Newspapers across India are covered with reports about cases of malaria, dengue, chikungunya or viral fevers of unknown origin increasing rapidly to alarming proportions, and yet one of the biggest stake-holders to this issue i.e. architects and urban planners appear completely unaware of their role in this extremely dangerous and yet interesting natural drama that seem to be heading for a climax now. It is important that those connected with habitat-building start understanding the forces of nature that work on the human-animal and take them in consideration while designing before it is too late.
The role of malaria parasite is one of the least understood and yet one of the most important one in the lives of those living in tropics. It has been, and still remains, The biggest killer of humanity, inflicting disease and death across tropical countries like India even after arrival of modern medicines and focused state-efforts to mitigate it. The seriousness of the economic burden of malaria can be understood from the fact that, in India, even the most conservative number of malaria cases per year is nearly 10 million. It would not be very far from truth to say that nearly all human beings living in tropical parts of India have to suffer this dreaded malaise at least once during lifetime.
Malaria parasite is not the only culprit in causing so much misery to humanity, as it gets the most able support of another (even more crucial for habitat designers) creature that has assisted parasite’s cause by carrying it from door-step to door-step across human dwellings in our cities and towns.
If we look for natural forces in recent times that have shaped human bodies, amongst all living beings, mosquito will take the crown hands down. It has been one of the most faithful companions of humanity since the development of agricultural societies that required proximity of water. It is strange that, while we were quick to notice the correlation between formation of cities and rivers, we have still not noticed the other common factor i.e. mosquito as our co-inhabitant in this link.
Mosquitoes were quick to capitalize on human need and preference for water and have evolved to live alongside us very efficiently. We have fought them since ages, but these able arthropods have managed to survive and thrive in human territory, acting as flying hypodermic needles that not only suck human blood but transport and transfer some of the deadliest parasites known to humanity across populations.
The number of diseases carried by mosquitoes is huge, ranging from the killer malaria to dreaded yellow fever. The types of parasitic creatures that ride piggy-back on these vectors range from worm that causes elephantiasis to complex protozoa like plasmodium that causes many variants of malaria and a plethora of viruses that cause a range of very painful ailments to their human host.
The reason why all these parasites love mosquito is its ability to carry them right inside human blood-stream, from where they can move across human body and thrive. As this relationship benefits parasites enormously, it appears that, at some point in the evolutionary history they may have been instrumental in ensuring that human (mammalian, in some species) blood becomes a mandatory need for a mosquito female for successful fertilization of her eggs, making it necessary for mosquito to seek human company. As evolution has now tangled fate of mosquitoes with that of humans, this relationship too has evolved to considerable complexity and a certain amount of stability over time.
At this point, it is important to look at the way evolutionary relationships developed, especially in host-parasite tableau. Though a parasite benefits from being very efficient in parasitism, it is prevented from overwhelming the host population; as, sans hosts, the parasite will self-destruct. This means that all such relationships reach a state of balance over time under natural circumstances. It is this “natural circumstances” and “stability” that needs our attention in understanding the issue that requires serious consideration of habitat designers.
Mosquitoes have lived alongside us and used us to their gain (and that of the parasites that ride on them), but this relationship has remained comparatively stable. Time and again, imbalance is caused by factors like suitable weather conditions leading to plague-like mosquito menace (such as that is considered to be one of the main causes of decline of ancient Rome and Greece) or arrival of DDT that caused huge decline in arthropod numbers (that led to a false sense of victory against malaria across Asia), but very soon the stability is restored by either side recovering from the losses. But, in nature, it is never wise to take such stability for granted; as, even if it is achieved, wages of such a war are never easy to bear.
To understand why we require careful consideration of this issue at this point in human history, we must understand the mosquito life cycle and the way in which natural stability has been established in history and how we are threatening it in a very dangerous way.
Mosquito life-cycle has become a well-know bit of information due to educating efforts made by the State to mitigate them, but there are finer aspects of it that are often missed. Mosquito needs water to lay its eggs, so mosquito presence is linked not only with presence of water, but also with post-monsoon period when such water is found to be in abundance under natural circumstances.
In tropical country like India, number of vector-borne diseases increases seasonally in this post-monsoon period and declines as summer arrives. It is not hard to decipher that this cyclic nature is linked with availability of free-standing water suitable for laying eggs. Considering the fact that mosquito has small life-span, its population requires constant replenishment from breeding. If breeding becomes difficult, mosquito numbers decline and humanity becomes free from its menace to recover.
So, the entire human-mosquito relationship has evolved and stabilized based on this cycle that prevents mosquitoes from overwhelming human population by constantly spreading diseases.
The natural mechanism that causes this much needed decline in mosquito population is evaporation of open water-bodies during summer months. In an un-built natural habitat, summer brings near vanishing of water suitable for mosquitoes to breed and reduces their numbers so drastically that only a very small seed population is available at the end of the summer to exploit arrival of rain water and breed again.
This natural phenomenon is most crucial in ensuring that mosquito population rarely reaches astronomical numbers capable of causing huge and epidemic spread of vector-borne diseases.
