Abstract:
Babesia rossi infection causes a severe inflammatory response in the dog, which is the
result of the balance between pro- and anti-inflammatory cytokine secretion. The aim of this
study was to determine whether changes in cytokine concentrations were present in dogs
with babesiosis and whether it was associated with disease outcome. Ninety-seven dogs
naturally infected with B. rossi were studied and fifteen healthy dogs were included as controls.
Diagnosis of babesiosis was confirmed by polymerase chain reaction and reverse line
blot. Blood samples were collected from the jugular vein at admission, prior to any treatment.
Cytokine concentrations were assessed using a canine-specific multiplex assay on
an automated analyser. Serum concentrations of interleukin (IL)-2, IL-6, IL-8, IL-10, IL-18,
granulocyte-macrophage colony stimulating factor (GM-CSF) and monocyte chemotactic
protein-1 (MCP-1) were measured. Twelve of the Babesia-infected dogs died (12%) and 85
survived (88%). Babesia-infected dogs were also divided into those that presented within 48
hours fromdisplaying clinical signs, and those that presented more than 48 hours after displaying
clinical signs. Cytokine concentrations were compared between the different groups
using the Mann-Whitney U test. IL-10 and MCP-1 concentrations were significantly elevated
for the Babesia-infected dogs compared to the healthy controls. In contrast, the IL-8 concentration
was significantly decreased in the Babesia-infected dogs compared to the controls.
Concentrations of IL-6 andMCP-1 were significantly increased in the non-survivors compared
to the survivors. Concentrations for IL-2, IL-6, IL-18 and GM-CSF were significantly higher in those cases that presented during the more acute stage of the disease. These findings suggest
that a mixed cytokine response is present in dogs with babesiosis caused by B. rossi,
and that an excessive pro-inflammatory response may result in a poor outcome.
