Examination of the diagnostic and therapeutic effectivity among dogs suspected of an Ehrlichia canis infection on the island of Aruba

Abstract

The presence of Ehrlichia canis DNA in blood samples from 47 Aruban domestic dogs, exhibiting signs of canine monocytic ehrlichiosis (CME), was tested. PCR amplification and Reverse line blot hybridization techniques were used in order to test for the presence of E.canis DNA in the blood samples. Ehrlichia canis DNA was only detected in one (2.1%) of the 47 blood samples. Serological testing for Ehrlichia canis antibodies using the Snap® 3Dx ® test was also performed on the 47 blood samples. Out of those 47 blood samples 22 (46.8%) were positive for E.canis antibodies. In order to test the effectivityof the treatment of CME, blood samples were taken at 30 days and 60 days post treatment. The PCR amplification, Reverse line blot hybridization (RLB) and serological testing methods were repeated for these blood samples as well. None of these blood samples were positive for E.canis DNA, but 38% of the blood samples which were previously negative on the Snap® 3Dx ® test were now positive. This finding suggests that the methods used for demonstrating E.canis DNA in this research were insensitive. The blood samples were also tested for other tick borne pathogens using the PCR and RLB methods. Respectively Babesia canis vogeli DNA was present in 6 (12.8 %) and Anaplasma phagocytophilum DNA was present in 1 (2.1%) of the 47 pretreatment blood samples. This is the first time that Babesia canis vogeli infections have been identified in the Aruban dog population, more research will be needed in order to determine the clinical significance of this infection. A. phagocytophilum is a zoonotic disease spread by ticks of the Ixodus species, until now only Rhipicephalus sanguineus ticks have been identified among the Aruban dog population. The positive A. phagocytophilum result could have been due to a cross reaction with A. platys on the RLB. More research is needed on the tick species present in the Aruban dog population in order to determine the relevance of A. phagocytophilum infections in dogs as well as its zoonotic risk.