The influence of environmental factors on Covid-19: towards a research agenda

Considerable attention was paid in the early days of the Covid-19 pandemic to its spatial distribution in the hope that environmental factors might be found to play a key role in influencing its spread in two ways: by restricting it to a narrow band of countries with specific environmental factors; and hoping that a rise in temperature in the summer would kill it off.

• Researchers at Maryland University (Sajadi, M.M. et al., 2020) thus used maps of the early stages of Covid-19 to suggest that it spreads more easily in cold, damp climates, and that its highest incidence would be between latitudes 30-50 N.  At the time, I suggested on 3rd April that there were too many anomalies for this to be valid, that it was only based on limited data (where the coronavirus had spread by early March 2020) and that it was necessary to understand better the actual physical processes involved.  However, the idea that there might be environmental factors that will control Covid-19 still persists.
• Likewise, in the early days of the pandemic there was much optimism that the new coronavirus might act in similar ways to some of its predecessors and be seasonal in character, waning in the summer months when it gets warmer.  Again, this was in part based on the timing of its outbreak (in China in December 2019 ) and its rapid spread through Europe with an approximately similar timing to seasonal flu.  However, many experts were cautious about this possible scenario (see Jon Cohen in Science, 13th March 2020, and Alvin Powell in the Harvard Gazette, 14th April 2020).

Nevertheless, the much more rapid spread of Covid-19 in Europe and North America than in Africa and South Asia has led some to continue to argue that the devastating impact of lockdown in countries nearer the equator, particularly on the lives of some of the poorest people living there, may be un-necessary if this pattern can indeed be explained by environmental factors.  The lockdown has already been partially rolled back, for example, in countries such as Pakistan (with some factories reopening on 12th April , and congregational prayers at mosques durong Ramadan being permitted from 21st April) and South Africa (with initial steps being taken to reopen the economy on 1st May).  Clearly, the rate and distribution of the spread of Covid-19 is influenced by many factors, including government policies (with the UK performing especially badly, see my recent post),  demographic characteristics (with the elderly being particularly vulnerable), population distribution (spreading slower in sparsely settled areas), characteristics of the several strains and mutations of the Sars-Cov-2 coronavirus (summary in EMCrit), and the inaccuracy and unreliability of reported data about infections and deaths (see my comments here).

The role of environmental factors remains uncertain, despite a considerable amount of research (see systematic review by Mecenas, P. et al., 2020 – thanks to Serge Stinckwich for sharing this) which has sought to draw conclusions from the distribution of cases in parts of the world with different climates, and has suggested that cold and dry conditions helped the spread of the virus whereas warm and wet climates seem to reduce its spread.  A more recent study by Jüni et al. (8th May 2020) has claimed that epidemic growth has little or no association with latitude and temperature, although it has weak negative associations with relative and absolute humidity.  Unfortunately, very few studies have yet sought to do experimental research that actually measures the survivability and ease of spread of Sars-Cov-2 under different real-world environmental conditions.  Moreover, if as appears likely, most infections actually occur indoors, it is not the external climatic conditions that will influence rates of infection but rather the artifical environments created indoors through heating and ventlaltion systems that will be of most significance in influencing its spread.

Two related approaches to this challenge are necessary: identifying its survivabililty in a range of different environments (and surfaces), and analysis of the effect of different environments on the distance that it can be spread by infected people.

Research on the survivability of Sars-Cov-2 in different contexts

Several reported studies have explored the stability of the new coronavirus on different surfaces.  In a widely cited study, van Doremalen et al. (13th  March 2020) suggested that the stability of HCov-19 (Sars-Cov-2) was very similar to that of Sars-Cov-1 (the SARS outbreak in 2003), and that viable virus could be detected as follows:

• in aerosols up to 3 hours after aerosolization
• up to 4 hours on copper
• up to 24 hours on cardboard and up to 47-72 hours on plastic and stainless steel.

This important study has subsequently been used as the standard estimate for the survivability of the coronavirus.  However, it was undertaken in the USA under very specific relatively humidity (for aerosols at 65%; for surfaces at 40%) and temperature conditions (for both at 21-23^o C) (See also more recently, van Doremalen et al. 16 April 2020).  A rapid expert review of Sars-Cov-2’s survivability under different conditions (Fineberg, 7th April 2020) notes that the number of experimental studies remains small, but that elevated temperatures seem to reduce its survivability, and that this varies for diffferent materials.  Nevertheless, Fineberg emphasises that laboratory conditions do not necessarily accurately reflect real-world conditions.  In referrring to natural history studies, he also emphasises, as noted above, that conflicting results have emerged because such studies are “hampered by poor quaity data, confounding factors, and insufficient time since the beginning of the pandemix from which to draw conclusions” (p.4).

