What you need to know now about Zika virus in Indiana

First there was the swine flu of 2009. Then Ebola in West Africa. On Monday the World Health Organization announced a new international public health emergency: an outbreak of the mosquito-borne Zika virus.

This outbreak in South America and a previous one in the South Pacific have been potentially linked to an uptick in neurological disorders and brain defects, which the international health agency has deemed “an extraordinary event.”

So far there have been no Zika cases transmitted in the United States.

A few cases have cropped up in people who have traveled and been infected outside the country, though no Indiana resident has yet tested positive for the virus, said Jennifer Brown, state public health veterinarian for the Indiana State Department of Health.  The department oversees surveillance, infection and control of insect-borne diseases in people.

However, she adds, that just as Indiana residents have contracted other mosquito-borne diseases such as chikungunya and dengue fever abroad, some will likely come home with Zika.

“At this time I do expect we will see cases of Zika virus infection in Indiana residents who have traveled to these countries where this outbreak is occurring,” she said.

The potential threat of the virus is great enough that federal and state health officials are taking steps to prevent it from causing problems here and concerning enough from an international perspective for the Geneva-based World Health Organization to make it a priority. While it's nowhere near as deadly as either Ebola or the swine, or H1N1, flu, the Zika virus requires a coordinated medical response, the agency says.

The U.S. government is advising pregnant women not to travel to affected areas. State health officials ask that Indiana residents whose doctors suspect they may have Zika act with the utmost precaution, lest they be bitten by a mosquito, which then becomes infected and transmits the disease to others here.

“What we’re asking people to do is avoid mosquito exposure for the first week of their illness,” Brown said. “At this time of the year that’s unlikely to be an issue, but in the summertime that recommendation will become more important.”

Here are 10 things you need to know about the Zika virus:

1. What is the Zika virus? The Zika virus is transmitted by certain mosquitoes in tropical and subtropical parts of the world and typically causes a mild illness. Symptoms include rash, fever, conjunctivitis (a k a pink eye), and joint pain. There have been rare reports of infected mothers passing the virus to their newborns during childbirth and transmission of the virus through blood transfusions or sexual contact, according to the Centers for Disease Control and Prevention.

2. Is this a deadly disease? Rarely. Only about 1 in 1,000 cases of Zika virus results in death, according to Purdue medical entomologist Catherine Hill.

In most cases the symptoms, which begin two days to a week after being bitten by an infected mosquito, will resolve on their own. Many people who fall ill do not even see the doctor. Only about one in five people bitten display any symptoms at all, according to the CDC.

3. This doesn’t sound so bad. Why is everyone concerned? A number of infected women in this current outbreak in Brazil have given birth to infants with a birth defect known as microcephaly, in which the baby’s head does not develop normally.

Scientists also saw an atypical rise in Guillain-Barré syndrome, a neurological condition, in French Polynesia during the first outbreak there a few years ago.

Brazilian researchers also have noted an increase in Guillan-Barré Syndrome, a neurological disorder, according to the World Health Organization.

Still, there has been no definitive proof Zika is to blame. In her statement announcing the public health emergency, WHO Director General Dr. Margaret Chan said that a causal relationship between Zika and birth defects was “strongly suspected though not yet scientifically proven.”

4. Where is the outbreak currently? More than 20 countries in South and Central America and the Caribbean are included in the current outbreak, as well as Cape Verde and Samoa. Mexico and Puerto Rico also have seen cases of local transmission, meaning that people in those areas have contracted the virus through the bite of an infected mosquito.

5. If the virus has existed in the past, why would it suddenly cause a problem now? The virus has existed but not necessarily in this part of the world. So people in North America and South America have no resistance built up to the virus.

“We have an immunologically naïve population, which means that the population has never seen this virus before,” Brown said.

This may have helped the virus spread more rapidly in the current outbreak and make those it infects more vulnerable to it.

6. How do doctors diagnose Zika? The only way to make a definitive diagnosis is through a blood test, and only the CDC offers that test, Brown said.

7. Who, if anyone, should be concerned about this in Indiana? The CDC has recommended that all pregnant women in the United States postpone travel to any area affected in this outbreak. Non-pregnant women of child-bearing age and others are not included in the warning.

“Currently we think that the risk is for women who are exposed to the virus during their pregnancies,” Brown said.

Women who are contemplating becoming pregnant in the near future should consult with their health care providers before traveling to any of the affected areas, Brown said.

8. I’m planning to travel. What can I do to lower my risk? Follow the CDC recommendations if you are a pregnant woman or one planning a pregnancy in the near future, Brown said. If not, take precautions to avoid mosquito bites, such as wearing insect repellent and long sleeves whenever you’re outside. Unlike other species, Aedes mosquitos feed at both day and night, according to the CDC.

If you do feel ill either while abroad or upon your return, see a physician and be sure to mention that you have recently been outside the country, Brown said. If your physician shares that suspicion, state health officials ask that you remain inside, away from mosquitoes for at least a week.

9. I’m not planning to travel. What can I do to lower my risk? Two types of Aedes mosquitoes are known to transmit the virus, Brown said. The species the virus prefers does not reside in Indiana, but its second choice, the Asian tiger mosquito, does. Still, that’s no cause for panic.

“At this time I believe the risk for Zika virus infection in Indiana residents is limited to people who travel outside the country,” Brown said. “We are monitoring the situation carefully.”

Zika will likely first show up in other areas of the country, where both species of mosquito live, such as south Florida, Brown said.

If you want to lower your risk of contracting any mosquito-borne disease, such as West Nile virus, which already exists in Indiana, from late April to the first hard freeze take precautions against mosquito bites whenever you head outside.

Since mosquitoes like to breed in containers of standing water, from those as small as bottle caps to discarded tires, make sure you do not have standing water in containers on your property.

10. How about a vaccine? At this point there is no vaccine against the virus.

Call IndyStar reporter Shari Rudavsky at (317) 444-6354. Follow her on Twitter: @srudavsky.