As everyone not living under a rock can attest, the Zika virus situation is rapidly unfolding and evolving. Last week I wrote up the most common questions I was receiving about this epidemic, along with my answers, for anyone curious. I am humbled by the number of times the piece was shared, and glad that it opened the door for additional questions from folks who are concerned. With an additional week of situational reporting and fact finding by those on the ground, it feels like an appropriate time to issue an update. Here are the latest questions and answers:
1.) You didn’t mention Guillain-Barre Syndrome, but I keep hearing that Zika causes it. What’s going on there?
G-BS is a neurological syndrome that can happen after certain infections occur. It causes numbness, weakness, and in severe cases paralysis. Most patients recover fully, though a small number are left with muscle weakness. Post-infectious G-BS cases appear to be linked to the body’s immune response against certain infectious agents; namely, these responses begin attacking the patient’s own neurons once the infectious agent is gone. I strongly considered bringing it up, but ultimately decided against it because the link between G-BS and Zika is not nearly as strong as the link between microcephaly and Zika. That said, enough patients have now been evaluated and reported that there does seem to be an association. How it works, why it happens, and how often it occurs is completely unknown. In other words, we cannot say that “5% of Zika patients will go on to develop G-BS”, because we simply do not know yet. The hopeful news here is that the patients who developed G-BS after Zika infection seem to recover fully after a few weeks. As with other post-infectious G-BS cases, those suffering from G-BS are not capable of transmitting Zika.
2.) Since this virus is so new, how do you KNOW it is only dangerous for certain people?
Zika is not new. It was first discovered in Uganda in 1947. It is newly emerging in the Western Hemisphere, which means it seems new simply because it is new to us. Frankly speaking, no one thought much about it historically because the clinical disease is so mild. The connection to complications is being realized now that Zika has appeared in a population that was large enough to see the effect, and that recorded things like microcephaly and G-BS, such as that of Brazil.
3.) What happened in Texas??
Reports of a Zika case in Dallas caused alarm earlier this week, because infection occurred in a woman who had not travelled to another part of the world and contracted the disease; she contracted it at home. As it turns out, she was infected by sexual transmission from a partner who had been infected while travelling. I actually touched on this in Questions 8 and 12, but as with any pathogen present in blood and body fluids, sexual transmission is possible. Zika had been detected in the semen of infected men, and transmission was strongly suspected in this publication following cases in French Polynesia. It now seems that we have confirmed the suspicion. All this means is that, in addition to travel restriction and mosquito precautions, persons who have travelled to areas experiencing Zika epidemics should employ barrier protection (i.e., condoms) during sexual contact for at least 4 weeks after retuning. As a friendly reminder, 80% of Zika-infected patients have no symptoms, so this precaution is important even to those who feel well.
4.) Now what is going on in Florida?
Yesterday, Florida governor Rick Scott declared a state of emergency related to Zika virus. It is important to note that this is not a state-wide decree; it applies only to the counties that have reported Zika cases. All cases in Florida are travel-associated. Why has Florida taken this step when other states have not? As a former Floridian myself (I used to work here), the answer is very clear: Florida is home to Aedes mosquitoes, and has the landscape and climate to support their widespread breeding. Other states are populated with them, but most lack either the permissive climate or the population density that Florida has. If local transmission associated with mosquitoes were to occur in the US, Florida would be the best bet. That said, Governor Scott’s state of emergency does something very important: it allocates funds to be directed to mosquito control. That is how the cycle is best interrupted. The state of emergency does not indicate that an emergency has happened; rather, it is employing a mechanism to prevent one.
5.) Why is the WHO saying one thing and the CDC saying another?
Many people have expressed frustration at “mixed messages” about Zika, and in some ways I think this leads people to question the advice that is being expressed. Here’s the thing…the World Health Organization (WHO) is an international agency, and speaks to an audience that includes countries in the midst of a ferocious epidemic. The Centers for Disease Control and Prevention (CDC) is a United States domestic agency, and speaks to an audience that is not. Why does the WHO recommend mosquito contact prevention while the CDC has recommended a full travel ban for pregnant/potentially pregnant women? Does that mean that no one is sure what is going on? No. It simply means that the WHO is speaking to the world, and the CDC is speaking to the United States. Look at it this way: if asked about the best source of drinking water, would you give the same answer to a resident of Poland Spring, Maine and Flint, Michigan? Probably not, because the possible options are not the same. The same idea applies here.
I hope this update was helpful-keep Zika in perspective!