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How pandemics originate and evolve



By Prof.Kirthi Tennakone

National Institute of Fundamental Studies

History tells us pandemics have devastatingly interrupted civilizations. They killed millions of humans and brought forth misery and poverty, but never wiped out a civilisation. Epidemics and pandemics begin, escalate and wane or re-emerge. However, the causative agent rarely disappears; it opts for a less vicious coexistence. Smallpox is the only epidemically potent disease that has been eliminated absolutely – not via natural processes but by the intervention of human intelligence.

Life has been created by natural forces endowing an essence for it to reproduce and undergo change. We ourselves and the virus exist because of this, which also enables the virus to adapt itself to the environment, survive and expand causing the pandemic. In ancient times, humans had to await the consequences of the same natural forces to face a pandemic – those who remained fit and immune survived and reproduced.

Today, human intelligent intervention makes things more favourable to us than to the virus, and helps many who lack the natural immunity survive. The eventuality of the present pandemic will be determined by the effort we make to combat it.


How pandemics originate

Persian philosopher Ibn Sina was probably the first to conjecture that living entities in the human body caused diseases. Later, Louis Pasteur proved infections occurred when microscopic organisms entered the body and proliferated and those microbes could pass from one individual to another.

Microbes do not emerge spontaneously; nor do they arrive from the sky. They exist everywhere in the environment as creations of biological evolution. Humans, animals and plants harbour them. Microbes associated with a given species, often symbiotic, pose no danger to the host, whose immunity prevents their undue proliferation. They are selective; those present in one species would not easily move to a different type of host and get established. Nevertheless, the complexity of living things allow exceptions. Occasionally a pathogen or innocuous microbes concealed in animals or found in the environment can jump to a human causing diseases.

An illness acquired from an animal is referred to as a zoonotic disease or a zoonosis. Sometimes, the zoonosis turns out be contagious. Almost all calamitous epidemics and pandemics have arisen from accidental transfer of a bacteria or a virus from an animal species to humans and subsequent evolution- their origin is zoonotic. Ebola, Severe Acute Respiratory Syndrome, Middle East Respiratory Syndrome and COVID-19 are zoonotic diseases. The zoonotic infections such as plague, smallpox, measles and swine flu caused first magnitude pandemics in the past.


Ebola Virus Disease: near pandemic situation 2014-2016

A previously unknown sickness broke out near the Ebola River in Congo in 1976, killing almost 80% of persons who contracted it. The cause of the disease, subsequently named Ebola, was found to be a virus endemically associated with bats. Although the virus does no harm to the bats, when transferred to humans via contact during hunting, a fatal condition, similar to a flu occurs. The exposure to body fluids of the infected persons passes the disease to the community. The Ebola outbreak 2014-2016, spread across West Africa. Some cases were also reported in Europe and the United States.


Severe Acute Respiratory Syndrome (SARS) and Middle East Respiratory Syndrome (MERS): The older cousins of COVID-19

Coronaviruses with crown like spikes on the surface exist everywhere. Until early 2000s, they were not considered a threat to humans. In 2002, a new contagious respiratory disease, SARS, emerged in China and spread rapidly to several other countries. International corporation; coordinated by WHO quickly elucidated the nature of the condition. The cause of the disease was identified to be a virus harboured by some bats, transferred to humans by palm civets. Handling civet cat meat in wet markets is believed to have caused the transmission of the pathogen to humans. The epidemic was effectively controlled by isolation of infected persons, use of masks, protective equipment, physical distancing and thermal sensing of passengers in airports. In July 2003, WHO declared SARS had been contained.

Another respiratory viral disease MERS first reported in Saudi Arabia in 2012 crossed continents due to air travel. The second major MERS outbreak occurred in South Korea in 2015. Compared to SARS, MERS is more virulent but less contagious, and spreads through close contacts of infected persons. The origin of MERS virus is zoonotic, bats being the primary source and camels the intermediate which transferred the pathogen to humans. The virus may have undergone genetic change in camels facilitating its adaptation to humans.


