The MERS-CoV virus, closely related to the coronaviruses found in bats, has moved from the Middle East to other parts of the world. The WHO’s Director General calls it her greatest concern. It is a short walk between the parking lot at Mumbai Airport and the Arrivals lounge. Yesterday, at 2 am, it seemed like the thin edge of a Mass Extinction Event.
The whole wedge? Seven billion and counting, desperately short on food and water. Today’s extreme weather is Robert Frost’s clichéd prophecy: fire or ice, take your pick, the world’s going to end anyway.
The oceans aren’t exactly boiling yet, but very soon they’ll be offloading CO2 and hydrogen sulfide by the megaton. Beneath the raging Arabian, the continental shelf cracks up clathrates and blows off methane every time the floor shifts and sea levels change.
On my brief walk, I had a foretaste of these several scenarios of doom. A fair fraction of that 7 billion milled about the split-level parking lot, sheltering from the torrential rain. Nearby, a gutter had erupted in a flood of sewage that belched out pure methane.
That gutter was once a river. It was choked with concrete to build the airport 50 years ago. Over the last decade, rising sea levels have caused it to burst free every monsoon.
The extreme weather had also sent several millions racing to the urinal. The acrid reek of ammonia made every breath a punishment. Doom, at 2 am, was deafening. No, it was not the drone of multiple Pratt & Whitney engines. The city was hard at its favourite pastime—razing the past and building the future. In floodlit lots all around me, Caterpillars drilled right down to the craton, ignoring fault lines.
Despite the noise and the miasma, I had hope. The last stretch of my walk was trellised with Rangoon creeper. Its pretty red and pink flowers shed fragrant linalools into the night. With daylight, there would be enough photosynthesis for the planet to mainline on oxygen again.
As I waited beneath the buoyant peacock-feather canopy, I noticed, just beyond the restraining rail, a bonsai banyan tiptoed in a terracotta basin. It seemed perfectly at home within the constricted urban biome. It was biology, not art. It looked more like speciation than a human shot at wabi-sabi.
Speciation? Aren’t we already changing in ways we haven’t even begun to examine? Isn’t it dystopia right now? My favourite in wacko science is Peter Ward’s Medea hypothesis which blames earlier Mass Extinctions (the Big Five) on a microbial coup. As oceanic oxygen levels fall, anaerobic microbes take over and release a fug of hydrogen sulfide to snuff out life. While I’m not buying into the hypothesis, microbial coups are certainly being pulled off every which way.
Perhaps the takeover will be silent and insidious. We won’t notice it because words like extinction and pandemic have lost their edge. We have seen this scenario unfold so often in 3D at the Multiplex that life itself has become just another Game Boy. The desensitisation to disaster is so universal that perhaps the next contagion will silence us even as we’re leaning forward to refresh our Facebook page.
I’m at the airport to see if I can spot any evidence of our newest pandemic. Flights from the Middle East have landed, four of them. There’s nothing to suggest they have arrived from a new Ground Zero. The lounge rings with welcome as laughing families eye the loaded trolleys, and welcome home weary travellers.
If anyone of these people develops a pneumonia within ten days, it could turn out to be the newest bogie, MERS-CoV. As of June 2013, MERS-CoV has claimed 61 lives. The first case of Middle East Coronavirus Respiratory Syndrome was diagnosed in the summer of 2012 in Jeddah, Saudi Arabia. This novel coronavirus was isolated from a patient with pneumonia and renal failure. In September, the same virus was isolated in a patient in England who had recently spent time
in Saudi Arabia. Backtracking led to a cluster of similar cases in April 2012—this time in Jordan. Some of these patients died.
Most cases on record so far have originated in the Middle East, justifying the tag ‘Middle East Respiratory Syndrome caused by Coronavirus’—MERS-CoV for short. In recent cases, in April and May, from Al-Ahsa in Eastern Saudi Arabia, there is evidence of person-to-person transmission.
But how did the disease emerge? The jury is still out on that, but as the coronavirus is widespread in nature, it has been possible to find a close relative.
Genomically, MERS-CoV’s closest relations are a couple of coronaviruses found in two types of bats. That’s enough evidence to state that MERS-CoV is a zoonosis. It infects animal species other than our own. Bats, yes, but where does it travel to from the bat? Probably to an intermediary host X—and propinquity with this host X produces the human infection. As yet, host X has not been identified.
How, then, can we be certain these sporadic infections in different countries are a developing pandemic, and not sheer coincidence?
The detective work that’s needed to establish the chain of events is challenging—and not very different from the leap of faith that anecdotal observations demand.
Anecdotal observations also refresh information by zooming in on time and place. For example, an angry teenager once gave me a two-minute update on the urban reservoir of bubonic plague. I doubt if she had even heard of the disease.
She was grumbling about the frequent building projects around her home. So what had upset her? Was it the noise? The dug-up road? “The moment those demolition guys arrive, rats take off and head right over as if we’re their only refuge. Eeek! One dived right in through my bedroom window last night.”
