WASHINGTON (Reuters) - U.S. Health and Human Services Secretary Sylvia Burwell said on Wednesday that no cases of the Zika virus had been passed by mosquitoes to people in the continental United States.
In testimony to the House Ways and Means Committee about her department's budget request, Burwell said cases of the virus had occurred in travelers returning to the United States, and that there had been one case of sexual transmission in Dallas. The virus has been passed from mosquitoes to people in the U.S. territory of Puerto Rico, she said.
President Obama is asking Congress for over $1.8 billion in emergency funds to fight Zika at home and abroad, and pursue a vaccine.
Burwell said the government needed the money to prepare for mosquito control, especially in the southern states, as the country heads into the summer months.
She said that of two kinds of mosquitoes thought to transmit the virus, "one is a very efficient transmitter; meaning it will bite four individuals in a meal." That mosquito is limited to the deep southern U.S. states, she said.
The other mosquito can be found in about 20 states, and may be a transmitter, she said.
Zika has spread quickly in South and Central America and the Caribbean, raising fears of the possibility of a birth defect known as microcephaly, a condition marked by abnormally small head size that can result in developmental problems. Most infected people have no symptoms or mild ones including fever and skin rashes.
Burwell gave U.S. senators a closed-door briefing a day earlier about the Obama administration's battle plan for Zika, pushing back against Republican assertions that the administration had no immediate need for money and could divert existing funds from a longstanding campaign against Ebola in Africa.
She said the government needs to ramp up preparedness and mosquito control in Puerto Rico, Florida, Texas and other Southern states while pursuing new research and an accelerated vaccine program.
Reporting by Susan Cornwell; Editing by David Alexander, Bernard Orr