ENSO and cholera: A nonstationary link related to climate change?

Abstract

We present here quantitative evidence for an increased role of interannual climate variability on the temporal dynamics of an infectious disease. The evidence is based on time-series analyses of the relationship between El Niñ o͞Southern Oscillation (ENSO) and cholera prevalence in Bangladesh (formerly Bengal) during two different time periods. A strong and consistent signature of ENSO is apparent in the last two decades (1980 -2001), while it is weaker and eventually uncorrelated during the first parts of the last century (1893-1920 and 1920 -1940, respectively). Concomitant with these changes, the Southern Oscillation Index (SOI) undergoes shifts in its frequency spectrum. These changes include an intensification of the approximately 4-yr cycle during the recent interval as a response to the well documented Pacific basin regime shift of 1976. This change in remote ENSO modulation alone can only partially serve to substantiate the differences observed in cholera. Regional or basin-wide changes possibly linked to global warming must be invoked that seem to facilitate ENSO transmission. For the recent cholera series and during specific time intervals corresponding to local maxima in ENSO, this climate phenomenon accounts for over 70% of disease variance. This strong association is discontinuous in time and can only be captured with a technique designed to isolate transient couplings.

Influence of temperature and rainfall on the evolution of cholera epidemics in Lusaka, Zambia, 2003–2006: analysis of a time series

“…25,26 In recent years, numerous studies have demonstrated the association between the re-emergence and dynamics of infectious diseases and environmental factors. 7,27 We identified such an association between temperature and rainfall and the increase in the number of cholera cases in three outbreaks occurring in Lusaka (2003Lusaka ( -2006, which is in concordance with suggested environmental theories for re-emergence of infectious diseases. It is worth noting that most studies relating climate to cholera describe coastal regions.…”

Growth of Vibrio cholerae O1 Ogawa Eltor in freshwater

“…Laboratory experiments showed a positive correlation between temperature and the metabolic activity of V. cholerae O1 in defined sea salt solution in a temperature range from 10 to 25 u C (Singleton et al, 1982a). Furthermore, a more frequent detection of V. cholerae O1 in estuary waters and a higher morbidity rate among people in Bangladesh was shown to be associated with increasing temperatures (Louis et al, 2003;Rodo et al, 2002).…”

Long-term projections and acclimatization scenarios of temperature-related mortality in Europe

“…S cientists have described a wide range of potential negative impacts of climate change 1 on many vulnerable aspects of natural systems and human populations 2,3 , and particularly the sensitivity of our society to atmospheric temperatures 4,5 . In particular, increasing attention has been paid to warm extremes [6][7][8][9][10] , which are expected to become more frequent, longer and more severe 11 .…”