Assessment of torque teno virus prevalence in a wastewater treatment plant in iran, tehran
Shadi Tavakoli nik
,1,* Seyed reza mohebbi
,2 Seyed masoud hosseini
,3 Hamed mirjalali
,4 Esfandiar jalilzadeh
,5 Mohammad reza zali
1. Department of Microbiology, Faculty of Biological Sciences, Shahid Beheshti University
2. Gastroenterology and Liver Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences
3. Department of Microbiology, Faculty of Biological Sciences, Shahid Beheshti University
4. Foodborne and Waterborne Diseases Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
5. Department of Water and Wastewater Quality Control Laboratory, Water and Wastewater Company, Tehran, Iran.
6. Basic and Molecular Epidemiology of Gastrointestinal Disorders Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
Torque teno virus (ttv) was detected for the first time as a cause of hepatitis with unconventional etiology in japan. although multiple researches could not reveal a clear and strong association between ttv and serious health risks, some types of ttv are possibly linked to human diseases. ttv is a non-enveloped virus which has a circular single-stranded dna. ttv is a member of anellovirus belongs to the family circoviridae. ttv can be isolated from healthy individuals and hepatitis patients therefore, it is considered to be transmitted by oral fecal route. since ttv has high stability in environment and also be excreted and transmitted through stool, it can be used as an indicator of water-fecal contamination. the aim of this study was to determine the presence of ttv in the effluent of a treatment plant in tehran.
13 effluent samples of the treatment plant of the city of tehran were obtained monthly for a year from september 2017 to july 2018.the samples were concentrated by means of positive charge filters adsorption-elution technique. adsorbed viruses were eluted with beef extract reagent and eluates were concentrated using organic flocculation method. viral dna was extracted and nested-pcr was carried out to amplify and detect ttv genome.
The study samples comprised of 7 effluent wastewater samples before chlorination and 6 effluent wastewater samples after chlorination. totally, 9 of 13 samples (76.92%) were positive for ttv. all 7 effluent wastewater samples before chlorination (100%) were positive for ttv and 50% of effluent wastewater samples after chlorination were positive for ttv.
The results indicate that ttv is one of the most prevalent contaminations of the tehran’s wastewater treatment plant. setting up a new sewage treatment system and methods is necessary to avoid river and surface water pollution.
Torque teno virus, ttv, wastewater, tehran, molecular detection