"I, Sylvia M. Burwell… do hereby determine that a public health emergency of national significance exists within the Commonwealth of Puerto Rico relating to pregnant women and children born to pregnant women with Zika," the statement noted on Friday.
Burwell's pointed out that the declaration to declare public health emergency was made after consulting US federal and local public health officials.
Earlier this month, the number of pregnant women in Puerto Rico who tested positive for the Zika virus reached 521, according to the US Centers for Disease Control and Prevention (CDC).
The CDC confirmed nearly 6,600 cases of locally transmitted Zika virus in Puerto Rico as of August 10.
The current Zika outbreak started in Brazil in the spring of 2015. The virus is transmitted by daytime-active mosquitos. It does not cause serious complications in adults, but the virus can cause severe brain defects and microcephaly in newborns.
