About the Authors
Medical College, Aga Khan University, Karachi, Pakistan
Department of Community Health Sciences, Aga Khan University, Karachi, Pakistan
The authors have declared that no competing interests exist.
Conceived and designed the experiments: HK MK. Performed the experiments: HK AT. Analyzed the data: HK AT MK. Contributed reagents/materials/analysis tools: HK. Wrote the paper: HK AT ZF.