Zika virus to spread to all but 2 countries in the Americas, WHO predicts
The World Health Organization anticipates that the Zika virus will spread to all but two countries in South, Central and North America.
The mosquito-borne disease has raged in South America and other regions for several months.
Twenty-one countries and territories of the Americas have reported cases of the virus since Brazil reported the first cases of local transmission in May 2015, WHO's regional office for the Americas said in a statement.
"Aedes mosquitoes -- the main vector for Zika transmission -- are present in all the region's countries except Canada and continental Chile," the statement said.
The Centers for Disease Control and Prevention urged pregnant women to postpone travel to Bolivia, Brazil, Cape Verde, Colombia, Ecuador, El Salvador, French Guiana, Guadeloupe, Guatemala, Guyana, Haiti, Honduras, Martinique, Mexico, Panama, Paraguay, Saint Martin, Suriname, Samoa, Venezuela and Puerto Rico. The CDC also recommended that women who have recently traveled to these places during their pregnancy be screened and monitored for the virus.
That's because the virus has been linked to an uptick in babies born with a neurological condition called microcephaly, which can cause abnormally small heads and serious, sometimes deadly, developmental delays.
The WHO attributed the virus' rapid spread to the fact that people in the Americas lack immunity because they haven't been exposed to it before.
No prevention or treatment
There is no prevention or treatment for the disease. Travelers to hazardous areas are urged to prevent mosquito bites by using repellent and covering exposed skin.
The Aedes aegypti mosquito, which transmits the disease, bites all day long, so people need to reapply repellent and not let their guard down, officials warn.
Aedes albopictus mosquitoes, which are found throughout the United States and are known for transmitting dengue fever and chikungunya, may also transmit the virus, the CDC said.
Symptoms of the virus include fever, rash, joint pain and red eyes, and can last from a few days to about a week. But 80% of infected people have no symptoms.
Three British travelers have been infected with the virus, health officials said over the weekend.
"As of January 2016, three cases associated with travel to Colombia, Suriname and Guyana have been diagnosed in UK travelers," Public Health England said on its website.
The government agency did not provide further details about the cases but added that the virus "does not occur naturally in the UK."
In the United States, there are confirmed cases of the virus among individuals who have traveled to infected countries, including in Illinois, Florida and Texas, among others. However, there are no known cases of locally transmitted illness.
"These imported cases might result in local human-to-mosquito-to-human spread of the virus in limited areas of the continental Unites States that have the appropriate mosquito vectors," according to a new report on the spread of the virus issued by the CDC Friday.
There is at least one known case of a baby born with microcephaly believed to be linked to Zika in Hawaii.
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Five things you need to know about Zika
The World Health Organization anticipates that the Zika virus will spread to all but two countries in South, Central and North America.
The mosquito-borne disease has raged in South America and other regions for several months.
Twenty-one countries and territories of the Americas have reported cases of the virus since Brazil reported the first cases of local transmission in May 2015, WHO's regional office for the Americas said in a statement.
"Aedes mosquitoes -- the main vector for Zika transmission -- are present in all the region's countries except Canada and continental Chile," the statement said.
The Centers for Disease Control and Prevention urged pregnant women to postpone travel to Bolivia, Brazil, Cape Verde, Colombia, Ecuador, El Salvador, French Guiana, Guadeloupe, Guatemala, Guyana, Haiti, Honduras, Martinique, Mexico, Panama, Paraguay, Saint Martin, Suriname, Samoa, Venezuela and Puerto Rico. The CDC also recommended that women who have recently traveled to these places during their pregnancy be screened and monitored for the virus.
That's because the virus has been linked to an uptick in babies born with a neurological condition called microcephaly, which can cause abnormally small heads and serious, sometimes deadly, developmental delays.
The WHO attributed the virus' rapid spread to the fact that people in the Americas lack immunity because they haven't been exposed to it before.
No prevention or treatment
There is no prevention or treatment for the disease. Travelers to hazardous areas are urged to prevent mosquito bites by using repellent and covering exposed skin.
The Aedes aegypti mosquito, which transmits the disease, bites all day long, so people need to reapply repellent and not let their guard down, officials warn.
Aedes albopictus mosquitoes, which are found throughout the United States and are known for transmitting dengue fever and chikungunya, may also transmit the virus, the CDC said.
Symptoms of the virus include fever, rash, joint pain and red eyes, and can last from a few days to about a week. But 80% of infected people have no symptoms.
Three British travelers have been infected with the virus, health officials said over the weekend.