As mosquitoes can be found across varied climates, there are many interesting examples that provide us some clues about their hidden capabilities that are reigned-in naturally by seasonal cycles in tropics. Mosquitoes that live in arctic are cursed with a really small window of free-standing water in a very short arctic summer when the ice thaws to form pools. Even this fortnight long window is so well capitalized by these efficient killers that they breed in astronomical numbers and are assumed to be the cause of reindeer movement/migration. There are recorded instances of a cloud of mosquitoes descending on a standing reindeer that is observed to collapse due to loss of blood under their attack.
After establishing the dangerous capabilities of this human enemy number one, let us return to the Indian context. We are a country with a well-recognized vector problem, but strangely it has remained limited to medical professionals and entomologists. Medicine is trying to find vaccines or drugs to deal with diseases caused by mosquitoes-borne parasites and entomologists are trying to find way of controlling this insect using pesticides or genetic strategies. But, everyone seems to have failed in noticing that, while efforts are made to make it inconvenient for this dreaded vector by other professionals, architects and urban planner are making it more and more convenient for the mosquito to thrive around us.
If we look at the modern urban habitat that is rapidly coming around us, we see no consideration for the fact that living in close proximity free-standing or open water is actually more disastrous for a human being than living in a tiger-infested jungle.
Before we move forward, we better understand a very strange fact that is nearly counter-intuitive for humans and thus architects. Human fascination for water is actually nothing more than out-of-sync instinct that we have inherited from our past when it was important for survival to live alongside water. Water was so important for staying alive that it was biologically viable to pay the enormous cost of vector-borne diseases that came with it.
If we look at contemporary situation, it has escaped everyone’s notice that it is entirely possible for human habitats to move far away from open and standing water-bodies that harbor the dreaded killer. We actually don’t need water around us to survive, as we did hundred years ago. Driven by an outdated instinct that still retains capability of evoking strong emotional response, we continue bringing water close to us under the name of environmental upliftment or visual beauty. We build water-bodies of all kinds just for “improving” urban landscape without giving any consideration to a biological and natural force that actually has capacity of causing tremendous damage.
Most unfortunately for India, there is an added dimension to this issue that makes things really dangerous. As mentioned above, mosquitoes prosper in proximity of open waters, and yet we see large number of European cities enjoying presence of scenic lakes, riverfronts or canal networks within their built environment. And it is no surprise that these highly enjoyable urban elements have caught eyes of Indian architects and urban designers who have trained or travelled abroad making them wish to bring these features to Indian cities. Unfortunately, for the well-wishing urban designers and architects, a spanner is thrown in the machinery by our local conditions.
Why Europe can enjoy living alongside water and why we can’t is decided by a biological limitation of an insignificant looking insect. Mosquitoes need to lay eggs in comparatively warm waters. Their eggs are sensitive to cold and will not survive the natural winter cold that Europe has. So regardless of being present even in Europe, mosquitoes have rarely been able to become overwhelming. But, in India, our natural warm climate ensures “breed-ability” of mosquitoes around the year, provided they have access to free standing waters. If we ape Europe (as we seem to be) and rampantly build water-retaining structures in our cities, there is a distinct possibility that we are uncapping the natural mechanism that has traditionally mitigated mosquito populations in India.
This situation is capable of scaring the daylight of those who understand the exponential mathematics of nature. A round-the-year opportunity of breeding will mean that every year a larger and larger seed population will be available for mosquito to build upon allowing them to reach numbers that will be astronomical in true sense.
There is an even more dangerous dimension of this that epidemiologist will relate to. Such a huge number of parasite-carrying vectors will increase the number of interactions between humans and parasites, allowing them to evolve a lot faster. There is also a possibility of new parasites evolving or even jumping across species to use a new method of transmission or even bring new diseases.
As blood-drinking mosquitoes do carry many other parasites that are not transferred currently to humans, it will be benefiting for such parasites to evolve to take humans as a new host species. One of the very scary (and theoretically entirely possible) examples of this could be the HIV (AIDS virus). Carried by blood, it is not riding the mosquito like dengue or chikungunya as it is broken apart by mosquito’s immune system. But, those who understand rapid genetic changes viruses are capable of will tell you that it may just need a very small change in the structure of a protein or two for HIV or any such virus to ride these flying hypodermic needles.
One of the biggest fallacies that modern humans harbor is about being immune to natural forces that run the circle of life on Earth. We must understand that our survival on this planet is under constant threat if we do not consider the web of life that is built around us through eons of stabilizing processes. If we blindly trifle with it, it can easily get destabilized and, even if we find some technological solution over time, the process would cost dearly to all of us.
It is about time that architects and urban planners start considering the role of mosquito in Indian context and take it seriously. The shimmering city-lights of Zurich lake-front are lovely to look at, but we must consider that in our country it may cost human lives. The current apathy towards this issue is akin to building weapons of mass destruction in our own cities. There is a serious need of awareness to this issue. Presence of water is surely pleasing for all human being, making water-retaining structures very popular urban elements. But, as we now understand the forces of nature, we must reconsider building them, especially in hot-dry parts of India.
If we won’t address this issue, nature, being a very unforgiving lady, will not show any consideration for our carelessness.