Zika virus found in Florida blood bank, mosquitoes

Despite increased surveillance, spraying, and testing, Florida is still experiencing signs of widening Zika virus transmission, based on positive blood bank samples and detection of another positive mosquito pool.

Also, Public Health England found Asian Tiger mosquito eggs in southeast England, a first for that country.

Pool, blood bank detections

According to the Florida Department of Agriculture and Consumer Services, an eighth pool of mosquitoes has tested positive for Zika virus in Miami Beach, one of two active transmission zones in Miami-Dade County. The positive sample was from a trap located at 1236 Drexel Ave in Miami Beach.

Despite testing 5,400 mosquito samples across the state, all eight positive traps have come from Miami Beach. According to an online statement, the department said “Miami-Dade County’s Mosquito Control team will continue to conduct inspections to reduce mosquito breeding and perform spray treatments as necessary in a minimum of 200-yard radius around the trap location.”

In addition to the positive mosquito pool, a Seattle Times story yesterday confirmed that Zika virus had been found in a few units of donated blood in Florida. The Food and Drug Administration confirmed this discovery but did not say how many units had been detected.

In July, blood donations stopped in Broward and Miami-Dade counties until Zika testing began. Earlier this year, it was estimated that 1% of all blood donations in Puerto Rico were positive for Zika virus, and many have suggested that a similar trend will be seen in Florida.

In August, FDA officials urged at-risk states (Florida, Texas) to begin testing blood bank donations for Zika virus.

More cases in Miami

The Florida Department of Health (Florida Health) said today there were three new travel cases of Zika in Florida, one in a pregnant woman.  There were also two new non-travel related cases, both tied to the Miami Beach transmission zone.

There are now 745 travel-related infections in Florida, and 165 locally acquired cases of Zika. The number of infections involving pregnant women has climbed to 110.

Asian Tiger mosquitoes in the UK

Finally today comes reports out of Kent that the eggs of the Asian Tiger mosquito (Aedes albopictus) were found for the first time in the United Kingdom. The Asian Tiger mosquito can carry Zika virus, and dengue. Though native to Asia, the bug has been imported to other parts of the world through trade.

Public Health England found 37 Ae albopictus eggs in a trap near a service station in Folkestone, which is in southeast England. Writing in ProMED Mail, the online reporting system of the International Society for Infectious Diseases, Jolyon Medlock, PhD, head of medical entomology and zoonoses ecology for Public Health England said, “Owing to the warmer climate in southern England, the ability for eggs to overwinter, and the connectivity of the lorry/coach park, the potential for establishment and further dissemination requires careful consideration.”

Almost 500 New Yorkers have tested positive for Zika virus

Nearly 500 New Yorkers — including 49 pregnant women — have tested positive for the Zika ­virus, a more than tenfold increase since April, city officials said ­Tuesday.

Five of the 483 victims contracted the virus through sex.

The others are believed to have been infected from mosquito bites while traveling outside the United States — a majority in the Dominican Republic.

While no transmissions have been reported via local mosquitoes, Mayor de Blasio and other officials urged Congress to pass a stalled health package to provide resources to combat the virus before it becomes a full-bore crisis.

“We need the federal government to act now and pass the authorization of $1.9 billion in funding,” de Blasio said at the city’s public health lab in Kips Bay. “Without federal dollars, we cannot deepen our work and we won’t have the assurance that other ­jurisdictions are doing all they can do to fight Zika.”

The majority of the cases have been found in women — 340 compared to 143 men — and one infant was born with a birth defect that results in a smaller head, known as microcephaly.

“A public health crisis that begins with neglect by the public sector . . . becomes much more difficult to address going forward,” said state Assemblyman
Brian ­Kavanagh (D-Manhattan), who joined the mayor in advocating for federal funds.

“We know that even now, no matter what we do, it’s going to increase and get worse in the United Stated before it gets better.”

In April, the city announced plans to invest $21 million over three years to conduct research and testing of Zika, and to monitor and reduce the local mosquito population.

De Blasio said the city has already targeted mosquitoes for pesticide spraying — despite the lack of cases of local transmission — as a preventive measure.

City Health Commissioner Dr. Mary Bassett said Zika isn’t a ­major issue for most people.

“Eighty percent of them, they don’t even know they’ve been infected — 80 percent of Zika infections are asymptomatic,” she said.

