Viruses are strange creatures, and their effects can range from benign to deadly.  It seems like we are hearing about new viruses all the time, and recently the Zika virus has been all over the news.  What should we make of all this?

Fact:  What is it?

The Zika virus is a flavivirus, which is part of the same family as yellow fever, West Nile, dengue, and many others.  It was first discovered in a monkey with a mild fever in the Zika Forest of Uganda in the 1940s.

Fact:  How is it spread?

Zika is transmitted when the Aedes aegypti mosquito bites a person with an active infection.  The virus is spread as this mosquito bites others.  The Aedes is the same mosquito that transmits dengue, yellow fever, and other viruses.  Cgqg2la8L5aAH7eXAAKYfCLg1RU281This particular mosquito can be recognized by the white markings on its legs.  This bug hales from Africa, but is commonly found in tropical and subtropical regions throughout the world.  Interestingly enough, only the female bites for blood which she needs to mature her eggs.  She finds her hosts based on chemical compounds that are emitted by mammals.  Over the past 20-30 years, this particular mosquito has become one of the most widespread mosquito species in the world.  Scientists have recently discovered that the Zika virus can also be spread through sexual contact.  A man can spread this virus to his partner.  In the cases that are currently known, the men had symptoms.  However, the virus can spread before, during, and after symptoms have shown.  The virus can also be present in the semen longer than it can in blood, though we do not know for how long.  Other transmission vehicles include blood transfusions (multiple cases in Brazil).  There have been testing that proves that animals can get the virus from mosquitos, but there is no absolute proof that the animals can transmit it to humans.  There was a study in Indonesia in the 1970s that suggested horses, cows, goats, ducks, and bats could become infected, but no evidence existed that they develop disease or pose a risk of transmission to humans.

Fact:  Symptoms?

Most people infected with Zika virus won’t even know they have the disease because they won’t have symptoms.  Those who do express symptoms will experience rash, fever, joint pain, and/or conjunctivitis (red eyes).  The incubation time is not specifically known, but the CDC & WHO states that it is likely a 2-7 days.  The symptoms themselves will be somewhat mild and should only last 3-7 days in most cases.  Because of the mild nature of this virus, it vary rarely causes death.  For this reason, people may not realize they have been infected and it will remain in their blood for roughly a week.  Once a person has been infected, they are likely to be protected from future infections.

What we don’t know?

The medical community does not know how long the virus is present in semen in men who have had Zika.  Scientists are also unsure if men who never develop symptoms can have Zika in their semen, and they do not know if those men can transmit the virus.  Furthermore, scientists do not know if a woman can transmit the virus to her sexual partner.  If the woman is pregnant, there seems to be a link between the Zika virus and babies born with microcephaly (small head / brain).  This link is not absolute, but there is definitely increasing evidence.  We simply do not know if the virus will infect the fetus if the mother is infected, nor do we know what birth defects can be caused by this virus.  There are several other reasons microcephaly can develop, so it makes it that much harder to make a definitive statement to link Zika to that specific birth defect.

How to protect yourself?

Until more is known about this virus, pregnant women should avoid travel to areas where the virus is spreading.  Pregnant women should also take steps to protect themselves during intercourse.  Everyone should take steps to avoid mosquito bites that include long-sleeved shirts and pants, use of insect repellents, and avoid breeding sites like standing water.  Should you have any concerns, then see a healthcare provider.


More information can be found on the CDC website at