03/08/07

Cholera linked to rainfall in West Africa

A Vibrio cholerae bacterium Copyright: Janice Carr/CDC

By: Godefroy Macaire Chabi

We encourage you to republish this article online and in print, it’s free under our creative commons attribution license, but please follow some simple guidelines:

You have to credit our authors.
You have to credit SciDev.Net — where possible include our logo with a link back to the original article.
You can simply run the first few lines of the article and then add: “Read the full article on SciDev.Net” containing a link back to the original article.
If you want to also take images published in this story you will need to confirm with the original source if you're licensed to use them.
The easiest way to get the article on your site is to embed the code below.

For more information view our media page and republishing guidelines.

The full article is available here as HTML.

Press Ctrl-C to copy

<div class="article-wrap">
<div id="article-introduction">
<h1>Cholera linked to rainfall in West Africa</h1>
<h4>By: Godefroy Macaire Chabi</h4>
</div>
<br />
<br />

<div id="article-body">
<p>Climate variability and increases in rainfall influence the risk of cholera outbreaks in Africa, say researchers.</p>
<p>This information could be used to develop a ‘cholera early-warning system’, predicting outbreaks by integrating real time weather monitoring with information about factors causing disease and population characteristics.</p>
<p>The study, by researchers from the French Laboratory of Genetics and Evolution of Infectious Diseases (GEMI), was published in the journal BMC Infectious Diseases.</p>
<p>Africa is the continent most affected by cholera, write the authors; more than 95,000 cases were reported in 2004.</p>
<p>Cholera outbreaks are caused by the bacteria <em>Vibrio cholerae.</em> When ingested — usually in contaminated water — they produce a toxin that causes acute diarrhoea.</p>
<p>To better understand the dynamics of cholera epidemics and their link with climate variability, the researchers compared cholera cases from 1975–1995 in five non-endemic countries along the tropical Atlantic coast of Africa —Benin, Cote d’Ivoire, Ghana, Nigeria and Togo — with rainfall over the same period.</p>
<p>In all five countries, they found cholera outbreaks synchronised with increases in rainfall in cycles of 2–5 year periods.</p>
<p>The results were similar to those obtained in similar studies in Bangladesh and Peru.</p>
<p>"The influence in rainfall increase on cholera outbreaks can best be explained by flood waters in disease transmission," write the authors.</p>
<p>"On the scientific level, this work is very interesting," says epidemiologist Didier Bompangue from the Democratic Republic of Congo.</p>
<p>But he adds that the study does not yet answer operational questions such as when to intervene, in what context and how. </p>
<p>Renaud Piarroux, professor of parasitology and head of the Health and Rural Environment team at the University of France-Comté in France, who has worked in Africa, emphasised that because the study looked at coastal populations, it may not explain outbreaks further inland.</p>
<p>"It is important that research is carried out where the problem is, both in coastal area, as well as in the areas far away from the coast," he says.</p>
<p><a onclick="pageTracker._trackPageview('/tracking/external/'+this.href);" target="_blank" href="http://www.biomedcentral.com/1471-2334/7/20" rel="noopener noreferrer">Link to full paper in BMC Infectious Diseases</a></p>
<p>Reference: <em>BMC Infectious Diseases </em>7, 20 (2007)</p>

</div>
<div class="quick-links-wrapper">
<h3>You might also like</h3>
[related-articles]
</div>
<p>This article was originally published on <a href="https://www.scidev.net" target="_blank">SciDev.Net</a>. Read the <a href="https://www.scidev.net/global/news/cholera-linked-to-rainfall-in-west-africa/" target="_blank">original article</a>.</p>
<script type="text/javascript">
(function(e,t,n,r,i,s,o){e["GoogleAnalyticsObject"]=i;e[i]=e[i]||function(){(e[i].q=e[i].q||[]).push(arguments)},e[i].l=1*new Date;s=t.createElement(n),o=t.getElementsByTagName(n)[0];s.async=1;s.src=r;o.parentNode.insertBefore(s,o)})(window,document,"script","//www.google-analytics.com/ga.js","ga");var _gaq=_gaq||[];var _gaq=_gaq||[];_gaq.push(["_setAccount","UA-3223906-8"],["_trackEvent","article interaction","republished","https://www.scidev.net/global/news/cholera-linked-to-rainfall-in-west-africa/",null,true])
</script>
</div>

Climate variability and increases in rainfall influence the risk of cholera outbreaks in Africa, say researchers.

This information could be used to develop a ‘cholera early-warning system’, predicting outbreaks by integrating real time weather monitoring with information about factors causing disease and population characteristics.

The study, by researchers from the French Laboratory of Genetics and Evolution of Infectious Diseases (GEMI), was published in the journal BMC Infectious Diseases.

Africa is the continent most affected by cholera, write the authors; more than 95,000 cases were reported in 2004.

Cholera outbreaks are caused by the bacteria Vibrio cholerae. When ingested — usually in contaminated water — they produce a toxin that causes acute diarrhoea.

To better understand the dynamics of cholera epidemics and their link with climate variability, the researchers compared cholera cases from 1975–1995 in five non-endemic countries along the tropical Atlantic coast of Africa —Benin, Cote d’Ivoire, Ghana, Nigeria and Togo — with rainfall over the same period.

In all five countries, they found cholera outbreaks synchronised with increases in rainfall in cycles of 2–5 year periods.

The results were similar to those obtained in similar studies in Bangladesh and Peru.

"The influence in rainfall increase on cholera outbreaks can best be explained by flood waters in disease transmission," write the authors.

"On the scientific level, this work is very interesting," says epidemiologist Didier Bompangue from the Democratic Republic of Congo.

But he adds that the study does not yet answer operational questions such as when to intervene, in what context and how.

Renaud Piarroux, professor of parasitology and head of the Health and Rural Environment team at the University of France-Comté in France, who has worked in Africa, emphasised that because the study looked at coastal populations, it may not explain outbreaks further inland.

"It is important that research is carried out where the problem is, both in coastal area, as well as in the areas far away from the coast," he says.

Link to full paper in BMC Infectious Diseases

Reference: BMC Infectious Diseases 7, 20 (2007)