The Aedes aegypti mosquito in action.
In May 2015 the Pan American Health Organization issued an alert regarding the first confirmed Zika virus infection in Brazil. In less than a year, the World Health Organization declared the Zika virus a public health emergency of international concern.
Although the first human cases of Zika virus were detected in 1947, the outbreaks were limited to tropical Africa, Southeast Asia, and the Pacific Islands. Currently there is renewed concern about this disease due to its recent association with birth defects, with reports of Zika transmission through sexual activity, as well as with the spread of Zika virus to the US. In addition, the potential for this disease to be transmitted through blood and semen has resulted in the FDA’s recent guidance to the Blood and tissue banking industry.
In this post we present an overview of what we know and the recommendations that have been made by the FDA.
What is Zika?
Zika is a virus that is transmitted to humans by a mosquito (Aedes Aegypti/Aedes Albopictus). The time between exposure to the Zika virus and infection is not known but is thought to be a few days to a week or so. Most people that have the disease don’t have symptoms. In those that do, the most common symptoms of the Zika virus infection are fever, joint pain, rash, headache, and conjunctivitis. Less frequently observed symptoms include digestive problems, abdominal pain, diarrhea and constipation, mucous membrane ulcerations, and itchiness. Some cases of Guillain-Barré Syndrome (ascending paralysis) have been associated with Zika virus.
It is important to emphasize that 80% of the patients infected with Zika are asymptomatic (without symptoms) and may not be aware that they carry the disease. Once a person has been infected, he or she is likely to be protected from future infections.
Babies born from mothers infected with Zika virus appear to have a risk of being born with smaller sized heads (Microcephaly).
The following is a list of the reported means of transmission:
- Mosquito bites – The risks of being infected by a mosquito bite includes traveling to areas where the virus is known to exist. Please refer to the CDC website for a complete list of these countries. http://www.cdc.gov/zika/geo/index.html
- Sexual transmission – There have been reported cases where the virus has been sexually transmitted by an infected partner (by a man to his sex partners).
- Transfusion-transmission – There are possible cases that have been described in Brazil. These reports are currently being investigated.
- Mother to child – Infected pregnant women can pass on the virus to their fetus during the pregnancy and during delivery to their newborn.
Zika virus has been found in semen at least 2 weeks and possibly up to 10 weeks after the illness onset. The virus is present in semen longer than in blood, but the persistence of Zika in the semen remains unknown.
There is therefore a risk for transmission of Zika Virus by HCT/Ps (Humans Cells, Tissues, and Cellular and Tissue-Based Products), which include, among others, corneas, bone, skin, heart valves, hematopoietic stem/progenitor cells (HPCs) from cord blood and peripheral blood, and reproductive tissues such as semen and oocytes. However, this is presently based on limited information.
What are the FDA recommendations for Sperm and Blood donors including mothers who donate their umbilical cord blood to public banks?
FDA’s guidance suggest that donors should be considered ineligible if they have any of the following risk factors:
- Medical Diagnosis of Zika virus infection in the past 6 months.
- Residence in, or travel to, an area with active Zika virus transmission within the past 6 months.
- Sex within the past 6 months with a male who is known to have either the risk factors listed in the items 1 or 2 above.
Additionally, donors of umbilical cord blood, placenta, or other gestational tissues should be considered ineligible if the birth mother who seeks to donate gestational tissues has any of the following risk factors:
- Medical diagnosis of Zika infection at any point during that pregnancy.
- Residence in, or travel to, an area with active Zika transmission at any point during that pregnancy.
- Sex at any point during that pregnancy with a male who is known to have either of the risk factors listed in items 1 or 2, above.
What should I do if I think I have symptoms of Zika Virus?
Contact your healthcare provider if you develop the symptoms described above and have visited an area where Zika is found. If you have recently traveled, tell your healthcare provider when and where you traveled.
Can I be tested for the Zika virus?
Your healthcare provider my order a blood tests to look for Zika virus infection.
FDA has issued an Emergency Use Authorization (EUA) for a diagnostic tool for Zika virus that will be distributed to qualified laboratories and, in the United States, those that are certified to perform high-complexity tests.