Text and Data Mining valid from 2019-02-06
Received: 8 June 2018
Accepted: 29 January 2019
First Online: 6 February 2019
Ethics approval and consent to participate
: The study was approved by the Institutional Review Board of Aminu Kano Teaching Hospital (Reference number NHREC/21/08/2008/AKTH/EC/1280) and informed consent was taken from parents or guardians of all enrolled study participants.
: Not applicable.
: The authors declare that they have no competing interests.
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