“For other people — for nonpregnant women — it’s self-limited, unpleasant, but full recovery is expected. People get fever, headache, joint pains, a rash, red eyes, and then it goes away in a couple of days,” she added.

“But the problem is that it’s transmitted from the mother to her baby, and that is the true victim of Zika — the developing baby. And that’s why we are so focused on protecting pregnant women.”


Bats Proposed as Latest Weapon to Fight Zika Virus in Miami

One Miami city official has an unusual proposal to combat the spread of the Zika virus. City Commissioner Kristin Rosen Gonzalez has proposed using bats, which eat mosquitoes, including the species known to spread the virus.

“Some people are laughing and they are not taking it seriously. But bats, depending on the species, eat up to 3,000 mosquitoes in one day, and they avoid humans,” Gonzalez told ABC News today. She has sponsored a resolution that proposes placing bat houses in the city to curb the mosquito population.

The first outbreak of locally transmitted Zika virus was reported in Miami in July. In the months since, city officials have continued to battle the ongoing outbreak, which has infected dozens in the Miami-area. Larvacide, insecticide and door-to-door inspections have all been used to try and reduce the population of the Aedes aegypti mosquito that spreads the Zika virus.

The resolution seeks to authorize the city manager to “research a potential pilot program for the placement of bat houses and habitats in the city to control the city’s mosquito population due to the continued presence of mosquitoes carrying the Zika virus.” The measure was discussed at the commissioners meeting today.

“It was a goodwill gesture to the environmentalists, who were really upset about us spraying all the neurotoxins,” Gonzalez said of her resolution, but added that she isn’t sure if it will be adopted because “it makes people nervous.”

The Miami City Commission reviewed the resolution today and passed it to Miami-Dade County, which holds the authority to either adopt or reject the resolution.

The measure of floated as an alternative to spraying chemicals, Gonzalez said, adding: “This was really the one environmental solution.”

The American Mosquito Control Association notes on its website that bats have historically not been an effective method of curbing mosquito populations, and that mosquitoes comprise less than 1 percent of gut contents of wild-caught bats, saying that bats feed on “whatever food source presents itself.”

“There is no question that bats eat mosquitoes, but to utilize them as the sole measure of control would be folly indeed,” the AMCA states, “particularly considering the capacity of both mosquitoes and bats to transmit diseases.”

Zika arrives in US: Debunking top myths about the virus

Material to prevent Zika infection by mosquitoes are displayed at the 69th World Health Assembly at the United Nations European headquarters in Geneva, Switzerland, May 23, 2016. REUTERS/Denis Balibouse  - RTX2ECWZ

Material to prevent Zika infection by mosquitoes are displayed at the 69th World Health Assembly at the United Nations European headquarters in Geneva, Switzerland, May 23, 2016. REUTERS/Denis Balibouse – RTX2ECWZ

With the Rio Olympics starting Friday in the country where over 165,000 suspected Zika cases have been reported this year, and local mosquito-borne Zika virus transmission reported in Florida, it’s natural to be concerned about the infectious disease that’s been dominating headlines.

While some information about the outbreak is available— such as transmission,  symptoms and containment efforts— questions about the virus remain.

Should I be concerned?

According to the experts, the answer depends on where you live and if you are pregnant or considering becoming pregnant.

Certain areas of the country, specifically Florida and the Gulf Coast, particularly Louisiana and Texas, have a high concentration of the Aedes aegypti mosquito and may be more at risk of a Zika virus outbreak.

“Zika is far more contained than people realize,” Dr. Peter Hotez , Director of the Texas Children’s Hospital Center for Vaccine Development, told FoxNews.com. “Areas of concern are cities like Brownsville, Texas, Corpus Christi, Houston, New Orleans, Tampa, Miami.”

While there is an outbreak in a very circumscribed area of Miami, Hotez believes the whole city to be at risk, as individuals with Zika in their bloodstream are traveling to other parts of the city.

“If you’re living in a city at risk and are pregnant, you need to give a lot of thought to how you’re going to alter your behavior— maximizing your time indoors, talking with your obstetrician about how to apply DEET or an alternative insect repellent,” Hotez, who is also Founding Dean of the National School of Tropical Medicine at Baylor College of Medicine, said.

