Assessment of Reticulocyte Count as a Prognostic Indicator for Canine Ehrlichiosis: Implications for Diagnostic and Therapeutic Strategies

Canine ehrlichiosis is increasingly recognized in India, with significant implications for canine health. It is a tick-borne disease, caused by Ehrlichia canis. It is prevalent in various regions, particularly in areas with high tick populations. Anaemia is one of the most common and important manifestation of this disease. Anemia results from the destruction of red blood cells and bone marrow suppression. The prevalence of canine ehrlichiosis correlates with the density of tick vectors and can be exacerbated by environmental factors. Canine anemia can be classified as either regenerative or non-regenerative. Objective of the study was, investigating the prognostic value of reticulocyte counts in dogs with ehrlichiosis. The study involved 212 dogs screened between February 2023 and March 2024. Risk factors such as age, sex, breed, and season were recorded. Canine ehrlichiosis was diagnosed by finding morula stages in monocytes and neutrophils in thin blood smear examination. The pathogen was confirmed through PCR-based molecular examination. Reticulocyte count was performed through supravital stain new methylene blue (NMB). Reticulocytes contain ribosomal RNA, which is less condensed than in mature erythrocytes. NMB has a high affinity for ribosomal RNA, resulting in a blue coloration of these immature cells. This staining reaction makes reticulocytes clearly distinct compared to mature red blood cells under a microscope, facilitating their identification and quantification. The study found that the haematological parameters of infected dogs were significantly lower than healthy dogs. The mean ±SE values of Hb, TEC, PCV, and corrected reticulocyte were significantly lower (p<0.001) in infected dogs compared to healthy dogs. These findings suggest that significantly lower values of Hb, TEC, PCV, MCV, MCH, MCHC, and corrected reticulocyte indicate anaemia, normocytic, normochromic anaemia, and non-regenerative anaemia. It can be concluded than in canine ehrlichiosis, anemia is one of the most common finding accounting aprox 28% of total diagnosed cases. Accurate anemia characterization is key for diagnosing and treating ehrlichiosis.