An epidemiologist would know exactly what she meant. The rat is the reservoir for the plague bacillus. Disturbances in habitat upset the delicate balance of co-existence between host and microbe. As the rat explores new housing, the bacillus too is faced with the necessity to adapt. And when a microbe does this, it spells trouble. It comes out of sanyas, flexes its muscles, and bops the host with a virulent attack of illness. A sick rat full of fleas is the starting point for a pandemic. Even as I write, the plague bacillus is leading a quiet life in reservoirs all over the planet, waiting for the opportune moment to bare its teeth.
Like this teenager, people notice local events that trigger illnesses—even if they don’t always make the connect. During the Bombay Plague of 1896, while researchers were still two years away from cracking the rat-flea-plague nexus, locals had already connected the dots between ‘rat-fall’ and the new killer fever.
When a mysterious new illness strikes, it’s important to ask the people at Ground Zero what caused it. The untrained eye can see so much more than the tutored one.
What is the story on MERS-CoV? How did the first patient fall sick? What sign-post marked the onset of his illness? Nobody seems to know. To the two people intimately concerned with disease—the patient and the physician—the data on tap is woefully sketchy.
Any of those passengers who left the airport last night might report to me next week with a respiratory illness. How will I know it is not MERS-CoV? I will be informed by what I find, and try to match that against what I know. The facts on MERS-CoV are still too few and too general. There are many pulmonary illnesses that cause respiratory failure, and any rapidly progressive disease that causes a system to fail carries a high mortality rate. I need to know more before I can yell ‘pandemic’.
When a disease emerges, its pattern of emergence can be worked out with hindsight. Where did it come from? It led a peaceful life in a reservoir host till this co-existence was threatened by a drastic change. This change could be environmental or a direct threat to the host. It could be natural or induced by human activity. The Nipah virus emerged in Malaysia, in 1997, when intensive pig-duck farming was introduced in the natural habitat of fruit-bats. The fruit-bat is the natural reservoir of the virus, and when the bats fed around the pig sty, the virus accomplished the species leap.
Changes in land-use force uneasy propinquities. The new neighbor will become the new host. Very likely it is a new species—unused to the microbe and therefore more susceptible to illness. Microbes, and in particular, viruses, are constantly evolving and acquiring newer traits of virulence. When this newly infected host is human, a new disease has emerged.
Why was this first patient infected? Was he in close contact with the animal host? Was there a vector that carried the infection between them?
When a new zoonosis emerges, at first the numbers infected are few, while the spread occurs between the animal host and the human. As the microbe gains in virulence, the chain of transmission becomes shorter, and the disease is transmitted between humans. This isn’t always sustainable, and the outbreak maybe limited to a few clusters of cases. This is where speed steps in.
Before air travel shrank our planet, journeys took time. It could take weeks for an infected host to reach his destination. During this time his illness could subside, or else, kill him. The chances that he would be infective when he reached his destination were much smaller then. Today, one can zip across the globe in a day.
Most human diseases aren’t exclusively human because pathogens are fairly eclectic in their reach. Our bugs slum about a lot. 80 per cent of viruses, 50 per cent of bacteria, 40 per cent of fungi, 70 per cent of protozoa and 95 per cent of parasites have had careers in various other species before infecting us. So what kind of animals have they colonised?
Livestock would be the first guess. Domestication means intimate contact. The natural barriers inherent to traditional farming disappear when urbanisation and commercial exploitation take over, and a historically safe co-existence becomes a potentially dangerous one.
Does this mean that these reservoir hosts should be constantly monitored? Will that help us anticipate, and perhaps, prevent a new disease from emerging?
Think of the size of such a project—5,000 species of mammals and 10,000 species of birds under scrutiny. Even if it were cost effective, such a plan would be scientifically jejune. The known population of pathogens runs into a few thousands, not even considering the undiscovered, the unexperienced and the unknown. Paranoia on such a grand scale is impractical even for a wealthy nation—so what about us?
This doesn’t really help me when my next patient walks in. I cannot afford to let the pursuit of the extra-ordinary distract me from the ordinary. What I need to do instead is to re-examine the ordinary and the everyday with an improved understanding of the origins of disease.
Every morning as I leave home, I drive past a fish stall next to a garbage dump. In trees overhead, alabaster white against dark foliage, egrets wait to swoop down on the chance tidbit. The Municipality will not back me on this, but what I see is a ticking bomb, zoonoses waiting to explode.
There are potential pandemics all around us, but it’s plain good sense, and not exoticised science, that’s going to prevent them. All we can manage is the here and now and the everyday. Isn’t that a sensible place to start? Policymakers are very slow to implement the scientific discoveries they fund and endorse. Hasn’t the political brouhaha in Haiti shown us that?
The prevention of pandemics shouldn’t be left to bureaucrats.
What is the story of MERS-CoV? What happened in the oases of Al-Ahsa? Its date palms are celebrated in song and legend.
What species of bat nest in these palms? Bats are the largest reservoir of coronaviruses. Are the bats of Al-Ahsa sick?
We should explore the origins of the illness and not leave its control to panicked airport authorities. There was no pretense at surveillance last night as relieved travellers happily reunited with their families. They had come in from MERS-CoV hotspots. Was the virus lurking among them?
In the coming months, the strategy should change. Ramadan is two weeks away, and the Hajj follows. Three million people from every corner of the world will congregate at Mecca.
That confluence should not become a failed lesson in epidemiology.
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