Background: Canine monocytotropic ehrlichiosis (CME), caused by Ehrlichia canis, is a significant tick-borne disease among canines, particularly in the tropical regions and urban areas of India. The standard treatment for CME is a 28-day course of oral doxycycline. However, some dogs may struggle with oral doxycycline due to its associated side effects. This study aimed to assess the effectiveness of parenteral doxycycline in natural cases of non-myelosuppressive CME within a shorter treatment duration of 15 days.
Methods: To confirm the presence of parasitic DNA, we utilized blood and splenic aspirates and performed 16S rRNA nested PCR. We established non-myelosuppression through bone marrow aspiration cytology, focusing on myeloid and erythroid cells. Among the cases confirmed by PCR, we randomly assigned 22 non-myelosuppressive cases into two groups. Group I received injectable doxycycline at a dosage of 10 mg/kg once daily for 15 days, while Group II received oral doxycycline at the same dosage for 28 days, also administered once daily. Our study highlights the utility of bone marrow aspiration for clinicians in identifying CME patients based on the presence or absence of myelosuppression.
Results: Injectable doxycycline demonstrated minimal side effects and proved to be convenient for dogs. After 15 days of therapy, group I showed negative results for 16S rRNA on nested PCR in both blood and splenic aspirates. Furthermore, erythrocyte and thrombocyte levels significantly (p≤0.05) improved in the group treated with injectable doxycycline.
Conclusion: Hence, injectable doxycycline therapy effectively eliminated parasitic DNA within a 15-day treatment period and demonstrated its efficacy.