title: Black-backed jackals (Canis mesomelas) are natural hosts of Babesia rossi, the virulent causative agent of canine babesiosis in sub-Saharan Africa.
abstract: BACKGROUND
  Babesia rossi, which is transmitted by Haemaphysalis spp. and is highly virulent to domestic dogs, occurs only in sub-Saharan Africa. Since dogs are not native to the region, it has been postulated that the natural host of B. rossi is an indigenous African canid. Although various attempts at artificial infection indicated that black-backed jackals (Canis mesomelas) could become subclinically infected with B. rossi, data on occurrence of B. rossi in free-ranging jackals was lacking. A long-term behaviour study in which free-ranging black-backed jackals were radio-collared offered the opportunity of collecting blood specimens from a large number of free-ranging jackals.
  
  
  METHODS
  Genomic DNA was extracted from the EDTA blood samples (n = 107). PCR products were subjected to Reverse Line Blot hybridization using Theileria and Babesia genera-specific as well as 28 species-specific oligonucleotide probes, including Babesia canis, Babesia rossi, Babesia vogeli and Babesia gibsoni. The near full-length parasite 18S rRNA gene was amplified from two selected samples (free-ranging jackals), cloned and a total of six recombinants were sequenced.
  
  
  RESULTS
  Of 91 free-ranging jackals, 77 (84.6%) reacted with the Babesia genus-specific probe; 27 (29.7%) also reacted with the B. rossi probe. Of 16 captive jackals, 6 (37.5%) reacted with the B. rossi probe, while one further sample reacted with the Babesia genus-specific probe only. After cloning, 6 recombinants yielded identical sequences identical to that of B. rossi (L19079) and differing by 2 base pairs from B. rossi (DQ111760) in GenBank. The observed sequence similarities were confirmed by phylogenetic analyses using neighbour joining and maximum parsimony.
  
  
  CONCLUSIONS
  Black-backed jackals are natural hosts of B. rossi.
authors.affiliation: Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort, 0110, South Africa. banie.penzhorn@up.ac.za.|Research Associate, National Zoological Gardens, Boom Street, Pretoria, South Africa. banie.penzhorn@up.ac.za.
authors.forename: Barend L
authors.initials: BL
authors.lastname: Penzhorn
authors.affiliation: Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort, 0110, South Africa.
authors.forename: Ilse
authors.initials: I
authors.lastname: Vorster
authors.affiliation: Wildlife Damage - Research and Management, P.O. Box 783540, Sandton, 2146, South Africa.
authors.forename: Robert F
authors.initials: RF
authors.lastname: Harrison-White
authors.affiliation: Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort, 0110, South Africa.
authors.forename: Marinda C
authors.initials: MC
authors.lastname: Oosthuizen
mesh_terms: D017954:Africa South of the Sahara / Q000453:epidemiology; D000818:Animals; D001403:Babesia / Q000235:genetics / Q000302:isolation & purification* / Q000472:pathogenicity; D001404:Babesiosis / Q000097:blood / Q000453:epidemiology* / Q000469:parasitology*; D004197:Disease Reservoirs; D004283:Dog Diseases / Q000097:blood / Q000453:epidemiology* / Q000469:parasitology; D004285:Dogs; D046030:Jackals / Q000469:parasitology*; D009693:Nucleic Acid Hybridization; D010802:Phylogeny; D016133:Polymerase Chain Reaction / Q000662:veterinary
keywords: Babesia rossi; Black-backed jackal; Canis mesomelas; Natural host; South Africa