Abstract:
Numerous studies have reported on the occurrence of Babesia rossi in domestic dogs in South Africa, but information on the occurrence of B. rossi in free-ranging indigenous canids, e.g. African wild dogs and black-backed jackals, is meagre. In addition, it is also not known whether the B. rossi that occurs in subclinical indigenous wild canids is genetically the same as the one that occurs in susceptible domestic dogs. This study aimed at investigating the occurrence of B. rossi in apparently healthy free-ranging black-backed jackals (n = 77) from Mogales Gate Biodiversity Centre and a population of captive black-backed jackals (n = 25) from S.A. Lombard Nature Reserve. In addition, an apparently healthy free-ranging population of African wild dogs (n = 52) from Kruger National Park (KNP) and a few captive African wild dogs (n = 5) from the National Zoological Gardens (NZG) were investigated. Domestic dogs (n = 75) that were suspected to be suffering from babesiosis at the outpatient clinic of the Onderstepoort Veterinary Academic Hospital also formed part of the study. Results of the Reverse Line Blot hybridization assay revealed B. rossi to be present in 66 domestic dogs (88%), in 5 (10%) free-ranging African wild dogs and 22 (29%) free-ranging black-backed jackals, and 7 (28%) captive black-backed jackals.
Phylogenetic analysis of the near full-length 18S rRNA gene sequence confirmed the occurrence of B. rossi in black-backed jackals and domestic dogs. This study confirms that B. rossi occurs freely in domestic dogs and black-backed jackals, and is therefore not host-specific. Elucidation of B. rossi in African wild dogs through molecular characterisation of the 18S rRNA gene was not successful; on the contrary, sequence analysis confirmed Hepatozoon canis DNA in B. rossi-positive specimens, affirming mixed infections. RLB also detected mixed infection in domestic dogs and black-backed jackals. Simultaneous detections with the Theileria / Babesia-group specific, Babesia genus-specific 1, Babesia genus-specific 2 and Babesia rossi probe were detected in individual domestic dog specimens. In black-backed jackal specimens, the highest multiple detections were with the Ehrlichia / Anaplasma group-specific probe together with the Babesia genus-specific 1 probe. In African wild dog spe cimens simultaneous detection on individual specimen were observed with the Babesia genus 1 and Babesia genus 2 probes. This study was able to indicate that wild canids and domestic dogs share similar tick-borne parasites of importance. This highlights the importance of tick control, especially in domestic dogs as they are more susceptible to these tick-borne pathogens that are less problematic to wild canids.
