Prevalence of co-infection with Ehrlichia spp. or Theileria spp. in dogs naturally infected with babesiosis in the Eastern Cape

Abstract

This study describes the prevalence of Ehrlichia canis or Theileria equi co-infections in dogs that are naturally infected and clinically sick due to babesiosis. Canine babesiosis and ehrlichiosis are tick-borne diseases of great significance in South Africa. Theileriosis in dogs in South Africa is still poorly understood. Co-infection with multiple tick-borne pathogens has been documented and is perceived as a common occurrence in South Africa. The Mdantsane State Veterinary Clinic in Mdantsane, Eastern Cape Province, South Africa was used as the centre where sample collection took place. Limited data on the prevalence and distribution of tick-borne diseases in the Eastern Cape Province are available and thus this population of dogs can be viewed as a novel study population. The main objective of this study was to determine the prevalence of co-infections with E. canis or T.equi in dogs with babesiosis in the Eastern Cape province. Possible associations of population characteristics and haematological and biochemistry measures with a co-infection in these dogs were also investigated. The study population included 150 dogs naturally infected with babesiosis that presented to the Mdantsane State Veterinary Clinic between January 2021 and November 2021. Quantitative polymerase chain reaction was used to confirm the Babesia spp. that the dogs were infected with and to identify co-infections. Association with co-infection for the following parameters were evaluated: sex, breed, age, duration of sickness, leukocyte count, band neutrophil count, monocyte count, platelet count, absolute reticulocyte count, and serum globulin concentration. Positive and negative predictive values of monocytosis, leukopenia, band neutrophilia, thrombocytopenia, and on regenerative absolute reticulocyte count for co-infection were also calculated. Babesia rossi was identified in 149/150 samples and B. vogeli in only 1/150 samples. A co-infection prevalence of 2.0% (3/149; 95% confidence interval: 0.4–5.7) with B. rossi and E. canis was found. No other co-infections were reported. No investigated variables showed significant associations with coinfections. Monocytosis, in particular, was not associated with co-infection. Co-infection with other tick-borne pathogens in dogs with babesiosis is uncommon in the Eastern Cape province. These findings raise the possibility that B. rossi may have a protective effect against other tick-borne pathogens. It is advised that further testing, ideally with the use of polymerase chain reaction, be done when a co-infection is suspected to practice responsible antibiotic stewardship.