If a better understanding of Sars-Cov-2’s survivability in different parts of the world is to be gained, it is therefore essential urgently to undertake real world studies of its viability on similar surfaces in various places with different temperature and humidity profiles.

The dispersal distance of Sars-Cov-2

The standard advice across many countries of the world is that people should maintain a minimum distance of 2 m (in some countries 1.5 m) between each other to limit the spread of Covid-19 (see, for example, Public Health England).  This is double the WHO’s advice for the public, which is to “Maintain at least 1 metre (3 feet) distance between yourself and others. Why? When someone coughs, sneezes, or speaks they spray small liquid droplets from their nose or mouth which may contain virus. If you are too close, you can breathe in the droplets, including the COVID-19 virus if the person has the disease“.  The 2 m figure was adopted early by some CDCs, and appears to be more of an approximate early guess (based on the previous Sars-Cov-1 outbreak) that has taken root, rather than an accurate scientifically based figure.

Since then, more rigorous research has been undertaken, much of which suggests that 2 m may not be enough. Setti et al. (23rd April) thus note that Sars-Cov-2 has higher aerosol survivability than did its predecessor, and that a growing body of literature supports a view that “it is plausible that small particles containing the virus may diffuse in indoor environments covering distances up to 10 m from the emission sources”.  They also conclude that “The inter-personal distance of 2 m can be reasonably considered as an effective protection only if everybody wears face masks in daily life activities”. A particularly interesting laboratory based study a month previously by Bourouiba (26th March 2020) provides strong evidence that the turbulent gas clouds formed by sneezes and coughs provide conditions that enable the coronavirus to survive for much longer at greater distances: “The locally moist and warm atmosphere within the turbulent gas cloud allows the contained droplets to evade evaporation for much longer than occurs with isolated droplets“.  She concludes that the “gas cloud and its payload of pathogen-bearing droplets of all sizes can travel 23 to 27 feet (7-8 m)”.  Furthermore, another study by Blocken et al. (9th April) noted that the 1.5 m – 2 m distance was based on people who were standing still, and that there could be a potential aerodynamic effect for people cycling and running.  For someone running at 14.4 km/hr the social distance in the slipstream might be nearer 10 m.

Such studies have been controversial (for a summary, see Eric Niiler in Wired, 14th April), but they highlight that in practice:

• the “safe’ distance between people is unknown;
• there is little strong scientific evidence for the 1 m – 2 m recommendations for social distancing; and
• this distance is highly likely to vary in different environmental contexts.

Not enough conclusive reseach has yet been undertaken on the extent to which environmental factors, such as humidity, pressure, altitude, wind and temperature actually affect how far Sars-Cov-2 will disperse, and at what infectious dose (see Linda Geddes, NewScientist, 27th March 2020, where viral load is also discussed; see also ECDC, 25th March 2020).  It seems likely, though, that dispersal will indeed vary in different conditions, and thus in different parts of the world.  We just don’t yet know how great such variability is.

The latest systematic review published in The Lancet, and cited in The Guardian (2nd June 2020) sugggests that distance does matter, and that not only is 2 m safer than less than 1 m, but also that face masks can indeed reduce substantuially the risk of infection.

Towards a research agenda

This post has emphasised that we actually know remarkably little with certainty about how Sars-Cov-2 physically survives and disperses in different environmental contexts.  This has hugely important ramifications for the spread of Covid-19 in different parts of the world, and thus the mitigating policies and actions that need to be taken.  If, for example, Covid-19 does not survive in hot humid conditions, and is also dispersed over shorter distances in such circumstances, then it might be possible for governments of countries where such conditions prevail not to have to impose such stringent social distancing requirements as those that have been put in place in Europe.

Urgent experimental research is therefore required in real-world environments on:

• the survivabililty of Sars-Cov-2 in a range of different physical environments (and surfaces), and
• the effects of different environments on the distance that it can be spread by infected people.

A standard protocol and methodology for such research should be created that could then be used collaboratively by scientists working in different parts of the world to address these crucial issues.  Contrasting environments that would warrant the earliest such research (given the high number of economically poor countries therein) would include: high altitude savanna (as in the Bogotá savanna, and the much lower montane Savanna of the Angolan scarp), tropical and subtropical savanna (as in parts of Brazil and Kenya), tropical rainforests (as in Indonesia and Brazil), semi-arid and arid landscapes (as in much of northern and south-west Africa, the Arabian peninsula, and parts of South Asia).  It is also very important to undertake such resaerch both in urban and rural areas, and indoors as well as outside.  If scientists can indeed co-operate to provide a swift answer to the questions raised in this post, then it would be possible to provide much more tailored advice to governments concerning the mitigating measures (including the use of masks) that they should be taking to protect the highest number of people while also maintaing essential economic activity.

[Updated 8th May, 12th May, 30th May 2020 and 2nd June]

Servants of the poor – WSIS TalkX

It was a great honour to have been invited – a few hours beforehand – to give one of the inaugural WSIS TalkX presentations last Thursday evening as WSIS 2019 drew towards its close.  Seven of us had been asked if we would like to talk about our lives in technology for around 5 minutes. I opted to go last – just before the closing cocktail party.  Several colleagues had to leave before the end to get to other commitments and so they spoke first; I knew I would be remaining to enjoy the wine.  Before me there were some amazing, inspirational speakers: Stephenie Rodriguez, Joel Radvanyi, Gloria Kimbwala, Ayanna T Samuels, Sebastian Behaghel and Ted Chen…

With little time to prepare it was difficult to know quite what to say.  We had been asked to tell our own stories, and so I chose five images as five “scenes” around which to tell my tale.  Posting the images on social media, I had hoped that people might be able to see them as I spoke…

In reality, I’m not sure that many people actually saw the pictures, and I know many were rather confused when I began and introduced myself in the persona of one of my aliases.  I had, though, been introduced by the Master of Ceremonies as someone learning from the life of Hassan-i Sabbah…

To see and hear what I had to say, click on the image above (or here).  Fully to understand it, though, you would need to listen to the other six talks, because I tried hard to link it to what the speakers had to say – especially, for example, about the best university in the world, and the SDGs!

The basic message is simple – if we really believe in empowering the poor and the marginalised through digital technologies we must become their servants…

Nehru Place, Delhi: a digital hive

I went seeking some new and interesting ICTs on my last full day in Delhi, and my colleague Anushruti kindly therefore took me to Nehru Place in South Delhi.   I had never been there before, and it turned out to be a fascinating exploration of Delhi’s digital world; a hive of activity, with hundreds of small tech companies each competing for business, seemingly mainly selling mobile devices or offering laptop and phone repair services.

Nehru Place was built in the early 1980s as a commercial district, focusing primarily on the financial and business sectors.  However, as new financial centres have emerged across the city, its traditional role has all but vanished, and it has now been taken over by numerous small ICT businesses; it has often been described as the IT hub of South Asia.  It has a very informal atmosphere, with people also selling software (often pirated) and other small digital goods as pavement vendors on the wide streets between the buildings.

It is a very male dominated environment, and I was also fascinated by the gendering of the ICT advertisements on display (there is definitely a research project to be done on this); the dominance of a few corporate names on the hoardings, mainly Chinese, such as Lenovo, Oppo and Vivo, was a further reminder that India does not yet have much indigenous ICT manufacturing.  The prices of many of the goods on sale were also surprisingly high (India is definitely not the place to buy Apple laptops!).

As the photographs below show, Nehru Place has a  run down feeling to it, but the informality and vibrancy are clearly indicative of a lively digital scene, and it very much reminded me of a digital beehive, with everyone labouring away in their own little cell of the honeycomb that is Nehru Place.  Sadly, I couldn’t actually find what I was seeking to purchase, despite being directed from one shop to another in the hope that I would be able to!

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Alawalpur: farming, mobile ‘phones and cattle

On a very hot Sunday afternoon yesterday, with temperatures reaching the high 90^os F (high 30^os C), colleagues (Priya Chetri, Srishti Minocha and Anushruti Vagrani) at IIT Delhi kindly took me out into the Haryana countryside where they are conducting a baseline survey on the use of mobile devices by farmers.  In the first instance, this is investigating how helpful meteorological forecasts are to the farmers, but in the longer term it is also going to explore how sensors might be able to provide more refined information that would enable farmers to increase yields and thus profitability.

This was a great opportunity to immerse myself once again in the sights, sounds, smells, tastes and touch of the Indian countryside.  We spent most of our time talking with farmers in the large village of Alawalpur, but after the interviews were over we were also shown one of  the village’s special sites, the Baniewala Mandir.  The temple itself was fascinating, but I had never expected to find the 500 cattle that are so well cared for alongside.  The freshly made chai massala made from their milk after the interviews were done was absolutely delicious!

I hope that the following pictures reveal something of the adventure.  I learnt so much, and am very grateful to Priya, Srishti and Anushruti for taking me there and to Dr. Upasna Sharma for arranging the trip.

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The dogs of IIT Delhi campus

I am greatly enjoying living on the IIT Delhi campus, but have to admit that I am uneasy when walking past the many dogs that are usually roaming around in packs, seemingly on the look out for trouble!  There is always a sense of trepidation walking past them when they block the entrance to a building, or lie across the path!  Waking up in the night to hear them viciously barking, is also not exactly soothing!

Temperatures rose today, and I was surprised to see most of the dogs apparently asleep in the late afternoon sun.  This was definitely an opportunity to take my courage into my hands and photograph them!

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Chandni Chowk

The first time I visited Chandni Chowk (Moonlight Square) in Old Delhi was more than 40 years ago in 1976 (picture to the right).  I remember its vibrancy, the vivid colours, the energy, the diversity of smells, the complexity of everything that was there.  It fascinated me.  I got lost.  I wandered.  I explored back alleyways.  I emerged, having felt something of the depth of Delhi; the ever living past in its present.

I had not been back until two days ago.  Much had changed; little had changed.  I was struck anew by the splendour of some of the old buildings; the mix of religions; the melting pot of cultures that was Old Delhi; the old wooden doors; the delicious food; the wonderful colours, especially of the saris; the dogs and cat; the pale skinned mannequins.  I had to go there, just to feel, smell, hear, see and taste Old Delhi; a special treat was to eat at Parawthe Wala on Paranthe Wali Gali – it is most definitely worth searching out for every imaginable sort of paratha!

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I was so spoilt by my friend and colleague Anushruti Vagrani from IIT Delhi, who took me back to Chandni Chowk, and had patience with me as I just absorbed anew everything about the market.

“Indian Treasures”: exhibition at gettyimages gallery in London

The small Indian Treasures exhibition on until the 7th October at the gettyimages gallery on Eastcastle Street (near Oxford Circus tube station) in London, is an amazing opportunity to see photographs of “India” dating from the mid-19th century.  It has been well curated, and represents a collection of very diverse photographs, drawn mainly from a European gaze on “British India”.  However, the collection also includes photographs from Indian photographers, and illustrates seven themes: photographs by Samuel Bourne between 1863 and 1870; sun pictures from the 19tb century, illustrating both landscapes and people; methodologies, including four tinted photocrom prints; images by the photojournalist Felice Beato; studio portraiture; Princes of India; and the work of the London Stereoscope Company.

The exhibition raises so many fascinating questions, especially at a time when we “celebrate” 70 years of the independence of India and Pakistan, and remember the many atrocities that accompanied the birth of these two countries.  In particular, it highlights the way in which imagery was used to reinforce cultural stereotypes, and also the use of photography in the 19th century to capture what are seen as particular racial types.

I was particularly struck by comparisons between the countries in the 19th century and how they are seen today:

• Most photographs displayed were of India, rather than Pakistan, although mosques in Lucknow and Delhi were indeed depicted alongside temples from Tamil Nadu;
• The pictures generally depict a very clean and tidy India, with relatively smart new buildings and largely empty streets, a far cry from the hustle and bustle of the modern sub-continent;
• The mountain scenes from the Himalayas, which are a wonderful resource for learning more about environmental change, and especially glacial retreat;
• Jantar Mantar (described as the Old Observatory) near Delhi is shown apparently in an almost empty landscape, far removed from the urban  landscape that surrounds it today;
• The shell marks on the walls of the Shahi Mosque at Qudsia Bagh serve as a reminder of the violence and atrocities of the war known by the British as the “Indian Mutiny”; and
• It is a very male view – especially of the haunted faces of teh seemingly aloof and distant India princes; women appear mainly as nautch girls, although there is also a fascinating image of women at a bathing  ghat on the Ganges near Benares.

Above all, I was left with huge admiration of the work of photographers from a century and a half ago, who dragged their cameras and equipment across the continent to “capture” these haunting memories of India’s treasures.  This is an exhibition to be savoured and enjoyed.  Not only are the images stunningly evocative, but they also force us to rethink our understandings of the British Raj.

 

Hats (periodic markets) in South Bihar, 1976-1977

This is the last, and most important, in my series of images from 1976 and 1977 when I was in what was then South Bihar (now Jharkhand) in India.  I had the enormous privilege of assisting Sudhir Wanmali who was then undertaking research on the hats, or periodic markets in Singbhum District.  He taught me so much, not formally but just by being with him, watching and listening to how he interviewed, and above all by seeing the ways in which he interacted with people.  His wisdom, enthusiasm, generosity and passion for research were, and indeed still are, inspirational.

The hats are markets that take place regularly in different locations, and provide an opportunity not only for rural people to sell to the itinerant traders and others in the market, but also to buy things that they need and do not produce themselves.  As the following images show, it was possible to buy and sell almost anything you might need there, from the cloth, pots and brightly coloured glass bangles brought in by traders, to sweet potatoes, onions, tomatoes and many other vegetables, as well as the cattle and goats being sold by the farmers.  Some traders also collected products such as lac, collected in the forests by the people who lived there, and others would also buy up small amounts of paddy that farmers brought for sale. At the end of the day, I remember rice beer being sold in simple cups made of leaves.  The pictures below are mainly from places such as Bangaon, Hat Gamharia, Nakti, Tebo and Jagannathpur.

Sudhir’s work was published in an excellent monograph – Wanmali, S. (1981) Periodic Markets and Rural Development in India, Delhi: BR – but is also written up in other papers, including:

• Wanmali, S. (1980) The regulated and periodic markets and rural development in India, Transactions of the Institute of British Geographers, new series 5(4), 466-86.
• Johnson, J. and Wanmali, S. (1981) A Q-analysis of periodic market systems, Geographical Analysis, 13(2), 262-275
• Wanmali, S. (1985) Networks of distribution of goods and services in rural India: some spatial considerations, in ICRISAT,  Agricultural Markets in the Semi-Arid Tropics. Proceedings of the International Workshop, 24-28 October 1983, ICRISAT, 133-138

At the time, I was also working on medieval England and drew parallels between marketing systems that had been created there in the 14th century, and those that I had experienced in Singbhum. This was published as:

• T. Unwin (1981) Rural marketing in medieval Nottinghamshire, Journal of Historical Geography, 7, 231–51.

I very much hope that these pictures, now some 40 years old, not only contribute to the archive of Jharkhand’s past, but also reflect the beauty of this special part of the world.  I often wonder how the lives of the many people I met there turned out…

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Agriculture and rural life in South Bihar, 1976-1977

Working with my dear friend and colleague, Sudhir Wanmali, in what was then rural South Bihar (now Jharkhand) in the mid-1970s was one of the most influential times of my life.  It taught me so much: that rural people are universally exploited by those living in urban areas; that rural life in South Asia is incredibly hard; and that South Bihar (as it was then known) is amazingly beautiful.  I very much hope that the images below show something of that inspiration, but they cannot sufficiently capture the smells and sounds of rural life in India in the 1970s.

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Small towns and villages in South Bihar and West Bengal, 1976 and 1977

Continuing digitizing the slides from my research and travels in India in 1976 and 1977, I share here some pictures of small towns and villages in what was then South Bihar (now Jharkhand) and West Bengal.  These include pictures of the towns of Chaibasa and Chakradharpur, as well as several villages in this beautiful part of India.  I remember particularly the paintings on the walls of the houses in the villages, and some of the writing on them as well, not least the slogan “Fight for malaria”! The pictures here also show the sadness of smallpox, with the solitary gravestone, and also other such stones which I was told marked village boundaries.  There are also images of tile and brick making, and the sequence closes with a village school, which I had forgotten about but now makes me think of all of the other schools, particularly in Africa, that I have visited in the last 15 or so years.   Other rural, agricultural scenes will follow in a future post!

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