A mosquito borne illness possibly linked to birth defects-is on the rise globally, called
Zika virus (ZIKV) is a member of the virus family Flaviviridae aFlavivirus, transmitted by daytime-active Aedes mosquitoes, such as A. aegypti. Its name comes from the Zika Forest of Uganda, where the virus was first isolated in 1947.
In humans, the virus causes a usually mild illness known as Zika fever, which since the 1950s has been known to occur within a narrow equatorial belt from Africa to Asia. In 2014, the virus spread eastward across the Pacific Ocean to French Polynesia, then to Easter Island and in 2015 to Mexico, Central America, the Caribbean, and South America, where the Zika outbreak has reached pandemic levels.
Zika virus is related to dengue, yellow fever, Japanese encephalitis, and West Nile viruses. The illness it causes is similar to a mild form of dengue fever, is treated by rest, and cannot yet be prevented by drugs or vaccines. There is a possible link between Zika fever and microcephaly in newborn babies bymother-to-child transmission, as well as a stronger one with neurologic conditions in infected adults, including cases of the Guillain–Barré syndrome.
In January 2016, the U.S. Centers for Disease Control and Prevention (CDC) issued travel guidance on affected countries, including the use of enhanced precautions, and guidelines for pregnant women including considering postponing travel. Other governments or health agencies soon issued similar travel warnings, while Colombia, the Dominican Republic, Ecuador, El Salvador, and Jamaica advised women to postpone getting pregnant until more is known about the risks. On February 2, 2016, Dallas County Health and Human Services confirmed the first case of transmission in the United States.
The first known case of Zika virus transmission in the United States was reported in Texas on Tuesday by local health officials, who said it likely was contracted through sex and not a mosquito bite, a day after the World Health Organization declared an international public health emergency.
The virus, linked to severe birth defects in thousands of babies in Brazil, is spreading rapidly in the Americas, and WHO officials on Tuesday expressed concern that it could hit Africa and Asia as well. Zika had been thought to be spread by the bite of mosquitoes of the Aedes genus, so sexual contact as a mode of transmission would be a potentially alarming development.
The U.S. Centers for Disease Control and Prevention confirmed it was the first U.S. Zika case in someone who had not traveled abroad in the current outbreak, said CDC Director Dr. Tom Frieden on Twitter.
However, the CDC has not investigated how the virus was transmitted.
After this case, the CDC advised men to consider using condoms after traveling to areas with the Zika virus. Pregnant women should avoid contact with semen from men exposed to the virus.
The Dallas County Department of health said on Twitter that the person was infected through sexual contact with someone who had traveled to Venezuela. The person infected did not travel to the South American country, county health officials said.
The Texas Department of State Health Services was slightly more cautious in its assessment, saying in a statement, "Case details are being evaluated, but the possibility of sexual transmission from an infected person to a non-infected person is likely in this case."
County authorities said there were no reports of the virus being transmitted by mosquitoes in the Texas county.
Previously, international health officials had noted one U.S. case of possible person-to-person sexual transmission. But the Pan American Health Organization said more evidence was needed to confirm sexual contact as a means of Zika transmission. The medical literature also has one case in which the virus was detected in semen.
The virus has been reported in more than 30 countries and linked to microcephaly, in which babies have abnormally small heads and improperly developed brains.
The American Red Cross on Tuesday asked blood donors who have traveled to Zika virus outbreak areas such as Mexico, the Caribbean, or Central or South America to wait at least 28 days before donating. However, the risk of transmitting the virus through blood donations remained "extremely" low in the continental United States, the disaster relief agency said.
The Dow Jones transportation average ended 2.9 percent lower following news of the first U.S. transmission of the Zika virus.
MONITORING NEEDED
The WHO has said the virus could infect 4 million people in the Americas. It said on Tuesday it launched a global response unit to fight the mosquito-borne virus.
"Most important, we need to set up surveillance sites in low- and middle-income countries so that we can detect any change in the reporting patterns of microcephaly at an early stage," Dr. Anthony Costello said in Geneva. Costello is WHO's director for maternal, child and adolescent health.
Twenty to 30 sites could be established worldwide, mainly in poor countries without robust healthcare systems, Costello said.Brazil is the country hardest hit by Zika. In an address to a joint session of Brazil's Congress, President Dilma Rousseff said her government will spare no resources in mobilizing to combat the mosquito that transmits the virus. With no vaccine or treatment for Zika, efforts to curb its spread have focused on eradicating mosquito breeding sites.
