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

Justine Daudi Maganira; Winifrida Kidima; Chacha John Mwita; Peter Halvarsson; Johan Höglund

doi:10.1080/20008686.2020.1772668

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

Infect Ecol Epidemiol. 2020 Jun 4;10(1):1772668. doi: 10.1080/20008686.2020.1772668.

Authors

Justine Daudi Maganira^{1

2}, Winifrida Kidima³, Chacha John Mwita⁴, Peter Halvarsson², Johan Höglund²

Affiliations

¹ Department of Biosciences, Sokoine University of Agriculture, Morogoro, Tanzania.
² Department of Biomedical Sciences and Veterinary Public Health, Swedish University of Agricultural Sciences, Uppsala, Sweden.
³ Department of Zoology and Wildlife Conservation, University of Dar Es Salaam, Dar Es Salaam, Tanzania.
⁴ Department of Aquatic Sciences and Fisheries Technology, University of Dar Es Salaam, Dar Es Salaam, Tanzania.

Abstract

The presence ofTaenia solium 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 (cox1) 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 cox1 gene of T. solium. A total of 17.2% (n = 33) samples were positive with the universal ddPCR, whereas T. solium DNA was confirmed by the specific ddPCR only in 3.1% (n = 3) of the surveyed households. The detection of T. solium DNA in this study spells out a low risk of exposure to T. solium eggs from contaminated household soil. Based on our results, ddPCR seems to be a promising technology for screening T. solium eggs in soil.

Keywords: Kongwa; Taenia solium; Tanzania; ddPCR; eggs; soil contamination.

Grants and funding

This study was financially supported by the Swedish International Development Cooperation Agency (Sida) under Sida - Tanzania Bilateral Programme [Contribution No. 5410004501] as part of the Food Security programme involving the Swedish University of Agricultural Sciences and University of Dar es Salaam.