Aspen Ideas Press Conference: Zika Virus
CDC Deputy Director Faces ‘Unprecedented’ Public Health Crisis
ASPEN – On Thursday, June 23, I attended an Aspen Ideas Festival Press conference regarding the imminent public health threat posed by the Zika virus and had the privilege of meeting Dr. Anne Schuchat, Principal Deputy Director of the CDC. In this post I will outline the history of the Zika virus, its nature, and the current situation. All quotations and statistics are from Dr. Schuchat, unless otherwise noted.
Zika Virus Background:
In 1947, the first case of Zika was identified in Ugandan monkeys. By 1952, the first human case of Zika was identified.
Symptoms of Zika include fever, rash, joint pain, and red eyes. Because these symptoms are similar to many other mild diseases, many Zika infections have been misidentified or not reported at all.
Zika is especially worrisome within pregnant women because it can cause a variety of birth defects, including most notably microcephaly, a condition where a baby’s brain growth is stinted. Depending on the severity of the microcephaly, individuals can encounter a range of medical problems including seizures, developmental delay, intellectual disability, problems with movement and balance, hearing loss, and vision problems. “There is no known cure or standard treatment for microcephaly.”
The virus can be transmitted through the Aedes species of mosquito or it can be spread through sexual contact from a man to another individual. The virus usually clears from the blood after a week or two; however, it remains in semen longer because of the biologically protected nature of the testes. Once infected, an individual is likely protected from future infections.
Zika Virus Current Situation
Since May of 2015 when the first confirmed Zika virus infection in Brazil was detected, individuals containing the virus have been found up through South America and on US soil. There have been 820 travel-associated US cases of Zika, five of these in Colorado. Of these 820, 265 have been pregnant women.
Active transmission of the virus – meaning the mosquitoes in an area are infected and can transfer the virus – has not appeared in the United States yet. However, territories including Puerto Rico have seen this active transmission. There have been 1,860 Zika cases, mostly mosquito acquired, in these territories – 216 of which have been during pregnancies. These rates will continue to increase, though. 1.1 percent of donated blood in the last week had evidence of the virus. If this rate is indicative of Puerto Rico’s larger population of 3.5 million, there could be upwards of 35,000 infections.
Why Zika Virus is Unprecedented
A mosquito born virus has never caused birth defects or pregnancy complications like this before. Moreover, as Dr. Schuchat points out, “We have never had a mosquito born virus that can also be spread sexually.” It’s “the most complicated response the CDC has ever had… a full court press.” More than 1,000 of the CDC’s 15,000 workers have been involved with the Zika response.
How to Contain the Spread of the Zika Virus
Aedes mosquitoes can be found in 30 states. Often called the “Cockroach of Mosquitoes,” they are hardy and don’t need much water. However, their flight range only has about a quarter mile radius.
Possible methods to limit this vector range from the basic to the more far-fetched, including: mosquito repellents, local mosquito control, mosquito traps, genetically modified mosquitoes, bacterial infected mosquitoes, and gene drive mosquitoes.
Zika Virus Sexual Contact
Two-thirds of pregnancies in Puerto Rico are unplanned; one-half of pregnancies in the United States are unplanned. In order to address the sexual transmission of this disease, contraceptives have to be available and used by the population.
A Look into the Future
The CDC has set up focused surveillance in California, Texas, Florida, Hawaii, Arizona and Louisiana, and Los Angeles County. They believe these areas with high levels of travel from South America will not only have the largest number of Zika infections, but will be the first places where Zika will be transmitted.
Zika Virus Vaccine
Efforts have been made to develop a vaccine for Zika. One pair of companies, Inovio Pharmaceuticals and GeneOne Life Science, will soon undergo their first human trial of their vaccine.
Zika Virus at the Olympics
Less than .25% of travel to Zika affected areas will be from Olympic travel. Therefore, the Olympics and the resulting diaspora of fans will not significantly affect the spread of Zika.
What We Still Don’t Know about the Zika Virus
The percentage of babies to incur birth defects from infected mothers is unknown. One study suggests up to 29 percent of Zika-infected pregnancies result in “a bad outcome,” while another study points to around one percent. Of these studies, evidence seems to indicate that the effect of Zika is most acute within the first and second trimester of pregnancy.
A Final Note
Almost all experts believe that Zika will eventually be transmitted in the United States; however, most predict it will be limited to “a handful of local cases” because of the prevalence air-conditioning, window screens, and relatively low population densities. In US territories, though, poverty and population density is making this epidemic difficult to stop.
For more information, visit: https://www.cdc.gov/zika/