A localise Zika virus outbreak in Miami inspired the Centers for Disease Control and Prevention( CDC) to issue a rare travelling advisory on Monday, cautioning pregnant women or women who wish to become pregnant against traveling to a 1-mile radius of an region simply north of downtown Miami.
The Zika virus transmission zone encompasses the Miami neighborhood of Wynwood, Florida, as well as portions of Edgewater.
The agency said that since it first announced the first active transmission of the Zika virus within the U.S. on Friday, additional occurrences were identified in the same part of Florida merely north of downtown Miami.
CDC director Dr. Thomas Frieden told reporters on a conference call that testing by state and local officials as well as CDC personnels has turned up persistent mosquito populations in that area, along with additional Zika suits. Frieden said there is a risk of continued Zika transmission in that area.
The CDC travel advisory is a step the agency had been taking to warn against foreign travel by U.S. citizens to countries where Zika transmission was ongoing, including Brazil, where the Rio Olympics will kick off on Friday.
Frieden said it is the first time the CDC had issued a traveling advisory regarding a place inside the U.S ., other than a Zika-related advisory in Puerto Rico, where far more widespread transmitting of the virus is occurring.
The CDC said women who are considering becoming pregnant can travel to the affected area, but health officers recommend they wait at least eight weeks before trying to conceive a child.
According to the 2010 Census, the advisory affects about 20,214 people.
The limited area of the advisory is based on the fact that the mosquito that spreads the Zika virus is not known to venture further than 150 meters during its entire lifetime, Frieden said.
Zika is spread through mosquito bites of the Aedes aegypti mosquito, which can also spread dengue fever and chikungunya, and can also be transmitted sexually. The virus is the first mosquito-borne illness known to cause birth defects, according to Frieden, as it has led to an increase in cases of microcephaly, a devastating condition in which newborns are born with unusually small head sizings and brain abnormalities.
This is the first time weve considered birth defects caused by a mosquito bite, Frieden said.
While it can also cause health complications in adults, most of those infected with the virus don’t notification any symptoms at all, which induces seeing the virus more difficult.
Florida Governor Rick Scott said on Monday that 10 additional Zika instances had been identified in his nation since Friday, bringing the total number of known locally-acquired examples to 14.
The governor requested that a CDC emergency response team be dispatched to his country to assist coordinate the Zika control endeavours. This team is already en route to Florida, Frieden said.
Pregnant females living in the 1-mile region where active Zika transmission is happen are being told to minimize their exposure to mosquitoes, and wear mosquito repellent containing DEET, Frieden said.
Mosquito control is falling short
Frieden said part of the reason for the travel advisory is that “aggressive” mosquito control efforts in the Miami area have fallen short of expectations, perhaps because the Aedes aegypti mosquito has become resistant to insecticides use against it in that area.
Another reason may be because there are areas of standing water that are providing breed locations for the mosquitoes, according to the CDC director.
“Mosquito control efforts in the specific community dont appear to be working as wed hoped, ” Frieden said.
So far, though, health officials have not received any mosquitoes that have tested positive for Zika. However, Frieden said that is extremely difficult to do, with human infections typically demonstrating up before mosquitoes test positive.
Frieden rejected the notion that the narrow advisory is aimed at pleasing Florida’s multibillion dollar tourism industry. There wouldnt be a technological or scientific basis to give a broader recommendation, he said.
This won’t rapidly spread nationwide
While Aedes aegypti mosquitoes are present in at the least 30 nations, the Florida instances do not necessarily herald a larger outbreak.
However, this does mark a turning point, since until Friday, Zika had not been transmitted by mosquitoes in the Lower 48 states.
The way Zika spreads is very different from the route other mosquito viruses spread, Frieden said , noting that there is no animal host where the virus circulates. With Zika it is quite focal and generally requires that mosquitoes get reinfected by people.
A similar pattern has been find with U.S. outbreaks of dengue and chikungunya, with those occurring in limited areas, predominantly near the Gulf Coast where warm, muggy weather is more common.
Mashable’s Miriam Kramer contributed to this report .