Funding for this research was provided by:
Received: 11 September 2019
Accepted: 29 December 2019
First Online: 14 January 2020
Ethics approval and consent to participate
: This study was granted ethics approval by the Oxford Tropical Research Ethic Committee (OXTREC) (Ref. 5121/16) and by the local authorities (People’s Committee of Dong Thap province).
: Not applicable
: The authors declare that they have no competing interests.