Significant titres of IHA is seen in all types of amoebiasis except-
**Core Concept**
The question tests the understanding of **amoebiasis**, specifically the immunological response measured by **Indirect Haemagglutination Antibody (IHA) test** in different forms of the disease. Amoebiasis is caused by the protozoan parasite **Entamoeba histolytica**.
**Why the Correct Answer is Right**
Significant titres of IHA are seen in most forms of amoebiasis, indicating an immune response to the infection. However, in **asymptomatic carriers** or those with **luminal amoebiasis**, the immune response might not be as pronounced due to the lack of tissue invasion by the parasite.
**Why Each Wrong Option is Incorrect**
**Option A:** This choice might be incorrect because significant IHA titres can indeed be seen in certain types of amoebiasis, depending on the specifics of the infection and the individual's immune response.
**Option B:** Similarly, this option could be incorrect as it might represent a form of amoebiasis where an immune response, and thus IHA, would be expected.
**Option C:** This could potentially be the correct answer if it represents a form of the disease where tissue invasion is minimal or absent, such as luminal amoebiasis.
**Clinical Pearl / High-Yield Fact**
A key point to remember is that **luminal amoebiasis**, where the parasite primarily stays within the intestinal lumen without significant tissue invasion, tends to have lower or absent IHA titres compared to invasive forms of the disease.
**Correct Answer:** D. Luminal amoebiasis.