The document discusses the linkages between biodiversity and emerging infectious diseases. It summarizes the aims of the BIODIS/CESAB working group, which are to understand how biodiversity impacts disease spillovers and transmission in wildlife, test these relationships using different host-disease models and field studies, and understand which host traits influence disease infection and transmission. The group is made up of researchers studying various disease systems like Lyme disease, West Nile virus, and Buruli ulcer. They use mathematical modeling and have published several papers investigating whether the "dilution effect" concept, where higher diversity lowers disease risk, applies broadly. Their work examines how local diversity in host reservoirs and vectors influences disease transmission patterns.

1. The linkages between biodiversity
and the transmission of emerging
infectious diseases
Jean-François Guégan
IRD, UMR MIVEGEC, Montpellier
and programme FutureEarth/OneHealth
On behalf of the BIODIS/CESAB working group

2. BIODIS / CEBA – Aims and introduction
• Understanding the complex linkages between biodiversity and emerging
infectious disease spillovers and transmission. Wildlife as a source of new
infections and a natural barrier against these infections
• Testing through different host-disease models, field studies and regions,
the generality, or not, of the dilution effect concept
• Understanding what key parameters and traits make an host a good
vessel for disease infection and transmission
• Relaxing some basic assumptions to the theory, seeing the generality of
the model concept.

3. COS à 40 - 12 septembre 2016
Vanessa Ezenwa, Ass. Professor, Athens Univ., GE (6 months Fulbright Foundation)
Felicia Keesing, Professor, Bard College, NY
Annapaola Rizzoli, Mach Foundation, Italy
Xavier Bailly, INRA, Clermont-Ferrand
Marion Vittecoq, Sansuire Foundation, France
Simon Blanchet, CNRS, France
Gerardo Suzan, UNAM, Mexico
Parviez Hosseini, EcoHealth Alliance, NY
Carlos Zambrana-T, EcoHealth Alliance, NY
Marco Vignuzzi, Pasteur Institute, Paris
Gabriel Garcia, post-doctorant, Mexico (27 candidates)
+ 2 Master students (12 months Fulbright Foundation for M. Goldberg)
Benjamin Roche
James N. Mills
Jean-François Guégan
PhD
Postdoc
BIODIS / CEBA – Group members

4. Transmission of Lyme disease in the U.S.A.
Peromyscus leucopus
Species richnessin small mammals Species richness in lizards
Numberofdiseasecases
inhuman(/100000)
Numberofdiseasecases
inhuman(/100000)
Transmission by tick vectors,
Ixodes scapularis
Two host reservoirs as main
hosts, Peromyscus leucopus Tamias striatus
but numerous host reservoirs with different competencies

5. The dilution effect concept in a nutshell
Focus Biodiversité, CNRS (2006)
prevalenceprevalence

6. © Photo by G. Balança, Cirad

7. Host reservoir competency
Distributionfrequency
Theoretical distribution of
competencies
LP avian flu HxNy
What we really observe!
Host reservoir competency distribution and disease transmission
Host reservoir competency
Distributionfrequency

8. Lyme disease (reservoirs)
Host reservoir competency distribution and disease transmission
Host reservoir competency
Distributionfrequency
Theoretical distribution of
competencies
What we really observe!
Host reservoir competency
Distributionfrequency

9. West Nile virus (vectors)
West Nile virus (birds)
Host reservoir competency distribution and disease transmission
Host reservoir competency
Distributionfrequency
Theoretical distribution of
competencies
What we really observe!
Host reservoir competency
Distributionfrequency

10. West Nile virus (vectors)
Host reservoir competency distribution and disease transmission
Host reservoir competency
Distributionfrequency
What really exists in local
species communities!
What we accept top be!
Host reservoir competency
Distributionfrequency

11. B. Roche, A.P. Dobson, P. Rohani, J.F. Guégan (2013) Am Nat
Mathematical modelling in epidemiology
SS II
Si
Si Ii
Ii
µNi
bNj
τi
SS II RR
Sj
Sj Ij
Ij Rj
Rj
τj

12. Local species richness in vectors
Localglobalcomptence
forhostreservoirs
High proportion of species with
low competencies
West Nile virus transmission in the U.S.A.
High proportion of species with
high and very high
competencies

13. West Nile virus (Camargue)
West Nile virus (Louisiana)
West Nile virus transmission in the U.S.A.
Local species richness in vectors
Localglobalcomptence
forhostreservoirs
High proportion of species with
low competencies
High proportion of species with
high and very high
competencies
West Nile virus (California)

14. Species richness in vectors
Speciesrichness
Dilution
Dilution
Amplification
Existence of tradeoffs
between
amplification and
dilution trends
Amplification
Inhostreservoirs

15. Buruli ulcer and its disease agent, Myc. ulcerans, in tropical regions

17. Is dilution effect a widespread disease pattern?
Roche et al. (resubmitted)
Ecology

18. BIODIS / CEBA – Scientific production
Four scientific papers published or in press
PLoS Pathogens, Phil. Trans. R. Soc. Lond. B., Oikos, Ecology and Evolution
Four scientific papers submitted or in preparation
Ecology, ….
Seven scientific conferences given in international congresses
and 6 communications in front of policy-makers and the public

19. http://www.malinfemerg.org/

20. Thank you for your attention!