NEW YORK (CBSNewYork) — New York City is stepping up to help Puerto Rico combat the Zika virus.

Puerto Rico has seen 474 locally transmitted cases, more than any other state or territory in the United States.

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The virus is largely spread by mosquitoes, but experts said it can also be spread by unprotected sex. That’s why the city Health Department is donating 1 million condoms to the island to help reduce the spread of Zika through sexual transmission.

ZIKA INFORMATION FROM THE CDCBasics | FAQ | Info For Pregnant Women | Symptoms, Diagnosis & Treatment | More Info |  10 Facts About The Zika Virus

“In light of Puerto Rico’s healthcare crisis, we are proud to announce we’ve donated 1 million condoms to our neighbors,” Mayor Bill de Blasio said in a statement. “We stand with the Puerto Rican people.”

“New York City is home to the largest population of Puerto Ricans in the continental U.S., and many New Yorkers travel back and forth to the island,” Health Commissioner Dr. Mary T. Bassett said. “We share the fight against mosquito borne viruses.”

The virus can cause severe birth defects, including microcephaly, a condition in which a baby’s head is far smaller than normal.

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Last month, de Blasio announced a $21 million, three-year plan to help protect New Yorkers from the Zika virus. The plan includes monitoring and controlling the mosquito population, expanding the capacity to meet the demands of increased testing of pregnant women and launching an awareness campaign.

Meanwhile, U.S. Sen. Richard Blumenthal (D-Conn.) blames Republicans for failing to act on President Barack Obama’s $1.9 billion spending plan to combat Zika, as WCBS 880’s Marla Diamond reported.

“The mosquitoes that carry this disease don’t know a red state from a blue state, and the Congress has to come together,” Blumenthal said.

Blumenthal noted that the type of mosquito that carries Zika has been found in northeastern states.

“We face a public health emergency,” he said. “Zika is a vicious virus capable of crippling and killing and it will only spread further as the warmer months approach.”

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Blumenthal said the funding will not just help curtail the spread of Zika, but it will also aid two Connecticut-based labs that are working on a vaccine.