CORONAVIRUS – THE POSTMAN ALWAYS RINGS TWICE

CORONAVIRUS – THE POSTMAN ALWAYS RINGS TWICE.

Introduction

At the time of writing[1] there are more than 700’000 confirmed cases of COVID-19 around the globe and more than 30’000 deaths – and growing. Media attention has also gone viral with 2.5 million articles written and 1.5 billion social media engagements in March only. Over 24’000 scientific articles have been posted, underlining the huge global scientific efforts to come to grips with the current pandemic. 

Thus far, relatively limited attention – at least in the media –  has been paid to what made this virus emerge and what this means for the future. As a recent New York Times article put it: It may have started with a bat in a cave, but human activity set it loose. 

The links in the text refer to many authoritative sources consulted and are aimed to give background and due credit.

This article draws on reliable media sources, specialist websites and journals. It does not pretend to be  a scientific article nor is it written by a health specialist, but it is written from a risk management perspective. The approach is to place the current crisis and interrelated issues as an ‘ecology of risk’.

The virus: What  are we talking about ?

Coronaviruses are a large family of viruses which may cause illness in animals or humans. COVID-19 is the disease caused by an infection of the SARS-CoV-2 virus.[2]

Human coronaviruses were first identified in the mid-1960s. Sometimes coronaviruses that infect animals can evolve and make people sick and become a new human coronavirus. Three recent examples of this are SARS-CoV in 2002[3], and MERS-CoV in 2012[4]  and the current SARS-CoV-2.

SARS-CoV-2 is the seventh coronavirus known to infect humans, and the present outbreak is the third documented spillover of an animal coronavirus to humans in only two decades that has resulted in a major epidemic. Analyses clearly show that SARS-CoV-2 is not a laboratory construct or a purposefully manipulated virus.

Preliminary  studies in China have identified two strains of the SARS-CoV-2, indicating it has mutated at least once:

• The more aggressive L type strain (accounting for 30% of cases) was found to be prevalent in the early stages of the outbreak in Wuhan. But its frequency decreased from early January, which the researchers attribute to human intervention. 
• ·The S type strain (accounting for 70% of cases), meanwhile, is continuing to infect new patients, which experts believe could be because it is less severe, meaning people carry it for longer before going to the hospital, increasing the risk of it passing it on. 

But further comprehensive research is necessary. More recent analysis reports that the virus is not mutating significantly as it circulates through the human population. That relative stability suggests the virus is less likely to become more or less dangerous as it spreads. This increases the chance that any vaccine or immunity that is developed will be long-lasting.

Previous pan/epidemics

SARS and MERS were more limited epidemics. The scale of the current pandemic has few precedents. And we don’t have to go back as far as the bubonic plague, or so-called Black Death, which devastated Europe from 1347 to 1352, killing an estimated 20 million people. (And which saw quarantine[5] used for the first time.) 

There are similarities and differences between COVID-19 and influenza. But a look at the numbers behind a flu epidemic is sobering There have been multiple flu pandemics in the 20th century. The Spanish flu pandemic of 1918, (of avian origin) is estimated to have caused 50 million deaths, with anywhere from 20% to 40% of the world's population infected with the virus (double the number of people killed during the WW I). The Asian flu pandemic of 1957–58 (of avian origin) resulted in the death of about 1.1 million people and the Hong Kong flu pandemic in 1968 (of avian origin) is estimated to have caused around 1 million deaths. The more recent influenza in 2009 (of swine origin) is estimated to have led to 60.8 million cases, 274,304 hospitalizations and 12,469 deaths in the United States. Worldwide numbers estimate  that between 150’000 and 575’000 people died during the first year the virus circulated.[6] Experts have warned that a new flu pandemic is due and could kill 20 million people globally.

In the 1980s AIDS[7] emerged. It got its name in 1982, and refers to the most advanced stages of HIV infection. HIV[8] continues to be a major global public health issue, having claimed more than 32 million lives so far. According to estimates by WHO and UNAIDS, 36.7 million people were living with HIV globally at the end of 2016. That same year, some 1.8 million people became newly infected, and 1 million died of HIV-related causes. It is generally accepted that it originated in non-human primates in Central and West Africa, and that the global pandemic had its origins in the emergence of one specific strain in the 1920s in what is today Kinshasa (DRC).

