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Cholera outbreaks at Lake Tanganyika induced by climate change

A. Context

Cholera is one of the deadliest diseases in Africa. It reappeared in the area of theAfrican Rift in the late 70’s. The African Rift has been highlighted as major area ofcholera propagation (Bompangue et al., 2008a). A link between cholera, phytoplanktonblooms and copepod zooplankton has been demonstrated in Asia (Colwell et al.,1996). The African Great Lakes have been suspected to play a role as a reservoir ofthe bacteria V. cholerae, while human infection and movement are probably involvedin the propagation of the disease inland.

B. Objectives

The objectives of the CHOLTIC project are to better understand the environmentalconditions that trigger cholera outbreaks in the Lake Tanganyika region via aninterdisciplinary study including the following aspects:

  1. In situ monitoring of meteorology, limnology, phytoplankton, zooplankton, fishabundance and bacteriology during a period of three years and collaborationwith DRC health authorities and epidemiology researchers.
  2.  Remote sensing to produce time series of daily images of Chl-a and lakesurfacetemperatures for the period 2000-2014.
  3.  Eco-hydrological modeling to investigate links between climate, nutrient mixingand variable abundance of different planktonic groups.
  4.  Microbiological monitoring and confirmation.
  5.  Genetic characterization by mass spectra identification of cholera strains.
  6.  Data analysis of spatio-temporal relationships between environmental factorsand health data.

C. Conclusions

Meteorological monitoring at Uvira and Mpulungu recorded air temperature,Meteorological monitoring at Uvira and Mpulungu recorded air temperature,atmospheric pressure, rainfall levels, relative humidity, wind speed, wind direction andsolar radiation.Limnological monitoring was implemented from 2011 to 2014 at five sites (threecoastal and two pelagic). Parameters included T°, pH, dissolved oxygen, conductivity,turbidity, transparency and chl-a concentrations. Marked short-term variability wasobserved in relation to internal waves and pulse of hypolimnion nutrient. Isotherms indeep waters were found to be good indicators of pulsed fluctuations of parameters.