Funding for this research was provided by:
National Institute on Drug Abuse (T32DA023356, R01DA031074, DP2-DA040256-01, R37DA019829)
Fogarty International Center (R25TW009343, D43TW008633)
National Institute of Allergy and Infectious Diseases (P30AI36214)
National Institutes of Health (1TL1TR001443)
Canadian Institutes of Health Research (New Investigator Award)
Received: 16 March 2017
Accepted: 26 September 2017
First Online: 3 October 2017
Ethics approval and consent to participate
: The study was approved by the research ethics board at the University of California San Diego Human Research Protection Program. All participants provided written informed consent for study participation.
: Not applicable.
: The authors declare that they have no competing interests.
: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.