Brazil, which has more than 4,000 suspected cases of microcephaly that may be linked to Zika, is scheduled to host the Olympics in Rio de Janeiro in August.
Rousseff also said Brazil and the United States will enter a partnership to develop a Zika vaccine as soon as possible to stem the spread of the virus.
VACCINE EFFORTS
French drugmaker Sanofi SA on Tuesday announced that it has launched a project to develop a vaccine against the virus, the most decisive commitment yet by a major vaccine maker. The company said its Sanofi Pasteur vaccines division would use its expertise in developing vaccines for similar viruses such as yellow fever, Japanese encephalitis and dengue.
Other companies also joined the race on Tuesday to develop a vaccine. The University of South Australia said it was working on a Zika vaccine with Australian biotech Sementis Ltd.
U.S. drug developer NewLink Genetics Corp said it has started a project to develop Zika treatment options.
Experts have said a Zika vaccine for widespread use is months if not years away.
Costello said the Aedes mosquitoes that carry the Zika virus "are present ... through Africa, parts of southern Europe and many parts of Asia, particularly South Asia." Africa and Asia have the world's highest birth rates.
WHO Director-General Margaret Chan said on Monday it was "strongly suspected but not yet scientifically proven" that Zika causes microcephaly.
The first Irish cases of Zika virus have been detected in two people with a history of traveling to a country affected by the mosquito-borne infection, the Health Service Executive of Ireland said.
Chilean health officials said they have confirmed three cases in Chile of people infected with the Zika virus, all of whom were infected while traveling elsewhere in Latin America.
An Australian state health service said two Australians were diagnosed with the virus after returning from the Caribbean, confirming the first cases of the virus in the country this year.
Zika virus is spread to people through
mosquito bites. The most common symptoms of Zika virus disease are fever, rash,
joint pain, and conjunctivitis (red eyes). The illness is usually mild with
symptoms lasting from several days to a week. Severe disease requiring
hospitalization is uncommon.
In May 2015, the Pan American
Health Organization (PAHO) issued an alert regarding the first confirmed Zika
virus infection in Brazil. The outbreak in Brazil led to reports of
Guillain-Barré syndrome and pregnant women giving birth to babies with birth
defects and poor pregnancy outcomes.
In response, CDC has issued travel
notices for
people traveling to regions and certain countries where Zika virus transmission
is ongoing.
Where has Zika virus been found?
·
Prior to 2015, Zika virus outbreaks have occurred in areas of
Africa, Southeast Asia, and the Pacific Islands.
·
In May 2015, the Pan American Health Organization (PAHO) issued an
alert regarding the first confirmed Zika virus infections in Brazil.
·
Currently, outbreaks are occurring in many countries.
·
Zika virus will continue to spread and it will be difficult to
determine how the virus will spread over time.
o
For the latest Travel Notice Information
Zika in the United States and
its territories:
·
No locally transmitted Zika cases have been reported in the
continental United States, but cases have been reported in returning travelers.
·
Locally transmitted Zika virus has been reported in the
Commonwealth of Puerto Rico.
·
With the recent outbreaks, the number of Zika cases among
travelers visiting or returning to the United States will likely increase.
·
These imported cases could result in local spread of the virus in
some areas of the United States.
Countries and territories with active Zika virus transmission
· Barbados
·
Bolivia
·
Brazil
·
Colombia
·
Commonwealth of Puerto Rico, US territory
·
Costa Rica
·
Curacao
·
Dominican Republic
·
Ecuador
·
El Salvador
·
French Guiana
·
Guadeloupe
·
Guatemala
·
Guyana
·
Haiti
·
Honduras
·
Martinique
·
Mexico
·
Nicaragua
·
Panama
·
Paraguay
·
Saint Martin
·
Suriname
·
U.S. Virgin Islands
·
Venezuela
Prevention
Language:
·
Español (Spanish)
·
No vaccine exists to prevent Zika virus disease (Zika).
·
Prevent Zika by avoiding mosquito bites (see below).
·
Mosquitoes that spread Zika virus bite mostly during the daytime.
·
Mosquitoes that spread Zika virus also spread dengue and
chikungunya viruses.
When traveling to
countries where Zika virus or other viruses spread by mosquitoes are found,
take the following steps:
·
Wear long-sleeved shirts and long pants.
Symptoms, Diagnosis, & Treatment
Symptoms
·
About 1 in 5 people infected with Zika virus become ill (i.e.,
develop Zika).
·
The most common symptoms of Zika are fever, rash, joint pain, or
conjunctivitis (red eyes). Other common symptoms include muscle pain and
headache. The incubation period (the time from exposure to symptoms) for Zika
virus disease is not known, but is likely to be a few days to a week.