While there are 1,825 Zika cases in the continental U.S., compared with other regions— Puerto Rico has 5,582— it’s a drop in the bucket, said Dr. Federico Laham,  medical director for pediatric infectious disease at Arnold Palmer Hospital for Children  in Orlando.

“If you are not pregnant or not an adult planning to have a partner who is pregnant, I don’t think [there’s] any reason for concern or any need for testing,” Laham told FoxNews.com.“Zika is believed to be an uncomplicated infection with self-limited symptoms that don’t have any long-lasting complications.”

How active are Zika-carrying mosquitoes?

The Aedes aegypti mosquito is an urbanized mosquito that has adapted to human habitats, especially urbanized areas where there’s crowding, which could be a suburb or any area with a certain density of people.

“Aedes aegypti tends to be a day biter, but once it’s inside houses, it could bite anytime,” Hotez said, adding that West Nile virus is still a concern, as it’s prevalent in the same places that have Zika.

In their lifespan, mosquitoes that carry Zika generally travel less than 150 meters (164 yards), according to the CDC, though the World Health Organization reports an average flight range of 400 meters (437 yards). The average lifespan of an Aedes aegpyti mosquito is two weeks.

The Aedes albopictus mosquito can also carry Zika, but it is not as efficient in spreading the virus as Aedes egypti, because it also feeds on birds and other mammals, interrupting transmission.

Should women at all stages of pregnancy be worried about microcephaly?

Yes and no. While the effects of Zika on pregnant women and their unborn babies are still unknown, the most concerning stage is early pregnancy.

“Because of its similarity to other infections and findings about microcephaly, many of these things take a long time to develop and may affect the fetus early in pregnancy,” Laham said. “A mom can pass the infection to the baby at the time of birth if she gets the infection later on, but we doubt that will result in any kind of congenital problems like microcephaly. It takes time to develop— it’s not something that happens in a few days or weeks.”

Studies have shown evidence of Zika in amniotic fluid, placenta and fetal brain tissue.

Hotez agreed that the effects on unborn fetuses and young children are still unknown, but said it’s too early to know determine there are any neurological effects.

Is everyone who gets Zika symptomatic?

No. Cautioning that there is still a steep learning curve for Zika, Hotez said that research suggests 80 percent of infected people do not show symptoms, but he believes the percentage to be higher.

In the recent cases of local transmission in Florida, four out of the five patients did not have symptoms.

That being said, one of Hotez’s biggest worries is Zika cases that aren’t being reported.

“My big nightmare scenario is we’re missing Zika transmission in certain cities and as a consequence we could start seeing microcephaly cases seven, eight, nine months from now,” he said. “That would be really tragic.”

Can you be ‘cured’ of Zika?

Yes, once you’re infected you’re immune to the virus.

“The vast majority of [infected] people will develop antibodies and then you’re fine,” Hotez said. “You’re basically self-cured and immune.”

The lack of funding by Congress— right before the peak infection period of July-September— means the disease will be fought on the local level, leading to Hotez’s worry that cases aren’t being transmitted.

“[Congress] just left without making a decision, which was really shocking,” he said.

Will Zika stay in my system forever?

No. Most infected individuals will have Zika in their system for a period of  2 to 3 weeks and in the bloodstream for about a week.

However, if pregnant woman is infected, there is the possibility that the virus could go into the fetus, then back into the mother, he added.

The CDC advises non-pregnant couples use condoms or abstain from sex for at least eight weeks after onset if a female partner is diagnosed with or experiences symptoms of Zika and for at least six months if a male partner is diagnosed or has symptoms.

Will kissing spread Zika?

Probably not. In June, a letter to the New England Journal of Medicine detailed a case of Zika potentially being transmitted through oral sex, bringing to question whether the virus could be spread by other biological fluids, such as saliva during kissing.

“I don’t think [transmission through kissing] has been well-established at all,” Hotez said. “We want to keep our eyes on the prize— the overwhelming mode of transmission is still fro mosquito bites.”

Does Zika cause paralysis?

Still unclear. Zika has been linked to Guillen-Barre, a neurological illness that mostly lasts a few weeks and causes muscle weakness, and, sometimes, paralysis. According to the CDC, researchers do not fully understand what causes the syndrome, but most patients report a bacterial or viral infection before they have symptoms.

