Received: 8 July 2019
Accepted: 4 October 2021
First Online: 8 November 2021
: Ethical clearance was obtained from the Ethics Review Committee of the Faculty of Applied Sciences, Rajarata University of Sri Lanka. Informed written consent was obtained from all study participants (mothers) and one of the parents for children under 16. Informed written consent was obtained from children above 16.
: Not applicable.
: The authors declare that they have no competing interests.