Development of a real-time recombinase-aided amplification (RT-RAA) molecular diagnosis assay for sensitive and rapid detection of Toxoplasma gondii.

Toxoplasma gondii, a protozoan intracellular parasite, is present in a wide range of hosts, including virtually all species of warm-blooded vertebrates. Toxoplasmosis spreads to humans through a variety of pathways, including contaminated food or water, and close contact with various types of domestic animals. It poses a severe threat to human health, and contributes to important economic losses, not only in cost-of-illness but also in surveillance programs. It is thus necessary to develop a rapid point-of-care field diagnostic technology to control or prevent pathogen transmission to economically important livestock animals, domestic animals, and human beings. In this study, we develop a real-time isothermal amplification method capable of detecting the T. gondii genome in swine and feline blood samples. This method can detect toxoplasma genome with a lowest detection limit of 102 copies of per reaction under optimal reaction conditions of 36 °C for 25 min. The assay displayed advantages in sensitivity and specificity in comparison to traditional real-time PCR, and can be performed in a portable instrument.