Guillen-Barre is rare and is found in 1 in 1,000 Zika patients, with some estimating 1 in 500 cases, Hotez said.

“It’s a very, very unusual complication and that shouldn’t really force any kind of fear,” Laham said. “Literally any virus like flu or the cold can cause all types of crazy infections.”

Guillen-Barre is usually an immune response to a virus.

“In the case of Zika, it happens so early on in the course of illness many of us are thinking Zika may cause Guillen-Barre by some kind of direct invasion of nervous tissue,” Hotez said.

51 people, including 2 pregnant women, infected with Zika in Georgia

DEKALB COUNTY, Ga. – For the first time, public health leaders are reporting two pregnant women in Georgia are infected with Zika.

The Centers for Disease Control and Prevention in DeKalb County is keeping a close eye on numbers of Zika cases across the country.

In Georgia, there are now 51 travel-related cases and two of those patients are pregnant. One of the cases was sexually transmitted.

“Our priority population at risk is pregnant women. We want to protect pregnant women above all else,” state epidemiologist Cheri Drenzek said.


Drenzek says because of the risk of severe birth defects associated with Zika, those two Georgia women have been added to a national registry.

“As of this week, 479 individuals across the nation are being tracked,” she said. “Of (those), we actually have documented 21 adverse outcomes nationally, not here in Georgia. Some were live born infants with birth defects, some were pregnancy losses.”

Other Georgia health leaders say they are closely monitoring mosquitoes to try and prevent local transmissions.

“These types of mosquitoes feed on people and so what we’d been doing is watching those populations around positive cases and keeping the numbers down,” Chris Kumnick, with the Georgia Department of Public Health, said.

A spokeswoman for the DPH told Channel 2’s Lori Geary neither one of the pregnant women have delivered their babies yet.

One traveled to Honduras, the other to Jamaica, before getting diagnosed with the Zika virus.

Florida Department Of Health Confirms Five New Cases Of Zika Virus


MIAMI (CBSMiami) – The Florida Department of Health announced Monday there are seven new cases of Zika across the state.

Three of the cases are travel related, with one of those cases in Miami-Dade County. Two of the travel related cases involve pregnant women.

There are four new non-travel related cases in Miami-Dade. One is linked to the Miami Beach investigation, two are linked to the new area of local transmission in Miami-Dade and the fourth case is being investigated to determine where the exposure occurred.

Last week the department confirmed Zika was spreading in an area from NW 79th St. to the North, NW 63rd St. to the South, NW 10th Ave. to the West and N. Miami Ave. to the East. The area is about 1 square mile.

As of Monday, there were 160 non-travel related cases of the Zika virus and 739 travel-related cases. Of those, 108 of the cases involved pregnant women.

The department says they have evidence that Zika is only actively being transmitted in the two small areas in Miami Beach and this new area.

So far, the local transmission zones in Miami-Dade County are the following:

Miami Beach Area – 28th Street to the north, 8th Street to the south, intercoastal water to the west and the Atlantic Ocean to the east.
Miami Area – NW 79th St. to the North, NW 63rd St. to the South, NW 10th Ave. to the West and N. Miami Ave. to the East.

Horrible Idea! | Miami Beach Might Fight Zika With Bats | Miami New Times |


Miami is at war with the Aedes aegpyti mosquito. Althoughminuscule, the tiny, zebra-striped bug is wreaking havoc on the area’s economy through the Zika virus. Government officials have declared an all-out assault on the blood-suckers, but the county’s first line of defense — the much-debated pesticide naled — might not be working well in Miami Beach.

In war, sometimes you need to get creative. And just in time for Halloween, Miami Beach Commissioner Kristen Rosen Gonzalez is proposing the city attract bats to the area in the hopes the spooky little mammals will gobble up as many mosquitoes as they can.

Rosen Gonzalez proposes the city build bat houses, which are small and look like birdhouses except with slit-shaped holes for the little winged members of the order Chiroptera.

The commissioner’s proposed ordinance notes mixed results in using naled to kill mosquitoes and the fact that “bats can eat up to 1,000 mosquitos per hour and offer an environmentally friendly approach to mosquito control.”

Rosen Gonzalez did not immediately return a call to her cell phone about the plan. The city commission will debate her ordinance at this week’s meeting, and if the bill passes, the city would research the best spots to place bat houses and report back by November 9.

