Scientists while conducting routine surveillance for yellow fever in the Zika forest of Uganda in the year 1947 isolated the Zika virus in samples taken from a captive sentinel rhesus monkey. A year later this virus was recovered from the Aedesafricanus mosquito from the same forest. By 1952 the first human cases were detected in Uganda and Tanzania. By 2016 it has spread to many parts of the world and will continue to spread and it will be difficult to determine how the virus will spread over time.
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.
- 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.
- Stay in places with air conditioning or that use window and door screens to keep mosquitoes outside.
- Sleep under a mosquito net if you are not able to protect yourself from mosquito bites.
- Use Environmental Protection Agency (EPA)-registered insect repellents. When used as directed, EPA-registered insect repellents are proven safe and effective, even for pregnant and breast-feeding women.
Always follow the product label instructions
Reapply insect repellent as directed.
Do not spray repellent on the skin under clothing.
If you are also using sunscreen, apply sunscreen before applying insect repellent.
- If you have a baby or child:
Do not use insect repellent on babies younger than 2 months of age.
Dress your child in clothing that covers arms and legs, or
Cover crib, stroller, and baby carrier with mosquito netting.
Do not apply insect repellent onto a child’s hands, eyes, mouth, and cut or irritated skin.
Adults: Spray insect repellent onto your hands and then apply to a child’s face.
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.
- 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.
- People usually don’t get sick enough to go to the hospital, and they very rarely die of Zika.
- Zika virus usually remains in the blood of an infected person for about a week but it can be found longer in some people.
- The symptoms of Zika are similar to those of dengue and chikungunya, diseases spread through the same mosquitoes that transmit Zika.
- See your doctor if you develop the symptoms described above and have visited an area where Zika is found.
- If you have recently traveled, tell your doctor when and where you traveled.
- Your doctor may advice specialized blood tests to look for Zika or other similar viruses like dengue or chikungunya.
- There is no vaccine to prevent or specific medicine to treat Zika infections.
- Treat the symptoms:
Get plenty of rest.
Drink fluids to prevent dehydration.
Take medicine such as paracetamol to relieve fever and pain.
Do not take aspirin and other non-steroidal anti-inflammatory drugs.
If you are taking medicine for another medical condition, talk to your doctor before taking additional medication.
- If you have Zika, prevent mosquito bites for the first week of your illness.
During the first week of infection, Zika virus can be found in the blood and passed from an infected person to a mosquito through mosquito bites.
An infected mosquito can then spread the virus to other people.
Potential complications of Zika virus disease
During large outbreaks in French Polynesia and Brazil in 2013 and 2015 respectively, national health authorities reported potential neurological and auto-immune complications of Zika virus disease.
Recently in Brazil, local health authorities have observed an increase in Guillain-Barrésyndrome which coincided with Zika virus infections in the general public, as well as an increase in babies born with microcephaly in northeast Brazil. Agencies investigating the Zika outbreaks are finding an increasing body of evidence about the link between Zika virus and microcephaly. However, more investigation is needed to better understand the relationship between microcephaly in babies and the Zika virus. Other potential causes are also being investigated.
Zika Time line