How pandemics evolve

Pandemics and epidemics begin when an infectious agent enters a community possessing no immunity to resist. A tragic example is measles epidemic in Fiji. In 1875, an Australian delegation carried the virus to the island whose natives were never exposed to the measles – a disease quite common in Asia and Europe. In a matter of months 30 percent of the population died!

Zoonotic viruses are particularly dangerous because humans are not exposed to them at the beginning. The absence of immunity allowed an epidemic in one locality to expand as a pandemic. Furthermore, when a virus originally found in an animal, genetically and associatively distant from humans, is harboured in an intermediate host closer to humans, some genetic intermingling could occur via processes referred to as recombination and re-assortment. This way, the virus acquires a foreignness needed to evade the human immune response and a kinship favourable for adaptation. Domesticated animals sometimes carry viruses originally derived from humans but genetically modified. A virus found in a wild animal co-infecting a domesticated one can copy genetic information from the latter producing a new kind of virus, adaptable to humans and also withstand host immunity.

The origin of the virus causing COVID-19 named SARS-Cov-2 has been traced to a bat species. The genetic make-up of SARS-Cov-2 tally nearly 95 percent with a virus found in so-called horseshoe bats. It is not conclusive whether the virus passed directly from a bat to humans or through an intermediate host. There exists no evidence to support the conspiracy theories that the virus leaked from a laboratory. Finding out how the virus came into being would shed light on how to control it effectively.

Once a pathogen enters a population devoid of immunity, the number of infected people begins to expand exponentially at a rate proportional to the population density reaching a peak. Thereafter, because of the decrease of susceptible persons owing to acquisition of immunity and deaths, the disease wanes.

Mathematical models predict above behaviour and point to the important concept of the effective reproduction number of a progressing epidemic. Effective reproduction number (RE) is the average number of people who acquire the infection from one infected individual at a given time. The idea of reproduction number was first introduced by the British Physician Ronald Ross, who took up mathematics to find a way to eradicate malaria. Ross showed that in order to control an epidemic RE needed to be kept below one. His suggestions for doing this paved the way for the eradication of malaria epidemics in Sri Lanka. In the initial phases of the COVID-19 pandemic in Wuhan, China RE has been in the range 3-5. Control measures such as physical distancing, wearing masks and isolation reduce RE, but the issue is reducing the number further to reach values below one. The mode of evolution of the COVID-19 pandemic is complicated by human migration by imposition and withdrawal of preventive measures.

Transmissibility and virulence

The virus is not after vengeance to be noxiously virulent and kill as many as possible; evolution in that direction renders no advantage because if a large majority of infected persons die, the virus will be deprived of hosts to feed on and reproduce.

The probability that someone will catch the infection from an infected person depends on the rate and quantity of the pathogen transmitted. A severe infection produces larger progeny of viruses; this has some advantage to the virus. Generally, pathogens compromise between transmissibility and virulence giving a higher weightage to the former. The transmissibility of COVID-19 is high because the infected shred the virus before symptoms fully develop. Contrastingly, in case of SARS; the infected release the pathogen at later stages when symptoms are readily identifiable enabling isolation; this is the main reason why SARS was contained and the COVID-19 transmission continues.

The virus aggressively attacking elderly and sparing younger could also be an advantage to the virus. Severely sick elderly patients release larger quantities of virus, infecting the younger who take care of them. The younger move about and infect others. The virus wants to procreate and exploits everything possible for that purpose!

