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Precipitates found around Schistosoma haematobium eggs from human urine prior to circumoval precipitin test
Insights
Schistosoma haematobium eggs in urine precipitates contain immunoglobulins. Pepsin treatment is necessary before performing the circumoval precipitin (COP) test for accurate diagnosis of Schistosomiasis haematobium.
Area of Science:
- Parasitology
- Immunology
- Medical Diagnostics
Background:
- Schistosoma haematobium infection is diagnosed using the circumoval precipitin (COP) test.
- Eggs of S. haematobium are found in urine, and their surface exhibits precipitates.
- The nature and origin of these precipitates are not fully understood.
Purpose of the Study:
- To investigate the composition of precipitates on Schistosoma haematobium eggs recovered from urine.
- To determine the optimal method for preparing eggs for the COP test.
Main Methods:
- Eggs were recovered from schoolchildren's urine in Kenya.
- Eggs were treated with pepsin and trypsin to assess precipitate removal.
- Fluorescent antibody tests and immunodiffusion were used to identify precipitate components.
- Urine supernatants were incubated with pepsin-treated eggs.
Main Results:
- Precipitates on S. haematobium eggs were removed by pepsin but not trypsin.
- IgG and IgM were detected in the precipitates using fluorescent antibody tests.
- Immunodiffusion revealed IgG, IgM, IgA, and C3 in urine.
- Pepsin-treated eggs incubated with urine supernatants formed similar precipitates.
Conclusions:
- Precipitates on S. haematobium eggs in urine are primarily composed of immunoglobulins.
- Pepsin treatment is crucial for removing these precipitates before conducting the COP test.
- Findings are relevant for improving the immunodiagnosis of Schistosomiasis haematobium.
Abstract:
Schistosoma haematobium eggs were recovered in urine from schoolchildren in Mwachinga Village, Kwale District, Kenya. The surface of the eggs showed a pattern similar to that observed in a circumoval precipitin (COP) test. Observed precipitates were removed by treatment of the eggs with pepsin, but were not affected by trypsin. Similar precipitates occurred after incubating the pepsin-treated eggs with urine supernatants from the same children. Attempts were made to identify the components that might contribute to observed bleb (precipitate) formation. The fluorescent antibody test revealed both IgG and IgM in the precipitate, while urine examination by immunodiffusion revealed IgG, IgM, IgA and C3. These components probably participated in the bleb formation. This possibility seemed more likely because of the presence of anti-egg antibodies in the immunoglobulins identified in the urine, and agrees well with the expected activity of pepsin on these immunoglobulins. These results, therefore, suggest that S. haematobium eggs recovered in urine contain precipitates formed mainly by immunoglobulins; it is necessary to treat such eggs with pepsin before carrying out a COP test. The relevance of these findings to the immunodiagnosis of Schistosomiasis haematobium in man is discussed.