What You Need to Know About the Zika Virus
This week, the World Health Organization declared the Zika virus a global public health emergency. Here’s what doctors currently know.
1. The Zika virus is primarily transmitted by a mosquito.
Dr. Cynthia Archer, a specialist in Internal Medicine, says the Zika virus is typically transmitted by an Aedes mosquito that has ingested blood from an infected human or primate. Dr. Keshab Paudel, also an internist, says Aedes mosquitoes are the same mosquitoes that spread dengue and chikungunya viruses.
2. It may also be transmitted sexually as well as during pregnancy.
Dr. Paudel also notes that the CDC (Centers for Disease Control and Prevention) has reported one possible spread of the virus through blood transfusion and one report of possible spread of the virus through sexual contact. Infectious Disease expert Dr. H. Hunter Handsfield says infection via sexual transmission may be rare. “In one case,” he says, “an infected man returned to the U.S. and his wife soon caught it, in circumstances that suggested no mosquito exposure. Zika was found in his semen and it was transmitted sexually. The same thing can occur with Ebola. In both cases, sexual transmission appears to be rare, and non-sexual contact (e.g. touching, coughing, shared utensils, or bathrooms) is not known to be a risk.” However, these cases are under investigation, says OB/GYN Dr. Andrea Arguello, as is the possibility that the virus may be passed from a mother to her fetus during pregnancy.
3. As yet, there is no vaccine or cure for the Zika virus.
Currently, there is no vaccine or cure for the Zika virus. Dr. Arguello says the best course of action is to prevent a Zika infection by avoiding travel to areas that are at high risk for Zika. If infected, Preventive Medicine specialist Dr. Thomas Jeanne says treatment involves fluids, rest, pain relievers, and other supportive care, as the illness is fairly mild and typically lasts no more than a week.
4. You can avoid infection by limiting your travel plans and being cautious with those you see.
Because Zika is primarily transmitted by mosquitoes, Dr. Handsfield says the most effective means of preventing infection are through vector control (reducing mosquitoes in the environment) and exposure control (avoiding mosquito bites). As of February 3, 2016, the CDC has marked these countries and territories as having active Zika virus transmission:
[caption id=”attachment_32871" align=”aligncenter” width=”800"]
Countries and territories with active Zika virus transmission[/caption]
Americas
- Barbados
- Bolivia
- Brazil
- Colombia
- Commonwealth of Puerto Rico, U.S. territory
- Costa Rica
- Curacao
- Dominican Republic
- Ecuador
- El Salvador
- French Guiana
- Guadeloupe
- Guatemala
- Haiti
- Honduras
- Jamaica
- Martinique
- Mexico
- Nicaragua
- Panama
- Paraguay
- Saint Martin
- Suriname
- U.S. Virgin Islands
- Venezuela
Oceania/Pacific Islands
- American Samoa
- Samoa
- Tonga
Africa
- Cape Verde
Although Zika is primarily transmitted by mosquitoes located in warmer regions, there’s potential for a more global reach through travel and other human movements. Dr. Handsfield notes that while there isn’t yet mosquito transmission of Zika in the United States, that could change as temperatures rise and the mosquitoes make their way north to the southeastern states, such as Florida, other Gulf states, and the Carolinas. Transmission of Zika to other continents, such as Europe and Australia, can still occur through infected travelers. Dr. Jeanne says Zika may be transmitted by blood and bodily fluids, so cover any wounds and avoid unprotected sex if you’ve recently traveled to an affected area — also avoid unprotected sex with those who recently traveled to an affected area.
This kind of transmission doesn’t yet mean you have to completely avoid those infected or potentially infected. “There is no known transmission by contact with a contaminated environment, shared utensils or food, toilets, etc.” says Dr. Handsfield. “However, it’s a new problem and new or different information could become available.”
