The word “Flavivirus” might not mean much to you, but chances are the word “Zika,” one of the viruses within the Flavivirus genus, is, thanks to its notorious 2015 outbreak. At its peak, Zika infected more than 200,000 people, initiating a panic across the world and derailing thousands of travel plans. Thanks to the efforts of quick-moving doctors and health officials, only one case of Zika in has been reported in the US. But does that mean the Zika virus no longer poses a threat?
A brief history of the Zika Virus
First, let’s go over a quick background of the virus.
The Zika virus, a tropical, mosquito-borne flavivirus, was first discovered in 1947 in Uganda in monkeys. Ten years later, the first human cases of Zika were reported in Uganda and the United Republic of Tanzania.
The disease was never prolific in humans until 2015, when the first cases of the infamous Zika virus outbreak were reported in Brazil. Health officials were aware of the disease, but dubbed it the “mystery virus” as it wasn’t identified as Zika until further research was done. Experts had no idea the virus would come to infect hundreds of thousands of people across multiple countries and continents, including the United States.
Brazil was the perfect breeding ground for the virus: a warm, tropical climate ripe with Aedes aegypti mosquitoes and millions of people susceptible to the virus. Just one year later, the World Health Organization (WHO) declared the outbreak a global health emergency.
Thus concludes the (greatly) attenuated story of how a once-obscure disease rose to the ranks of a global health emergency.
Symptoms of Zika
Reported symptoms of Zika are mild and not unlike those of the common flu: headache, joint pain, fever, nausea and rash. Symptoms typically appear one to two weeks after initial infection and last about a week long. Most cases go away on their own and some are even asymptomatic (however, there’s currently no good statistics on this, as asymptomatic patients typically do not get tested).
Based on these symptoms, Zika doesn’t seem deadly. So why did the WHO declare it a global health emergency?
Deadly and Dangerous Complications of Zika
While Zika itself isn’t extremely volatile, it has longer lasting complications that make it a more deadly disease. Scientists have discovered adult Zika patients are much more likely to get Guillain-Bárre syndrome, a condition much more dangerous than Zika where the immune system attacks the nerves, causing temporary paralysis.
To bring us back to the main question: if the Zika virus is almost nonexistent now, aren’t we in the clear? The unfortunate answer is no.
Though reported infections have reached nearly zero, the Zika epidemic has not fully been put to rest. This is because Zika is a known teratogen. And if ‘flavivirus’ wasn’t a household term to you, teratogen will definitely be even more obscure!
Zika’s teratogenic characteristics can be found around the world today, and heavily in Brazil, in babies and children. If a woman is infected at any time during her pregnancy, her baby is at risk for birth defects such as blindness, restricted body movements, and microcephaly (which is characterized by abnormal head size and an underdeveloped brain). Unfortunately even though these babies weren’t directly infected, they still endure lifelong debilitating effects. These are the long suffering victims of the Zika virus.
Is there anything that can be done?
Thankfully the answer to this question is yes! There are many research avenues and questions of which finding an answer to will greatly help for the next outbreak*.
Currently, scientists do not know the mechanisms of how the Zika virus causes birth defects such as microcephaly. Uncovering and understanding this mechanism could lead to a drastic decrease in birth defects caused by the Zika virus. By knowing how the virus affects fetuses, scientists could potentially develop therapeutic strategies to avoid microcephaly and other Zika induced teratogenesis. This would be huge, as Zika’s fetal effects are what make it such a dangerous virus.
Interestingly, there have also been reported cases of Zika being a sexually transmitted infection. This is especially important to note because of the teratogenic effects of Zika. Additionally, the Zika virus has been found to stay in sperm for up to 3 months after initial infection. Because of this, the infection could be spreading without the participants realizing and could potentially result in a child with devastating birth defects. Studying how Zika is sexually transmitted as well as why and how it survives for so long in sperm would be very helpful to limit not only the spread of the virus but also the likelihood of having an affected child.
A large challenge presented to both doctors and scientists is the lack of specific testing. Current tests prove differentiation between the flaviviruses to be difficult and therefore diagnosis relies heavily on which regions the patient has traveled and at what times. Specifically, Zika is rather troublesome to differentiate from a sister flavivirus, Dengue. Their antibodies (how the virus is detected in these tests) have 50% homology and many of the regions where these viruses are found overlap. This makes accurate diagnosis a challenge. While the viruses may be fairly similar, the treatments are different and specific to their respective virus. Developing highly specific testing would prove valuable for both patients and public health.
Furthermore, highly specific testing could be used for population screenings in susceptible countries. Now that we know Zika causes devastating birth defects and can be sexually transmitted, it is important to know who is infected, especially for those planning on starting a family. Population screenings would also be advantageous to keep track of the virus and its infection patterns for further research. Additionally, developing these tests to be as non-invasive as possible would be beneficial for encouraging or requiring those who have traveled to susceptible regions to get testing done to ensure they haven’t been infected.
Lastly, and perhaps the most effective research strategy, is figuring out how to modify the mosquito vector to prevent spreading. Preventing mosquitoes from being vectors is a hot research topic because mosquitoes are vectors for a large variety of deadly infections and diseases. It would be the most effective strategy for preventing another outbreak as without mosquitoes, humans cannot contract the infection.
Hopefully, by focusing on these research topics, scientists will be able to develop strategies and therapies to relieve the effect of the Zika virus and its catastrophic fetal repercussions. Ultimately, the goal of further research would be to successfully eliminate Zika from the world and use it as a model to eradicate other infectious viruses.
*One caveat to mention: another Zika outbreak is highly unlikely to occur during our lifetime. Once a person is infected with Zika, she creates antibodies to fend against subsequent infections and is therefore considered immune. She most likely will not be infected again. While not everyone was infected during the 2015 outbreak, most living in the highly susceptible regions where Aedes aegypti are common, have been infected and are now immune. Likely enough people are immune from this outbreak that it would be challenging for the virus to spread again. However, immunity does not carry from parent to child and the next generation to come will all be susceptible to the Zika virus. While this research might not directly benefit us, it will benefit our children.