Rapid Detection of Toxoplasma gondii: Prevalence Investigation of T. gondii Infection Among Stray Cats and Dogs in Zhejiang Province Based on a New Loop-Mediated Isothermal Amplification-Lateral-Flow-Dipstick (LAMP-LFD) Device

Background: Toxoplasma gondii (T. gondii) is worldwide spread caused Toxoplasmosis threatening warm-blooded animal and human health, especially for immunodeficient population and pregnant women. Simple and applicable diagnostic methods are urgently needed for the prevention of toxoplasmosis. The molecular diagnosis of T. gondii infection generally requires high technical skills, sophisticated equipment and a controlled lab environment.Methods: In this study, we developed a loop-mediated isothermal amplification-lateral-flow-dipstick (LAMP-LFD) assay that specifically targets the 529 bp for the detection of T. gondii infection in a new kind of portable device, which is universal, fast, user-friendliness, experimental sensitivity and low risk of aerosol contamination. Results: The detection limit of the LAMP-LFD assay is 1 fg of T. gondii DNA and no cross-reaction with other parasitic pathogens including Leishmania donovani, Plasmodium vivax, Cryptosporidium parvum, etc. In total, 318 stray cat and dog blood samples were collected from Deqing, Wenzhou, Yiwu, Lishui and Zhoushan cities in Zhejiang province, Eastern China. The current infection prevalence of T. gondii was 4.76% and 4.69% in stray cats and dogs respectively, detected by LAMP-LFD device.Conclusions: In conclusion, the established LAMP-LFD was an efficient and avoidable aerosol-contaminated device that can detect 1 fg genomic DNA of T. gondii, and suitable for T. gondii detection in the basic medical institution and even in field areas.