In vitro titration of Theileria parva tick derived stabilates

Area of Science:

• Veterinary Parasitology
• Immunology
• Cell Biology

Background:

• East Coast fever, caused by Theileria parva, is a fatal tick-borne disease affecting cattle in Africa.
• Current immunization relies on infection and treatment using live T. parva sporozoites, with doses determined by in vivo titration.
• In vivo titration poses ethical concerns and can be inefficient.

Purpose of the Study:

• To propose and validate an alternative in vitro method for quantifying T. parva sporozoites in tick-derived stabilates.
• To establish a more ethical and efficient approach for research on T. parva stabilates.

Main Methods:

• Serial dilution of T. parva stabilates incubated with bovine peripheral blood lymphocytes.
• Undisturbed incubation for 10 days to reduce titration variability.
• Stabilat centrifugation to prevent fungal contamination without significant sporozoite loss.

Main Results:

• The in vitro method provides a viable alternative for sporozoite quantification.
• Extended incubation (10 days) minimized variability in replicate titrations.
• Centrifugation effectively reduced fungal contamination, and fungistatics showed limited impact on fungal growth but did not inhibit T. parva development.

Conclusions:

• In vitro titration of T. parva sporozoites is a promising, more ethical, and efficient research tool.
• This method can improve the preparation and storage protocols for T. parva tick-derived stabilates.
• Further research can leverage this in vitro technique for East Coast fever control strategies.