The BWSSB officials on Monday said there is no case of water contamination at Shamanna Garden from where 20 suspected gastro-entritis cases were shifted to Isolation Hospital. Assistant Executive Engineer K Narasanna said the samples of water were taken from the spot and tested in the presence of BBMP health inspector. "The samples showed sufficient chlorination and so it has been clearly proved there is no problem with the water quality,' he said. Chief Engineer (Maintenance), BWSSB, Venkataraju said, "Drinking water was supplied to the area on Saturday and Monday. We received calls from residents who suspected some water contamination but subsequent tests showed no problem with water.' Testing woes There has always been a difference of opinion amongst the medical fraternity regarding the hanging drop method of testing for cholera. While some consider the method an accurate indicator, others see stool test as accurate indicator. GE and cholera cases are common during summer. It is mango season and many a time mosquitoes breed on mango - people sometimes don't wash them properly and eat infected mangoes resulting in GE, said Medical Officer, St Martha's Hospital, Dr R Sashikanth. Most cases, however, are water-related, he added.