Zika Virus Disease
A usually mild mosquito-borne viral infection that can also spread through sex and from a pregnant person to a fetus.
What causes Zika Virus Disease?
Zika virus spreads mainly through infected Aedes mosquitoes. It can also spread through sex, during pregnancy to a fetus, and rarely through blood or laboratory exposure.
Symptoms and what to notice
Most infected people have no symptoms. When illness occurs, it may include rash, fever, red eyes, joint or muscle pain, and headache.
How long can it last?
Symptoms typically begin several days after infection and usually last several days to about a week. The virus can remain in some body fluids longer than symptoms last.
How serious is Zika Virus Disease?
Illness is usually mild, but infection during pregnancy can cause congenital Zika syndrome and other pregnancy complications. Rare neurological complications, including Guillain-Barré syndrome, can occur.
Treatment and management
There is no Zika-specific antiviral. Care is supportive with rest, fluids, and clinician-approved fever or pain relief. Avoid aspirin and other NSAIDs until dengue has been ruled out.
Vaccine: who and when?
No vaccine is licensed to prevent Zika virus disease in the United States.
Cost note: No vaccine price applies. Testing and medical evaluation costs vary by indication, provider, public-health access, and insurance.
Trusted source
Patient cost varies by insurance, provider, location, and eligibility. Coverage and public-health access differ, so listed prices are examples rather than guaranteed patient prices. This page is for general education and does not replace individualized medical advice, diagnosis, vaccination assessment, or treatment.
Zika Virus Disease: History, Symptoms, Transmission, Pregnancy Risks, Treatment, and Prevention
Zika virus disease, commonly called Zika, is an infection caused by the Zika virus. It is transmitted primarily through the bite of infected Aedes mosquitoes, particularly Aedes aegypti and Aedes albopictus. The virus can also spread through sexual contact and from a pregnant person to a developing fetus.
For most people, Zika infection causes no symptoms or only a mild illness. Fever, rash, joint pain, headache, muscle pain, and red eyes are among the most common symptoms. Most symptomatic infections resolve within several days to about a week.
The major public health concern surrounding Zika is different from the severity of the illness experienced by most infected adults. Zika virus infection during pregnancy can cause serious abnormalities in the developing brain and eyes of a fetus and can lead to a group of birth defects known as congenital Zika syndrome.
Zika infection has also been associated with uncommon neurological complications, particularly Guillain-Barré syndrome.
Although the enormous Zika epidemic that affected the Americas during 2015 and 2016 has subsided, the virus has not disappeared. Transmission continues at relatively low levels in parts of Africa, the Americas, Asia, and the Pacific, and outbreaks can still occur.
Important: This article provides general educational information and is not a substitute for individual medical advice, diagnosis, or treatment.
What Is Zika Virus?
Zika virus is an enveloped, single-stranded RNA virus belonging to the Flaviviridae family.
Under current virus taxonomy, Zika virus belongs to the genus Orthoflavivirus, and the species is classified as Orthoflavivirus zikaense.
It is closely related to several other medically important viruses, including:
- Dengue virus
- Yellow fever virus
- West Nile virus
- Japanese encephalitis virus
These similarities are clinically important because antibodies produced against related flaviviruses can sometimes complicate laboratory interpretation of Zika antibody tests.
Zika virus particles are approximately 40 nanometers in diameter and contain an RNA genome surrounded by a protein shell and lipid envelope.
Zika Virus Quick Facts
| Feature | Information |
|---|---|
| Disease | Zika virus disease |
| Virus | Zika virus |
| Current taxonomic species | Orthoflavivirus zikaense |
| Virus family | Flaviviridae |
| Genetic material | Single-stranded RNA |
| Main vector | Aedes mosquitoes |
| Important mosquito species | Aedes aegypti and Aedes albopictus |
| Incubation period | Approximately 3 to 14 days |
| Symptomatic illness | Usually mild |
| Typical symptom duration | Several days to about one week |
| Asymptomatic infections | Approximately 80% |
| Pregnancy concern | Congenital Zika syndrome and other pregnancy complications |
| Important neurological complication | Guillain-Barré syndrome |
| Specific antiviral treatment | None |
| Approved preventive vaccine | None |
| Main prevention | Mosquito bite prevention and prevention of sexual transmission |
The History of Zika Virus Disease
Zika has one of the most remarkable histories among modern emerging infectious diseases.
