According to the Centers for Disease Control and Prevention (CDC), most people infected with Zika virus won’t even know they have it as they have no symptoms. So how do you know if you have it?

Jim Fredericks, of the National Pest Management Association, said earlier this year that it is important to stay alert. “I don’t know that we need to be worried [about Zika specifically], but we always need to be aware of mosquitoes and concerned about mosquito bites,” he said. “The mosquitos that transmit this particular diesase are in the United States already, but in order for transmission to occur, infected people need to be here [as well].”

In addition to being transmitted through mosquito bites, a recent report in The New England Journal of Medicine stated that evidence now shows that the virus can also be transmitted sexually.

A new concern with the Zika virus is a link with Guillain-Barre syndrome. According to a study published in The Lancet, between October 2013 and April 2014, French Polynesia experienced both the largest Zika virus outbreak ever at the time, as well as an unusual increase in Guillain-Barre syndrome, suggesting a possible association between the two.

The only way to definitively diagnose Zika virus is through saliva and urine tests. Many never seek medical attention because the symptoms are so mild. The World Health Organization states that Zika can also be misdiagnosed as dengue. So what are the symptoms?

• Joint pain is one of the most common symptoms
• Rashes beyond what typically seen with the usual mosquito bite
• Headache lasting 2 to 7 days
• Mild fever
• Conjunctivitis (red eyes)
• Muscle pain
• Intense lower back pain
• Temporary paralysis
• Fatigue

Care for Zika mainly focuses on treating symptoms. Get plenty of rest, drink fluids to prevent dehydration, take acetaminophen to relieve fever and pain, avoid aspirin and other NSAIDS until dengue is ruled out, to reduce bleeding risks.

If you do have Zika, do what you can to prevent mosquito bites to avoid spreading the virus to other people.

A new study from Emory University has discovered that the Zika virus apparently has a unique ability to cross from mother to fetus through the placenta. Typically the placenta plays a protective role in the development of a fetus. Zika, however, passes through the placenta to cause birth defects, such as microcephaly, in the developing fetus.

Study author and pediatrics professor Dr. Mehul Suthar said, “Our results substantiate the limited evidence from pathology case reports.” He added that little is known about exactly how the Zika virus replicates in the placenta.

The study examined cells donated by healthy women who had Cesarean births at full term. The researchers found that Hofbauer cells, protective cells produced by growing fetuses, did not kill Zika cells, which instead continued reproducing, causing unusual signs of antiviral and inflammatory responses in the Hofbauer cells. This caused the researchers to question which of the receptors was allowing the virus to enter the Hofbauer cells, and whether or not their immune status was altered during the different stages of pregnancy.

Results of the study help to explain why the highest risk of Zika infection occurs during the first and early second trimesters of pregnancy. This is the time when the placenta has not developed enough to ward off infection. The researchers found that resistance to Zika varies among pregnant women, which partly explains why only some women infected with Zika have babies affected by the virus.

Suthar said, “Host genetics and non-viral factors, including nutrition and microbiota, as well as timing may be influencing infectivity.” He said that understanding these factors better could help design preventative measure.

Study findings were published in the journal Cell Host & Microbe on May 27.