Soil contamination by Taenia solium egg DNA in rural villages in Kongwa district, Tanzania.

The presence of DNA from eggs in soils around the households in four Tanzanian villages in Kongwa district were analysed in relation to seasonal fluctuations and infection risk implications. A total of 192 pooled soil samples from five sampling points per household were examined by droplet digital Polymerase Chain Reaction (ddPCR) from 96 pig-keeping households both during the dry and rainy seasons. The pooled samples were first processed by a flotation-double sieving technique, followed by screening for worm DNA employing universal primers targeting the mitochondrial cytochrome c oxidase subunit I () gene of human taeniid species and some other helminths. All DNA positive samples were later confirmed by a specific ddPCR probe assay targeting the mitochondrial  gene of . A total of 17.2% (n = 33) samples were positive with the universal ddPCR, whereas  DNA was confirmed by the specific ddPCR only in 3.1% (n = 3) of the surveyed households. The detection of  DNA in this study spells out a low risk of exposure to  eggs from contaminated household soil. Based on our results, ddPCR seems to be a promising technology for screening  eggs in soil.