Variations of the virus

Zoonotic viruses undergo major genetic changes via recombination or re-assortment and adapt to human system. Mutations enable them to fine-tune the traits favourable for adaptation by small genetic adjustments. When viruses replicate, their genetic code is sometimes copied erroneously, resulting in random variations. The process is analogous to typographical errors you make when you retype your essay. Even if you retype thousand times, you would not expect to find an improved version of the essay as result of random typographical errors. However, when a virus replicate trillions of times; a more adaptable one may originate and replicate endlessly – these are new strains of the virus. Recently, more contagious strains have been found to proliferate in the UK, Brazil and South Africa. The British Prime Minister announced that the variant identified in his country seemed to be more virulent.

Convergent evolution of strains

The three strains of the virus (United Kingdom, Brazil and South Africa) seemed to have evolved independently. Yet, all the three variants have undergone similar changes in the spike protein, enabling the virus to attach to host cells more strongly; this is essential for efficient spreading. The qualities acquired indicate that mutations have got selected for the definite purpose of convergence to the same cause – to spread the disease fast.

Convergent evolution is quite common in nature. A prototypical example is the near identical streamlined body shapes of the shark and the dolphin. Shark is classified as a primitive fish, whereas the dolphin has been an evolutionarily modern four-legged mammal that lived on land adapted to the ocean. Both shark and dolphin independently evolved towards the optimum hydrodynamic body features to be able to swim fast.

Future of the Present Pandemic and Future Pandemics

It is too early to determine the degree of effectiveness of existing vaccines to new and emerging strains. Fortunately, some vaccines can be easily reprogrammed to provide immunity to new strains. The world will soon acquire the arsenal of weapons needed to fight it. Efficacious vaccines have been demonstrated, and many are in the pipeline. Antiviral drug research progresses although to date there exist no cure for COVID-19. The virtues of physical distancing, wearing masks, contact tracing and isolation are gaining acceptance. Hopefully wide vaccinations programmes and strict adherence to preventive measures will help subdue the pandemic; a concerted effort is imperative. As pointed out in the editorial The Island editorial of 21st January 2021 ensuring equitable access to vaccines is an urgency. This the factor determining what lies ahead and how the pandemic will halt.

Doing the needful forthwith is prudent because given sufficient time the virus might mutate in response to a single political decision implemented somewhere, irrespective of the geographical location.

The other issue would be the emergence of new pandemics in the future – most likely those of zoonotic origin. During the past two decades many such diseases have surfaced. Excessive interference with environment; clearing forests, maintaining millions of farm animals in unnatural conditions and climate change resulting from burning fossil fuels probably contribute this dangerous trend.

When humankind turns cruel to animals, destroy flora and engender environment, the return could be a pandemic!

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Sinharaja world heritage



Conservation Outlook Assessment: Significant Concern

By Professor Emeritus Nimal Gunatilleke

Continued from Yesterday


Water diverted from Ampanagala reservoir to Muruthawela will be used to meet the irrigation deficit of Muruthawela and Kirama Oya systems and the balance will be transferred to Chandrika Wewa, through existing LB canal of Muruthawela scheme up to 13.8 km and a new canal of 17.0 km. After that, the water requirement of Hambantota harbour is to be transferred to Ridiyagama tank through the Walawe river and Liyangasthota anicuit. However, due to the extreme length of the diversion through the three-river basins of Nilwala, Kirama Ara and Urubokka Oya, it will lead to a massive conveyance losses of the diverted water while on the way to the Walawe basin. Furthermore, enormous costs associated with its construction, a failure to fully realise the intended outcomes due to a shortage of water budget will simply be a burden that Sri Lanka cannot afford with her current economic condition, according to Eng. Prema Hettiarachchi. It may be worth recording that the water ingress into the grouted tunnel of the Uma Oya near Ella has still not been fully repaired, even though the Uma Oya project is nearing completion. An expensive lesson to be learnt on the nature of the weathered geological structure, lineaments and implementing its unexpected and costly mitigatory measures which will eventually to be paid back by this and future generations of tax payers of this country.

