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Update on the Zika virus: Cases decline, concerns remain | Aug 24, 2017

While the Zika virus was discovered 70 years ago, a rash of outbreaks shone a spotlight on the virus within the past few years. Attention rose considerably in 2015, when some of the first U.S.-based cases were discovered. While it appears Zika cases are on the decline, this doesn’t mean that the virus isn’t a continuing concern.

In fact, Zika has had such a large-scale impact recently that stipulations have temporarily been put in place in certain regions to protect travelers against the spread of the condition. Researchers – including those at the University of Arizona Mel & Enid Zuckerman College of Public Health – continue to work to better understand Zika, including the ways it can be spread and potential strategies for prevention.

As more information surfaces about Zika, it’s important that public health professionals ensure their community is updated. Safeguarding local members – particularly women who are pregnant or may become pregnant – should continue to be a top priority.

A brief history

Before we examine the latest research and developments surrounding the Zika virus, it’s important to understand its history. According to the World Health Organization, the virus was first discovered in 1947, and numerous cases have been reported since then:

● 1947-1952: Researchers first observed Zika in samples taken from captive monkeys in Uganda. It wasn’t until 1952 that the first human cases were identified, including cases in Uganda and the United Republic of Tanzania.
● 1969-1983: This period saw considerable expansion in the geographical areas impacted by the Zika virus. Sporadic cases began being reported in Asia as well as Africa.
● 2007: The virus continued to spread across the globe, and the first large outbreak was identified on the island of Yap in the Pacific. Before this incident, there had been 14 isolated cases, but no real outbreaks.
● 2013-2014: Zika outbreaks were reported in four areas of the Pacific Islands. The outbreak in French Polynesia included thousands of potential cases, and was one of the largest seen to date.
● 2015-current: According to the Centers for Disease Control and Prevention, the first cases of Zika in the U.S. were reported in 2015. Since then, there have been more than 5,300 symptomatic cases identified, including those resulting from traveling to affected areas, mosquitoes or sexual transmission.

Update: Reported cases on the decline

Zika reports spiked across the globe – particularly in the U.S. – in 2015 and 2016, causing the National Institutes of Health to label it “a pandemic.” Thankfully, since then, Zika cases have dropped considerably.

The Pittsburgh Post-Gazette reported that while over 5,100 cases were identified in the U.S. in 2016, only 185 infections had been pinpointed through August 2017. Reports were even declining in high-risk regions like Pennsylvania, which saw 175 symptomatic cases in 2016, and only four so far this year.

Antibodies mount an effective defense

But what, exactly, is causing this recent, sharp decline in reported Zika cases? According to a 2016 study, individuals are developing strong antibodies against the virus, to the point that it may choke it out completely.

British scientists who authored the study noted that antibodies build up after an initial infection, helping to guard against the progression of the virus and promote the development of immunity, according to Reuters. This is especially true for individuals living in areas with a high concentration of mosquito-based infections.

“The researchers … estimated that infections from the mosquito-borne virus will become so widespread in affected countries that populations will develop what is called ‘herd immunity,’” Reuters’ Julie Steenhuysen reported. “This occurs when a higher percentage of the population has become immune to an infection either through developing natural immunity or through vaccination, making a wider outbreak less likely.”

As individuals continue to develop antibodies and immunity, researchers predict that Zika outbreaks could “burn out” in the next two to three years.

Despite declines, risks continue

Although Zika reports are decreasing, Kirsten Mertz, Allegheny County Health Department medical epidemiologist, told the Post Gazette that concerns still remain, particularly for pregnant women who are at a higher risk of infection, and having infants with Zika-related birth defects.

Currently, many researchers are focused on studying how Zika can impact a woman during the early stages of pregnancy. Cases have shown that the greatest risk of infection takes place during this period.

What’s more, health professionals and scientists are still unsure of how the virus is able to impact fetuses of infected women. As Mertz said, in order to impact the fetus, the Zika virus has to go through the placental barrier which most viruses are unable to do.

Overall, health professionals are reminding local citizens that while Zika may not be in the news as much, cases are still being reported, and the virus is still something to be concerned about.

“It’s still there, and it’s important people remain vigilant to protect themselves from mosquito bites in areas where Zika is being locally transmitted,” noted Atlanta CDC spokesperson Benjamin N. Haynes.

Zika in Florida: First sexually transmitted case reported

As scientists, researchers and health professionals continue to work to better understand the Zika virus, the spotlight is shifting to cases emerging in Florida.

According to CDC, Florida State has one of the most reported symptomatic Zika cases thus far in 2017. New York and California round out the top 3 states. According to reports from early August 2017, 12 cases were discovered in a single week in Florida. The state also saw the first instance of sexually transmitted Zika. On August 1, the Florida Department of Health confirmed the case, noting that there wasn’t currently any evidence of mosquito-transmitted cases anywhere in the state.

This particular case centered around a couple where one partner was ill with symptoms associated with Zika infection after traveling to Cuba. Both individuals were tested for the virus, and both tested positive.

“It is important to remember Zika can also be transmitted sexually and to take precautions if you or your partner traveled to an area where Zika is active,” the Florida Department of Health stated in public statement.

Technology in the fight against Zika infection

Overall, the more information and tools the public has to fight the spread of Zika – especially in high-risk regions – the better. In this spirit, researchers from Mel and Enid Zuckerman College of Public Health developed a new community-based app called Kidenga. The platform leverages the participation of users to help track mosquito activity as well as identified symptoms connected with the virus. Users report symptoms or confirmed illnesses, enabling researchers to more easily pinpoint areas where the virus is being transmitted.

Currently, Kidenga is being used to monitor potential outbreaks of Zika, dengue and chikungunya, viruses which are all transmitted by the same type of mosquito and have similar symptoms. Since its release in the fall of 2016, the app has seen 1,300 reports each week, and is being used by individuals in 33 states and more than 100 countries across the globe. Researchers have also launched a Spanish version of the app in the hopes of increasing engagement and participation from communities near the U.S.-Mexico border.

Kacey Ernst, Ph.D., MPH, associate professor of epidemiology at the UA Zuckerman College of Public Health and lead investigator, noted that while the app is a beneficial start for stemming and preventing Zika outbreaks, these efforts must continue.

“Now more than ever communities need to work together to identify and solve public health problems,” Ernst said. “As funding is stagnant or declining, novel ways to improve health with limited resources are required.”

The role of public health professionals

Public health professionals should work to ensure that their local communities are participating in Zika prevention, and understand the risks and potential symptoms associated with the virus. Awareness is the first step, identifying and reporting cases early on can make a considerable difference in overall public health.

Public health professionals should educate the community on the known ways the virus spreads – including mosquito-borne, and now sexual transmission. In addition, professionals and officials should also maintain a high focus on precautions for pregnant women in order to prevent the birth defects caused by the virus.

Taking a cue from Ernst, public health professionals can encourage community members to use the Kindega app, especially if they have plans for holiday travel. Kindega offers details about current Zika outbreaks and where the most transmissions are taking place. The platform also provides the most up-to-date information on prevention strategies, helping to keep the public informed.

To continue supporting these efforts, professionals should pursue an advanced education. A Master’s degree from the University of Arizona Mel & Enid Zuckerman College of Public Health can help you stay relevant and prepare you to assist your local community in the prevention of Zika and other public health issues. To find out more, explore our program details and other educational resources today.

Recommended Readings:
The University of Arizona and the Zika virus
What can Public Health Students Learn from the Zika Virus?
The Zika virus and public health