• World
  • Zika

CDC Says 31 Americans Diagnosed with Zika

2 minute read
Updated: | Originally published: ;

Health officials said Thursday that 31 people in the U.S. have been diagnosed with the Zika infection in the past year hours after the head of the World Health Organization warned that the virus is “spreading explosively” in the Americas.

The U.S. figure represents the total number of infections in 11 states and Washington D.C., according to the U.S. Centers for Disease Control and Prevention. Health officials said that the infections are all thought to have originated with travel to Latin America. The U.S. territory of Puerto Rico has seen an additional 19 confirmed cases.

“The level of concern is high, as is the level of uncertainty,” said Margaret Chan, Director-General of the World Health Organization, at a briefing. “Questions abound. We need to get some answers quickly.”

See the Impact of Zika in Brazil

Mylene Helena Ferreira holds her five-month-old son David Henrique Ferreira, who has microcephaly, in Recife, Brazil, Jan. 25, 2016.
Mylene Helena Ferreira holds her five-month-old son David Henrique Ferreira, who has microcephaly, in Recife, Brazil, Jan. 25, 2016.Mario Tama—Getty Images
Homes are lit as the sun goes down in Ibura, one of the neighborhoods with the highest numbers of suspected cases of children born with microcephaly in Recife, Brazil, Jan. 27, 2016.
Homes are lit as the sun goes down in Ibura, one of the neighborhoods with the highest numbers of suspected cases of children born with microcephaly in Recife, Brazil, Jan. 27, 2016.Felipe Dana—AP
Soldiers inspect a house during an operation against the Aedes aegyti mosquito in Recife, Brazil, Jan. 27, 2016. Health authorities in the state at the center of a Zika outbreak have been overwhelmed by the surge of babies born with microcephaly, a neurological disorder associated with the mosquito-borne virus.
Soldiers inspect a house during an operation against the Aedes aegyti mosquito in Recife, Brazil, Jan. 27, 2016. Health authorities in the state at the center of a Zika outbreak have been overwhelmed by the surge of babies born with microcephaly, a neurological disorder associated with the mosquito-borne virus.Ueslei Marcelino—Reuters
A technician of the Fiocruz Institute stores Aedes aegypti mosquitoes to be used in research, in Recife, Brazil, Jan. 27, 2016.
A technician of the Fiocruz Institute stores Aedes aegypti mosquitoes to be used in research, in Recife, Brazil, Jan. 27, 2016.Felipe Dana—AP
Doctors scan the brain of a newborn to detect microcephaly, a neurological disorder associated with the Zika virus, at the Obras Sociais Irma Dulce hospital in Salvador, Brazil, Jan. 27, 2016.
Doctors scan the brain of a newborn to detect microcephaly, a neurological disorder associated with the Zika virus, at the Obras Sociais Irma Dulce hospital in Salvador, Brazil, Jan. 27, 2016.Christophe Simon—AFP/Getty Images
Staff prepare to draw blood from Ludmilla Hadassah Dias de Vasconcelos, who has microcephaly, at the Oswaldo Cruz Hospital in Recife, Brazil, Jan. 26, 2016.
Staff prepare to draw blood from Ludmilla Hadassah Dias de Vasconcelos, who has microcephaly, at the Oswaldo Cruz Hospital in Recife, Brazil, Jan. 26, 2016.Ueslei Marcelino—Reuters
Matheus Lima, 22, holds his two-year-old son, Pietro, who suffers from microcephaly, at his home in Salvador, Brazil, Jan. 28 , 2016.
Matheus Lima, 22, holds his two-year-old son, Pietro, who suffers from microcephaly, at his home in Salvador, Brazil, Jan. 28 , 2016.Christophe Simon—AFP/Getty Images
Girls gather nearby as health workers fumigate against the mosquito that transmits the Zika virus in Recife, Brazil, Jan. 28, 2016. Health officials believe as many as 100,000 people have been exposed to the Zika virus in Recife, although most never develop symptoms.
Girls gather nearby as health workers fumigate against the mosquito that transmits the Zika virus in Recife, Brazil, Jan. 28, 2016. Health officials believe as many as 100,000 people have been exposed to the Zika virus in Recife, although most never develop symptoms.Mario Tama—Getty Images
Gisele Felix, who is five months pregnant, stands on a terrace next to her son, Joao, at her home in Rio de Janeiro, Brazil, Jan. 28, 2016. Felix, who is concerned about the Zika virus, has not gone out of her house during her 30-day vacation, keeping all the windows and doors closed in an effort to keep out mosquitoes.
Gisele Felix, who is five months pregnant, stands on a terrace next to her son, Joao, at her home in Rio de Janeiro, Brazil, Jan. 28, 2016. Felix, who is concerned about the Zika virus, has not gone out of her house during her 30-day vacation, keeping all the windows and doors closed in an effort to keep out mosquitoes.Pilar Olivares—Reuters

The virus, which can lead to severe birth defects, has led to a slew of emergency measures in countries across the Americas. El Salvador called on women to delay having children for two years. Brazil has sent more than 200,000 troops to eradicate the mosquitoes that carry the disease. U.S. officials have said the country is launching a “full-court press” to address the issue.

WHO officials will meet on Monday to decide whether the disease outbreak qualifies as an international public health emergency.

More Must-Reads From TIME

Write to Justin Worland at justin.worland@time.com