Updated 20/05/22

1st July 2022 – 1st December 2025 (42 months)

Madagascar

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© IRD - Dominique Vinckenbosch

Context

The massive presence of plastic debris, mainly composed by micro-fragments (diameter less than 5 mm) and macro-waste, in the worldwide Oceans is today a major ecological and sanitary concern.

Once in water, plastics are colonized by micro-organisms, some of which are pathogenic and threaten marine biodiversity and humans. They could act as a vector if they are ingested by marine animals, that are then consumed by humans. Today one question remains: is this transfer possible, in order to evaluate if these pathogens on plastic debris represent an actual health risk for humans through the consumption of sea food.

Some of the least developed tropical island countries are located in or around ocean zones that concentrate drifting marine plastics. Moreover, these countries experience an intensive urbanization accompanied by an increase in the use of single-use plastics. They are also subject to increasing population pressures in coastal areas with partial or no sewage treatment. This results in raw sewage spills in coastal areas, which are particularly important during the rainy season, and further contribute toward high fecal bacterial abundance in waters, which could potentially be pathogenic for human. Altogether this could facilitate the colonization of plastics with pathogens. Since the populations of tropical island countries depend to a very large extent on coastal fishing, the transfer of these pathogens to these populations via plastics ingested by sea produce could be substantial. This question will be studied in the socio-ecosystem of the Grand Récif of Toliara (South West Madagascar), with in situ and experimental microbiological analyses, as well as an anthropological analysis of fisheries, selling and consumption practices.

© IRD/CNRS - Thierry Bouvier

Objectives

This ANR project VectoPlastic developped in Madagascar and coordinated by UMR MARBEC aims at assessing the microbiological risk of marine plastics for humans and marine biodiversity.

In the context of a "One Health" approach, the VectoPlastic project will implement several methods to address the following objectives:

  • To quantify the variability in abundance of the major pathogens, their virulence genes and their resistance to antibiotics related to marine plastics of various kinds and sizes
  • To demonstrate the transfer of pathogens linked to plastics through two economical models (Siganus sutor fish and Penaeus monodon shrimp)
  • To assess the persistence of plastic pathogens once ingested by the two ocean species, up to the stalls in markets
  • To describe the practices of fishermen, producers, sellers and consumers and to examine whether these stakeholders are aware of, and respond to, the health risk associated with plastics
  • To assess the integrated health risk linked to the consumption of selected seafood products by coupling it with biological and social data
  • To suggest recommendations to the political sphere, in order to limit health risks linked to plastics

© IRD/CNRS - Thierry Bouvier