Dengue scares at my Hougang apartment!

My tenant told me that he got a letter from NEA that they insisted to visit my place to check my house to see if there were any areas breeding mozzies.

Everything was good... except that we need to cover the area at the toilet seats... My mum then go buy some silicons to cover it up... Sigh... Hope this is ok... There are many cases of dengue cases near my block... So I hope my 2 tenants take care!