160418-F-NL936-001 by Airman Magazine via Flickr CC BY NC 2.0
I had the pleasure of giving a Grand Rounds presentation to Sinai’s Department of Obstetrics and Gynecology yesterday on the Zika virus, focusing on what we’ve learned about it since it’s emergence in this hemisphere in 2016, things of importance that we haven’t figured out yet, and what lies ahead for Zika as a threat in 2018. A few particularly interesting points to me include:
- Zika was first characterized in Africa in 1947, and felt to not be that big of a deal; since then, it’s clear that Zika has mutated from it’s original African strain to subsequent Asian and American strains, the latter two of which appear to be more easily transmitted to humans and attain higher levels of virus in us
- the number of Zika cases has dramatically decreased in the Americas in 2017, likely as a result of acquired immunity to the circulating American strain, at the last area in the US of concern for local transmission in Brownsville, Texas, was declared Zika free in August 2017
- research has come up with some very solid theories about how Zika invades the placenta and the brain tissue of the fetus in a pregnant woman during infection, subverting the usual immune response and setting up continued reservoirs of infection in those tissues, leading in part to dreaded birth defects
- an association of Zika infection with an increase in the rare Guillain-Barre syndrome appears to be consistently true, although is still a rare event
- the CDC’s Zika testing algorithm (who to test, and how) is slightly confusing, but hinges both on how sick someone with suspect Zika is, where they’ve traveled to, and the timing
- travel counseling amounts to “if you are going to a place with known or recent Zika, be very careful about mosquitos and be sensible about sex especially if a pregnant woman or woman of reproductive age, since the virus can be sexually transmitted up to 2 months after infection in women and up to 6 months after infection in men”
- there are a number of promising vaccines in development but they aren’t out yet, and whether they see the light of day may depend on whether Zika dies out or returns
- there are a lot of unknowns at this point, but excellent questions include: will another Zika lineage arise and cause another massive wave of infections, or will it stay in the background at a very low level like West Nile? does being infected previously with another vector-borne virus like Dengue mean anything about how sick or not sick someone gets with Zika?
- the prime reason to remain concerned about Zika is the prevention of children from getting Congenital Zika Syndrome as a result of the infection, and the burden of care said children will require throughout their lives
At the end of the day, just don’t get bit by mosquitos, man.