"As of January 2016, three cases associated with travel to Colombia, Suriname and Guyana have been diagnosed in UK travelers," Public Health England said on its website.
The government agency did not provide further details about the cases but added that the virus "does not occur naturally in the UK."
In the United States, there are confirmed cases of the virus among individuals who have traveled to infected countries, including in Illinois, Florida and Texas, among others. However, there are no known cases of locally transmitted illness.
"These imported cases might result in local human-to-mosquito-to-human spread of the virus in limited areas of the continental Unites States that have the appropriate mosquito vectors," according to a new report on the spread of the virus issued by the CDC Friday.
There is at least one known case of a baby born with microcephaly believed to be linked to Zika in Hawaii.
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Five things you need to know about Zika
A relatively new mosquito-borne virus is prompting worldwide concern because of an alarming connection to a neurological birth disorder and the rapid spread of the virus across the globe.
The Zika virus, transmitted by the aggressive Aedes aegypti mosquito, has now spread to at least 25 countries. The Centers for Disease Control and Prevention is warning pregnant women against travel to those areas; health officials in several of those countries are telling female citizens to avoid becoming pregnant, in some cases for up to two years.
"That's a pandemic in progress," said Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases at the National Institutes of Health. "It isn't as if it's turning around and dying out, it's getting worse and worse as the days go by."
Here are five important things to know:
1. What is Zika and why is it so serious?
The Zika virus is a flavivirus, part of the same family as yellow fever, West Nile, chikungunya and dengue. But unlike some of those viruses, there is no vaccine to prevent Zika or medicine to treat the infection.
Zika is commanding worldwide attention because of an alarming connection between the virus and microcephaly, a neurological disorder that results in babies being born with abnormally small heads. This causes severe developmental issues and sometimes death.
Since November, Brazil has seen nearly 4,000 cases of microcephaly in babies born to women who were infected with Zika during their pregnancies. To put that in perspective, there were only 146 cases in 2014. So far, 46 babies have died.
Other Latin American countries are now seeing cases in newborns as well, while in the United States one Hawaiian baby was born with microcephaly after his mother returned from Brazil. In Illinois, two pregnant women who traveled to Latin America have tested positive for the virus; health officials are monitoring their pregnancies.
The CDC is also asking OB-GYNs to review fetal ultrasounds and do maternal testing for any pregnant woman who has traveled to one of the 23 countries where Zika is currently active.
A smaller outbreak of Guillain-Barre syndrome, a rare autoimmune disorder that can lead to life-threatening paralysis, is also linked to Zika in a several countries.
2. How is Zika spread?
The virus is transmitted when an Aedes mosquito bites a person with an active infection and then spreads the virus by biting others. Those people then become carriers during the time they have symptoms.
In most people, symptoms of the virus are mild, including fever, headache, rash and possible pink eye. In fact, 80% of those infected never know they have the disease. That's especially concerning for pregnant women, as this virus has now been shown to pass through amniotic fluid to the growing baby.
"What we now know," said Dr. Lyle Petersen, director of the CDC's Division of Vector-Borne Diseases, "is that fetuses can be infected with the virus. That's not new for infectious diseases, but it is new for this virus."
"This is a very remarkable and unusual situation," agreed Fauci, "because the other flaviviruses don't do that to our knowledge. You just don't see that with dengue or West Nile or chikungunya."
In addition, the CDC says there have been documented cases of virus transmission during labor, blood transfusion, laboratory exposure and sexual contact. While Zika has been found in breast milk, it's not yet confirmed it can be passed to the baby through nursing.
There have been only two documented cases linking Zika to sex. During the 2013 Zika outbreak in French Polynesia, semen and urine samples from a 44-year-old Tahitian man tested positive for Zika even when blood samples did not. Five years before that, in 2008, a Colorado microbiologist named Brian Foy contracted Zika after travel to Senegal; his wife came down with the disease a few days later even though she had not left northern Colorado and was not exposed to any mosquitoes carrying the virus.
3. Where is the Zika virus now?
The Zika virus is now being locally transmitted in Barbados, Bolivia, Brazil, Cape Verde, Colombia, Dominican Republic, Ecuador, El Salvador, French Guiana, Guadeloupe, Guatemala, Guyana, Haiti, Honduras, Martinique, Mexico, Panama, Paraguay, Puerto Rico, Saint Martin, Suriname, Samoa, the U.S. Virgin Islands and Venezuela, says the CDC.
Zika has arrived in the United States, but only from travelers returning from these infected areas. The concern, of course, is whether these imported cases could result in locally transmitted cases within the United States.
