Note (12SEP2016): The politicians and bureaucrats quibble while the mosquitos nibble. Consequence? Nobody knows. As time passes, however, the potential for a truly unfavorable outcome increases.
Compared to some other infectious diseases, the importance of Zika seemingly pales. Last year, for example, there were 214,000,000 reported cases of malaria. Adding diarrheal diseases, HIV, pneumonia, and tuberculosis yields the startling figure of one in five deaths per year. Zika? Fewer than 500,000 reported cases with fewer than 60,000 confirmed although the numbers likely are much higher.
The official version of the current epidemic of viral infection from Zika is that it is a mild disorder characterized by fever, arthralgia, myalgia, conjunctivitis; and rash. As many as 80% of those infected suffer no clinical signs or symptoms. A question arises whether that official version is valid.
The virus itself is a mosquito-borne RNA-based flavivirus. It firstly was identified in a monkey in Uganda in 1947. For the next sixty years, only a few human cases were reported. Then, in 2007, an outbreak occurred in Micronesia on the island of Yap, where more than 70% of islanders older than age-three were exposed to the virus. In Autumn 2013, a large outbreak occurred in French Polynesia, where more than 30,000 were exposed to the virus. The genome of this more virulent virus in Micronesia and possibly others in Asia and now in the Americas very likely are different from that of their forbear, the relatively indolent virus in Africa.
How did Zika travel to the Americas? Most likely, via a traveller to Brazil from the South Pacific. During the past year or so, 47 countries have reported initial cases of Zika. One of the many wonders of modern travel!
Indeed, modern travel has become a boon to pathological agents and their vectors. Aedes, for example, remained confined to western Africa until the 15th-century, long before travel by jet-propelled aircraft. Also boons to pathological agents have been massive urbanization coupled with poor sanitation — trends likely to continue.
The vector for this arbovirus is the female Aedes mosquito, which does not thrive in colder climates. Two species, different in their respective ecologies and activities, carry the virus — A. aegypti and A. albopictus. Although controversial, the former is believed active diurnally, feeds outdoors, and travels distances. The latter is believed active at dawn and dusk, feeds indoors, and remains more homebound. Both, however, bite multiple times; thereby, facilitating multiple transmissions by a single female. Unlike other mosquitos harboring other flaviviruses that can thrive in cold climates, Aedes remains confined to warmer climates although its populations can vary with the seasons.
Despite the official version, infection might be more serious than currently broadcast. Officials acknowledge that, for pregnant women, contracting the virus appears linked to a peculiar form of microcephaly in the fetus; thereby, rendering the often-severely defective and deformed offspring requiring intensive and expensive care for the rest of their lives — care largely unavailable in much of the world. Moreover, even those without microcephaly may suffer blindness or deafness.
Those neurological defects result from the virus penetrating neuronal stem-cells in the brains of fetuses. These cells allow for neurogenesis. The question is, Do the viruses penetrate the neuronal stem-cells of adults? Recent evidence suggests that the answer may be yes. The consequence could be a slowly progressive form of neurological degeneration as old neurons die but are not replaced.
Adding to concern is the issue of transmission by means other than the mosquito. Evidence documents the virus in human semen; thereby, allowing for human-to-human transmission via sexual activity; let us not forget that we humans are the most hyper-sexual animals on Earth. “Let’s make love?”
Another recent finding of the virus in saliva and urine renders human-to-human transmission by those means also possible. “Kiss me, you fool?”
Three, different laboratory-based tests can detect Zika. The tests for Zika, however, are neither entirely definitive nor reliable. A case of triple infection with Zika, dengue, and chicungunya has been reported, for example; the latter two also are carried by Aedes and can compromise the testing for Zika.
That blood contains the virus raises concerns for those receiving transfusions. Given that testing remains problematic, hopefully testing blood for presence of the virus will be as effective in preventing use of contaminated blood as in reässuring the public.
No vaccine exists for prevention, nor is it likely one will exist during the next, few years. No specific medications exist for treatment, which remains supportive only. Recently, the government has issued statements promising hope for treatments in the near future. Fortunately, at this time the risk of fatality appears very low with hospitalization rarely required.
PART TWO OF TWO
Despite its seemingly benign character, Zika is a RNA-based virus. Such viruses can mutate rapidly even during a single infection in a single victim; becoming more mild or more virulent, as the case may be. Concern arises if the virus is mutating into a progressively more virulent form with possibly severe residua or sequelae.
