Detection of Theileria orientalis genotypes in Haemaphysalis longicornis ticks from southern Australia

Abstract

BackgroundTheileria are blood-borne intracellular protozoal parasites belonging to the phylum Apicomplexa. Previously considered a benign parasite in Australia, outbreaks of clinical disease resulting from Theileria orientalis genotypes have been reported in Australia since 2006. Since this time, outbreaks have become widespread in south-eastern Australia, resulting in significant adverse impacts on local dairy and beef industries. This paper provides the first investigation into the possible biological and mechanical vectors involved in the rapid spread of the parasite.MethodsTo identify possible vectors for disease, ticks, biting flies and mosquitoes were collected within active outbreak regions of Gippsland, Victoria. Ticks were collected from cattle and wildlife, and mosquitoes and biting flies were collected in traps in close proximity to outbreak herds. Ticks were identified via DNA barcoding of the mitochondrial cytochrome oxidase I gene. Barcoded ticks were pooled according to species or phylogenetic group and tested for the presence of T. orientalis and the genotypes Ikeda, Chitose and Buffeli using real-time PCR.ResultsDNA barcoding and phylogenetic analysis identified ticks from the following species: Haemaphysalis longicornis, Ixodes holocyclus, Ixodes cornuatus, Ixodes hirsti, and Bothriocroton concolor. Additional Haemaphysalis, Ixodes and Bothriocroton spp. were also identified. Of the ticks investigated, only H. longicornis ticks from cattle carried theilerial DNA, with the genotypes Ikeda, Chitose and Buffeli represented. Mosquitoes collected in close proximity to outbreak herds included; Aedes camptorhynchus, Aedes notoscriptus, Coquillettidia linealis, Culex australicus, and Culex molestus. Low levels of T. orientalis Buffeli genotype were detected in some mosquitoes. The haematophagous flies tested negative.ConclusionsThis is the first demonstration of a potential vector for T. orientalis in the current Australasian disease outbreak.

Investigating the diversity of the 18S SSU rRNA hyper-variable region of Theileria in cattle and Cape buffalo (Syncerus caffer) from southern Africa using a next generation sequencing approach

“…The main vector in southern Africa for these genotypes is considered to be A. hebraeum (de Vos et al 1981), which have a large geographic distribution (Horak et al 2007;Spickett, 2013), with the implication that the buffalo specific genotypes would have been expected to occur in the Eastern Cape. The (Shastri et al 1985;Stewardt et al 1987;Stewardt et al 1989;Fujisaki et al 1994;Yin et al 2004;Hammer et al 2015). None of these species occur in Africa and the only species from this genus that parasitize cattle or buffalo is H. silacea which occurs in the Eastern Cape and parts of Kwa-Zulu Natal (Walker 1991;Horak et al 2007).…”

Prevalence and effect of Theileria orientalis infection in homebred calves in the Gloucester region of New South Wales, Australia

“…The distribution of T. orientalis , particularly in Australia, is closely related to the distribution of two species of bush ticks, Haemaphysalis longicornis and H. bancrofti , with H. longicornis considered to be the major vector for Theileria. Some native Australian fauna may act as intermediate hosts to these vectors …”

Evaluation of the acaricidal activity of 63 commercialized pesticides against Haemaphysalis longicornis (Acari: Ixodidae)

“…H. longicornis is known to be a vector of various diseases, such as Japanese spotted fever, Khasan virus, tick‐borne encephalitis virus and SFTS (severe fever with thrombocytopenia syndrome), in humans and transmits Babesia and Theileria parasites in animals (Hammer et al . ; Iwakami et al . ; Kim et al .…”

“…The Asian longhorned tick or cattle tick, Haemaphysalis longicornis Neumann, is an ectoparasitic hard tick that is distributed throughout East Asia, including Korea, Japan and China, as well as Australia, New Zealand and Hawaii (Fujisaki et al 1994;Hagimori et al 2005;Hoogstraal et al 1968). H. longicornis is known to be a vector of various diseases, such as Japanese spotted fever, Khasan virus, tick-borne encephalitis virus and SFTS (severe fever with thrombocytopenia syndrome), in humans and transmits Babesia and Theileria parasites in animals (Hammer et al 2015;Iwakami et al 2014;Kim et al 2009;Mackereth et al 2007;Telford & Goethert 2004;Uchida et al 1995). Various methods have been used to control ticks, such as the use of vaccines, microorganisms and acaricides, but chemical control is the most widely used method (Bianchi et al 2003;Labarta et al 1996;Lee et al 2015;Samish & Rehacek 1999;Willadsen et al 1996).…”