According to the Irrigation Department web site postings, Mahaweli Consultancy Bureau has initiated the Environment Impact Assessment (EIA), but due to the unavailability of concurrence of the Forest Department, revised TOR has not been issued by the CEA. Therefore, due to the unavailability of updated TOR, the EIA study has been delayed.

Environmentally, the most contentious issue highlighted in the news media is the proposed construction of a RCC dam at Madugeta to build a reservoir for which around 79 ha of forested (and some agricultural) lands in Sinharaja and a portion of prisine riverine forest in Dellawa would be inundated. On the Sinharaja side of the proposed Madugeta reservoir (right abutment) at present there are home gardens and small-scale tea plantations in addition to good riverine forests. In contrast however, proportionately a larger area of luxuriant forest of Dellawa, which is a part of the new ‘Sinharaja Rain Forest Complex’ would go under the chain saw for this reservoir construction (left abutment). The Geo-engineering report of May 2019 on GNDP has revised the siting of the dam to a more favourable location with supposedly reduced impacts but they forewarn that the three core-drilling along the proposed dam axis that had to be temporarily abandoned due to protests made by the villagers, need to be completed to confirm the geological suitability for the dam site.


Are there any Environment-Friendly Alternative Options?

As an alternative site for a dam on Gin Ganga, Eng. Nandasoma Atukorale (Specialist Engineer [Hydropower]) has proposed a location at the confluence of Mahadola with Gin Ganga at the village of Mederipitiya, way back in 2006. According to him, the riverbed at this site is 261 masl and have a catchment area of 132 km2. He proposes the construction of a 35 m high concrete gravity type dam that would form a reservoir with a storage capacity of 65 million cu.m and a potential discharge of 320 million cu.m of water annually which could divert 293 million cu. m of water to the SE Dry Zone. Most importantly, this region passes through a relatively narrow section of the river which is ideally suited for a dam according to him. However, geological suitability and socio-economic impacts of local communities need to be investigated, beforehand.

Quite interestingly, Eng. Athukorale claims that ‘although it is not economically very attractive, another 200 million cu.m of water could be diverted to the Nilwala basin by constructing a dam across Gin Ganga at the downstream of the confluence with Dellawa Dola at the village of Madugeta, with an 8000 m long tunnel which could be considered at a later stage provided further water shortages are experienced in the area’.


Now that the proposed Madugeta reservoir is receiving heavy criticisms from the environmental front, wonder whether Mederipitiya option proposed by Eng. Athukorale could be revisited for the diversion of Gin-Nilwala river water to the SE Dry Zone.

In a research paper titled ‘Comparison of Alternative Proposals for Domestic and Industrial Water Supply for Hambantota Industrial Development Zone’ Eng. Prema Hettiarachchi makes a comparison among three irrigation projects Kukule Ganga, Gin-Nilwala and Wey Ganga to convey water from the SW wet zone to SE dry zone.

She proposes yet another option that is probably still on the drawing boards to be considered which is the Wey Ganga diversion in Ratnapura District. According to her, this could meet the industrial and drinking water requirement (154 MCM + drinking water) of Hambantota metropolitan area at a significantly lower cost and with less damage to the environment. Further, there is a possibility of augmenting this scheme by diverting a part of Kalu Ganga catchment at a later stage.

Eng. Hettiarachchi further states that ‘by comparing the workload, it could be estimated to be nearly one third that of the Gin-Nilwala diversion. The Wey Ganga diversion can be carried out at a significantly lower cost by local agencies. That can also address the water scarcity of Hambantota metropolitan area including the requirements of international harbour and proposed industrial development zone with the relatively less environmental damage which is a major issue with respect to large scale projects. Construction period will also be less since the workload is less and can be carried out by the local agencies’.

What I have strived to show with this detailed irrigation engineering information available on public domain in the form of research publications, is that the Madugeta reservoir option is not the only one available for taking water from the wet zone rivers to the SE Dry Zone which is indeed a legitimate requirement for agricultural and industrial development of that region.