Covid 19 – a zoonotic disease

As is clear from the above examples, some viruses that cause diseases and may lead to epidemics among humans are of animal origin. Zoonotic diseases (also known as zoonoses) are caused by germs that spread between animals and people. They are caused by harmful germs like viruses, bacterial, parasites, and fungi. They can cause many different types of illnesses in people and animals, ranging from mild to serious illness and even death. 

Zoonotic diseases are very common. A 2014 study analysed a 33-year dataset (1980–2013) of 12’102 outbreaks of 215 human infectious diseases, comprising more than 44 million cases occurring in 219 nations. Figures indicate that 6 out of every 10 known infectious diseases in people can be spread from animals, and that 3 out of every 4 new or emerging infectious diseases in people come from animals. The total number of outbreaks and richness of causal diseases have each increased globally since 1980.

The main suspects

Animals that can transmit diseases are many: pets such as cats and dogs; camels; pigs; birds; reptiles and amphibians; wild animals – and bats. One quarter of mammal species overall are bats. And in tropical systems, bats make up 50 percent of the mammalian diversity. 

Bats have a bad reputation, which is not surprising considering the number of pathogens they carry that can infect humans. Rabies, Nipah, Hendra, Ebola and Marburg are all viruses carried by bats that can cause serious disease in humans. Some strains of the  Ebola and its close cousin the Marburg virus can kill up to 80-90% of humans infected. Most of these are emerging diseases and were identified in the 1960s in West and Central Africa.[9]

SARS-CoV-2 isn’t as novel as one might think.[10]. There is near consensus that bats serve as the reservoir host of the virus.[11]Both MERS and SARS viruses most likely originated in bats. Alarm bells went off after the outbreak of severe acute respiratory syndrome (SARS) in 2002 and 2003 in Guangdong province (China). After initial studies in 2005 and 2009, scientists set out how, in a cave the Yunnan, a province roughly a thousand miles southwest of Wuhan, coronaviruses had been found in multiple individuals of four different species of bats.

The jump from bats to humans is thought to pass via an intermediate animal. For SARS-CoV-2, the prime suspect is the Malayan pangolin but genetic evidence is so far not conclusive. Another candidate is the civet cat, which is thought responsible for transmission of the SARS outbreak in 2003. Mutations of a virus that make these jumps possible can occur in the source animal, during passage from animal to human and in humans after zoonotic transfer. But thus far the research is not conclusive and many questions remain unanswered. Detailed understanding of how an animal virus jumped species boundaries to infect humans so productively will help in the prevention of future zoonotic events.

Current response options

In the current crisis, in the absence of a vaccine and medication for treatment, authorities are  relying on  the behavioral side of the epidemic – social distancing, quarantine, basic hygiene and disinfection. Apart from admonishing people to wash their hands, governments have basically three options today:

1. The first is to argue that the more individuals are infected (say 60%) the better the population is protected. The virus will run its course and end since it can no longer circulate. This is the idea behind ‘herd immunity’[12] (or community immunity). The epidemic will be massive, the health system cannot cope, the human costs will be high but limited in time. 
2. The second option (China) is the inverse strategy: massive and strict isolation of individuals, cities and regions. Relatively fewer individuals will be infected, but a large majority of the population will remain ‘naive’ (not infected and thus have not developed immunity), and raises concerns that a lingering of the virus will spread into a renewed outbreak and epidemic. (Hence the absolute need for a vaccine to avoid a renewed outbreak.) 
3. The third, intermediary option is to flatten the peak of the outbreak and spread contagion out over time and hope that over that during that time at least 60% of the population will have been infected and that the necessary degree of ‘herd immunity’ has been reached. The epidemic will last longer, but the health system has a chance to cope. It’s this third option that is favoured in the West.

A secondary outbreak remains a possibility though. Immunity would only last as long as the coronavirus does not mutate. Also, the more contagious a disease is, the higher percentage of herd immunity you need.[13] And it remains to be seen whether immunity (or a vaccine) is full or partial, and whether it will last. No one knows at the moment. Today, the preferred remedy for COVID-19 is prevention (control the spread of the virus).

The human factor

As one researcher put it: “The problem is not the animals, it’s that we get in contact with them.” A virus may be the cause, but there is growing awareness that the epidemic is a man-made phenomenon. 

