Approaches to Integrated Parasite Management (IPM) for Theileria orientalis with an Emphasis on Immunity

Abstract

Integrated parasite management (IPM) for pests, pathogens and parasites involves reducing or breaking transmission to reduce the impact of infection or infestation. For Theileria orientalis, the critical impact of infection is the first wave of parasitaemia from the virulent genotypes, Ikeda and Chitose, associated with the sequelae from the development of anaemia. Therefore, current control measures for T. orientalis advocate excluding the movement of naïve stock from non-endemic regions into infected areas and controlling the tick Haemaphysalislongicornis, the final host. In Australia, treatment of established infection is limited to supportive therapy. To update and expand these options, this review examines progress towards prevention and therapy for T. orientalis, which are key elements for inclusion in IPM measures to control this parasite.

Distribution and Prevalence of Theileria orientalis Genotypes in Adult Lactating Dairy Cows in South West Region of Western Australia

“…Although the Ikeda genotype is considered highly pathogenic, the cattle positive for Ikeda genotype in this study did not exhibit clinical signs of disease. There are several possible scenarios which could explain the lack of clinical signs [ 6 , 25 , 26 ]. Firstly, the high prevalence of the Ikeda genotype detected in this study could be indicative of the presence of a genetically less pathogenic variant of the Ikeda genotype with low parasitaemia [ 6 ].…”

“…Thirdly, a high level of population immunity is present, representing the achievement of enzootic stability [ 6 ]. Fourthly, the cattle have recovered and remain asymptomatic carriers [ 26 ].…”

Detection of Theileria orientalis Genotypes from Cattle in Kyrgyzstan

“…The economic loss due to the pathogenic genotype of the T. orientalis amounts to millions of dollars annually. Integrated Parasite Management (IPM) is applied to reduce these economic losses [ 35 ]. In addition, occult carriers, such as sheep, have been found to be important in the spread of T. orientalis as a source of infection for naive ticks [ 10 ].…”

Characterisation of the Theileria orientalis Piroplasm Proteome across Three Common Genotypes

“…Measures for control of this parasite are limited. In Australia and New Zealand, the parasite is now endemic across the range of the vector tick with widespread immunity observed in adult cattle [ 10 , 11 , 12 ]. However, mixing of naïve and endemic animals remains a major risk for clinical outbreaks of disease and passive immunity confers little protection on young calves, with high parasitaemias routinely observed between 3 and 12 weeks of age [ 13 ].…”

“…Buparvaquone, which is used for the treatment of Theileria parva infection (East Coast fever) in Africa, is also effective against T. orientalis if used during the earlier stages of infection; however, it is not approved for use in some countries and has a lengthy withholding period due to the retention of residues in meat and milk products [ 14 ]. Blood transfusions are sometimes used to treat anaemia due to T. orientalis infection; however, this process is costly and is not always successful [ 11 ].…”