Description: You have probably heard of the Zika virus. It is a virus transmitted by mosquitoes and by sexual intercourse and is led to travel advisories specifically aimed at pregnant women considering traveling to or living in areas of Central and South America where the virus has been active. Most of what you have likely heard in the way of precautions, especially now that the virus appears to have arrived in Florida, are aimed at pregnant women as the effects of the Zika virus on the developing fetal brain can be quite severe. Some researchers are now begun to look more closely into the possibility of effects of the Zika virus on the adult brain. The article linked below describes one study looking at the brains of adult mice exposed to the Zika virus and while the question of how these findings may or may not generalize to the human population remains open it raises some potentially serious concerns.
Source: Zika infection may affect adult brain cells: New findings suggest risk may not be limited to fetuses of pregnant women, Rockefeller University, Science News.
Date: August 18, 2016
Links: Article Link — https://www.sciencedaily.com/releases/2016/08/160818131134.htm
Most of what you’ve likely heard about the Zika virus, perhaps as part of the press coverage of concerns leading up to the Brazil Olympics of this past summer (2016), has probably been focused on the potential effects of exposure to visit the virus to the development of microcephaly in the fetus is carried by pregnant women. When the potential for effects on adults have been mentioned typically been described as minimal and usually dismissed as involving flu-like symptoms but with no other longer-term consequences. It is certainly true that the rapid proliferation and migration of cells and particularly brain cells in developing fetuses means that that early period of development is a particularly vulnerable one for exposure to a broad range of external teratogens. And while the plasticity of the infant brain means that it potentially recovers much more effectively from the rare strokes of infancy (as compared to strokes among elderly individuals) the Zika virus seems to have the potential to cause changes in the fetal brain that cannot be fixed or neural plasticity. Researchers at Rockefeller University of look more closely at certain areas and cell types in the brains of adult mice exposed to the Zika virus. What they found is that a particular type of cell called a progenitor cell (or stem cell) may be vulnerable to attack by the Zika virus. These cells are particularly concentrated in areas of the brain having to do with learning and memory and as a consequence the Zika virus effect could be of some concern. What is unclear, assuming these results are replicable in mice, is whether these results would generalize to the brains of adult humans. The researchers wisely suggest that medical science should be gathering follow-up data on all individuals exposed to the Zika virus rather than focusing exclusively on the offspring of women exposed during pregnancy.
Questions for Discussion:
- What are the most common concerns are effects of the Zika virus that have been reported upon in the media?
- Why might the brains of developing fetuses be at particular risk to impact by teratogens such as the Zika virus?
- What brain cells were shown to be affected by exposure to the Zika virus and adult mice in the study linked above? What research studies need to be done to expand upon these findings and to look into their potential impact on human beings? What public health changes might we consider in relation to these findings, if any?
References (Read Further):
Hayes, E. B. (2009). Zika virus outside Africa. Emerg Infect Dis, 15(9), 1347-50.
Hongda Li et al. Zika Virus Infects Neural Progenitors in the Adult Mouse Brain and Alters Proliferation. Cell Stem Cell, August 2016 DOI: 10.1016/j.stem.2016.08.005
MacFadden, Derek R, MD; Bogoch, Isaac I, MD. Canadian Medical Association. Journal188.5 (Mar 15, 2016): 367. http://search.proquest.com/openview/92abdb3da89db3bb8a711198db3ea39c/1.pdf?pq-origsite=gscholar&cbl=41339
Sharifi-Mood, B., Sharifi, R., & Barati, Z. (2016). Zika Virus Infection. International Journal of Infection, (In Press).