טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
Ph.D Thesis
Ph.D StudentAbu Shqara Farah
SubjectDeveloping a Fast Method for Counting and Identification of
Enteric Viruses from Water and Wastewater
DepartmentDepartment of Civil and Environmental Engineering
Supervisor Professor Emeritus Yehuda Kott (Deceased)


Abstract

Hundreds strains of enteric viruses are spread via the fecal-oral route, thus reach the wastewater system might contaminate water sources, which may cause a viral epidemic. The methods used today for deticting and determination of enteric viruses are time consuming, or those that take less time, are costly.

The aim of the study was to find an inexpensive method that would enable to show and count enteric viruses in a short period of time.

Enteric viruses, attenuated Polio viruses (1, 2, 3), Coxsackie-B (1, 2, 5) and Echo viruses (5, 9) were grown in 50 mm plates on a BGM (Buffalo Green Monkey) cell line. After incubation at 37oC, 5% CO2 for 24 hours, the following steps were performed: a) the top agar was removed; b) the plates were washed with 5 ml of 10 mM MOPS (3-[n-Morpholino] butanesulfonic acid); c) the plates were filled with 2 ml of 0.02% Toluidine Blue (TB) for 1 min, and washed with 5 ml of 10 mM MOPS; d) blue color plaques were counted.

In order to confirm that the method is precise at extreme conditions, viruses were exposed to chlorine. The survived viruses were counted as mentioned after 24 hours.

Raw wastewater samples were examined for entericviruses as mentioned in the Standard Methods for the Water and Wastewater. Similar numbers of viruses were found using TB as compared with the neutral red procedure. Most probable number counts using TB proved to be reliable.

The application of Toluidine Blue reduced the examination time from 72 hours to 24 hours, as compared with the routine method.