·
The illness is usually mild with symptoms lasting for several days
to a week.
·
Zika virus usually remains in the blood of an infected person for
a few days but it can be found longer in some people.
·
Severe disease requiring hospitalization is uncommon.
·
Deaths are rare.
Diagnosis
·
The symptoms of Zika are similar to those of dengue and chikungunya,
diseases spread through the same mosquitoes that transmit Zika.
·
See your healthcare provider if you develop the symptoms described
above and have visited an area where Zika is found.
·
If you have recently traveled, tell your healthcare provider when
and where you traveled.
·
Your healthcare provider may order blood tests to look for Zika or
other similar viruses like dengue or chikungunya.
Treatment
·
No vaccine or medications are available to prevent or treat Zika
infections.
·
Treat the symptoms:
o
Get plenty of rest.
o
Drink fluids to prevent dehydration.
o
Take medicine such as acetaminophen to relieve fever and pain.
o
Do not take aspirin and other non-steroidal anti-inflammatory
drugs (NSAIDs), like ibuprofen and naproxen. Aspirin and NSAIDs should be avoided
until dengue can be ruled out to reduce the risk of hemorrhage (bleeding). If
you are taking medicine for another medical condition, talk to your healthcare
provider before taking additional medication.
·
If you have Zika, prevent mosquito biteness ] for
the first week of your illness.
o
During the first week of infection, Zika virus can be found in the
blood and passed from an infected person to another mosquito through mosquito
bites.
o
An infected mosquito can then spread the virus to other people.
·
Stay in places with air conditioning or that use window and door
screens to keep mosquitoes outside.
·
Sleep under a mosquito bed net if you are overseas or outside and
are not able to protect yourself from mosquito bites.
·
Use Environmental
Protection Agency (EPA)-registered insect
repellents. All EPA-registered insect repellents are evaluated for
effectiveness.
o
Always follow the product label instructions
o
Reapply insect repellent as directed.
o
Do not spray repellent on the skin under clothing.
o
If you are also using sunscreen, apply sunscreen before applying
insect repellent.
·
If you have a baby or child:
o
Do not use insect repellent on babies younger than 2 months of
age.
o
Dress your child in clothing that covers arms and legs, or
o
Cover crib, stroller, and baby carrier with mosquito netting.
o
Do not apply insect repellent onto a child’s hands, eyes, mouth,
and cut or irritated skin.
o
Adults: Spray insect repellent onto your hands and then apply to a
child’s face.
·
Treat clothing and gear with permethrin or purchase
permethrin-treated items.
o
Treated clothing remains protective after multiple washings. See
product information to learn how long the protection will last.
o
If treating items yourself, follow the product instructions
carefully.
o
Do NOT use permethrin products directly on skin. They are intended
to treat clothing.
If you have Zika, protect
others from getting sick
·
During the first week of infection, Zika virus can be found in the
blood and passed from an infected person to another mosquito through mosquito
bites. An infected mosquito can then spread the virus to other people.
·
To help prevent others from getting sick, avoid mosquito bites
during the first week of illness.
Information for travelers
·
Traveling? Visit
CDC's Travelers Health website to
see if the country you plan to visit has any travel health notices.
·
Mosquito Bite Prevention for Travelers
·
Read the Traveler's Health Yellow Book for more information on Protection against Mosquitoes, Ticks, Fleas & Other
Insects and Arthropods.
Transmission Through mosquito bites
Zika virus is transmitted to people
primarily through the bite of an infected Aedes species
mosquito. These are the same mosquitoes that spread dengue and chikungunya viruses.
·
These mosquitoes typically lay eggs in and near standing water in
things like buckets, bowls, animal dishes, flower pots and vases. They
prefer to bite people, and live indoors and outdoors near people.
o
Mosquitoes that spread chikungunya, dengue, and Zika are
aggressive daytime biters. They can also bite at night.
·
Mosquitoes become infected when they feed on a person already infected
with the virus. Infected mosquitoes can then spread the virus to other people
through bites.
Rarely, from mother to child
·
A mother already infected with Zika virus near the time of
delivery can pass on the virus to her newborn around the time of birth, but
this is rare.
·
It is possible that Zika virus could be passed from mother to
fetus during pregnancy. This mode of transmission is being investigated.
·
To date, there are no reports of infants getting Zika virus
through breastfeeding. Because of the benefits of breastfeeding, mothers are
encouraged to breastfeed even in areas where Zika virus is found
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