For decades after its discovery, it was considered an obscure tropical virus associated with occasional mild human infections. That perception changed dramatically after outbreaks in the Pacific and the enormous epidemic in the Americas revealed its ability to cause congenital abnormalities and neurological complications.
1947: Zika Virus Is Discovered in Uganda
Zika virus was first identified in 1947 in the Zika Forest near Entebbe, Uganda.
Scientists were conducting yellow fever surveillance and used rhesus macaque monkeys as sentinels for detecting mosquito-borne viruses.
One of these monkeys developed a fever. Researchers isolated a previously unknown virus from the animal’s blood.
The virus was named Zika virus after the Zika Forest where it was identified.
1948: The Virus Is Found in Mosquitoes
The following year, in 1948, scientists isolated the virus from Aedes africanus mosquitoes collected in the Zika Forest.
This finding provided early evidence that mosquitoes were involved in the natural transmission cycle of the virus.
1952: Evidence of Human Zika Infection Appears
In 1952, researchers reported evidence of Zika virus infection in humans in Uganda and what is now Tanzania.
Neutralizing antibodies against Zika virus were identified in human blood samples, demonstrating that people were being exposed to the virus.
1954: Virus Is Isolated From a Human
In 1954, Zika virus was isolated from a young girl in eastern Nigeria who was experiencing illness.
This provided further direct evidence that Zika could infect humans and cause disease.
1960s to 1980s: Zika Spreads Across Africa and Asia
Over the following decades, evidence of Zika infection appeared in several countries across Africa and Asia.
Antibodies, human infections, or infected mosquitoes were identified in countries including:
- Uganda
- Nigeria
- India
- Indonesia
- Malaysia
- Pakistan
Despite this broad geographic distribution, Zika attracted relatively little international attention.
Human infections appeared to be uncommon, and when illness occurred, it was generally mild.
There were no recognized major epidemics during this period.
2007: The Yap Island Outbreak Changes the Picture
The first recognized large outbreak of Zika virus disease occurred in 2007 on Yap Island, part of the Federated States of Micronesia.
Before this outbreak, only a small number of human cases had been documented in the medical literature.
During the Yap outbreak, researchers estimated that approximately 73% of residents aged three years or older had been infected.
Most infections were either asymptomatic or mild, and no deaths or major neurological complications were identified during the outbreak.
Nevertheless, the event demonstrated for the first time that Zika virus could spread extensively through a susceptible population.
2013 to 2014: French Polynesia and Neurological Complications
A much larger outbreak occurred in French Polynesia beginning in 2013.
Thousands of suspected infections were reported.
During this epidemic, physicians observed an unusual increase in cases of Guillain-Barré syndrome, a neurological condition in which the immune system damages peripheral nerves.
Later investigations strengthened evidence linking Zika infection with Guillain-Barré syndrome.
The virus subsequently spread to other Pacific islands.
2015: Zika Reaches Brazil
Brazil reported an outbreak of rash illness in early 2015, and Zika virus transmission was confirmed there in May.
The virus then spread rapidly through South and Central America, the Caribbean, and other parts of the Western Hemisphere.
During the outbreak, Brazilian clinicians noticed an unexpected increase in babies born with microcephaly, a condition in which an infant’s head and often the brain are smaller than expected.
Increasing evidence suggested that Zika infection during pregnancy could infect the developing fetus and interfere with brain development.
2016: Zika Becomes an International Public Health Emergency
On February 1, 2016, the World Health Organization declared that clusters of microcephaly and other neurological abnormalities associated with Zika infection constituted a Public Health Emergency of International Concern.
Research conducted during the epidemic established that Zika virus infection during pregnancy could cause serious congenital abnormalities.
The WHO emergency designation remained in place until November 2016. Zika then transitioned from an emergency response to a longer-term public health challenge.
What Happened After the 2015 to 2016 Epidemic?
Reported Zika cases declined substantially worldwide beginning around 2017.
However, Zika virus did not disappear.
Transmission continues at lower levels in several regions, and outbreaks can occur when environmental and epidemiological conditions allow infected mosquitoes to spread the virus.
