AHH / Disease Control / Kenya / Vaccines

Study shows promising new avenues to develop a product that could help in the control of Theileriosis

ILRI farm: Spraying unit

Cattle dry out after leaving the spraying unit (photo credit: ILRI/Onesmus Mulinge).

A recent study on ‘Identification of virulence factors of Theileria parva’ has confirmed the existence of a low virulent strain and identified the mechanism that was at the basis of this low virulence, showing some promising new avenues to develop a product that could help in the control of Theileriosis. This low virulent strain, Chitongo isolate induced less mortality and milder clinical symptoms than the Muguga isolate. Theileria parva, is a tick-borne intracellular protozoan parasite that infects lymphocytes of cattle and the African buffalo that causes East Coast fever (ECF).

‘The data strongly suggests that the low virulence of TpC could be due to the fact that its infective stage can only bind, infect and transform the CD8 subpopulation of lymphocytes, contrast to the more virulent T.parva isolates, that can bind and transform all lymphocytes, including B cells. As the p67 adhesion molecule of TpC is 100% identical to that of TpM, a second adhesion ligand must exist on sporozoites.

‘The main objective of the study was to provide firm evidence for the existence of a Theileria isolate with low virulence. An isolate from Zambia, TpC, suspected to be of low virulence was compared with with T.parva Muguga, a well studied isolate that induces high mortality and morbidity in cattle, for their capacity to infect cells in vitro and for their capacity to induce disease in vivo.’

According to the study, Chitongo isolate can help advance vaccination strategies in the following ways:

  1. Improvement of the Infection and Treatment Method vaccine
  2. Development of a sub-unit vaccine
  3. Attenuation of virulent strains

The study suggests that future studies should focus on the existence and identification of a second adhesion of Theileria sporo\oites. This would be a major advance in Theileriosis research, providing a new candidate antigen for a subunit vaccine, and provide essential information to understand the binding and infection process.

Related journal article: A Theileria parva Isolate of Low Virulence Infects a Subpopulation of Lymphocytes

Article Source credit: Identification of virulence factors of Theileria parva by Tindih Sheltone Heshborne

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