The Aedes albopictus, or Asian tiger mosquito, which along with Aedes aegypti transmits Zika virus, is present in many areas of the United States.
If mosquitoes in the United States do become carriers, a model created by Toronto researchers found more than 63% of the U.S. population lives in areas where Zika virus might spread during seasonally warm months. A little over 7% of Americans live in areas where the cold might not kill off the mosquito in the winter, leaving them vulnerable year round.
4. What can you do to protect yourself against Zika?
With no treatment or vaccine available, the only protection against Zika is to avoid travel to areas with an active infestation. If you do travel to a country where Zika is present, the CDC advises strict adherence to mosquito protection measures: Use an EPA-approved repellent over sunscreen, wear long pants and long-sleeved shirts thick enough to block a mosquito bite, and sleep in air-conditioned, screened rooms, among others.
If you have Zika, you can keep from spreading it to others by avoiding mosquito bites during the first week of your illness, says the CDC. The female Aedes aegypti, the primary carrier of Zika, is an aggressive biter, preferring daytime to dusk and indoors to outdoors. Keeping screens on windows and doors is critical to preventing entry to homes and hotel rooms. If that's not possible, says the CDC, sleep under mosquito netting.
5. What's being done to stop Zika?
Researchers are hard at work in laboratories around the world trying to create a Zika vaccine. Until those efforts bear fruit, health officials are implementing traditional mosquito control techniques such as spraying pesticides and emptying standing water receptacles where mosquitoes breed. The CDC is encouraging local homeowners, hotel owners and visitors to countries with Zika outbreaks to join in by also eliminating any standing water they see, such as in outdoor buckets and flowerpots.
Studies show local control is only marginally effective, since it's so hard to get to all possible breeding areas. And since Aedes aegypti has evolved to live near humans and "can replicate in flower vases and other tiny sources of water," said microbiologist Brian Foy, the mosquitoes are particularly difficult to find and eradicate.
Another prevention effort is OX513A, a genetically modified male Aedes aegypti, dubbed by critics as the "mutant mosquito" or "Robo-Frankenstein mosquito." The creation of British company Oxitec, OX513A is designed to stop the spread of Zika by passing along a gene that makes his offspring die. Since females only mate once, in theory this slows the growth of the population. Each OX513A carries a fluorescent marker, so he can be tracked by scientists.
Key West, Florida, residents gave the genetically modified male his monster nicknames while protesting a trial release of the mosquito in 2012 as a way to combat an outbreak of dengue fever in South Florida. That effort is under review by the Food and Drug Administration.
But field trials in Brazil in 2011 were hugely successful, according to Oxitec, eliminating up to 99% of the target population. A new release of males in the Pedra Branca area of Brazil in 2014 was 92% successful, according to the company. The mosquito has also been tested in the Cayman Islands, Malaysia and Panama.
Last year, Oxitec announced plans to build an OX513A mosquito production facility in Piracicaba, Brazil, that it says will be able to protect 300,000 residents.
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How to cut off the spread of a Zika virus
When I think about public health recommendations, I think about what I would want for my own family, and in this case, for my own wife. I don't think in terms of population management and rationing as a disease control officer must do.
What to do about the Zika virus?
As this -- another viral disease -- emerges, we're again facing down a primordial threat that reminds us we are animals in an ecosystem. It's an ecosystem that's changing with us and because of us. Beating back Zika will require openness to innovation in both technology and policy.
The primary mosquito species now transmitting Zika virus throughout numerous countries in the Americas, Aedes aegypti, actually evolved alongside humans to target us specifically, versus other animals.
Now it is spreading its domain, due to the warming climate and its predilection for our built-up environment. Mosquitos have already altered human history before by causing millions of deaths via the spread of yellow fever and Dengue, two viruses that are closely related to Zika.
Some 3,893 cases of microcephaly in infants (and untold miscarriages) in Brazil alone appear linked to the Zika virus.
While we lack definitive proof that the virus caused the severe cerebral and skull deformities these newborns are suffering with, the evidence we've got mandates decisive action. Doctors have found Zika virus in the amniotic fluid of affected fetuses and in the placentas and brains of miscarried fetuses with microcephaly.
We know from prior Zika outbreaks in the South Pacific that the virus can attack the nervous system, causing a paralysis called Guillain-Barre Syndrome.
Related viruses like West Nile are well known to infect the brain. But the Brazil outbreak is the first time Zika is being correlated to this microcephalic congenital deformity. The numbers alone are stark evidence: With no other new variable apparent than the rapidly spreading Zika virus, Brazil saw a 20-fold increase in microcephaly cases in 2015 over 2014.