WHO reports that dozens of countries and territories have documented evidence of mosquito-transmitted Zika infection. Surveillance is incomplete in some areas, meaning the true geographic distribution may be broader than confirmed case counts suggest.
How Does Zika Virus Spread?
Zika has several transmission routes.
Mosquito Bites
The primary route is the bite of an infected Aedes mosquito.
The two most important species are:
- Aedes aegypti
- Aedes albopictus
A mosquito can acquire Zika virus when it feeds on an infected person while virus is circulating in that person’s blood.
The virus can then multiply inside the mosquito. After becoming capable of transmitting the infection, the mosquito can infect another person during a subsequent blood meal.
Why Are Aedes Mosquitoes Important?
Aedes aegypti is particularly well adapted to living near humans.
It commonly:
- Lives in urban and residential environments
- Breeds in containers containing standing water
- Bites humans frequently
- Can bite during the daytime
- Can also bite around dawn, dusk, and at night
The same mosquitoes can transmit several other viruses, including dengue and chikungunya.
Can Zika Spread Through Sex?
Yes.
Unlike many mosquito-borne infections, Zika virus can be sexually transmitted.
Transmission has been documented from:
- Male to female partners
- Male to male partners
- Female to male partners
Zika virus can be transmitted sexually even when an infected person has no symptoms.
The virus can remain in semen longer than it generally remains in blood or other body fluids.
CDC currently recommends that people concerned about sexual transmission use condoms consistently or avoid sex for defined periods after possible exposure.
For males, the recommended period is at least 3 months after possible exposure, symptom onset, or diagnosis.
For females, the recommended period is at least 2 months.
Recommendations can be especially important when pregnancy is involved.
Can Zika Spread During Pregnancy?
Yes.
A pregnant person infected with Zika virus can transmit the virus to the fetus during pregnancy.
This route is medically significant because the virus can infect developing fetal tissues, particularly the nervous system.
Transmission may occur even when the pregnant person experiences no symptoms.
Can Zika Spread Through Blood?
Rare transmission involving infected blood or tissues can occur.
Concerns about transfusion transmission became particularly important during the large Zika epidemic because many infected people have no symptoms and may not know they are infected.
Can Zika Spread Through Breast Milk?
Zika virus RNA has been detected in breast milk.
However, the significance of this finding for transmission is uncertain, and breastfeeding has generally continued to be recommended because of its established benefits.
A person with concerns about Zika during breastfeeding should discuss their individual circumstances with a healthcare professional.
What Is the Incubation Period for Zika?
The incubation period is the interval between infection and development of symptoms.
For Zika virus disease, it is estimated to be approximately 3 to 14 days.
Do Most People Develop Symptoms?
No.
Approximately 80% of people infected with Zika virus do not develop recognizable symptoms.
This means a person can become infected and potentially participate in the transmission cycle without realizing they have Zika.
What Are the Symptoms of Zika Virus Disease?
When symptoms occur, they are usually mild.
Common symptoms include:
- Fever
- Maculopapular skin rash
- Joint pain
- Headache
- Muscle pain
- Red eyes or nonpurulent conjunctivitis
Other symptoms may include:
- Fatigue
- Swelling
- Pain behind the eyes
- Enlarged lymph nodes
- Vomiting
Symptoms generally last for several days to approximately one week.
What Does the Zika Rash Look Like?
A Zika rash is commonly described as a maculopapular rash.
This means the skin may have a mixture of:
- Flat red areas
- Small raised red bumps
The rash can spread across large areas of the body.
Because dengue, chikungunya, allergic reactions, and several other viral infections can also cause rashes, appearance alone cannot reliably diagnose Zika.
How Severe Is Zika Disease in Most Adults?
Most infections are mild.
Hospitalization is uncommon, and deaths directly associated with uncomplicated Zika infection are rare.
CDC reports that severe disease requiring hospitalization is uncommon and the case-fatality rate is below 1%.
The major concerns are complications occurring in a small proportion of patients and infection during pregnancy.
Zika Virus and Pregnancy
Pregnancy is the most important high-risk situation associated with Zika virus infection.
