What is Zika?
Zika is a virus. First identified in 1947 in rhesus monkeys in Uganda, it was found in humans in 1952 in Uganda and Tanzania. Outbreaks of Zika virus have been reported in Africa, Asia, and the Pacific islands, and most recently in the Americas.
Zika virus is transmitted to humans through a type of mosquito.
Zika virus is transmitted to humans most commonly through the bite of an infected mosquito of the Aedes species.
These mosquitos are generally active during the day and breed in standing water.
There are no reports of the virus being transmitted through breastfeeding.
There have been rare reports of the Zika virus passing through blood or semen.
What are symptoms of Zika infection?
Symptoms of Zika infection, also called Zika fever, are generally mild and include low grade fever (37.8°C/100°F to 38.5°C/101.3°F), rash, joint pain (commonly in the hands and feet), red eyes (conjunctivitis), muscle pain, headache, pain behind the eyes, and weakness. Less commonly, symptoms of Zika infection may include abdominal pain, nausea, diarrhea, mouth ulcers, or itching.
Signs and symptoms of Zika infection usually occur from 2 to 12 days after being bitten by an Aedes mosquito, and symptoms last about two to seven days. Many people infected with the Zika virus will have no symptoms. Severe symptoms are uncommon.
Many symptoms of Zika infection are similar to dengue and Chikungunya, which are transmitted by the same types of mosquitos in the same areas.
Zika may be transmitted from a pregnant mother to her baby.
The Zika virus can be transmitted from a pregnant mother to her baby any time during pregnancy or birth. Infection during pregnancy poses risks to the fetus such as microcephaly (small head) and other poor outcomes, including death.
Pregnant women are not any more likely to contract the Zika virus, however, the risk factors and outcomes for a fetus are not yet fully understood, so the Centers for Disease Control (CDC) recommends pregnant women and women who are trying to become pregnant take precautions and postpone travel to areas where Zika virus transmission is ongoing. If travel to an endemic area is unavoidable, pregnant women should talk to their doctors before their trip and follow precautions to avoid mosquitos.
If a woman becomes infected with Zika virus when she is not pregnant, there is no risk of birth defects for future pregnancies as the virus only remains in the body for about a week. If a woman conceives after the virus has cleared her system, it cannot cause an infection in a future baby.
Reminder: There are no reports of the virus being transmitted through breastfeeding.
Zika virus may cause birth defects in babies.
Many cases of microcephaly (small head) in infants born to women infected with Zika virus during pregnancy have been confirmed. This condition can cause developmental and intellectual disability. Several cases of fetal loss have also been confirmed in women infected with Zika. Other birth defects present in babies born to mothers infected with Zika virus during pregnancy include macular atrophy (a type of eye disorder).
The full range of possible outcomes associated with Zika infection during pregnancy is not yet known, and the factors that increase risk to the fetus are not understood. More research is needed to explain the possible connection between the Zika virus and babies born with microcephaly.
What is the treatment for Zika fever?
There is currently no vaccine available to prevent Zika. There are no medications to treat the virus. Treatment of Zika infection aims to relieve the symptoms, most of which are mild. Rest, drinking lots of fluids to prevent dehydration, acetaminophen (Tylenol) for fever and pain, and antihistamines for itching and rash are recommended. Avoid aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs) until dengue infection is ruled out.
Is Zika virus deadly?
In the majority of cases, Zika virus only causes mild symptoms. Severe illness and hospitalization is uncommon, and death is unlikely. In people with underlying medical conditions, Zika infection may cause more severe symptoms.
How can infection from Zika virus be prevented?
Zika virus infection prevention is centered around preventing and avoiding mosquito bites. Aedes mosquitos are most active during the day, but they will bite at any time, and they are found both indoors and outdoors. Recommendations for individuals include:
- Using insect repellents containing DEET, picaridin, IR3535, and some oil of lemon, eucalyptus, and para-menthane-diol products provide lasting protection. Apply any insect repellent on top of sunscreen, and do not apply the repellent under clothing.
- Wear long sleeves and long pants. Treat clothing with permethrin or buy permethrin-treated clothing.
- Sleep indoors with screened windows and doors, or use air conditioning. If that is not possible use mosquito netting.
Environmental control of mosquitos is also important. Get rid of breeding areas outside by ensuring there is no standing water. Empty all flowerpots, buckets, tires, or anywhere there is standing water.
If you have Zika infection, stay indoors and avoid mosquito bites for one week until your body rids itself of the virus. Infected people become a source of Zika virus if they are bitten by mosquitos that then transmit the illness to others.
How is zika fever diagnosed?
Zika fever is diagnosed through a blood test reverse-transcription polymerase chain reaction (RT-PCR) or serology (performed at the CDC Arboviral Diagnostic Laboratory and some state health departments). These tests are not commercially available in doctor's offices and a physician must send blood samples out for testing.
Cross-reaction with related flaviviruses including dengue, Chikungunya, Yellow Fever, and West Nile viruses is common and can make a diagnosis difficult. Special tests can be performed to measure antibodies to the viruses to help determine which flavivirus is causing the illness.
Images provided by:
World Health Organization. Zika Virus.
UpToDate.com. Zika Virus Infection.
CDC. Zika Virus.
CDC. Question and Answers: Zika Virus Infection (Zika) and Pregnancy.
Pan American Health Organization. Zika Virus Infection.
CDC. Zika Virus Prevention.
CDC. Zika Virus Diagnostic Testing.
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