Revenge of the Aztecs- Part II
Lessons and challenges from the outbreak of Zika virus.
Although it was discovered 69 years ago in the Zika Forest of Uganda, even as a physician I had not previously known of the Zika virus. I first read about it a month ago in the daily two-page news brief on a cruise ship as it left the harbor of San Juan, Puerto Rico – one of the very places we were now warned by pubic health authorities to avoid! Additional concern was generated by the fact that our cruise itinerary included two other islands in the Caribbean where the disease was breaking out.
The Zika virus belongs to the flavivirus family which includes Yellow Fever, West Nile Virus, and Dengue – serious players. It did not help matters that I had lost a friend to hemorrhagic Dengue fever on the Caribbean island of St. Croix a few years earlier. Like its sister viruses, Zika appeared to be transmitted primarily by mosquitoes carrying blood from one bitten person to another – the usual mechanism of arthropod vector transmission.
Where did it come from?
Although the primary infection itself may be asymptomatic, Zika’s usual symptoms are relatively mild and include fever, headache, joint pains, and conjunctivitis (red-eye). The first well documented epidemic of Zika in humans occurred on the Pacific island of Yap in 2007, and then in French Polynesia in 2013. Impressive was the high proportion of individuals infected. On the French islands, a possible connection was made to an increased incidence of the reactive and probably auto-immune Guillain-Barré syndrome which can cause life-threatening paralysis by attacking the nervous system . In 2015, some traveler, perhaps attending a world cup soccer match, probably brought the virus to South America where it exploded to infect over a million individuals so far. Additional millions are expected to become ill as the epidemic runs its course. Public anxiety and my own was amplified by the fact that so little is known about the disease and its natural history.
Ebola this was not, but in Brazil, the rise in Zika infections was accompanied by a noteworthy increase in the incidence of the congenital deformity called microcephaly in which the head and brain of the baby are dramatically small, with corresponding profound cognitive and physical disabilities. Other viruses have been associated with microcephaly. Sporadic cases of unknown cause have always been with us. The condition can range in severity from relatively mild to very severe. I suspect that some with milder forms of this birth defect were in the past displayed in circus sideshows and branded with the name “pin-head.” I do not know if anencephaly is part of the spectrum of this disorder, but microcephaly is one of the more severe neurologic birth defects in terms of its ability to profoundly disable a child. I am unaware if the functional severity of the disorder can be predicted prenatally.
Is our reporting any better?
What have we learned from earlier serious epidemics? The initial news reports over the first few weeks gave us the the usual mix of breathless drama and apparent compensatory reassurance that the sky may not actually be falling. I was reminded of the initial earnest but inaccurate reassurance offered at the time of the AIDS epidemic, that if you were not a sexually active gay man, that you were not at risk for acquiring AIDS. We quickly learned that transmission of the HIV virus was possible through heterosexual sexual contact, blood, or other biological material. A generation of young men with hemophilia acquired AIDS from their treatment with anti-clotting factors extracted from donated blood.
Not just mosquitos.
Ironically, within a month of these first American reports of the Zika outbreak, we have learned that transmission of Zika virus is also possible through direct person-to-person sexual contact, and that the virus can linger for as yet an undetermined time within the body. It is found in amniotic fluid. Men from the United States have contracted Zika infection in South America and brought it home to infect their sexual partners. It is always possible to over-reassure the public. Achieving a justifiable balance between realistic concern and reassurance can be a tricky job. The truth is, we currently know relatively little about the epidemiology, pathophysiology, or the long-term prognosis of Zika virus infection as it is appearing in the western hemisphere. I have confidence that our medical-scientific community will unravel the better part of these mysteries with the recognition that perfect knowledge will never be achieved. One scientific discovery inevitably poses additional questions to be answered. No one I have net in my career has claimed that science is inerrant.
There is no known treatment, and at least at present, no vaccine against Zika. The mosquito that transmits the disease from person-to-person is already well-established in the southern portions of the United States and I assume it is inevitable that outbreaks of locally-acquired Zika virus infection will occur in America just as Dengue and chikungunya have. How we deal with these threats will in my opinion define who we are as an American people.
Why has Zika spread so rapidly in South America?