Zika virus can cross from a pregnant person to the developing fetus and interfere with neurological and eye development.
The fetus can be affected even if the pregnant person never develops noticeable symptoms.
What Pregnancy Complications Can Zika Cause?
Zika infection during pregnancy has been associated with:
- Congenital Zika syndrome
- Microcephaly
- Brain abnormalities
- Eye abnormalities
- Fetal growth abnormalities
- Miscarriage
- Fetal loss
- Stillbirth
- Preterm birth
Not every infection during pregnancy results in fetal abnormalities.
The presence of Zika infection means the risk is increased, not that a baby will definitely be affected.
What Is Congenital Zika Syndrome?
Congenital Zika syndrome, or CZS, is a recognizable pattern of birth defects associated with Zika infection during pregnancy.
The condition primarily affects the developing brain, nervous system, eyes, muscles, and joints.
Possible abnormalities include:
- Microcephaly
- Abnormal brain development
- Intracranial calcifications
- Eye abnormalities
- Vision loss
- Hearing problems
- Feeding and swallowing problems
- Seizures
- Joint contractures
- Abnormally increased muscle tone
- Developmental impairment
Some children may appear relatively healthy at birth but develop neurological or developmental problems later.
What Are the Characteristic Features of Congenital Zika Syndrome?
Several particularly characteristic abnormalities have been identified.
They include:
- Severe microcephaly with abnormal skull development
- Thin cerebral cortex with characteristic intracranial calcifications
- Damage involving the retina and macula of the eye
- Congenital contractures of major joints
- Marked hypertonia or spasticity that restricts movement
The presentation varies considerably between affected infants, and not every child has every feature.
What Is Microcephaly?
Microcephaly is a condition in which a baby’s head is substantially smaller than expected for the baby’s age and sex.
A smaller head can reflect abnormal brain development.
Possible consequences depend on the severity and underlying brain abnormalities and may include:
- Developmental delay
- Intellectual disability
- Seizures
- Problems with movement
- Feeding difficulties
- Vision impairment
- Hearing impairment
Some infants with congenital Zika infection have a normal head circumference at birth but develop microcephaly later.
How Common Are Zika-Associated Birth Defects?
The risk varies depending on factors including the timing of infection during pregnancy.
CDC surveillance involving pregnancies in U.S. states and territories found Zika-associated birth defects in approximately 5% of infants born to women with confirmed or possible Zika infection during pregnancy.
The risk was higher when infection occurred earlier in pregnancy. CDC data found Zika-associated birth defects in approximately 8% of pregnancies with confirmed infection during the first trimester.
These numbers describe the studied population and should not be interpreted as an exact risk estimate for every individual pregnancy.
Does Having Zika Affect Future Pregnancies?
Current evidence indicates that a previous Zika infection does not appear to create an ongoing risk for future pregnancies once the infection has cleared.
CDC states that previous Zika infection itself does not affect future pregnancies.
What Neurological Complications Can Zika Cause?
Although uncommon, Zika virus infection has been associated with several neurological conditions.
The most recognized is Guillain-Barré syndrome.
Other rare complications include:
- Encephalitis
- Meningoencephalitis
- Myelitis
- Encephalopathy
- Uveitis
- Severe thrombocytopenia
What Is Guillain-Barré Syndrome?
Guillain-Barré syndrome, or GBS, is an uncommon neurological disorder in which the body’s immune system attacks parts of the peripheral nervous system.
Symptoms may begin with:
- Tingling
- Numbness
- Weakness in the legs
- Difficulty walking
Weakness may move upward through the body.
Severe cases can involve muscles responsible for:
- Breathing
- Swallowing
- Speaking
GBS requires medical assessment and can require hospitalization.
Most people recover, but recovery may take weeks or months, and some patients can have lasting neurological problems.
Who Is Most at Risk From Zika?
Most healthy adults experience little or no illness.
The most important risk groups and situations include:
Pregnant People
Pregnancy creates concern because of the possibility of fetal infection and congenital abnormalities.
Developing Fetuses
The developing fetal nervous system is particularly vulnerable to Zika infection.
People Traveling to Areas With Zika Transmission
Travel to areas where Zika is currently circulating can increase the risk of mosquito exposure.
