* Corresponding authors

^a School of Public Health, University of California at Berkeley, California, USA
E-mail: zohir@berkeley.edu; krksmith@berkeley.edu
Fax: +1-510-642-5815
Tel: +1-510-643-0887

^b Epidemiology Division, School of Medicine, University of California at Irvine, California, USA
E-mail: edwardsr@uci.edu
Fax: +1-949-824-4773
Tel: +1-949-824-4731

^c Environmental Health Science and Policy, School of Social Ecology, University of California at Irvine, California, USA
E-mail: majohnso@uci.edu
Fax: +1-949-824-4773
Tel: +1-760-815-6492

^d EME Systems, Berkeley, California, USA
E-mail: tracy@emesystems.com
Fax: +1-510-848-5748
Tel: +1-510-848-5725

^e CDC-CAP/Universidad del Valle de Guatemala, Guatemala City, Guatemala
E-mail: eccz@cdc.gov
Tel: +502-5715-6194