Cholera , a deadly diarrheal disease , has been rare in the United States since the early 1900s , but in the developing world , where access to clean drinking water is more difficult , it is still a serious problem . Dr. Rita Colwell has studied cholera for nearly 50 years , and has written more than 700 publications and received at least 40 honorary degrees . The former director of the National Science Foundation and former president of the American Association for the Advancement of Science , Colwell is currently a distinguished professor at both the University of Maryland , College Park and Johns Hopkins University 's Bloomberg School of Public Health . CNN spoke with Colwell about her research and how she and her team helped develop an incredibly simple method to help the people of rural Bangladesh have cleaner , safer drinking water . The following is an edited portion of that interview . A medical miracle : Saving cholera victims . CNN : Tell me about cholera . Colwell : Cholera is ... transmitted by water . The bacteria that causes the disease ... ( naturally occurs ) in the aquatic environment . That 's a discovery that my laboratory made some 25 to 30 years ago . When ingested , it attaches to the intestine and a toxin is most frequently produced . The result is severe vomiting , diarrhea and if a person does n't have their fluid replenished , dehydration and eventually death ( results ) . CNN : Is there an antibiotic for cholera ? Colwell : You can take an antibiotic . It 's generally susceptible to tetracycline , a broad-spectrum antibiotic , and other antibiotics . There 's been a discovery some years ago of what 's called oral rehydration therapy , ORT , whereby a mixture in water of table salt , bicarbonate of soda and table sugar is mixed in appropriate concentration and sipped . This replenishes the fluid loss and is very effective in treating cholera . CNN : That 's interesting that it does n't seem people die from the bacteria attacking their systems , but rather the dehydration effects . Colwell : That 's predominantly the case . The toxin can have other effects but mainly it 's the sodium-potassium transport mechanism that gets interfered with . Bangladesh has two major epidemics every year : spring , which is right about now , and fall : September , October , November . This occurs year after year with almost no exception due to the fact that , as we have shown , the bacteria are associated with plankton . As the plankton become abundant , they bloom in the spring and fall , after which the cholera bacteria become abundant in the water and the disease occurs . CNN : Are cholera outbreaks connected to global warming ? Colwell : Temperature is a major regulator of the abundance of the cholera bacteria . The study that was carried out by Carla Pruzzo in Italy , with which we collaborated , was an analysis of plankton samples that had been stored for the past 40 years at a marine laboratory in England . They 'd been collecting samples every year for 40 years and so we analyzed the samples , and what Dr. Pruzzo and our team found was that as the water temperature is increasing , the numbers of vibrios ( small , comma-shaped bacteria ) and the number of cases of diseases caused by vibrio , namely cholera , have been increasing . It has been directly related to the warming of the sea temperature . CNN : Can you describe the method you developed in Bangladesh to control cholera ? Colwell : Having done an enormous amount of research showing the ecology of the cholera bacterium , ( we found ) it was definitely tied to plankton . The cholera bacteria is part of their natural flora . It occurred to us that by simple filtration to remove the plankton , we would filter about 99 % of the bacteria , leaving just a few suspended in the water . So then , we hypothesized , we could reduce cholera significantly by educating women who collect water for their household to use cloth filtration . Probing the mysteries of probiotics . We found that sari cloth that comprised the dresses that women wear , if folded about four times , gave a very nice mesh filter , with small enough pore size to trap plankton . A three-year study was funded by the National Institutes of Health and Nursing Institute that involved about 50 villages and over 150,000 people , and sure enough , by having women filter their water collected from the ponds and rivers every day , we showed about a 50 % decrease in cholera . A very simple step , and very important . CNN : How did you get the message out to everyone that they should be doing this ? Colwell : We worked with the women in the villages and we trained them , essentially as extension agents ... to go to the villages every week with a meeting for the women of the village to explain to them why it 's good to filter , how to filter , and the difference it would make to the health of their children . So with this constant reinforcement , we found that indeed , they did filter because they found that their children did n't get sick . And that , of course , was a big incentive . The project ended about six years ago , but we went back to see if they were still filtering , and we found 75 % of them were . CNN : So , do you think that clean water is the key to controlling waterborne diseases like cholera ? Or , do you think it 's getting people the education about better sanitation ? Colwell : It 's a combination of sanitation and safe water . ... We do not have cholera in the United States . We have not had it since about 1930 when filtered , chlorinated household water was made available . Similarly in Europe , back in the 1890s and 1900s , cholera epidemics were devastating . In fact , cholera played into outcomes of major wars when troops became debilitated by the cholera bacterium . So , a combination of proper sanitation and filtered , chlorinated , safely distributed water -- not just cholera , but at least two dozen diseases transmitted by contaminated water can be prevented . CNN : What could we do as a nation to help this effort to getting education about sanitation and clean drinking water to more developing countries ? Colwell : I think education for both proper sanitation and for filtering water is very badly needed . I also work with Safe Water Network , which is a philanthropic organization that delivers kiosks ... that provide filtered water on a larger scale . We need to think of water availability depending on the environment and the conditions on which the water can be made available . It 's not all one-size-fits-all . For example , filtration in a major city probably is n't as effective as chlorinating the water and having it distributed safely , which many cities in developing countries do . ... But for the remote villages , they do n't have that kind of access , so their simple filtration is really , really helpful . These women changed medicine .
" She has been studying malaria for half a century . Her team found an innovative way to control the disease in Africa . Research has shown cholera is linked to global warming , she says . Clean water availability is not ` ` one - size - fits - all ''