Sexual Partners of Recently Exposed People
Because Zika can persist in reproductive fluids, sexual transmission can occur after travel or infection.
How Is Zika Virus Diagnosed?
Symptoms alone cannot reliably diagnose Zika.
The illness can resemble several other mosquito-borne diseases, particularly:
- Dengue
- Chikungunya
Laboratory testing may therefore be necessary in selected patients.
Testing decisions depend on:
- Symptoms
- Pregnancy status
- Travel history
- Place of residence
- Sexual exposure
- Timing of exposure
- Current Zika activity in the area
What Tests Are Used for Zika?
Two major categories of testing are used.
Nucleic Acid Amplification Testing
A nucleic acid amplification test, commonly called NAAT, looks directly for viral genetic material.
RT-PCR is one example.
A positive molecular test can provide strong evidence of a current or recent infection.
Antibody Testing
Serological testing searches for antibodies produced by the immune system against Zika virus.
IgM antibodies may be detectable after infection.
However, antibody testing has important limitations.
Zika belongs to the same virus family as dengue and several other flaviviruses. Antibodies against these viruses can cross-react, making it difficult in some circumstances to determine exactly which virus caused an infection.
Additionally, IgM antibodies can remain detectable for months, which can make the timing of infection difficult to establish.
Is Routine Zika Testing Recommended for Everyone?
No.
Testing is generally reserved for people whose symptoms, pregnancy status, travel history, or exposure history make Zika infection clinically relevant.
CDC does not recommend Zika testing simply to determine whether it is safe for someone to become pregnant.
Testing recommendations can change depending on current outbreaks, so clinicians should use current public health guidance.
How Is Zika Virus Disease Treated?
There is currently no specific antiviral medication approved to cure Zika virus infection.
Treatment for uncomplicated disease is supportive.
Supportive care may include:
- Rest
- Adequate fluids
- Treatment of fever
- Appropriate pain relief
- Monitoring for complications
Acetaminophen may be used when appropriate for fever or discomfort.
Why Should Aspirin and NSAIDs Initially Be Avoided?
Zika can resemble dengue fever.
Dengue can increase the risk of serious bleeding.
For this reason, CDC recommends avoiding aspirin and other nonsteroidal anti-inflammatory drugs, or NSAIDs, until dengue has been ruled out.
This precaution helps reduce bleeding risk if the person’s illness is actually dengue rather than Zika.
Patients taking medications for other medical conditions should consult their healthcare provider before changing or adding medication.
Is There a Zika Vaccine?
No Zika vaccine is currently approved for routine human use.
As of September 2026, CDC states that there are no vaccines available to prevent Zika virus infection.
Zika Vaccine Status
| Question | Current Status |
|---|---|
| Is there an approved Zika vaccine? | No |
| Is there a civilian Zika vaccine in the U.S.? | No |
| Is there a military Zika vaccine? | No approved vaccine |
| Is there a vaccine brand name? | No |
| Is there a recommended vaccination schedule? | No |
| Are experimental vaccines being researched? | Yes |
| Main current prevention | Prevent mosquito bites and sexual transmission |
Vaccine development remains an area of scientific research, but no candidate has yet become a routinely approved Zika vaccine.
How Can Zika Infection Be Prevented?
Without an approved vaccine or preventive medication, prevention focuses primarily on avoiding mosquito bites and preventing sexual transmission.
Use Mosquito Repellent
CDC recommends using an EPA-registered insect repellent when appropriate.
Follow the instructions on the product label.
Wear Protective Clothing
Long-sleeved shirts, long pants, and other clothing that reduces exposed skin can help reduce mosquito bites.
Use Window and Door Screens
Screens can help prevent mosquitoes from entering homes.
Air conditioning can also reduce exposure in some settings by allowing windows and doors to remain closed.
Remove Standing Water
Aedes mosquitoes often lay eggs in small containers containing water.
Potential breeding sites include:
- Buckets
- Flowerpots
- Tires
- Bottles
- Water storage containers
- Outdoor toys
- Bird baths
- Gutters
- Small containers around homes
Regularly emptying, cleaning, covering, or removing these containers can reduce mosquito breeding around homes.
Remember That Aedes Mosquitoes Bite During the Day
Mosquito prevention should not be limited to nighttime.