Rosen Gonzalez proposes the city build bat houses, which are small and look like birdhouses except with slit-shaped holes for the little winged members of the order Chiroptera.

The commissioner’s proposed ordinance notes mixed results in using naled to kill mosquitoes and the fact that “bats can eat up to 1,000 mosquitos per hour and offer an environmentally friendly approach to mosquito control.”

Rosen Gonzalez did not immediately return a call to her cell phone about the plan. The city commission will debate her ordinance at this week’s meeting, and if the bill passes, the city would research the best spots to place bat houses and report back by November 9.

Miami-Dade County’s naled usage has sparked protests at Miami Beach City Hall. The pesticide is part of an environmentally frowned-upon group of pesticides called organophosphates and is banned in the European Union. A host of environmental scientists have decried its use. Some of them warn thatnaled might cause birth defects and that, in some cases, the pesticide can degrade into a chemical called dichlorvos, which the U.S. Environmental Protection Agency (EPA) lists as a possible carcinogen.

But the U.S. Centers for Disease Control and Prevention says the chemical is vital to fight the spread of Zika, and the EPA claims the chemical can be sprayed safely in small doses from planes. While Miami-Dade County Mosquito Control says naledhas helped knock down the mosquito population in Wynwood, Dr. Phil Stoddard, the mayor of South Miami and a biologist at Florida International University, has released a study that says the pesticide did not work in Miami Beach.

After multiple rounds of aerial spraying, county officials found a new pool of Zika-positive mosquitoes September 23. Last week, Gov. Rick Scott announced a new zone of “active Zika transmission” in Little River and Little Haiti, thus renewing Miami’s pesticide debate yet again.

Though naled is certainly controversial, bats, meanwhile, are adorable and can legally hang out wherever they want.

It apparently takes a lot of calories to fly around all day, and bats basically need to gobble mosquitoes and other tiny insects at a near-constant rate to maintain their energy level. After the town of North Hempstead, New York, on Long Island, installed bat houses to fight Zika in July, New Times half-jokingly mused that an army of bats might work as a solid line of defense against mosquitoes.

Most bat scientists agree that attracting bats to a mosquito-infested area definitely won’t hurt, but caution that bats won’t eradicate Zika alone because the creatures fly at night and Aedes mosquitoes fly during the day, which means the bats might not eat any Zika-carrying bugs at all.

Most bats are also highly sensitive to pesticides. The national group Bat Conservation International warns that aerially sprayed pesticides could kill any newly attracted bats.

But in mosquito-ravaged Florida, the idea isn’t all that far-out. In 1929, real-estate developer Richard Clyde Perky built a 30-foot-tall bat house on Sugarloaf Key, near Key West, to help drive mosquitoes from the island. With the bugs gone, he hoped to turn the key into a tourist’s paradise. After filling the tower with guano (bat poop) to attract the critters, he released a huge cloud of bats onto the key.

But they all just flew away, and not a single bat ever moved into the tower. It still stands empty today. (Turns out it can take bats up to a year to figure out that they can safely live inside bat houses.)

Regardless, people seem to have taken the recent suggestion to heart. After New Times published its initial piece about bat-related pest control, a middle-school Girl Scout in West Kendall, Michelle Moscoso, built three bat houses in her neighborhood as part of a scouting project.

For those who want to build bat houses on their own, the Moscoso family had one word of warning: Make sure the house faces north or south. If they face east or west, the sun will hit them, and you’ll cook the bats inside.

Here’s a copy of Commissioner Rosen Gonzalez’s ordinance:






#Horrible Idea! | #Miami #Beach Might Fight #Zika With #Bats | #Miami #New #Times |



NY overtakes Florida in Zika cases as 1 in USA | Maps of Zika in the United States | Zika virus |

Zika Cases Reported in the United States

Laboratory-confirmed Zika virus disease cases reported to ArboNET by state or territory (as of October 12, 2016)

	Map of the United States showing Travel-associated and Locally acquired cases of the Zika virus.  The locations and number of cases can be found in the table below.

*See detailed map of the areas with active Zika virus transmission below.