One possible explanation for the apparent rapid spread of Zika is that the virus mutated in some way, facilitating its transmission by mosquitoes or becoming more severe in its human hosts. This is the reason we worry about influenza virus every year. A couple of million turkeys and chickens were slaughtered in America in past months to prevent a new strain of avian influenza from spreading. Bird flu and swine flu were bad enough, but the true plague of Spanish flu that emerged after the First World War killed millions worldwide. It is thought that mutations allowed the virus to become more virulent. Our peoples may have been softened up by the rigors of prolonged war. It has been hypothesized that some more distant mutation allowed the Zika virus to leap from monkeys to humans in the first place, so another transformative mutation would not be an anomally.
Been here before or not?
Was the disease really new in South America? Had the disease been overlooked there or elsewhere all this time, perhaps in a milder form? Probably not, because at least in its present form, it has a relatively distinctive clinical profile. Were the people of South America particularly vulnerable to a new arrival? So far, the leading hypothesis is that this is an old-world virus that recently found its way across the oceans to a land populated by millions of individuals who had not been previously exposed. Such individuals would lack the genetically-programmed immune system, fine-tuned over centuries, to fight it off. This example of Darwinian evolution in action is the standard explanation of how the Conquistadors of the European old-world delivered the coup de grâce to the Aztec civilization and other indigenous peoples of South America. In North America we conquerors did something of the kind to the original peoples. It is believed that Part-I of the current Revenge of the Aztecs was a reciprocal gift of syphilis from the New World back to the Old.
Does Zika really cause microcephaly?
It is the transmission of the virus across the placenta and the presumed resulting devastation upon the gestating fetus that is striking terror into women, their families, and public health authorities alike. Careful journalists and medical professionals continue to use use the word “suspected” or “unproven” to describe an association with microcephaly. Strictly speaking, this is correct, but this speaks to the rigor and built-in skepticism of the scientific process. Nonetheless, the causal connection appears likely enough that for the time being we are operating as though the connection is real. In a Pascalian framework of balancing harm against benefit, the adverse consequences of falsely rejecting causality far outweigh the risk of being temporarily incorrect. For this reason, pregnant women or women who might become pregnant are being advised by public health authorities not to travel to much of South America or the Caribbean. Men will be encouraged to use condoms there. Even the Pope, for whom I have some admiration, is advocating the use of condoms – but only for the prevention of disease of course. (Even a Pope can only cross his Cardinals so far!) It has not been lost on anyone that the 2016 Summer Olympic Games are scheduled to be held in Brazil. This is a high-stakes wager and some female athletes are already not placing their bet.
Why has microcephaly not been noticed before?
The recent epidemics of clinical Zika virus infection occurred in small Pacific islands with correspondingly small populations such that uncommon complications might not have been noticed. It is possible that a careful retrospective look at those outbreaks will clarify matters. On the other hand, after apparently having jumped the ocean to countries with millions of susceptible people and a reasonable health surveillance system, any increase in the frequency of microcephaly or Guillain-Barré could be immediately obvious. Troublesome to me are reports already of 9 pregnant North American women who contracted Zika infection from travel and who have had obstetric difficulties. Two had miscarriages, one delivered a child with severe microcephaly, and two chose to have abortions. This early anecdotal evidence is not reassuring. Houston, we may have a problem for which termination of pregnancy is medically justifiable!
If Zika were our only problem…
Zika virus is not the only illness running wild among us.
The same morning I learned about Zika- and from the same New York Times abstract – I read about an epidemic of tuberculosis flourishing in Marion, Alabama and spreading from there to adjacent communities. As I write this article, I am thinking about what such epidemics reveal about our healthcare system, or for that matter how Americans feel about themselves and their relationship to their neighbors. In Michael Moore’s latest movie, “Where to Invade Next,” he makes the case that compared to at least some other “advanced” societies, we in America have an underlying “us vs. them” posture suffusing our public life that causes us to reject our interdependence on each other.
Just a member of the herd.
Epidemiologists use the term “herd-immunity” to describe the phenomenon that when a critical threshold of a population becomes immune to an infectious illness, either because of natural exposure or vaccination, that epidemic outbreaks become rare. Some diseases like smallpox can be eliminated altogether! Expressed from another perspective, like herds of animals or schools of fish, we derive at least some protection from predators by acting in unison. It is argued that the increasing numbers of “free riders” who for one reason or another choose not to immunize themselves or their children are responsible for increasingly frequent epidemics of pertussis, measles, and other previously uncommon but dangerous infectious diseases. We are forgetting that little more than 100 years or so ago we could expect that as few as half our children would to live to adulthood.