Aedes mosquitoes can bite during the day as well as around dawn and dusk.
Prevent Mosquitoes From Biting an Infected Person
Someone who has Zika should continue avoiding mosquito bites during the early phase of infection.
Otherwise, a mosquito could bite the infected person, acquire the virus, and subsequently infect other people.
CDC recommends that people returning to the United States from areas with Zika risk take mosquito-bite precautions for approximately 3 weeks after return.
How Can Sexual Transmission of Zika Be Prevented?
Condoms can reduce sexual transmission.
Abstinence eliminates sexual transmission during the relevant risk period.
CDC’s general prevention timeframes after possible exposure are:
| Person potentially exposed | Recommended period for condoms or abstinence |
|---|---|
| Male | At least 3 months |
| Female | At least 2 months |
The timeframe begins after travel or possible exposure, or from symptom onset or diagnosis when applicable.
Pregnancy changes the importance of these precautions because preventing infection of the pregnant partner also protects the fetus.
Zika and Travel
Travel guidance is especially important for:
- Pregnant travelers
- People planning pregnancy
- Partners of pregnant people
- People undergoing fertility treatment
CDC classifies countries and territories according to Zika risk and updates its recommendations as transmission patterns change.
Pregnant travelers are advised to avoid areas with an active CDC Zika Travel Health Notice. For places with current or past transmission, travelers should discuss the individual risk with their healthcare provider and carefully follow mosquito and sexual transmission prevention recommendations.
Because Zika risk can change, travelers should check current CDC travel guidance rather than relying on an old country list.
How Widespread Is Zika Today?
The enormous outbreak of 2015 and 2016 is no longer occurring at the same scale.
Reported global cases declined considerably beginning around 2017.
However, Zika remains present in tropical and subtropical regions, including parts of:
- The Americas
- Africa
- Southern Asia
- The Western Pacific
Occasional outbreaks continue to occur.
WHO reports that 92 countries and territories have documented evidence of mosquito-transmitted Zika infection, although global surveillance is limited.
The continuing presence of Aedes mosquitoes means areas with suitable mosquito populations can remain vulnerable to renewed transmission.
Can You Get Zika More Than Once?
Scientists continue to study the duration and completeness of immunity following Zika infection.
Evidence suggests that infection produces an immune response, but the exact duration of protection and its implications for reinfection are not fully established for every population.
Previous infection should therefore not be treated as a reason to ignore mosquito precautions in areas where Zika is circulating.
Is Zika the Same as Dengue?
No.
Zika and dengue are caused by different viruses, although both belong to the Flaviviridae family and are often transmitted by the same Aedes mosquitoes.
They can also produce similar symptoms.
| Feature | Zika | Dengue |
|---|---|---|
| Main vector | Aedes mosquitoes | Aedes mosquitoes |
| Fever | Usually mild | Can be high |
| Rash | Common | Common |
| Joint pain | Common | Can occur |
| Conjunctivitis | Characteristic | Less characteristic |
| Severe bleeding risk | Uncommon | Important in severe dengue |
| Congenital birth defects | Major concern | Not characteristic in the same way |
| Sexual transmission | Documented | Not a usual transmission route |
| Vaccine availability | No approved vaccine | Vaccines exist for selected populations |
The clinical overlap is one reason suspected Zika cases may also need evaluation for dengue.
Is Zika the Same as Chikungunya?
No.
Chikungunya is caused by chikungunya virus and is unrelated to Zika at the virus-family level.
However, both can be transmitted by Aedes mosquitoes and may produce:
- Fever
- Rash
- Joint pain
- Headache
Chikungunya is particularly known for sometimes producing severe and persistent joint pain.
Laboratory testing may be necessary to distinguish these infections.
When Should Someone Seek Medical Care?
Most Zika infections do not require emergency treatment.
Medical evaluation is particularly important when someone develops possible Zika symptoms after:
- Traveling to an area with Zika risk
- Living in an area where Zika is circulating
- Having sex with someone who may have been exposed
- Experiencing possible Zika exposure during pregnancy
Pregnant people should contact their healthcare provider if they believe they may have been exposed to Zika, especially if symptoms develop.
