Emergence of new types of Theileria orientalis in Australian cattle and possible cause of theileriosis outbreaks

Abstract

Theileria parasites cause a benign infection of cattle in parts of Australia where they are endemic, but have, in recent years, been suspected of being responsible for a number of outbreaks of disease in cattle near the coast of New South Wales. The objective of this study was to identify and characterize the species of Theileria in cattle on six farms in New South Wales where disease outbreaks have occurred, and compare with Theileria from three disease-free farms in Queensland that is endemic for Theileria. Special reference was made to sub-typing of T. orientalis by type-specific PCR and sequencing of the small subunit (SSU) rRNA gene, and sequence analysis of the gene encoding a polymorphic merozoite/piroplasm surface protein (MPSP) that may be under immune selection. Nucleotide sequencing of SSU rRNA and MPSP genes revealed the presence of four Theileria genotypes: T. orientalis (buffeli), T. orientalis (ikeda), T. orientalis (chitose) and T. orientalis type 4 (MPSP) or type C (SSU rRNA). The majority of animals showed mixed infections while a few showed single infection. When MPSP nucleotide sequences were translated into amino acids, base transition did not change amino acid composition of the protein product, suggesting possible silent polymorphism. The occurrence of ikeda and type 4 (type C) previously not reported to occur and silent mutation is thought to have enhanced parasite evasion of the host immune response causing the outbreak.

Distribution and abundance of ticks infesting livestock population along Karakorum highway from Mansehra to Gilgit, Pakistan

“…Tick distribution was found highest (P<0.05) in the Mansehra district followed by the Haripur, Batagram, Shangala, Kohistan, Diamer, Gilgit and Astor districts. Host age and sex (1) is much higher in the developing countries of Asia (Siddiqi and Jan, 1986;Khan et al, 1993;Sajid et al, 2007Sajid et al, , 2008Sajid et al, , 2009Sajid et al, , 2011Yi-Lun et al, 2011;Iqbal et al, 2013;Ali et al, 2013;Sultana et al, 2015) and Africa (Walker and Koney, 1999;Walker, 2003), where control measures are infrequently applied, than in Australia (Springell, 1974;Kamau, 2011), Europe (Papadopoulos et al, 1996;Hostis and Seegers, 2002) and the Americas (Guimaraes et al, 2001;Lohmeyer et al, 2011). Extensive research studies have been conducted on the prevalence of the tick fauna and associated risk factors in various districts of Pakistan.…”

“…Ticks are prevalent worldwide from Asia (Haque et al, 2011;Bilkis et al, 2011;Sajid et al, 2011;Razmi and Ramoon, 2012;Singh and Rath, 2013), Africa (Reye et al, 2012;Tiki and Mekonnen, 2011;Elghali and Hassan, 2012), North and South Americas (Guimaraes et al, 2001;Lohmeyer et al, 2011), Australia (Springell, 1974;Kamau, 2011) and Europe (Kirby et al, 2004;Scharlemann et al, 2008). Ticks not only cause direct losses, but also act as vectors for various pathogens of bacterial, rickettsial, protozoal, and viral origin (Petney et al, 2007).…”

Semiquantitative Multiplexed Tandem PCR for Detection and Differentiation of Four Theileria orientalis Genotypes in Cattle

“…The major clinical signs of this disease include fever, anemia, jaundice, lethargy, weakness, abortion, and/or mortality (16-18), with significant production losses in dairy cattle (22). Thus far, four genotypes (Buffeli, Chitose, Ikeda, and type 5) of T. orientalis have been reported in Australia (13,18,(20)(21)(22)(23).…”

“…(4)(5)(6). Presently, 11 genotypes of T. orientalis complex (designated Chitose or type 1, Ikeda or type 2, Buffeli or type 3, types 4 to 8, and N-1 to N-3) have been identified using a number of molecular markers, including major piroplasm surface protein (MPSP) (7,8), 23-kDa piroplasm membrane protein (p23) (9)(10)(11)60), small-subunit (SSU) rRNA gene (8,12,13), and/or the first and second internal transcribed spacers of nuclear ribosomal DNA (ITS-1 and ITS-2, respectively) (12,14). Of these genotypes, Ikeda and Chitose are recognized to be associated with clinical outbreaks of oriental theileriosis, mainly in the Asia-Pacific region (15)(16)(17)(18)(19)(20)(21).…”

“…The major clinical signs of this disease include fever, anemia, jaundice, lethargy, weakness, abortion, and/or mortality (16-18), with significant production losses in dairy cattle (22). Thus far, four genotypes (Buffeli, Chitose, Ikeda, and type 5) of T. orientalis have been reported in Australia (13,18,(20)(21)(22)(23).Currently, the diagnosis of oriental theileriosis is usually based on the observation of clinical signs, the detection of piroplasms of T. orientalis in blood smears (19,24,25), and/or the use of serological (26) or conventional molecular techniques (7,27,28). Each of these approaches has limitations.…”