It wasn’t until 1952 that the first humans (in Uganda and United Republic of Tanzania) were identified as being infected with the virus. Since these first outbreaks, the mosquito-borne virus has been identified in Asia, Africa, the Pacific and both North and South America (1).
Not everyone who has the disease exhibits symptoms. On February 10, 2016, USA Today reported that Centers for Disease Control and Prevention (CDC) Director Tom Frieden told the House Foreign Affairs Committee that “80% of people who contract the virus will have no symptoms at all” (2).
The World Health Organization (WHO) advises that the Aedes mosquitoes “usually bite during the morning and late afternoon/evening hours”. It was believed that the only way to contract Zika virus was through the bite of an infected Aedes mosquito. However, the first known case of the virus being sexually transmitted was reported in Texas in February 2016.
Those who succumb to the disease experience:
–> Joint pain
–> Mild fever
–> Skin rashes
According to the WHO, “There is no specific treatment or vaccine currently available.” The symptoms usually last between 2 to 7 days. It’s rare that anyone dies from the virus. What makes this a potentially doomsday virus is what scientists currently believe the virus does to a fetus.
Zika Dangerous to a Fetus
The WHO fact sheets state that with the 2013 French Polynesian and 2015 Brazilian outbreaks the government authorities “reported potential neurological and auto-immune complications of Zika virus disease” (3).
There has also been an increase in Guillain-Barré syndrome among recent Brazilian cases. An increase of microcephaly in newborn babies was reported in northeast Brazil. The WHO reports that various government investigations into abnormal births discovered a “link between Zika virus and microcephaly.” That link isn’t yet understood.
Microcephaly is an abnormal incomplete development of the brain and the infant’s head is equally small. Intrauterine transmission of the virus was reported on February 10, 2016 in a paper published in the New England Journal of Medicine (4).
The Zika virus (ZIKV) was described in the report as a “widespread epidemic” with cases being reported in South America, Central America and the Caribbean during 2015. The correlation between the virus and the apparent increase in cases of fetus microcephaly from mothers infected with ZIKV was discussed.
The report presented the case of a young UK woman living in Brazil who contracted a fever with a rash during the latter part of her first trimester. She returned to England and during a routine ultrasonography at 29 weeks of gestation, doctors discovered her fetus had “microcephaly with calcifications in the fetal brain and placenta”.
The prognosis for neonatal health was poor and the mother opted to terminate the pregnancy. The fetal autopsy revealed the severity of the infant’s brain development. In addition, “The complete genome of ZIKV was recovered from the fetal brain.”
To date, the known Zika cases in the US are not the result of direct transmission within the country, but are cases of people returning from one of the known regions common to Zika infection.
Zika May Be Sexually Transmitted
The possibility of the Zika virus being sexually transmitted isn’t a new consideration within the medical community. The CDC posted a dispatch in February 2015 that discusses a December 2013 semen testing of a Tahitian man infected with Zika and that the virus ZIKV was isolated from the semen sample. The report stated, “ZIKV transmission by sexual intercourse has been previously suspected” (5).
On February 5, 2016, the CDC posted that there is evidence pointing to the possible transmission of the Zika through sexual intercourse. The CDC describes three cases where the person contracting the virus had not traveled with their sex partner to the infected region, leaving the highly probable cause to have been through sexual intercourse. One of those cases currently under investigation was recently reported by Dallas County Health and Human Services in Texas (6).
Scientists don’t understand why the virus has suddenly emerged and spread so rapidly, but it is sweeping South America and the Caribbean. Brazil has the highest rate of Zika infection followed by Colombia. The Zika damage to the fetus occurs during the first trimester.
On February 11, 2016, the Daily Mail reported that the Deputy Health Minister Eduardo Espinoza of El Salvador urged women to avoid pregnancy until 2018 (7). The Colombian government is also advising women to delay their pregnancies between six to eight months.
The El Salvador warning comes after 96 pregnant women were recently diagnosed with Zika. In 2015, El Salvador had a total of 5,397 people diagnosed with Zika. However, none of the babies were born with microcephaly. What changed over the course of a year?
A zero birthrate for two years seems drastic to many, while a six to eight month delay is still a long time to anyone wishing to start a family. How would a zero population growth over a two-year period impact the economy of El Salvador?
International Health Emergency
In February 2016, WHO declared a Public Health Emergency of International Concern (PHEIC) for Zika associated microcephaly as well as other neurological disorders. So far, “more than 20 countries and territories in the Americas” are experiencing a Zika epidemic. Thousands of Zika cases have been reported in Cabo Verde, western Africa.
Perhaps the greatest concern the WHO voiced is the worldwide spread of the virus through international travel. With an expected 500,000 attendees to the 2016 Summer Olympics in Brazil, WHO has advised pregnant women to avoid traveling to the Olympics (8).
In spite of WHO’s concerns, organizers of the Rio de Janeiro Summer Olympics stated they won’t cancel. It isn’t even open for discussion. According NY Daily News, Sports Minister George Hilton said, “the WHO had not banned travel because of Zika.”
Officials hope that the South American winter weather that’s drier than their summers will keep the mosquito threat at bay. The games are scheduled to open on August 5.
What’s being Done to Combat Zika Virus
On February 8, 2016, Science Alert reported that an Indian company claims it have created two possible Zika vaccines and they are ready to start pre-clinical trials (9).
Bharat Biotech started research 18 months ago to create a combination vaccine that could be used to inoculate against Japanese encephalitis, Chikengunya and Zika. Due to the Zika outbreak, the company has stepped up their timetable to get pre-clinical trials underway.
One vaccine is recombinant, meaning it only contains DNA from the Zika virus, not the actual virus. The other vaccine is inactivated meaning it contains “whole particles of Zika virus” but these aren’t active. The inactivated vaccine is designed to stimulate an immune response. Other researchers are also working on possible Zika vaccines.
Another possible solution is right out of a science-fiction novel, genetically engineered sterile male mosquitoes. The company Oxitec (owned by Intrexon) created the sterile mosquitoes that subsequently mate with the infected female mosquitoes (10).
The company told CBS News that they’d conducted “multiple trials” in Piracicaba, Brazil with the result that they’d “cut the population of the disease-carrying Aedes aegypti mosquito by 90 percent within six months.”
The company plans to expand from the small trial area of 5,000 people to a location with 60,000 residents. In 2009, Oxitec started working with the Florida Keys Mosquito Control District (FKMCD) for a “non-pesticide method to control mosquitoes transmitting dengue fever.”
Environmentalists are fighting the FKMCD’s efforts for FDA approval with an online petition against the field trail. The timetable for possible approval is unknown. Should Zika become an epidemic (11) in the US that timetable might become defined.
Until a vaccine or sterile genetically engineered mosquitoes are turned loose, the best thing a pregnant woman can do is avoid traveling to known Zika infected areas. Those living in the areas are advised to cover up and use insect repellent.
References & Image Credits:
(2) USA Today
(7) Daily Mail
(8) NY Daily News
(9) Science Alert
(10) CBS News
(11) TSW: The H5N2 Bird Flu Is Midwest US on the Brink of an Epidemic
(12) Stripe on stripe via photopin (license)
(13) Zika Virus Photos