5. You should also take mosquito precautions.
If you live in or travel to an affected area, take very careful mosquito bite prevention: To deter mosquitoes from biting, Infectious Disease specialist Dr. Michael Ein suggests using insect repellants that contain 20–50% DEET (10–30% for young children, according to Dr. Mary Lambe, a Family Medicine specialist) or picardin are very effective mosquito repellants. Permethrin-treated clothing is also highly effective. Psychiatrist Dr. Heidi Fowler also suggests using bed netting when sleeping, spraying the walls with insecticide, staying inside or wearing long pants and long-sleeved shirts from dusk to dawn. For natural bug deterrents, she suggests using aloe vera and basil. Also, don’t forget to get rid of standing water, as Dr. Arguello notes it’s where mosquitos breed.
6. Zika virus symptoms are mild.
The Zika virus illness is generally mild, though Dr. Jeanne says only 1 out of 5 infected people will actually develop symptoms. Common symptoms include fever, rash, joint pain, conjunctivitis (red eyes), headache, and muscle aches. Pediatrician Dr. Robert Kwok says the duration of the illness varies among patients: “The time from mosquito bite to symptoms is believed to be a few days to a week. Symptoms then last another few days to another week.”
7. If infected, you can be contagious for a few weeks.
There isn’t much certainty here. Dr. Kwok says, “The incubation period can be up to a week, and then the symptoms can be up to another week, so it may be an uncertain several weeks after the last mosquito bite before a person is non-contagious.” Dr. Arguello says the virus has been found to remain in the blood of an affected individual for longer than a week. “The most important course if you are sick is to observe rest and isolation to prevent transmission to others,” she says.
8. Doctors can conduct blood tests for the Zika virus through the CDC or other advanced laboratories.
To determine if an individual has been infected with the Zika virus, Internal Medicine specialist Dr. Kashif Abdullah says doctors typically ask questions and follow this procedure:
- Determine clinic symptoms, which include fever, rash, muscle pain, and red eyes.
- Ask about travel history to make sure it isn’t another infection like dengue
- Test the patient’s blood for the presence of the Zika virus — this must be done through the CDC or another advanced laboratory
Dr. Kwok says testing is only available at a limited number of labs, and this testing includes PCR testing of blood for the virus itself, and antibody testing to look for the patient’s immune system response to infection. In the United States, these labs include the CDC Arbovirus Diagnostic Laboratory and a few state health departments. Test results are usually available between 4–14 days after the lab receives the specimen, says Dr. Arguello. In other countries, such as Australia, testing is done at state public health laboratories.
9. Primates can also be infected by the Zika virus.
Dr. Cynthia Archer, a specialist in Internal Medicine, says, “The confirmed hosts that can manufacture Zika virus in sufficient quantity to pass it along to other mosquito vectors include primates (meaning monkeys) and humans. It still remains unknown if other mammal species are able to become ill due to Zika, and thus far no other species are known natural hosts. However, absence of evidence is not equivalent to evidence of absence.” Other primates that can catch the Zika virus include apes, says Dr. Kwok.
10. Talk to your doctor if you’re pregnant or trying to get pregnant and think you might be infected by the Zika virus.
Recently, an increase in Zika virus infections has correlated with an increase in women giving birth to microcephalic babies. There are several potential causes of microcephaly, including various infections and exposure to certain toxins (drugs, alcohol, etc). While Dr. Arguello notes the association between microcephaly (abnormal smallness of the head and brain) and Zika infection in pregnancy has still not definitively been established, the correlation has been strong enough for governments to caution women in affected areas to avoid pregnancy until the spread of the Zika virus is under control.
If you’re pregnant or trying to get pregnant and think you might be infected by the Zika virus, talk to a doctor. Dr. Kwok says doctors can test amniotic fluid through an amniocentesis to see if the virus has been transmitted to the fetus. A prenatal ultrasound can then show a small head or calcium spots in the brain, confirming microcephaly. According to the CDC, this is an approximate timeline for testing:
- Amniocentesis after 15 weeks of gestation
- Fetal ultrasound at 18–20 weeks
Ultimately, you should talk to a doctor, as timing and medical recommendations can vary according to each patient’s clinical circumstances. If fetal brain damage is discovered early in the pregnancy, there are options, says Dr. Kwok. You should also talk to a doctor if you’re trying to conceive and may have been infected.