Effects of Doxycycline Treatment on Hematological Parameters, Viscosity, and Cytokines in Canine Monocytic Ehrlichiosis

SIMPLE SUMMARY: Canine Monocytic Ehrlichiosis is a disease of dogs caused by intracellular bacteria transmitted through tick bites. This disease can cause changes in a dog’s blood, affecting the count of cells and components of the defense system, such as cytokines, as well as the viscosity of the blood. This study was conducted to explore these changes in naturally infected dogs with ehrlichiosis, who were untreated and treated with a doxycycline-based antibiotic at a dose of 10 mg/kg every 12 h for 28 days. Even after treatment, infected dogs exhibited a decrease in blood viscosity. The infection decreased total white blood cells, lymphocytes, and the cytokine tumor necrosis factor-alpha level and increased cytokine interleukin-1-beta. Infected dogs showed a correlation between cytokines interleukin 10 and 12 with blood viscosity. Treating dogs with monocytic ehrlichiosis with doxycycline can help restore blood parameters such as platelets and eosinophils, but it may also elevate levels of interleukin-1-beta and monocytes. Therefore, assessing viscosity and cytokine levels is vital when treating dogs with this condition. ABSTRACT: This study aimed to analyze the hematological parameters, blood viscosity, and cytokines of dogs infected by Ehrlichia canis untreated and treated with doxycycline. Initially, 47 dogs were examined, and 36 were suspected to have canine monocytic ehrlichiosis, which was confirmed through molecular polymerase chain reaction tests. This study consisted of 25 dogs, with 11 being healthy and 14 testing positive for E. canis. The dogs were divided into experimental groups based on their test results, including a control group of healthy dogs (N = 11), a group of infected dogs without treatment (N = 7), and a group of infected dogs treated with doxycycline (N = 7) at a 10 mg/kg dose every 12 h for 28 days. Blood samples were taken to determine hematological parameters, viscosity, and cytokine levels. It was observed that, regardless of doxycycline treatment, there was a reduction in total leukocytes and lymphocytes in infected dogs with Ehrlichia canis. The eosinophils and platelets decreased in dogs with Ehrlichia canis infections without treatment. Monocytes, eosinophils, and platelets increased when the dogs were treated with doxycycline. Regardless of treatment, infected dogs’ blood viscosity was lower than uninfected dogs. Infected dogs showed lower TNF-α and increased IL-1β. There was a correlation between the blood viscosity with the cytokines IL-10 and IL-12 in the infected dogs. The eosinophil count correlated with TNF-α in the group of infected and untreated dogs. In conclusion, treating dogs with monocytic ehrlichiosis using doxycycline can increase platelet and eosinophil levels but may also increase IL-1β and monocyte levels, exacerbating inflammation. Therefore, evaluating viscosity and cytokine levels is important when treating dogs with this condition.