Can we trust official reporting? Given the scenario with the recent epidemic of Ebola Hemorrhagic Fever, the answer for many is a resounding — no!
Accordingly, a question arises. Is the clinical picture murkier than that being reported by officials and the media? Possibly.
Consider a viral cousin to Zika; one spread by the same mosquito — Dengue Fever. The clinical presentation for Zika Fever is similar to that of Dengue Fever also common in the Caribbean and Latin America and returned to these United States of America after many years.
Consider the potential for clinical complications, neurological and auto-immunological. Fortunately, they remain infrequent.
Experts know much more about dengue than about Zika. The dengue-virus also is a flavivirus. It comes in three variants. Recovery from one variant provides no cross-resistance to the other two. Uncomplicated infection with dengue rarely is fatal although the symptoms are painful, resulting in the common label for the disorder being “Breaking Bones”. Reïnfection with a different strain, however, can cause Hemorrhagic Dengue — the auto-immunologic complication that carries a mortality of 50%, especially among the young. Should Zika mutate into acquiring similar characteristics, the consequences could be alarming.
There exists no approved vaccine for prevention of Dengue Fever although a vaccine now exists and might be converted into one for Zika. Then again, there is no vaccine for the common head-cold. No specific medications exist for treatment of Dengue Fever; treatment remaining supportive only.
One potential and disturbing sequel of both Dengue Fever and Zika Fever is Guillain-Barré Syndrome (GBS) — highly suggested but, as yet, unproven. What is GBS?
GBS is an auto-immunlogical disorder occasionally following viral infections and, rarely, vaccinations. Generally, the interval is from one to three weeks after the onset of the preceding, viral infection.
Typically, GBS presents with paresthesia followed by muscular weakness followed by paralysis. The signs and symptoms can spread from the extremities upwards to the head or from the head downwards to the extremities. The latter variant, especially, often is associated with respiratory distress. The loss of motoric function accompanied by pain can progress over two to three weeks followed by a period of stability for one to two weeks. Recovery usually requires several months to a year; in severe cases, it may be incomplete.
The pathology of GBS appears to involve the viral infection with its accompanying inflammation eliciting the production of antibodies that attack the myelin sheath of nerves; thereby, interfering with the conduction of electrical impulses from the Central Nervous System to muscles. The body attacks not only the virus but itself. Damage to the nerves is not continuous but segmental between the nodes of Ranvier; severe inflammation can destroy the nerve itself.
A potentially effective treatment for GBS is the use of high doses intravenously of immunoglobulin administered over a period of five days. Other immune-suppressing drugs may be useful. The use of corticosteroids remains more controversial.
The most severe cases of GBS require a high level of intensive and expensive nursing care over a prolonged period. Should the expected number of cases of Zika Fever actually occur and should a higher than expected number of them become associated with GBS, the consequence could overwhelm the American system of medical delivery. Whereas such an eventuality seems remote at the moment, it represents a potential risk of alarming dimensions.
“An ounce of prevention is worth a pound of cure.” -Benjamin Franklin (1706-1790)
The obvious, immediate response to the threat from Zika is control of its vector, mankind’s second-greatest enemy — the mosquito. Mankind’s greatest enemy? Time, at least for the individual.
Two questions arise. If current methods of controlling mosquitos prove inadequate, would we and should we resume the use of DDT? A promising alternative, currently delayed by the Food & Drug Administration, is the use of genetically-modified mosquitos to decrease the population of viable offspring. In fact, it may be possible to exterminate all mosquitos worldwide.
The basic point of this posting is to describe in some detail the potential devastation wreaked by viral and bacterial pandemics. Consider the recent threats posed by Ebola, HIV, SARS, and influenza. Many others lurk beyond our awareness. Controversial man-made, global warming notwithstanding, our proven, ecologically irresponsible behavior as a species is making Mother Nature angry — very angry.
To paraphrase an old commercial, “It’s not nice to make Mother Nature angry.”
If we humans do not reform our ways, she will punish us — guaranteed! The next epidemic may be less controllable and more virulent than recent ones. By then, reform will be too late.
Consider the scenario of Zika mutating; thereby, becoming strikingly more virulent with airborne transmission. The consequences could be horrific.
Hopefully, Zika will not represent a major hazard to public health. Even so, if not Zika, it will be another microbial agent. As a species, we are living on increasingly borrowed time, an inescapable consequence of our own behavior.
Science tells us, “In any given context, behaviors — and deficits of behavior — have their consequences .”
Shall we listen? Be past prologue, the answer is clear.
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