The nation’s highest ranking infectious disease expert delivered some sobering news on Zika to a Miami audience on Tuesday, telling them that the mosquito-borne virus is more widespread than Florida health officials have reported and that the rapid spread of pathogens such as Zika represents “the new normal” in an age of global travel and trade, booming cities and climate change.
“Here’s the plain truth: that Zika and other diseases spread by Aedes aegypti [mosquito species] are really not controllable with current technologies. So we will see this become endemic,” Tom Frieden, a physician and director of the Centers for Disease Control and Prevention told a group of about 100 people gathered at the InterContinental Miami hotel for The Atlantic magazine’s CityLab conference.
Frieden’s takeaway advice for public officials tasked with protecting the public from disease outbreaks: “Invest in public health,” he said. “It pays off.”
Unprecedented in its ability to spread by sexual contact as well as mosquito bites, and to cause birth defects — most notably microcephaly in children born to mothers infected while pregnant — Zika took health officials by surprise this year, Frieden said, noting that there’s still a lot that scientists do not know about the virus’s effects.
“Zika has surprised us,” he said. “It’s been difficult to predict. It’s had characteristics that we have not seen with other diseases before. What we anticipate will happen is that this season will calm down within the continental United States. We hope that Miami-Dade will stop having cases, but we can't promise that. ... We will see parts of the hemisphere where it will be endemic. It will come back every year.”
And though Florida has reported 1,064 Zika cases, including 190 mosquito-borne infections, Frieden said the real number likely is much higher.
“A rule of thumb,” he said, “is for every case you diagnose you’ve probably got 10 more.”
On Tuesday, Florida health officials reported two additional mosquito-borne Zika infections in Miami-Dade, including one in Miami Beach and a second that will require an epidemiological investigation to determine the source of exposure.
Not all of Frieden’s comments were gloom and doom, however. Interviewed on a stage by Jeffrey Goldberg, editor of The Atlantic, Frieden noted some successes in combating Zika, particularly in Miami’s Wynwood neighborhood, where he said the virus had stopped spreading after repeated rounds of aerial spraying of naled, a neurotoxin pesticide that kills adult mosquitoes, and BTI, a bacterial laravacide that kills their eggs.
“Literally within a day the mosquito counts went to zero,” he said. “More than 90 percent of mosquitoes that were in traps were killed. ... Mosquito counts haven't rebounded for the last month, and no more cases.”
That doesn’t mean that Wynwood is now immune to Zika, Frieden cautioned, but it’s an important new tool in the public health arsenal for combating the disease.
And though no new Zika infections have been reported in Wynwood since August, mosquitoes continue to spread the virus in two identified areas of Miami-Dade, including a 4.5-square-mile section of Miami Beach and a one-square-mile zone in Miami’s Little River neighborhood.
In addition, nearly 50 Zika infections have been reported in areas Miami-Dade that are outside of the identified zones — a fact that Frieden said led the CDC to update its guidance last week, advising pregnant women to get tested for the virus if they have visited any part of the county.
Frieden also took some gentle jabs at Florida’s Department of Health, noting that in Singapore public health officials “were fully transparent about the cases. They said here’s where they are. Here’s what we’re doing about them — all the information publicly available.”
Florida’s health department does not identify where Zika cases are located, whether those infections are travel-related or locally acquired. The state also refuses to identify counties where pregnant women with Zika reside.
Asked about Singapore’s approach compared to Florida’s when it comes to informing the public about a disease outbreak, Frieden smiled and said, “I said that for a reason. ... I think Florida recognizes that it should do that and that it will try to do that by next season. I think the more transparent the state is, the more people will have confidence in what’s happening.”
During his visit to Miami, Frieden said he met with Miami-Dade Mayor Carlos Gimenez and Miami Beach Mayor Philip Levine.
“I’m quite impressed with how intensively Miami-Dade is approaching this,” he said. “They’re responding to every case. They’ve got excellent mosquito control.”
He said vaccines typically take a decade to develop, but that a defense against Zika could be ready in less time.
“We're hoping that in two to three years one will be available,” he said.
Zika cases reported in Florida as of Oct. 25
Number of Cases
Total cases not involving pregnant women
Cases involving pregnant women regardless of symptoms*
* Counties of pregnant women are not disclosed
* Does not include local infections
Source: Florida Department of Health