Molecular investigation and genomic profiling of Anaplasma platys and Ehrlichia canis infections in dogs from Punjab, India.

BACKGROUND

Anaplasma platys and Ehrlichia canis are important tick-borne pathogens of dogs that cause significant morbidity and may result in severe disease. A. platys is the only known intracellular bacterium that infects platelets and causes canine infectious cyclic thrombocytopenia (CICT). This hospital-based study employed molecular diagnostic tools for the detection and molecular characterization of A. platys and E. canis in clinically suspected dogs in Punjab, India.

METHODS AND

RESULTS

Eighty-two dogs with clinical and hematological signs suggestive of ehrlichiosis or anaplasmosis were examined by conventional microscopy and PCR. Microscopic examination of Leishman-stained blood smears detected E. canis in only one sample (1.22%). In contrast, PCR detected E. canis DNA in 27/82 (32.9%; 95% CI: 23.7-43.7%) samples and A. platys DNA in 47/82 (57.3%; 95% CI: 46.5-67.5%) samples. Concurrent PCR positivity for both pathogens was observed in 19/82 (23.2%) samples. McNemar's test demonstrated a significant difference in detection rates (p = 0.0015), with A. platys detected more frequently than E. canis. Phylogenetic analysis supported the molecular identification of the detected isolates and showed that the Punjab isolates clustered with globally conserved lineages of both pathogens.

CONCLUSIONS

PCR demonstrated greater sensitivity than microscopy for detecting A. platys and E. canis in clinically suspected dogs. The study provides molecular evidence detection of these pathogens in dogs presented to a veterinary teaching hospital. Because this was a hospital-based investigation of clinically suspected animals, the findings should not be interpreted as estimates of prevalence in the general canine population.