As a neurologist I take keen interest in the Zika virus. Zika is a superspecialist that attacks the nervous system. We had good evidence by the time an article in the New England Journal of Medicine that showed serious abnormalities in 29% of Zika positive women tested by ultrasound. The World Health Organization has declared Zika an international health emergency. The fear is that Zika takes to neurons of developing babies causing microcephaly, developmental delay and death.  When pregnant women are infected symptoms range from nothing to a low grade temperature and  rash that spreads from head to toe. Presently Zika is epidemic in certain warm places in South and Latin America.  Zika travels in Aedes aegypti mosquitoes and infects human hosts. That it spread to humans from certain monkeys has not yet been proved. The virus is composed of RNA and a protein coat about the simplest and most primitive of life forms, if you call them that, that reproduce. Zika is a small stealthy minimalist.

Zika virus teaches many lessons. As a traveler your first task is figuring what to pack.You can take a lot of baggage, have all your stuff and might be pretty self-sufficient. Packing light is a better strategy, but you will be more dependent on your hosts for laundry, food and other needs. Viruses pack light, carrying only instructions for their own reproduction and machinery to take over host cells. They are parasites, so aren’t paying for lodging and reproduction services. Zika and other viruses have evolved into little information packets. Seen under powerful microscopes they are pretty little 20 sided icosahedrons (illustration), Platonic solids with equal triangular sides that fit into a sphere. Ancient philosophers were enthralled with such structures but Zika and other viruses come by their envelopes naturally, as information containers.

Viruses survive inside the mosquito and use the insect as a vector or airplane to get from host to host. Then they attach to specific cells recognizing proteins on their cell membrane. Zika takes nervous tissue as you prefer beef.or fish. It doesn’t eat the cell. It’s genetic information takes the cell over. Zika will either interfere with the reproduction of developing neurons or it can also cause Guillain-Barré syndrome a feared disease of peripheral nerves that leads to weakness and numbness and can leave victims on a mechanical ventilator.

Now that is interesting. Doctors always considered Guillain-Barré an autoimmune disease in which a person’s immune system attacks parts of their own body. But this particular disease runs a simple monophasic course in which a person soon gets worse and then they get better, so it behaves like an infection such as the common cold.  There have been other viruses associated with Guillain-Barré and many practitioners, myself included, have long suspected it is really an infection. This leads me to mention the suspicion that many other so-called autoimmune conditions like multiple sclerosis are actually chronic infections, not immune diseases. It makes a great deal of difference in developing strategies for treatment. Zika’s relation to Guillain Barre is instructive in this regard. A close cousin, the West Nile virus attacks the adult nervous system causing encephalitis and motor neuron disease. Both are Flaviviruses, one happy family. Since we know more about West Nile which also mostly causes mild symptoms, it can serve as a model in many ways for combating Zika. There are unrelated viruses specialized to attack nerve tissue. The Herpes family of viruses are much larger but are alive in the nerve cells in you and me. Don’t get me started on Herpes viruses!

Humans have been dealing with viral epidemics for a long while. But only recently have doctors studied viruses scientifically.Good people have painstakingly followed the life cycles of viruses and other parasites to find their vulnerabilities. The biography of the great naturalist Alexander von Humboldt,  “The Invention of Nature” by Andrea Wulf has an account Humboldt’s capsizing boat in the Amazon. All of his books and notes are about to be lost to posterity. Humboldt and company panic, fearing they’ll be eaten by crocodiles. Meanwhile his unflappable friend is calmly baling out the boat and finally gets everyone to calm down do the same. Calm circumspection saves the day. That’s just what we need to do. There are tons of rumors and conspiracy theories out there that provide a good source of entertainment. Let the most rational among us solve important problems and above all vote to fund them. Our CDC is a national and world resource.

For Zika it appears the best means of control will be finding a way to eradicate mosquitoes just the same as Teddy Roosevelt and William Gorgas did for yellow fever, by the way also a cousin flavivirus, to build the Panama Canal. That is another great story. The Aedes mosquito may be controlled with insecticides, but reproduces in plastic containers thimble sized pockets of water and even soda bottle tops used in poor neighborhoods. It seems likely that the range of the Aedes mosquito has increased with global warming and human travelers will carry the virus far and wide due to our obsession with travel. Any woman who is pregnant or likely to become pregnant needs to avoid endemic areas for the time being until a vaccine is in widespread use.The range of the virus encompasses large swaths of Africa, India and Asia and though the microcephalic cases were first seen in the Western hemisphere at the eastern tip of Brazil in close proximity the the Caribbean.  At least 15 or so groups are racing to develop a vaccine. A vaccine will take at least 18 months to go into clinical trials. Obviously you can’t just go and give a vaccine to pregnant ladies, particularly if it is a live vaccine. For the while any young women would do well to carefully plan pregnancies follow and stay away from latest known endemic areas. Any pregnant woman who has visited these places needs blood work and to be followed with ultrasound.