A Zika vaccine is possible, and that's a step National Institutes of Health leaders would surely facilitate.
But given the pace of Zika infections in South America, the long timeline for vaccine development allows for too much suffering. We've got to take other steps if we can.
Another approach is underway and showing success in some South American and Caribbean countries, and is under review by the Food and Drug Administration. This strategy targets the mosquitoes themselves.
A British biotech company, Oxitec, has produced genetically modified Aedes aegypti mosquitoes by inserting two genes, one that makes its eggs glow under UV light, to help with its identification, and one that causes its offspring to die.
This succeeds via the so-called sterile insect technique, dramatically dropping the population of natural, possibly disease-carrying, mosquitoes by keeping their females busy mating with the genetically modified males instead of the natural males.
This is a fancier version of the same technique that was successfully used to eradicate the screwworm as an American agricultural pest, and it's one the environmental visionary Rachel Carson lauded in 1962 in "Silent Spring":
"Some of the most fascinating of the new methods are those that seek to turn the strength of a species against itself - to use the drive of an insect's life forces to destroy it. The most spectacular of these approaches is the 'male sterilization' technique developed by the chief of the United States Department of Agriculture's Entomology Research Branch, Dr. Edward Knipling, and his associates."
Carson preferred such techniques to indiscriminate pesticides. Despite its reliable history and sound science, misinformation about the sterile insect technique abounds.
There is no biological mechanism by which the Oxitec bug's modified pieces of DNA can transfer into human DNA, or into other mammals and insects. But public fear over anything genetically modified is a powerful force.
The FDA first got Oxitec's proposal to begin using its mosquito in the Florida Keys in 2011. The original proposal came in response to a Dengue outbreak there. Now with Zika on the horizon I hope the public attitude changes and the FDA finally clears the project.
Without a medical development such as a vaccine, or a novel pest control such as the Oxitec mosquito, Zika seems destined to start spreading in the Southern United States, starting with Florida and south Texas. So far the only cases reported in the United States were infected in South America or the Caribbean, but the United States has not only the Aedes aegypti mosquito but also the far more widespread Aedes albopictus (Asian tiger mosquito), which can also carry the virus.
The Asian tiger mosquito's domain extends throughout the Southeast and up to New York state in the summer.
This leaves only public health recommendations for our protection. They should be upfront and realistic. The recommendation coming out of El Salvador, that women should put off pregnancy until 2018, is an example of an unrealistic public health recommendation.
El Salvador officials are making that recommendation because abortion is illegal in their country, and access to proper prenatal monitoring is poor. They're not being upfront with the population about these limitations that lead them to make the recommendation. The country also lacks widespread adoption of birth control, which dooms the recommendation to failure.
In the United States, the Centers for Disease Control and Prevention is publishing recommendations that call for pregnant women and women thinking of becoming pregnant not to travel to countries where Zika is spreading.The agency is also advising extra monitoring for pregnant women returning from countries on the Zika list. That's smart. But a close look at the recommendation reveals some rationing of care that I think government agencies should be making more explicit.
There's no commercial test for Zika, and the two methods we have, polymerase chain reaction technology and immunoglobulin, must be performed at the CDC or by a few of the better equipped state health departments.
Dangers of Zika virus 01:39
These agencies lack the staffing to test all pregnant women who have traveled to countries on the Zika list during their pregnancies, so the CDC guidelines call for testing only those women who've shown two or more symptoms of possible infection. Unfortunately the symptoms are both very vague (fever, rash, arthritis and eye inflammation) and don't occur in 80% of the people infected.
We should be testing all pregnant women who have been exposed, not just performing ultrasounds, which in many cases will not demonstrate microcephaly until late in the second trimester, too late for abortions in some states.
The bottom line on the Zika response is this: Unless we are confronted with our limitations we won't work effectively to overcome them.
The U.S. health care system was confronted with its limitations during the Ebola outbreak, when the CDC told hospitals to apply routine contact precautions when they suspected Ebola cases. That recommendation resulted in the transmission of Ebola to two nurses.
I think the CDC should have warned Americans that not all hospitals are ready for Ebola. That would have given providers proper pause. A correct calibration of confidence would have led to triaging patients to higher level centers sooner.
In this case the CDC should warn that we do not have capacity to test all women properly. This fact should weigh heavily on women who are considering travel to Zika-affected areas. It should affect family planning decisions, certainly in the southernmost regions of the United States with the Aedes aegypti mosquito.
As many of us dig out from a blizzard, it may seem premature to worry much about a plague borne by mosquitoes. But summer is coming.
Source: cnn.com
