Puerto Rico government officials on Friday reported the biggest weekly rise in Zika cases that the U.S. territory has ever seen.
Health Secretary Ana Rius said 1,336 new cases were reported in the past week, for a total of 4,437 cases since the mosquito-borne virus was first detected in December.
She said 76 of Puerto Rico's 78 municipalities now have Zika cases. A total of 553 pregnant women have Zika, which can cause severe birth defects.
Fifty-five people have been hospitalized for Zika-related illnesses, including 19 diagnosed with a temporary paralysis known as Guillain-Barre syndrome that has been linked to the virus. One person has died.
The spike comes a week after U.S. health officials urged Puerto Rico's government to consider aerial spraying to fight the virus. Rius previously said she supported fumigation with the insecticide Naled, but on Friday she told radio station WKAQ 580 that she has put that recommendation on hold.
"We are studying all the risks that Naled poses, and whether these are greater than the benefits we would receive," she said. "We are consciously seeking what we'll recommend to the governor."
Puerto Ricans have held numerous protests against aerial spraying, saying it would harm wildlife and people's health. U.S. government officials have said it is safe to spray with Naled.
Gov. Alejandro Garcia Padilla has not yet commented on the issue.
The U.S. Centers for Disease Control and Prevention has warned that up to 20 percent of Puerto Rico's nearly 3.5 million people could be infected with Zika in an outbreak expected to peak by this summer.