Veterinary Parasitology 197 (2013) 509–521 Contents lists available at ScienceDirect Veterinary Parasitology jo u r nal homep age: www.elsevier.com/locate/vetpar Epidemiological survey following oriental theileriosis outbreaks in Victoria, Australia, on selected cattle farms Piyumali K. Perera a , Robin B. Gasser a , Garry A. Anderson a , Michael Jeffers b , Cameron M. Bell c , Abdul Jabbar a,∗ a Faculty of Veterinary Science, The University of Melbourne, Parkville, Victoria 3010, Australia b Biosecurity Victoria, Department of Primary Industries, Geelong, Victoria 3220, Australia c Biosecurity Victoria, Department of Primary Industries, Bendigo, Victoria 3554, Australia a r t i c l e i n f o Article history: Received 22 April 2013 Received in revised form 27 June 2013 Accepted 29 June 2013 Keywords: Genetic variation Theileria orientalis Major piroplasm surface protein gene Single-strand conformation polymorphism (SSCP) Epidemiology Cattle a b s t r a c t This study investigated Theileria orientalis following outbreaks of oriental theileriosis in cat- tle in the state of Victoria, Australia, from September 2010 to January 2012, using traditional and molecular methods of diagnosis. A questionnaire was used to collect epidemiological information from cattle farms. Blood samples (n = 301), collected from individual symp- tomatic and asymptomatic cattle from 19 cattle farms, were examined for the presence of Theileria on stained blood smears and tested using a PCR-based approach, employing a region within the major piroplasm surface protein (MPSP) gene as a marker. The microscopic examination of stained blood smears detected stages consistent with Theileria piroplasms in 28.1% (79/281) of the samples. PCR products were amplified from 70.8% (213/301) of the samples. Mutation scanning analysis of all amplicons displayed seven distinct profiles. Following the direct sequencing of representative amplicons, the genotypes ikeda, chitose, buffeli and type 5 were detected in 91.1%, 32.9%, 2.4% and 1.4% of 213 blood samples, respec- tively. The distribution of these four genotypes varied among the 19 farms; genotype ikeda was detected on all farms, whereas genotypes chitose, buffeli and type 5 were detected on 14, 3 and 2 farms, respectively. Mix infections with genotypes ikeda and chitose were common (21.6%). Survey results revealed that oriental theileriosis affected mainly beef cows of more than two years of age, prior to calving, and disease was associated with abortion and cow deaths. Future investigations should focus on developing improved tools for investigating and managing oriental theileriosis. © 2013 Elsevier B.V. All rights reserved. 1. Introduction Theileriosis is a disease caused by protozoan parasites of the genus Theileria (Apicomplexa: Piroplasmida; Theileri- idae), transmitted by ixodid ticks. Usually, the geographical distribution of Theileria species is restricted to tropical and subtropical regions where suitable tick vectors occur. Thei- leria species infect primarily wild and domestic ruminants, ∗ Corresponding authors. Tel.: +61 3 9731 2022; fax: +61 3 9731 2366. E-mail addresses: robinbg@unimelb.edu.au (R.B. Gasser), jabbara@unimelb.edu.au (A. Jabbar). and cause economically significant diseases in cattle, sheep and goats. For instance, Theileria annulata and Theileria parva (the causative agents of tropical or Mediterranean and East Coast Fevers, respectively) are known to be the most pathogenic species for bovines, whereas other species, such as Theileria mutans, Theileria taurotragi and members of the Theileria orientalis complex, often cause asymptomatic infections in bovids (Uilenberg et al., 1977; Uilenberg, 1981; Jongejan et al., 1986). However, in the recent years, T. orientalis has been linked to clinical cases of oriental theileriosis in the Asia–Pacific region (Sugimoto and Fujisaki, 2002; Izzo et al., 2010; Aparna et al., 2011; 0304-4017/$ – see front matter © 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.vetpar.2013.06.023