Severe combined immunodeficiency in a Fell pony foal.

The study documents a case of a Fell pony foal suffering from severe combined immunodeficiency, a condition that led to the foal’s demise 21 days after birth due to symptoms of intestinal colic and pneumonia.

Overview of the Case

• The study revolves around a Fell pony foal which began showing signs of illness five days post-birth, symptoms included yellow watery diarrhea albeit with no outward signs of a systemic disease.
• The diarrhea ceased on the ninth day, however, the foal exhibited a marked lack of energy two days thereafter. This further progressed to intense lethargy, muscular weakness, and severe diarrhea in the subsequent days.
• Despite therapeutic endeavours, the foal’s health deteriorated, culminating in its demise on the 21st day due to symptoms of intestinal colic and pneumonia.

Haematological Findings and Diagnosis

• The foal’s haematological examinations reported a lower than normal erythrocyte count and non-selective lymphopenia, a condition signifying lower levels of lymphocytes in the blood. These observations are often associated with severe immunodeficiency.
• The foal’s phagocytic activity was found to be slightly increased whereas the lymphocyte activity was observed to be inhibited.
• A histopathological examination, which involves studying changes in tissues due to disease, revealed severe alterations in the foal’s lymphatic organs. T and B lymphocytes, along with antigen-presenting macrophages, were not located in their characteristic areas.
• The quantity of these critical cells was seen to be significantly reduced than usual. Changes in the lymphatic organs were compared to descriptions detailed in the literature about severe combined immunodeficiency.

Conclusion

• After an extensive examination, the foal was diagnosed with severe combined immunodeficiency (SCID), a rare genetic disorder responsible for a severely displeasing adaptive immune system.
• In this case, the disorder manifested as a substantial decrease in T and B lymphocytes, cells essential for immune response, alongside a disarrangement in the antigen-presenting macrophages. The resulting weaknesses in the foal’s immune system took a fatal toll, as it lost its fight against diarrhea, intestinal colic, and pneumonia within three weeks of its life.