I am only as healthy as the guy in the back of the bus.
It has been intrinsic to my philosophy of medical practice that none of us can be any healthier than our neighbor. The person coughing in the back of the airplane may be spewing tuberculosis bacilli into your air. It happens. The epidemic of HIV and hepatitis-C infection in nearby Scott County cannot help but funnel those viral diseases into our community and its schools where intra-venous and other drug abuse has already gained a resistant foothold. Kentucky leads the nation in new reported cases of Hepatitis-C.
No matter in whose image we were created, we are creatures of the earth and subject to the natural forces that shape it. Global changes in climate permit mosquitoes to breed happily in more northern environments, and for birds to fly over the pole from the Orient to carry dangerous strains of influenza virus to Minnesota, Wisconsin and the Ohio Valley to infect turkeys and chickens and maybe even us. We face very real threats to our survival as individuals and communities that will be difficult to deal with even under the best of conditions. I’ve heard it said by experts that it will take more than one generation to “fix” the epidemics of drug-associated viral disease in Scott County. Dealing with the non-medical determinants of health are as critical to dealing with infectious disease as they are for asthma. Rheumatic fever did not go away because of penicillin. Our apparent societal contentment with allowing large numbers of our neighbors to live outside of the healthcare system that serves the rest of us, is not in my mind a good omen for our future. I suggest that in a very real way, we as humans in this increasingly crowded and damaged world must recognize that our very survival both as individuals and as a society depends on recognizing that we are part of a global community.
Sadly, whether or not a developing fetus has microcephaly may not be detectable until the pregnancy is well along. Given the enormity of the disability, some women and their partners on both continents are making the difficult decision that termination of the pregnancy – abortion – is the best course of action for themselves and their fetus. They are making on behalf of their gestating child, the same kind of quality-of-life judgments that most of us believe are ethical and valid in our own end-of-life decisions, those of our parents, or in instances of fatal illness where the morbidity of treatment outweighs the opportunity of continued meaningful quality of life. We allow family members or other designated individuals to participate in quality of life decisions that can result in allowing nature to take its course. Who else other than the parents should be able make such a decision on behalf of their child, born or sill in the womb?
Today in South America, authorities of the Roman Catholic Church and governments which have traditionally followed that church’s dogma are prohibiting women, even those carrying a child with severe microcephaly, to terminate their pregnancy. These are the same authorities who would deny a woman access to abortion even in instances of rape, incest, or danger to the woman’s own health. They call it murder. Others call it mercy. My own thoughts about this are probably pretty evident. I recognize that others feel or have been taught to think differently. Until I hear equally strident demands to fund a healthcare and social-support system that will provide for all the needs of such disabled and their families – including indefinitely after parents themselves are gone – I have little sympathy for those who seek to impose their own religious beliefs on other people or on our healthcare system.
Our legislators in Kentucky are currently attempting to mandate an ultrasound evaluation of one type or another (?vaginal probe) for every woman who seeks an abortion. The intent, of course, is to shame a woman and her family into compliance with the beliefs of the legislators and a group of swing voters. Let’s hear from you who voted for this law! What will you allow when an ultrasound reveals, at it most assuredly will, that a given fetus has severe microcephaly or some other life-threating developmental abnormality? Aren’t you aware that one of the major reasons pregnant women currently get ultrasounds during their pregnancy is explicitly to look for such problems? Are you really that frightened that you will to be scored adversely by the Right-to-Life religious coalition and lose your job that you are willing to substitute your judgment or someone else’s for that of the parents of the child? (Of course you are.) Will you open your pocketbooks or increase taxes to ensure that all children, born or unborn, catastrophically ill or not, will not have to live in poverty? (You haven’t so far.)
I have no doubt that our coming experience with Zika virus will sharpen the religion-fueled deliberation over abortion, will reveal inevitable shortcomings in our healthcare and public health systems, and hopefully make us think about what it means to be what it means to be both a good neighbor and a good steward of our planet.
Peter Hasselbacher, MD
29 Feb 2016