Laboratory-confirmed Zika virus disease cases reported to ArboNET by state or territory — United States, 2015–2016 (as of October 12, 2016)§

States Travel-associated cases*
No. (% of cases in states)
Locally acquired cases†
No. (% of cases in states)
Alabama 28    (1) 0    (0)
Arizona 36    (1) 0    (0)
Arkansas 11    (<1) 0    (0)
California 296  (8) 0    (0)
Colorado 41    (1) 0    (0)
Connecticut 58    (2) 0    (0)
Delaware 15    (<1) 0    (0)
District of Columbia 25    (1) 0    (0)
Florida 708  (19) 128    (100)
Georgia 88    (2) 0    (0)
Hawaii 14    (<1) 0    (0)
Idaho 3      (<1) 0    (0)
Illinois 75    (2) 0    (0)
Indiana 39    (1) 0    (0)
Iowa 16    (<1) 0    (0)
Kansas 15    (<1) 0    (0)
Kentucky 24    (1) 0    (0)
Louisiana 32    (1) 0    (0)
Maine 11    (<1) 0    (0)
Maryland 103  (3) 0    (0)
Massachusetts 99    (3) 0    (0)
Michigan 60    (2) 0    (0)
Minnesota 47    (1) 0    (0)
Mississippi 23    (1) 0    (0)
Missouri 27    (1) 0    (0)
Montana 7      (<1) 0    (0)
Nebraska 11    (<1) 0    (0)
Nevada 14    (<1) 0    (0)
New Hampshire 10    (<1) 0    (0)
New Jersey 134  (4) 0    (0)
New Mexico 7      (<1) 0    (0)
New York 858  (23) 0    (0)
North Carolina 66    (2) 0    (0)
North Dakota 2      (<1) 0    (0)
Ohio 53    (1) 0    (0)
Oklahoma 27    (1) 0    (0)
Oregon 29    (1) 0    (0)
Pennsylvania†† 135  (4) 0    (0)
Rhode Island 32    (1) 0    (0)
South Carolina 48    (1) 0    (0)
South Dakota 2      (<1) 0    (0)
Tennessee 53    (1) 0    (0)
Texas 228  (6) 0    (0)
Utah 15** (<1) 0    (0)
Vermont 7      (<1) 0    (0)
Virginia 86    (2) 0    (0)
Washington 34    (1) 0    (0)
West Virginia 11    (<1) 0    (0)
Wisconsin 43    (1) 0    (0)
Wyoming 2      (<1) 0    (0)
Territories Travel-associated cases*
No. (% of cases in territories)
Locally acquired cases†
No. (% of cases in territories)
American Samoa 7      (8) 47           (<1)
Puerto Rico 75    (89) 25,355*** (98)
US Virgin Islands 2  (2) 469          (2)

§Only includes cases meeting the probable or confirmed CSTE case definition and does not include asymptomatic infections unless the case is a pregnant woman with a complication of pregnancy
*Travelers returning from affected areas, their sexual contacts, or infants infected in utero
†Presumed local mosquito-borne transmission
††One additional case acquired through laboratory transmission
**Includes one case with unknown route of person-to-person transmission.
***The Puerto Rico Department of Health is retroactively reporting cases, resulting in larger than normal increases in cases in recent weeks.

Active Zika Virus Transmission in Florida

Active Zika Virus Transmission in Florida

Miami-Dade County, FL. Red shows areas of active transmission where CDC recommends adherence to travel and testing guidance for pregnant women, women of reproductive age, and their partners. Yellow shows areas where CDC recommends cautionary travel recommendations and strict adherence to precautions to prevent mosquito bites.










#NY overtakes #Florida in #Zika cases as #1 in #USA | Maps of Zika in the #United #States | Zika virus |

Zika infection may affect adult brain cells, suggesting risk may not be limited to pregnant women

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Concerns over the Zika virus have focused on pregnant women due to mounting evidence that it causes brain abnormalities in developing fetuses. However, new research in mice from scientists at The Rockefeller University and La Jolla Institute for Allergy and Immunology suggests that certain adult brain cells may be vulnerable to infection as well. Among these are populations of cells that serve to replace lost or damaged neurons throughout adulthood, and are also thought to be critical to learning and memory.

“This is the first study looking at the effect of Zika infection on the adult brain,” says Joseph Gleeson, adjunct professor at Rockefeller, head of the Laboratory of Pediatric Brain Disease, and Howard Hughes Medical Institute investigator. “Based on our findings, getting infected with Zika as an adult may not be as innocuous as people think.”

