“Tilapia lake virus in the pathophysiological aspects: The impact of the infection on hematological and cardiac functions (6266)”

Tilapia lake virus in the pathophysiological aspects: The impact of the infection on hematological and cardiac functions.

Tilapia Lake Virus (TiLV), also known as Tilapinevirus tilapiae, is a negative-sense single-stranded RNA virus that has caused substantial economic losses in global tilapia aquaculture. Infected fish commonly exhibit clinical signs such as anorexia, abnormal swimming behavior, skin and fin hemorrhages, exophthalmos, and ascites. While TiLV possesses a broad tissue tropism, enabling its replication in various organs and cell lines, it widely affects pathological lesions to internal organs, including anemia, syncytial hepatitis, lymphoid depletion with an increase in melanomacrophages in the spleen and anterior kidney, as well as intestinal hemorrhages and dysbiosis. To gain deeper insight into TiLV pathogenesis, we investigated its impact on key physiological systems, including hematological parameters and cardiac function. Hematological analysis revealed that infected fish commonly developed anemia and leukopenia, likely resulting from the destruction of hematopoietic organs. Flow cytometry further demonstrated a significant reduction in lymphocyte populations via the direct induction of leukocyte apoptosis, suggesting this mechanism may contribute to the observed leukopenia. Furthermore, viral detection in granulocytes following infection suggests that these cells may play a role in systemic viral dissemination and viremia. Cardiac function was also significantly affected, as infected fish exhibited a negative chronotropic response with reduced cardiac output. However, despite the detectable viral presence in the heart, structural integrity and stroke work remained unchanged. These findings highlight the multifaceted impact of TiLV infection on host physiology, highlighting the need for further research to elucidate the underlying mechanisms driving disease progression and systemic dysfunction in infected tilapia.

1. LERTWANAKARN, TUCHAKORN, DEPARTMENT OF PHYSIOLOGY, FACULTY OF VETERINARY MEDICINE, KASETSART UNIVERSITY, Presenter