Investigation of mast cells in naturally infected sheep brains with listeriosis

Listeria monocytogenes is a serious and life-threatening zoonotic disease that causes Listeriosis. Listeriosis is seen with abortion and meningoencephalitis in ruminants, and septicemia in newborns. It has been reported that mast cells in the brain are associated with an increase in inflammatory cell infiltrates in the acute period after exposure to infection and that mast cell extracellular traps released from mast cells are directly related to the destruction of the agents. In this study, it was aimed to investigate the relationship between histopathological lesions and mast cells in sheep brains infected with Listeriosis. Pons-medulla oblongata regions taken from 17 infected sheep and 8 normal sheep brains were examined in the study. Histopathologically microabscess and perivascular infiltrations, and immunohistochemically, Listeria monocytogenes positivity and tryptase staining of mast cells were evaluated. As a result of the study, a significant increase in mast cells was observed in infected sheep brains. It has been observed that the increase of mast cells is directly related to brain lesions. Especially a high correlation has been found between mast cells and microabscess development. It was also observed that there was a high correlation between bacteria density and brain lesions, but not a significant correlation with mast cells. With these findings, it was concluded that mast cells increase in Listeriosis infection in sheep in proportion to the severity of brain lesions and may play a role in the development of acute inflammatory reactions, and also that the increased mast cell number may be related to the struggle with agents. Keywords: Encephalitis, Listeria monocytogenes, mast cells