Linkages between biodiversity and health - We are studying the impacts of biodiversity on vector-borne disease transmission. Since vector- and reservoir-hosts are a component part of biodiversity, any changes in species composition may impact on disease maintenance and transmission. We are developing such a theory for understanding West Nile transmission in Camargue, a flooded rea of southern France.
Spatial modelling of infectious diseases - We are interested in spatial modelling and patterning of infectious diseases, especially for vector-borne diseases, using network theory in ecology-epidemiology. This theory, as metapopulation dynamics theory, focuses on the influence of sub-populations, i.e. with distinct size, density and connectiviry, within the network. We are also developing cellular automata and multi agent modelling techniques, and their integration in geographical information system (GIS). The aim is to elaborate spatial models for specific situations as for the West Nile virus in Camargue.
Molecular Evolution of HIV -
We are interested in the evolution of primate lentiviruses, i.e. HIV, responsible for the
current AIDS pandemy as well as the SIV, their simian relatives. Recent works have revealed
an impressive diversity of HIV and SIV. Whereas HIV
is always fatal for its host, SIVs seem to be more gentle to their hosts. We are trying to
understand those epidemiological differences in a evolutionary perspective. To do so, our
work is based on the analysis of gene sequences, which includes both phylogenic reconstruction
and search for positive selection. Choisy et al (2004)
Resonance and Epidemiology -
The phenomenon of resonance is general and observed on dynamical systems under a
periodical forcing. It is characterized by a relationship between the amplitude of the
signal and the frequency of its forcing. When the latter gets a frequency close to the natural
frequency of the signal, the system "resonates" and the amplitude of its oscillations is
amplified. It is using this property that we can make a glass explode simply by whistling…
We are interested in the resonance phenomenon in population dynamics and epidemiology.
Global Distribution of Infectious Diseases -
We are attempting to understand the global distribution of infectious pathogens in the human
population. To do so we use the concepts of macroecology and perform comparative analysis in order
to infer on the processes responsible for the these observed distribution at large scale. We are
currently working on the mechanisms responsible for the structure organisation of pathogens in human
populations. Synopsis PLoS
Macroecological patterns and epidemiological theory - General laws in mainstream ecology and macroecology like Rapoport s rule which stipulates that more temperate free-living species have larger latitudinal extent of geographical range than tropical ones have seldom been tested for parasitic and infectious disease agents. To what extent this common rules observed for free-living organisms can be applied to microbes with direct contagious or indirect complex life-cycles? Can we define common properties between parasitic and free-living organisms?
Global Changes and Cholera -
The bacteria Vibrio cholerae does exist in a non-pathogenic state is most aquatic systems.
Environmental and/or bio-climatic perturbations have the potential to increase the probability that
pathogenic forms of these bacteria infect human populations. We are interested in the risk factors
associated with bio-climatic and/environmental changes in the startup of cholera epidemics in the
Time-space dynamics of infectious diseases - We interest in spatial and temporal dynamics of infectious diseases in human populations. In particular, we focused on periodicity and synchrony, on persistence and spread of these infections, especially of childhood diseases as smallpox, pertussis and measles. We used for that statistical analyses of epidemiological data bases (e.g. time series). We also compare dynamics in different environments and at various spatial scales in order to put in light general patterns.
Impact of Vaccination -
We study the effect of vaccination on the dynamics of infectious diseases in terms of
periodicity, synchronicity, persistence, transmission, etc… Our study models models
are measles and whooping cough. At a very local scale we work on a Senegalese rural population
of 30,000 inhabitants distributed into 30 villages. This a perfect metapopulation setup.
At a more global scale we perform comparative analyses of time series of cases from different
countries over the world.Broutin et al(2004)-1 et Broutin et al(2004)-2
Human Evolution -
Like every living species, the human gender has evolved and still evolves under natural selection.
We are trying to understand the differences in life-history traits that we observe in human populations
under a Darwinian scope. We are particularly interested in the selective pressure excerted by pathogens
on the evolution of these traits (birth weight, parturition age, etc…). Our approach makes use of
the study of mathematical models as well as comparative analysis involving generalized linear
statistical models. We progressively built a large dataset including information on the economy,
demography, geography, epidemiology, morphometry, etc… of more than 150 countries over the world. Thomas et al(2004) et Guégan et al(2000)