The spread of the Zika virus and the birth defects it causes are no longer a public health emergency of international concern, but a longer-term problem, the World Health Organization said Friday.

WHO officials denied that the change in status means Zika is less of a concern, but they said for funding and other bureaucratic reasons they need to move it to a different level.

Dejailson Arruda holds his daughter Luiza at their house in Santa Cruz do Capibaribe, Pernambuco state, Brazil. Luiza was born in October with microcephaly. Felipe Dana / AP

"There was no downgrading at all of this," Dr. David Heymann, chairman of the WHO’s emergency committee on Zika virus, told a telephone briefing.

"The committee agreed that Zika must be managed within the World Health Organization as are other important infectious diseases,” added Heymann, an infectious disease expert at the London School of Hygiene and Tropical Medicine.

"The committee felt that what is best now is a very robust technical response to the virus."

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Zika has spread across much of the Americas in less than a year. It first started causing concern in Brazil, where the previously innocuous virus appeared to be causing a horrific birth defect called microcephaly.

The need to investigate the link prompted the emergency, WHO said. It’s now been strongly established – Zika causes not only microcephaly, but a range of other terrible and subtle birth defects.

It also causes neurological complications in adults, including the paralyzing Guillain-Barre syndrome.

"We are sending the message that Zika is here to stay and WHO's response is here to stay."

The virus is carried by Aedes aegypti mosquitoes but now a study has shown it can be sexually transmitted, also. And it’s found in a range of bodily fluids, including urine and saliva.

"We are not downgrading the importance of Zika. In fact, by placing this as a longer program of work, we are sending the message that Zika is here to stay and WHO's response is here to stay in a very robust manner," said Dr. Peter Salama, executive director of WHO's Health Emergencies Program.

Heymann said the countries and other big donors that give a lot of money to emergency responses tend to be different from those that give to development projects.

“Development partners need to step up to the plate now,” he said.

Related: Read NBC's Full Zika Virus Coverage Here

But Lawrence Gostin, an expert in global health law at Georgetown University, said it’s a mistake.

"I think the international response to Zika has been lethargic, and with WHO's action to call off the global emergency, it has provided reason for governments and donors to pull back even more," Goston said in a statement.

"That is a recipe for the very lack of preparedness the world has seen time and again with infectious diseases."

Zika’s still causing outbreaks in Florida. The Florida health department reported four more locally acquired cases Friday, as well as more brought in by travelers from other affected areas.

“That is a recipe for the very lack of preparedness the world has seen time and again with infectious diseases.”

The state now has reported 234 home-grown cases, and 160 pregnant women have been affected.

Babies born with Zika-related birth defects are permanently affected. There’s no cure and the cost of rehabilitation to help them stay healthy can run to a million dollars or more, experts have estimated. Parents of Zika-affected children in Brazil and elsewhere say they are having trouble getting that help.

Labs are working to develop vaccines to prevent Zika, but they are years away from being affected. WHO and the Centers for Disease Control and Prevention both say fighting mosquitoes is the best way to prevent the spread of the disease.

Both also advise pregnant women to stay away from Zika- affected areas if at all possible.