The popular view is that natural ecosystems are the unique source of threats. Nature does pose threats, but it’s human activities that do the real damage. The health risks in a natural environment can be made much worse when the latter is interfered with it.

Humans coexist in a complex, interdependent relationship with the companion, production, and wild animals we depend on for our food, livelihoods, and well-being, as well as with the environments we live and work in together. The interface between humans, animals, and the environments we share can also be a source of diseases impacting public health and the social and economic well-being of the world population.[14]

Human behavior is one of the defining factors of an epidemic. The Ebola outbreak in western Africa emerged in December 2013 but it took another year before traditional burial practices were found to be a leading cause of the rapid spread of the causative virus.  Behavioral assessment was key to the identification of drug injection as the main factor of transmission of HIV. Human behavior often increases the risk of acquiring an infectious disease, however the systematic investigation of human risk behaviors is too often neglected in disease surveillance strategies. In recent years, WHO has started to develop the integrated biological–behavioural surveillance (One Health) in pandemic-threat warning systems.[15]

Socio-economic factors

So far, COVID-19 has been reported in only high- and middle-income nations where health systems are effective, and conditions are generally sanitary. Lower socio economic status (SES), whether measured by education, poverty, or other relevant indicators such as inequality and discrimination, income inequality predict worse health. This association has been documented for centuries and persists throughout the contemporary world.

But the possible spread of the disease to cities in low-income countries spells disaster. Rapid urbanization in the global South has added epidemiological and nutritional challenges and increasing disease and health burdens. Greater movement of people, animals, food and trade often provides favourable grounds for the emergence of infectious diseases, including zoonoses. These produce and reproduce risk accumulation in urban settings. 

The risks posed to humans by exposure to animals is modified by various biological, ecological, economic, political and sociocultural (social epidemiology) factors. Poverty can expose individuals and communities to a higher degree of risk to  contracting zoonotic diseases. Understanding the context within which spillover to humans can occur is an important component in the prevention of zoonotic outbreaks.[16]

Environmental pressures

The emergence new zoonotic diseases lies, among other, in the parallel bio-diversity crisis of massive species loss as a result of overexploitation of wild animal populations and the destruction of their natural habitats by the growth of human populations. Increasing demand for agriculture, wood, minerals and resources from the global north leads to the degraded landscapes and ecological disruptions that drives disease. The geographic patterns of global habitat clearance are contagious in themself while resource-efficient land use is not. Major landscape changes are causing wildlife to lose habitats, which means more species live closer to human habitats.

Together with rapid urbanization, road building is a main culprit. Roads penetrating into Earth’s remaining wildernesses are a major driver of habitat loss and fragmentation, wildfires, overhunting, and other environmental degradation.[17] The number and extent of roads will expand dramatically this century. Globally, at least 25 million kilometres of new roads are anticipated by 2050. This represents a 60% increase in the total length of roads over that in 2010. 90% of all road construction is occurring in developing nations, including many regions with exceptional biodiversity and vital ecosystem services. The effects of a road vary but it has an impact on the probability of creating new pathogens. Located and designed wisely, they can help rather than harm the environment.[18] A ‘road-zoning’ project has been initiated to map areas that should remain road-free and those in which transport urgently needs improving.

And next?

In the immediate, the search for drugs for treatment – use of antiviral drugs to reduce COVID-19 transmission and vaccines to combat COVID-19 – is the priority. Many avenues are explored in an extraordinary global and collaborative, rather than competitive, effort. Some existing treatments and drugs show promise, with the added advantage that they have been tested already and secondary effects are known.

Unfortunately, the story does not stop here. The majority of pathogens are still to be discovered. Pathogens do not respect species boundaries. Humans are create the conditions for the spread of diseases by reducing the natural barriers between virus host animals — in which the virus circulates naturally — and themselves. We can fully expect a new episode of pandemic influenza in the near future; we can expect large-scale human deaths and other pathogens with other impacts. Something with a mortality rate like Ebola spread by something like highly contagious measles would be catastrophic.

Prevent and prepare

We can’t predict where the next pandemic will come from, so we need mitigation planning to take into account the worst possible scenarios. The only certain thing is that the next one will certainly come.