Pre-feasibility studies have been conducted on these options since 1968 and a considerable wealth of technical information is already available with the Irrigation Department. Apparently, according to knowledgeable irrigation engineers, there are more environmentally friendly, and cost-effective options with greater assurance of water conveyance to the SE Dry Zone available for consideration. It is often the case that during pre-feasibility studies of these large engineering projects, environmental concerns are given the least priority. Steady supply of water during extreme drought events which are becoming more frequent depends very much on the nature of the vegetation cover of the watershed area. These environmental aspects need to be critically evaluated before such costly projects are designed. As an example, although, the major engineering work of the Uma Oya project has been almost completed, its cost-effectiveness is yet to be seen with a denuded watershed, a potential of heavy soil erosion on top of the unexpected heavy expenditure on tunnel boring and other engineering works.

Biologically speaking, the Dellawa Forest Reserve is an integral part of Sinharaja Rain Forest Complex representing the pristine climax forest vegetation of SE wet lowlands and provide a vital connectivity link to adjoining Diyadawa forest of equal significance via the remains of Dombagoda forest. Therefore, clearing a riverine strip of this forest for the construction of Madugeta Reservoir would lead to an irreparable and irreplaceable damage to its characteristic riverine/flood plain forest vegetation.

On the other hand, pledging a reforestation initiative of a much larger area with Hevea rubber as a compensatory measure proposed by the political administration is totally unacceptable. Preserving intact forests in protected areas has no substitutes or replacements. Furthermore, the Natural Heritage Wilderness Area act and the binding articles of the UNESCO Convention on Protection of the World Cultural and Natural Heritage to which Sri Lanka is a signatory, clearly state that causing direct or indirect damage to a natural heritage is legally not permissible.

In summary, the Sinharaja World Heritage Site is already in a state whose biological values are threatened and/or are showing signs of deterioration and significant additional conservation measures have been recommended to restore these values over the medium and long term. Adding more threats like the construction of reservoirs inside protected areas at this stage would inevitably downgrade the values further to a ‘critical conservation outlook’ which is not what the citizenry of Sri Lanka and the world at large would acknowledge as ‘sustainable development’.

The author of this article is a member of the National Sustainable Development Council of Sri Lanka and he thanks Dr Jagath Gunathilaka of Peradeniya University for providing the geotechnical information described herein. The author can be contacted at .)


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US seeking way out of Afghan killing field



As the Biden administration makes its initial moves to extricate the US’ remaining security forces personnel from Afghanistan, it would do well to ponder on former US President John F. Kennedy’s insightful comment on foreign policy: ‘Domestic policy can only defeat us; foreign policy can kill us.’ This is a rare nugget on the nature of foreign policy.

Considering the high costs, human and economic, a country could incur as a result of blundering on its foreign policy front, Kennedy could be said to have spoken for all countries. However, there is no denying that the comment is particularly applicable to expansionist powers or ‘hegemonic’ states.

Sensible opinion is likely to be of the view that the US decision on quitting Afghanistan should have come very much earlier; may be a couple of years after its bloody misadventure in the conflict and war-ridden country. Considering the terribly high human costs in particular the US’ 20 long years in Afghanistan have incurred, the US could be said to have committed one of its worst foreign policy blunders, overshadowing in severity the blood-letting incurred by the super power in Vietnam. However, in both theatres, the consequences for the US have been of unbearable magnitude.

The US death toll speaks for itself. At the time of writing more than 2,300 US security forces personnel have been killed and over 20,000 injured in Afghanistan. Reports indicate that over 450 Britons have died in the same quagmire along with hundreds of similar personnel from numerous other nationalities. Apparently, it took an exceptionally long period of time for the US to realize that Afghanistan for it was a lost cause.

