In the wake of heavy rains, Cuba has been visited for the first time in 130 years by an old public health enemy: cholera. According to CNN, the problem may have begun when floodwater contaminated drinking water wells with the bacterium Vibrio cholerae (CNN video). The outbreak appears to be limited mainly to the eastern part of the island nation, where there have been 158 confirmed cases and three deaths from cholera (article). Cuban officials said on July 14 that disease transmission through water is diminishing. But as Cuba beats back cholera, another Caribbean country, Haiti, is still contending with the disease, a sad legacy of the 2010 magnitude 7.0 earthquake. According to the U.S. Centers for Disease Control & Prevention (CDC), as of October, 2011, one year after the disease outbreak began, there were more than 470,000 cholera cases and over 6,600 cholera deaths. As of April, 2012, CDC reported cases have declined.
Drinking Water Disinfection
Cholera, an acute diarrheal disease, wreaks havoc in poor communities that lack safe drinking water and basic sanitation. A person infected with Vibrio cholerae passes the disease to others via unsanitary excreta disposal. One infected victim is capable of discharging a sufficient number of pathogens to infect hundreds of others. When this is coupled with improper hand washing, failure to sanitize food preparation surfaces, using contaminated water for preparation of food, beverages, and ice, unsafe disposal of cholera-infected materials, or many other similar scenarios, numerous pathways of transmission are opened.
Most cholera victims become severely ill; some display only mild symptoms and remain ambulatory but are still capable of transmitting the disease to others. In severe cases, death can occur within hours of the disease onset due to extremely rapid loss of fluids and essential salts. Rehydration, either orally or intravenously, is the only effective treatment for cholera. There are no effective antibiotics for cholera.
Because treatment measures simply cannot keep up with the rapid propagation of the disease, the best strategies to combat cholera epidemics always include preventive components, especially drinking water chlorination and safe disposal of the excreta of victims of the disease. Reports indicate domestic well water is being treated with chlorine or iodine by Cuban residents in areas affected by the outbreak. Chlorine bleach, for example, can be used to disinfect unsafe water in emergencies (see Environmental Protection Agency (EPA) directions). Due to presumed high demand, as of July 11, pharmacies were limiting sales of bleach to one bottle per customer at the cost of 1.75 Cuban pesos (approximately 7 US cents), according to The Miami Herald. Permanent, effective disinfection methods must be put into place for the best public health protection. In Haiti, International Action works to install chlorinators to disinfect reservoir water and also provides chlorine tablets to individuals to enable them to disinfect water at the household level.
Flood conditions render well water particularly vulnerable to microbial contamination, especially if the wellhead (the part of the well above the ground surface) is not properly sealed and becomes submerged, allowing dirty water to flow into the well. This can result in rapid contamination. According to the EPA , wells that are more than 10 years old or less than 50 feet deep are likely to be contaminated following a flood, even if there is no apparent damage.
Well water quality is best protected using a multi-barrier approach that includes proper design and construction of the well, regular monitoring for waterborne pathogens and prompt disinfection when necessary. Strategically locating wells an appropriate distance from potential sources of contamination such septic tanks and leach fields, latrines, livestock yards, manure and fertilizer storage is critical (for more information, see Is Your Well Drinking Water all Well and Good?).
Reducing the Cholera Threat
Although cases in Cuba and Haiti appear to be declining, cholera remains a serious public health threat in several Caribbean nations. Prevention, through permanent, proper disinfection of drinking water supplies and sanitary disposal of human waste, is critical to avoiding cholera and other waterborne outbreaks. In the meantime, public outreach should help communicate how people can recognize and avoid the risks of cholera.
Fred Reiff, P.E., is a retired official from both the Pan American Health Organization and the U.S. Public Health Service, and currently lives in Reno, Nevada.