Prevalence, risk factors and genotype distribution of Toxoplasma gondii DNA in soil in China

Abstract

In the present study, we performed a cross-sectional survey to determine the occurrence and genotype distribution of T. gondii DNA in soil samples collected from different sources from six geographic regions in China. Between March 2015 and June 2017, 2100 soil samples were collected from schools, parks, farms and coastal beaches, and examined for T. gondii DNA using three PCR assays targeting 529-bp repeat element (RE) sequence, B1 gene and ITS-1 gene sequences. Also, we investigated whether geographic region, soil source and type, and sampling season can influence the prevalence of T. gondii DNA in the soil. Soil samples collected from farms and parks had the highest prevalence, whereas samples collected from school playgrounds and coastal beaches had the lowest prevalence. PCR assays targeting 529bp RE and ITS-1 gene sequences were more sensitive than the B1 gene-based assay. Positive PCR products were genotyped using multi-locus PCR-RFLP, and ToxoDB #9 was the predominant genotype found in the contaminated soil samples. Multiple logistic regression identified factors correlated significantly with the presence of T. gondii DNA in the soil to be the source of the soil, including farms (odds ratio 3.10; 95% confidence interval [CI], 1.52 to 6.29; p = 0.002) and parks (2.59; 95% CI 1.28 to 5.27; p = 0.009). These results show that Chinese soil hosts T. gondii of the most prevalent genotype in China (ToxoDB#9) and that the soil type influences infection patterns.

RAA-Cas12a-Tg: A Nucleic Acid Detection System for Toxoplasma gondii Based on CRISPR-Cas12a Combined with Recombinase-Aided Amplification (RAA)

“…The basic RAA kits were purchased from ZC Bio-Sci&Tech (Hangzhou, China). A total of 30 soil DNA samples were provided by Dr. Wei Cong of Marine College, Shandong University, China [ 9 ]. Seven parasite DNA samples ( T. gondii , Cryptosporidium parvum , Neospora caninum , Enterocytozoon bieneusi , Blastocystis sp., Eimeria tenella , and Toxocara canis ) were prepared by our lab and stored at −20 °C until for RAA- and PCR-based assays.…”

“…Toxoplasmosis also can result in the abortion and stillbirth of livestock, causing considerable economic losses to animal husbandry [ 1 , 5 ]. As a foodborne and waterborne pathogen, T. gondii is capable of inadvertently appearing in vegetables, fruits, water and soil [ 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 ]. Human and animal infections occur through eating raw or undercooked meat or via the ingestion of water or food contaminated with sporulated oocysts [ 14 ].…”

“…For these molecular technologies, T. gondii -specific repetitive DNA sequences, such as B1 gene, ITS-1 and 18S rDNA, and 529-bp repeat element (RE), have shown good sensitivities for the detection of T. gondii [ 15 ]. In contrast, PCR and LAMP assays targeting the 529-bp RE sequence have suggested that they are more sensitive than the B1 gene-based assays [ 9 , 18 , 19 ], while the multicopy ITS-1 and 18S rDNA have shown a similar sensitivity of the B1 gene [ 20 , 21 ]. In addition to sensitivity evaluation of target molecules, LAMP is more sensitive than the routine PCR, but slightly lower than the RT-PCR [ 22 , 23 ].…”

“…In this work, by designing specific CRISPR-derived RNA (crRNA) probe targeting the 529 bp-RE sequence of T. gondii and combining RAA and Cas12a protein, termed RAA-Cas12a-Tg system, we presented an advanced approach for easy, rapid and accurate detection of T. gondii DNA by observing the fluorescence intensity with the naked eye under an ultraviolet light or via the detection of the fluorescence wavelength using a microplate reader ( Figure 1 ). Additionally, by examination of 30 soil DNA samples from our previous study [ 9 ], we also compared the T. gondii -positive results detected by the conventional PCR-based method and RAA-Cas12a-Tg system. Our verification indicated that RAA-Cas12a-Tg system has merits in the aspect of conveniency and sensitivity, and its applications may facilitate the control of toxoplasmosis in humans and animals.…”

Short Reports Low Prevalence of Toxoplasma Gondii DNA in the Fresh Milk of Cattle in China

“…Toxoplasmosis is a global zoonotic parasitic diseases, caused by Toxoplasma gondii, an important opportunistic protozoa, which can cause great nancial losses, especially for the animal production industries, and is of great importance for public health [1][2][3]. All kinds of hosts may be infected through ingestion of T. gondii oocysts or cysts containing bradyzoites, via ingestion of tachyzoites in nonpasteurized milk products or through the transplacental transmission [4].…”