Human expansion and mosquito invasion

By Prof. Kirthi Tennakone
ktenna@yahoo.co.uk

Humans have dominated the earth, marginalising animals and dealing with them primarily for their advantage. Even the most gigantic mammals, such as elephants and whales are torturously tamed or murdered. Animals are sacrificed in rituals or held in captivity and abused for celebrations. From birth to death, poor creatures deprived of all their rights suffer in factory farms. Territories and habitats where animals lived in harmony with plants are destroyed or altered, hampering biodiversity.

In contrast to animals, humans devise machines and new materials to facilitate living and being curious explore things physically invisible and beyond earthly confinement. Proud of their brains and capabilities, they declare themselves the supreme living species on earth.

Nonetheless, tiny mosquitos with a rudimentary brain-like nervous apparatus just sufficient to sense smells, heat and light, invade the premises we live and exploit for food, shelter and breeding. They torture us in the same way we cruelly harm helpless animals. Lands we claim to be ours and our homes are fearlessly invaded. A good percentage of all humans who took a breath on this planet have died from mosquito – borne infections.

Mosquitoes, by the diseases they transmit, kill nearly a million people each year, even at present. The healthcare systems of tropical and subtropical countries are severely burdened by mosquito carried – diseases. Malaria continues to be a global problem, and nearly half of the world’s population, at risk of exposure. According to the WHO, there were an estimated 247 million cases and 619,000 deaths in 2022. Fortunately, malaria is a curable disease.

Aedes mosquitos (Aedes aegypti and Aedes albopictus) transmit dengue, yellow fever, zika, chikungunya and several other maladies. Unless immunity subsides the pathogen, they resist treatment by drugs.

Aedes mosquitos continue to colonise more and more lands because their breeding has been eased by global warming. Climate change, detrimental to humans is advantageous to mosquitos.

Evolved around 100 million years ago, Aedes mosquitos originally lived in forests and passed a dengue-like viral disease to primates. The disease seems to have jumped into humans thousands of years ago. Indian and Chinese medical literature reveal an illness identifiable as dengue that had sickened people as early as the 9th century. Human mobility dispersed dengue mosquito eggs and the virus worldwide, establishing the disease in localities favourable for mosquito breeding – densely populated urban and suburban localities.

A dengue epidemic was reported in Colombo in 1913 when the British Government summoned a physician from London to examine the situation. Since the early 1960s, sporadic dengue outbreaks have emerged in Sri Lanka, escalating in intensity and coinciding with monsoon seasons. Other nations in the region followed a similar pattern. Many countries in Southeast Asia and Latin America report dengue surges in the current year and an increase in incidence compared to the previous year. Aedes mosquitos, the dengue vector have spread all over except Antarctica, posing a global threat. An expert in the European Centre for Disease Prevention and Control says the area invaded by Aedes mosquitos has increased threefold in one decade!

How did mosquitoes succeed in gaining an upper hand over Homo sapiens? Aesop’s fable “The Lion and the Elephant” hints at a clue. One day, a sleeping lion was awakened by the singing of a bird perched on a tree. The lion talked to an elephant passing by and said: “Look at that small bird, its scream irritated my ears and awakened me.” We are the masters of this jungle, but these tots dominate. Can we do something to teach them a lesson? Elephant replied, never underestimate the capabilities of small animals, days ago, an even tinier animal, a wasp, chased and stung me, I was helpless until it moved away on its own.

Parallelly, a few years ago Dalai Lama reminded us of the African proverb, “If you think you are too small to make a difference, try sleeping in a closed room with a mosquito”

According to the judgement of nature governed by physical laws, the ability of a species to proliferate, compete, and survive in the environment determines its success in performance. In this aspect, mosquitos, especially the Aedes species, outperform humans. Mosquitos achieved success entirely via incremental improvements in the process of evolution and not by intelligence, as in the case of humans. Given sufficient time, the evolution by its method never misses an opportunity. Human expansion and human qualities were a fitting opportunity for mosquitos to thrive.

Humans and animals are multicellular organisms possessing neurosensory and locomotive organs. A glaring distinction between them is the profound influence of the attitudes of a small minority of individuals on the entire species in the case of the former and the uniformity or absence of uniqueness among the same kind in the latter. In many instances, benevolent as well as malevolent turns in human society can be attributed to initiation by an individual. Few religious teachers directed the world toward ethical values. The discoveries of great scientists paved the way for modern technology. Philosophers, writers and artistes inspired entire societies. Similarly, wars, conflicts, mass murders and embezzlement are often initiated by a handful with vested interests.

Mosquitos (particularly Aedes species) have successfully exploited human qualities to their advantage. Their society is neither a democracy by name nor a dictatorship or a proletariat. Individualism does not exist in mosquito society and without leaders, criminals and intellectuals they advanced purely on the basis of evolutionary forces. The laws of evolution withstand sinister manipulations pursued for personal benefit.

As mosquitos breed fast mutations emerge more frequently and those with altered characteristics are often needed to face a new situation. If insecticides are sprayed resistant strains emerge. When a dengue outbreak ceases in the dry season after the monsoon, people neglect to clean the premises. Surviving mosquitoes lay eggs on wet patches and potential sites of stagnation and dormant eggs hatch in the next rainy season.

Perhaps, we already possess the knowledge necessary to eradicate mosquitos or exterminate them selectively and also find vaccines and cures to prevent the diseases they carry. However, the concerted global effort needed is exceedingly difficult to achieve because human society, unlike mosquitos, is divided at all levels and malevolent individualism prevails. Societies, dysfunction when few corrupt hold onto power infringing democratic freedom. The pressing problems of the day undoubtedly have solutions, but the constricted bottleneck would be the absence of consensus. The resources wasted on wars and defence under the pretext of created insecurities and extravagancies would aptly suffice the purpose. Mosquitos are a warning and a lesson.