Fig. 1.
Sampling sites. a Philippine map. b Metro Manila (filled square urban, La—Las Pinas, Pa—Paranaque). c Bulacan (filled circle rural, Bo—Bocaue, Ma—Marilao, Me—Meycauayan)
Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.