Although more research is needed to determine if this damage has long-term biological implications or the potential to affect behavior, the findings suggest the possibility that the Zika virus, which has become widespread in Central and South America over the past eight months, may be more harmful than previously believed. The new findings were published in Cell Stem Cell on August 18.

“Zika can clearly enter the brain of adults and can wreak havoc,” says Sujan Shresta, a professor at the La Jolla Institute of Allergy and Immunology. “But it’s a complex disease—it’s catastrophic for early brain development, yet the majority of adults who are infected with Zika rarely show detectable symptoms. Its effect on the adult brain may be more subtle, and now we know what to look for.”

Neuronal progenitors

Early in gestation, before our brains have developed into a complex organ with specialized zones, they are comprised entirely of neural progenitor cells. With the capability to replenish the brain’s neurons throughout its lifetime, these are the stem cells of the brain. In healthy individuals, neural progenitor cells eventually become fully formed neurons, and it is thought that at some point along this progression they become resistant to Zika, explaining why adults appear less susceptible to the disease.

But current evidence suggests that Zika targets neural progenitor cells, leading to loss of these cells and to reduced brain volume. This closely mirrors what is seen in microcephaly, a developmental condition linked to Zika infection in developing fetuses that results in a smaller-than-normal head and a wide variety of developmental disabilities.

The mature brain retains niches of these neural progenitor cells that appear to be especially impacted by Zika. These niches—in mice they exist primarily in two regions, the subventricular zone of the anterior forebrain and the subgranular zone of the hippocampus—are vital for learning and memory.

Gleeson and his colleagues suspected that if Zika can infect fetal neural progenitor cells, it wouldn’t be a far stretch for them to also be able to infect these cells in adults. In a mouse model engineered by Shresta and her team to mimic Zika infection in humans, fluorescent biomarkers illuminated to reveal that adult neural progenitor cells could indeed be hijacked by the virus.

“Our results are pretty dramatic—in the parts of the brain that lit up, it was like a Christmas tree,” says Gleeson. “It was very clear that the virus wasn’t affecting the whole brain evenly, like people are seeing in the fetus. In the adult, it’s only these two populations that are very specific to the stem cells that are affected by virus. These cells are special, and somehow very susceptible to the infection.”

Beyond fetal brain infection

The researchers found that infection correlated with evidence of cell death and reduced generation of new neurons in these regions. Integration of new neurons into learning and memory circuits is crucial for neuroplasticity, which allows the brain to change over time. Deficits in this process are associated with cognitive decline and neuropathological conditions, such as depression and Alzheimer’s disease.

Gleeson and colleagues recognize that healthy humans may be able to mount an effective immune response and prevent the virus from attacking. However, they suggest that some people, such as those with weakened immune systems, may be vulnerable to the virus in a way that has not yet been recognized.

“In more subtle cases, the virus could theoretically impact long-term memory or risk of depression,” says Gleeson, “but tools do not exist to test the long-term effects of Zika on adult stem cell populations.”

In addition to microcephaly, Zika has been linked to Guillain-Barré syndrome, a rare condition in which the immune system attacks parts of the nervous system, leading to muscle weakness or even paralysis. “The connection has been hard to trace since Guillain-Barré usually develops after the infection has cleared,” says Shresta. “We propose that infection of adult neural progenitor cells could be the mechanism behind this.”

There are still many unanswered questions, including exactly how translatable findings in this mouse model are to humans. Gleeson’s findings in particular raise questions such as: Does the damage inflicted on progenitor cells by the virus have lasting biological consequences, and can this in turn affect learning and memory? Or, do these cells have the capability to recover? Nonetheless, these findings raise the possibility that Zika is not simply a transient infection in adult humans, and that exposure in the adult brain could have long-term effects.

“The virus seems to be traveling quite a bit as people move around the world,” says Gleeson. “Given this study, I think the public health enterprise should consider monitoring for Zika infections in all groups, not just pregnant women.”


Information and Perspectives on Bed Bug Prevention, Protection and Safety

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Information and Perspectives on Bed Bug Prevention, Protection and Safety

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Information and Perspectives on Bed Bug Prevention, Protection and Safety

Information and Perspectives on Bed Bug Prevention, Protection and Safety