Received: 28 March 2019
Accepted: 5 July 2019
First Online: 15 July 2019
Ethics approval and consent to participate
: The study was approved by Mekelle University Institutional Review Board (ERC1287/2017). Written informed consent was obtained from each study participant and for those participants under the age of 18 years written informed consent was received from their legal guardians.
: Not applicable.
: The authors declare that they have no competing interests.