diagnostic test itself fails, creating a clinical 'false negative' trap.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Human Health and Disease - Class 12 |
| Concept | Widal Test Specificity |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |