Zoonoses, diseases passing from animals to humans, have tripled in the last century

With the effect of Cov­id-19 being felt around the globe, it would seem now is as good a time as any to focus on pre­ven­tion of future pan­dem­ics. A vast num­ber of emer­ging infec­tious dis­eases in humans are of anim­al ori­gin and, as such, the One Health approach has been thrust into the spotlight. 

In Novem­ber 2020, the One Health High-Level Expert Pan­el Frame­work was announced at the Par­is Peace For­um with the goal of integ­rat­ing human, anim­al, and envir­on­ment­al health sys­tems into one. Sym­bol­ic of this shift in think­ing from a human-centred to all-encom­passing approach, Thi­erry Lefrançois (Cirad) is the first veter­in­ari­an to join the French Cov­id-19 sci­entif­ic advis­ory board. 

With the concept of One Health, it is hoped that research­ers can identi­fy emer­ging dis­eases that could trans­fer from anim­als to humans as early as pos­sible. Why is the focus on envir­on­ment­al issues so important? 

Three-quar­ters of infec­tious dis­eases in humans are of an anim­al ori­gin because some micro-organ­isms (vir­uses, bac­teria, or para­sites) or para­sites, that can infect cer­tain anim­als and also humans. The asso­ci­ated dis­eases, called zoonoses, include Ebola of which bats are sus­pec­ted hosts, avi­an influ­enza in domest­ic and wild birds, Rabies in dogs or, of course, SARS-CoV­‑2 (Cov­id-19); even though we expect it to have ori­gin­ated in bats, we do not know which spe­cies allowed the trans­fer to humans (pan­gli­on, mink etc.). Zoonoses occur via a range of pro­cesses that are largely affected by the prox­im­ity between dif­fer­ent spe­cies and there­fore by the environment

It should be said that this inform­a­tion is not new: the sci­entif­ic com­munity has warned of the danger of zoonoses for years. Between 1940 and 2000, trans­mis­sion of dis­ease from anim­als to humans has more than tripled. The reas­ons for such are quite simple: vir­uses spread much more eas­ily between anim­als that are raised in dense, some­time unsan­it­ary, con­di­tions such as those in intens­ive farm­ing prac­tises – as the spread of the Cov­id-19 pan­dem­ic to Mink farms attests! On top of that, destruc­tion of hab­it­ats via defor­est­a­tion or repla­cing nat­ur­al zones with agri­cul­tur­al or urb­an install­a­tions pushes live­stock, domest­ic anim­als, and humans closer to wild anim­als, favour­ing the spread of dis­ease between spe­cies. Hence, the risk of infec­tious dis­eases is largely affected by eco­sys­tems, cli­mate factors, agri­cul­tur­al prac­tices, and a range of oth­er socio-eco­nom­ic factors. 

We are see­ing devel­op­ment of new tech­no­lo­gies that can help us detect where and when new epi­dem­ics may be happening.

How close are we to being able to pre­dict future pandemics? 

It is extremely dif­fi­cult to pre­dict which zoonoses [anim­al-human dis­eases] will trans­fer from one spe­cies to anoth­er and, in the past, there has been little suc­cess in doing so. Rather, we are see­ing devel­op­ment of new tech­no­lo­gies that can help us detect where and when new epi­dem­ics may be hap­pen­ing by pin­point­ing where the spread of dis­ease is becom­ing prob­lem­at­ic. As such, we can anti­cip­ate which patho­gens already in cir­cu­la­tion are likely to become pandemic. 

In the European pro­ject, MOOD¹, which CIRAD is coordin­at­ing, we are study­ing how we can use arti­fi­cial intel­li­gence to detect epi­dem­ics as early as pos­sible. The AI ana­lyses tex­tu­al data avail­able on the Inter­net – from social media posts, for example – as opposed to look­ing at tra­di­tion­al epi­demi­olo­gic­al data, which require bio­lo­gic­al samples and test­ing. Ana­lys­is of inform­a­tion in this way can offer insights very early on in an epi­dem­ic. We can seek out rel­at­ively inform­al terms like “swine flu” or “fever”, for instance, and com­pare their occur­rences to identi­fy where there may be clusters appearing.