Investment and trust in science

In the medium and long-term, we must hope for a shift towards renewed recognition of the value of fundamental and applied science as opposed to the promotion of ideology and the endless repetition of stale dogmas, be they right or left of the political spectrum. National and self-interest and ‘the market’ as principal guiding principles have shown their limits, again. The constant decline of budgets for research must be reversed and scientific collaboration rather than competition must be rewarded.

Socio-economic and political redesign

This requires a rebalancing of society’s priorities and values, nationally and internationally. The emphasis of well-being solely based on the growth of GDP, “healthy” financial markets and  a focus on generous dividends for shareholders can no longer be justified. This does not mean ‘big government’. What it does mean is leadership and political courage.

Ecology of risks

The risk sources are many and interconnected. Climate change and energy policies, species extinction and animal trade, environmental protection, land-use and food production, migration and urbanization, youth bubble are all part of the next pandemics equation.  

We have our work cut out for us.

[1] 29 March 2020

[2] The WHO’s interim name was nCoV-2019. It has also been referred to 2019-nCoV or HCoV-19.

[3] Severe acute respiratory syndrome.

[4] Middle East respiratory syndrome.

[5] The term comes from the Italian words quaranta giorni, which means 40 days.

[6] Unlike COVID-19, which is most dangerous to those over 65, 80% of the 2009 H1N1 pandemic were estimated to have occurred in people younger than 65 years of age. This differs greatly from typical seasonal influenza epidemics, during which about 70 percent to 90 percent of deaths are estimated to occur in people 65 years and older. The (H1N1) pdm09 virus was very different from H1N1 viruses that were circulating at the time of the pandemic. Few young people had any existing immunity (as detected by antibody response) to the (H1N1)pdm09 virus, but nearly one third of people over 60 years old had antibodies against this virus, likely from exposure to an older H1N1 virus earlier in their lives. Since the (H1N1)pdm09 virus was very different from circulating H1N1 viruses, vaccination with seasonal flu vaccines offered little cross-protection against (H1N1)pdm09 virus infection. No longer a pandemic, the virus continues to circulate as a seasonal flu virus, and causes illness, hospitalization, and deaths worldwide every year.

[7] Acquired Immune Deficiency Syndrome

[8] Human immunodeficiency virus

[9] Some argue they have been around for a long time but weren't diagnosed. 

[10] The most recent common ancestor (MRCA) of all coronaviruses has been estimated to have existed as recently as 8000 BCE, though some models place the MRCA as far back as 55 million years or more, implying long term coevolution with bats.

[11] The diversity of coronaviruses in bats and other species is massively under-sampled. However, most specialists agree that bats serve as the reservoir host of the virus.

[12] Herd immunity is a form of indirect protection from infectious disease that occurs when a large percentage of a population has become immune to an infection, whether through previous infections or vaccination, thereby providing a measure of protection for individuals who are not immune.

[13] To get herd immunity against measles, for example, 93% to 95% of people in a community have to be vaccinated. In other words, about 95 out of every 100 people have to get the vaccine to prevent the disease.

[14] Antimicrobial resistance in human pathogens is another major public health threat which is partly impacted by use of antibiotics in animal husbandry and agriculture. 

[15] Taking the systemic approach a few steps further, the One Health concept proposes a worldwide strategy for expanding interdisciplinarycollaborations and communications in all aspects of health care for humans, animals and the environment. Although the term is fairly new, the concept has long been recognized both nationally and globally. Since the 1800s, scientists have noted the similarity in disease processes among animals and humans, but human and animal medicine were practiced separately until the 20th century. In recent years, the One Health concept has gained more recognition in the public health and animal health communities.

[16] However, the same behavioral risk factors may be problematic in one context but not in another. For example,  the sharing of a water source with animals displaced by a change in land use may only have an adverse effect on human health if there is faecal–oral transmission of the zoonotic pathogen to humans. If such transmission requires contact with the animal blood, then the sharing of the water source should not increase the risks of either spillover or transmission. Once human-to-human transmission occurs, additional risk behaviours come into play.

[17] More  than 95% of deforestation, fires and atmospheric carbon emissions in the Brazilian Amazon occur within 50 kilometres of a road.

[18] A paved high- way slicing through a large forest tract can precipitate an environmental disaster. Conversely, in places where farming is already widespread and intact habitat is scarce, and where there are sizeable gaps between current and potential farm yields, building high-quality roads can improve farms’ efficiency, increase their profitability and limit their environmental impact.