afrol News, 30 April - According to a new study, the ongoing climate change already has led to the spread of some diseases in Southern Africa. In Zambia, a longer heat period has raised cholera infections by 5 percent.

A study, published by researchers from the Spanish Carlos III Institute of Health this month, associates the increase of cholera cases in Zambia with climatic factors. For the first time, the results confirm that the increase in environmental temperature six weeks before the rain season increases the number of people affected by this sickness by 4.9 percent.

"This is the first time that it has become evident in the sub-Saharan region that the increase in environmental temperature is related to the increase in cholera cases," explains Miguel Ángel Luque, one of the study's authors. Previous studies in Bangladesh already associated cholera cases with an increase in ocean surface temperature.

The research project, carried out in the Zambian capital Lusaka between 2003 and 2006, analyses data from three cholera epidemics, which occurred in a consecutive fashion. The results show that climatic variables - rain and environmental temperature - were related to an increase in cholera cases during the epidemic period.

Experts affirm that cholera has a marked seasonal component associated with the rain season. "As such, an increase in temperature six weeks before this period is related with a 4.9 percent increase in the number of cases of this sickness within the population," the Spanish researchers hold.

The study maintains that a 1º C increase in temperature six weeks before the beginning of the outbreak explains the 5.2 percent increase in cholera cases during an epidemic. In the same fashion, if a 50 millimetre rise in precipitation three weeks later is added to this increase, these values would be associated with a 2.5 percent increase in risk.

"The climate change is affecting the dynamic and resurgence of infectious sicknesses in a key fashion, concretely malaria and cholera. This year, countries such as Zimbabwe and Zambia are living a devastating cholera epidemic associated with a pandemic process which affects a large part of the continent, and the hypotheses signal that the rise in global temperature is possibly related to the process," adds Mr Luque.

The study's limitation is that the model of association between environmental variables and cholera is merely explicative. According to the researcher, "it would be ideal to have a predictive method, since the foreseen increase in cases could then be known beforehand, so as to be able to release an early alert in the region and put out a warning to health authorities."

Cholera outbreaks continue to be a problem for public health, given that they cause great human, social and economic losses. Just in 2001, the World Health Organisation (WHO) and the Global Outbreak Alert & Response Network participated in the verification of 41 cholera outbreaks in 28 countries, most of which in sub-Saharan Africa.

Today, the cholera epidemic's main focus is found in Zimbabwe. Despite the fact that the number of cases has decreased, the mortality rate continues to be elevated in almost all of the provinces, and a real risk exists that the outbreak will be reactivated in some areas.

Since the beginning of the regional cholera outbreak in August 2008 until 17 March this year, 91,164 cases were reported in Zimbabwe alone, 4,037 of them mortal.

By staff writer

© afrol News

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