Moreover, we can carry out “syn­drom­ic sur­veil­lance” by using Google searches for keywords or trends in phar­ma­ceut­ic­al sales. ­Hence, the goal here is not com­pletely around pre­ven­tion, instead it is more about detect­ing emer­ging pan­dem­ics as early as pos­sible by tap­ping into the huge amount of inform­a­tion already avail­able online. Exper­i­ments were done using this tech­no­logy to study the arrival of bird flu, with pos­it­ive res­ults show­ing that – had this type of approach been avail­able – it could have helped us act quicker.

Even though anti­cip­a­tion is key, are there still things that we can do in terms of prevention? 

Yes. And, actu­ally, pre­ven­tion is highly import­ant because it involves look­ing into socio-cul­tur­al sys­tems in a way that will allow us to avoid emer­gences and pre­vent cir­cu­la­tion of patho­gens in anim­als before they can be trans­mit­ted to humans. We are keep­ing close tabs on a num­ber of dis­eases around the world includ­ing the Afric­an Swine Flu, rabies or Nipah (an infec­tion found in bats in South-East Asia). Stud­ies show that efforts are likely to pay­off: invest­ment in pre­ven­tion costs 100 times less than a future pan­dem­ic². 

To do this, there isn’t much point in tar­get­ing spe­cif­ic anim­als because trans­mis­sion var­ies depend­ing on the spe­cies. Rather, we need to find a way of pre­vent­ing factors that favour trans­mis­sion, which tend to be loc­a­tion depend­ent. As such we have iden­ti­fied high-risk zones where we are focus­ing much atten­tion from Mex­ico to Zim­b­ab­we to Viet­nam. In an ideal world, we would be able to take biod­iversity into account in human urb­an and agri­cul­tur­al devel­op­ment. If we are expand­ing a town or city, then could we cre­ate path­ways for nature to move through? Will there be domest­ic anim­als or live­stock? Will it be zone of intens­ive farm­ing? Answer­ing these ques­tions can help ana­lyse the risks and con­sider envir­on­ment­al health with that of anim­als and humans. 

The concept of One Health has become an inter­na­tion­al col­lab­or­a­tion. What kind of the cooper­a­tion are we see­ing happen?

Gen­er­ally, States have been reli­ant on sep­ar­ate insti­tu­tions to deal with health, envir­on­ment and agri­cul­ture. But with One Health, we pro­pose an integ­rated approach on the very highest level. In mid-April 2021, the call for experts closed and the selec­ted inter­na­tion­al coun­cil will bring ~20 inter­na­tion­al experts togeth­er in May this year to work togeth­er and provide mul­tidiscip­lin­ary expert­ise to inter­na­tion­al organ­isa­tions involved in One health issues (WHO, OIE, FAO, UNEP). 

How­ever, top-level cooper­a­tion is not where our atten­tion is needed most. One Health needs to be taken ser­i­ously by the state, yes, but we need work in the field too. To identi­fy the right indic­at­ors we should be study­ing, we need to keep a close eye on what’s hap­pen­ing on the ground. That isn’t only the job of research­ers; it involves farm­ers, nation­al parks, civil ser­vices and so forth. 

Hence, we need things to hap­pen on the ter­rit­ori­al scale: “think glob­al, act loc­al.” For example, there is a shift in focus from pro­tec­ted zones in the form of nat­ur­al parks to “land shar­ing”. The lat­ter takes into account the fact that nature doesn’t recog­nise the bound­ary between a nation­al park and a human-occu­pied zone. Instead, the two need to be merged so that biod­iversity can be main­tained intelligently. 

At the One Plan­et Sum­mit in France on the 11^th Janu­ary 2021, Pres­id­ent Mac­ron announced the Prezode Pro­ject, with the aim “to reduce the risk of emer­gence and ensure the rel­ev­ance of sur­veil­lance and early detec­tion sys­tems at the loc­al, region­al and glob­al levels ³,⁴.” This is a very ambi­tious inter­na­tion­al ini­ti­at­ive, polit­ic­ally sup­por­ted at the highest level in France and will be fin­an­cially sup­por­ted by French Min­istry of research, Min­istry of Europe and for­eign affairs. Also, in the future by many more coun­tries and found­a­tions and organ­isa­tions around the world; we are mov­ing things for­ward with over 1,000 sci­ent­ists involved from 50 countries.