The lesson that the US and other expansionist powers ought to come to grips with is that it would not be an ‘easy ride’ for them in the complex conflict and war zones of the South. The ground realities in these theatres are of mind-boggling complexity and Afghanistan drives this point home with notable harshness. Power projection in South-west Asia and persistence with its ‘war on terror’ were among the apparent prime objectives of the US in Afghanistan as well as in Iraq but what the US did not evidently take into consideration before these military involvements were the internal political realities of these countries that are not at all amenable to simplistic analyses and policy prescriptions.

The Soviets ought to have come to grips with some features of the treacherous political terrain presented by Afghanistan in the late eighties but their principal preoccupations were related more to the compulsions of the Cold War. Simply put, the Soviets were bent on preserving the ‘satellite’ status of Afghanistan and their war effort was aimed at this in the main. Preparing Afghanistan for democracy was not even least among the Soviet Union’s concerns, of course.

However, the same does not apply to the US. The latter helped the Mujaheddin in the task of getting rid of the Soviet presence in Afghanistan but its aim was also to have a US-friendly regime in Kabul that would be a veritable bridgehead of US power and influence in the region on a continuous basis. In other words, the US expected the regime which replaced the Soviets to be pro-Western and essentially democracy-friendly. The US did not in any way bargain to have in Afghanistan Islamic fundamentalist regimes whose political philosophies were the anti-thesis of democracy as perceived in the US and practised by it.

However, the Islamic fundamentalist Taliban regime which eventually came to power in the mid-nineties in Afghanistan, once the Soviets withdrew, defied all Western expectations. As is known, the Taliban was not only repressive and undemocratic but was staunchly opposed to everything Western. There were no hopes of the Taliban working towards Western interests. Besides, the US did not expect to see in Afghanistan a country dangerously divided on ethnic, tribal and religious lines. The problems of Afghanistan have been compounded over the years by the coming together of the Taliban and the Al-Qaeda and these groups have world wide Islamic fundamentalist links.

It has been the aim of the US to have in Kabul religiously moderate, pro-democratic regimes but as developments have proved over the past few decades these administrations have not been in a position to hold out against the Taliban. In fact, it is the Taliban that is veritably at the helm of power in Afghanistan currently and years of futile attempts at trying to contain the Taliban have brought home to the US and its allies that they have no choice but to talk to the Taliban in order to secure some respite to effect ‘an honourable exit’ from the bloodied land. This is where matters stand at present.

However, as pointed out by commentators, it is the Afghan civilian population that has suffered most in the decades-long blood-letting in the country. Conservative estimates put the number of Afghan security forces personnel killed in Afghanistan at around 60,000 to date and the number of civilians killed at double that figure.

Accordingly, the Afghan people would be left to face an uncertain and highly risk-riddled future when the last of the US security forces personnel and their allies leave Afghanistan in September this year. The country would be left to its own devices and considering that the Taliban will likely be the dominant formation in the country and not its legitimate government, the lot of Afghan civilians is bound to be heart-rending.

There is plenty to ponder on for the US and other democratic countries in the agonies of Afghanistan. One lesson that offers itself is that not all countries of the South are ‘ready for democracy’. This applies to very many countries of the South that already claim to be democracies in the Western sense. Southern ‘democratic’ polities defy easy analysis and categorization in consideration of the multitude of identity markers they present along with the legitimacy that they have achieved in the eyes of their states and populations. What we have are dangerously volatile states riddled with contradictions. Relating to them will prove to be highly problematic for the rest of the world.

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The Soul



The Soul (also known as Ji hun) is based on the sci-fi novel ‘Soul Transfer’, written by Jiang Bo in 2012. The novel was widely popular and inspired director Cheng Wei-Hao to adapt the tale into a movie. The story is about a married couple who are determined to uncover the truth behind strange activities in their community. According to the official synopsis for the film from Netflix, while investigating the death of a businessman, a prosecutor and his wife uncover occult secrets as they face their own life-and-death dilemma. The film stars Chang Chen, Janine Chang and Christopher Lee among others.

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