Seek Urgent Medical Attention for Neurological Symptoms
Urgent evaluation is appropriate for symptoms such as:
- Increasing muscle weakness
- Difficulty walking
- Weakness spreading upward from the legs
- Difficulty swallowing
- Difficulty breathing
- Facial weakness
- Severe confusion
- Seizures
- Loss of consciousness
These symptoms can indicate a serious neurological complication and should not be managed at home without medical assessment.
Frequently Asked Questions About Zika Virus Disease
Is Zika virus still around?
Yes.
The number of reported infections is much lower than during the 2015 and 2016 epidemic, but Zika transmission continues in parts of the world and outbreaks remain possible.
What percentage of people with Zika develop symptoms?
Approximately 20% develop recognizable symptoms, while around 80% remain asymptomatic.
How long after a mosquito bite do Zika symptoms appear?
The estimated incubation period is approximately 3 to 14 days.
How long does Zika illness usually last?
Symptoms generally last several days to about one week.
Is Zika deadly?
Death from uncomplicated Zika infection is rare. Severe disease requiring hospitalization is also uncommon.
Can Zika cause birth defects?
Yes.
Zika infection during pregnancy can cause congenital Zika syndrome and other abnormalities involving the brain and eyes.
Does a pregnant person need symptoms for the fetus to be affected?
No.
Fetal infection and congenital abnormalities can occur even when the pregnant person had no noticeable Zika symptoms.
Can Zika cause microcephaly?
Yes.
The causal relationship between Zika infection during pregnancy and microcephaly became firmly established following the outbreak in the Americas.
Can Zika spread from person to person?
Yes.
Sexual transmission and transmission from a pregnant person to the fetus are documented.
Mosquito transmission remains the main route.
Can Zika spread through kissing?
Zika virus has been detected in saliva, but CDC reports no evidence that Zika is transmitted through saliva during deep kissing.
Can mosquitoes transmit Zika from one infected person to another?
Yes.
A mosquito can acquire the virus by feeding on an infected person and later transmit it to another individual.
Are antibiotics effective against Zika?
No.
Zika is caused by a virus, so antibiotics do not treat the infection.
Is there an antiviral medicine for Zika?
No specific antiviral treatment is currently approved.
Treatment is primarily supportive.
Is there a vaccine for Zika?
No approved Zika vaccine is currently available.
Should someone be tested for Zika before becoming pregnant?
Routine testing solely to determine whether it is safe to become pregnant is not currently recommended by CDC.
Can Zika cause Guillain-Barré syndrome?
Yes.
Zika infection has been associated with Guillain-Barré syndrome, although the complication is uncommon.
Does Zika only occur in South America?
No.
Zika transmission has occurred in Africa, Asia, the Pacific, the Caribbean, and the Americas.
Why Did Zika Become Such an Important Disease?
For most of the twentieth century, Zika seemed to be a minor tropical virus.
Its transformation into a major global health concern illustrates how an infectious disease can change in significance when it enters new populations and researchers discover previously unrecognized complications.
The sequence was remarkable.
Scientists discovered the virus in a Ugandan monkey in 1947. Human infection was recognized during the 1950s. For decades, only scattered mild illnesses were documented.
Then the 2007 Yap Island epidemic demonstrated that Zika could infect much of a population.
The French Polynesian epidemic revealed an association with neurological disease.
Finally, the enormous epidemic in Brazil and the rest of the Americas exposed the devastating consequences that infection could have during pregnancy.
The recognition that Zika virus can cross the placenta and interfere with development of the fetal brain fundamentally changed the medical understanding of the disease.
Today, Zika is no longer generating the enormous number of cases seen during the 2015 and 2016 epidemic, but it remains medically significant.
There is still no approved vaccine and no specific antiviral treatment. Prevention therefore depends on mosquito control, personal protection against mosquito bites, awareness of sexual transmission, appropriate travel precautions, and special attention to possible exposure during pregnancy.
For most infected people, Zika will cause no illness or only temporary mild symptoms. For a developing fetus, however, the consequences can be profound. That contrast remains the defining feature of Zika virus disease and the reason continued surveillance and prevention remain important.
Medical information reviewed against CDC, WHO, and current virus taxonomy resources available through September 2026.