Cholera is transmitted by ingestion of water or food that has been contaminated with human feces. If left untreated, it can be fatal.
Cholera is endemic in more than 50 countries worldwide. The last endemic cholera outbreak in the U.S. occurred in 1911. Most cases occur in African and Asian countries where populations do not have access to improved drinking water sources. The WHO maintains and publishes weekly reports of aggregate national cholera data. The 1969 WHO IHRs and the 2005 ratification require WHO notification of all cholera cases. Cholera, however, is estimated to be heavily underreported, with official estimates representing 5%–10% of all annual cases. It is estimated that an annual 1–4 million cholera infections occur worldwide, resulting in an estimated 21,000–143,000 annual deaths [10].
Cholera disease is particularly fatal to children. A simple scientific advancement, known as Oral Rehydration Therapy, replaces essential salts and body fluids through a sodium glucose mixture known as Oral Rehydration Salts (ORS). ORS are cheap, globally distributed, and credited for reducing cholera as well as other diarrheal disease mortality, in children by more than 54% from 1.3 million in 2000 to fewer than 600,000 in 2013 [11]. However, even with an inexpensive and effective solution to decrease cholera morbidity, cholera prevention is based entirely on providing clean water supplies for human consumption [12]. Many people in developing countries do not have access to safe drinking water on a daily basis [13] (Volume 1, Chapter 39). Recent epidemics have demonstrated poor infrastructure accelerates the spread of water-borne diseases during a natural disaster [10]. An example of an inadequate public health infrastructure follows.
On January 12, 2010, a 7.0 magnitude earthquake struck Haiti. The country was already the poorest country in the Western hemisphere. The Haitian population depended largely on the agricultural sector, residents lived in poverty in overcrowded slums, and Haitians had limited access to sanitation and clean water. Despite a severely limited public health infrastructure, there had never been a case of cholera reported in Haiti [14]. The earthquake and its aftermath killed an estimated 230,000 people and displaced most of the nation’s population. The international community was quick to respond and large-scale search and rescue missions began within days. On October 17, 2010, the first case of cholera was reported to international agencies [15].
Investigations by WHO found that cholera had been introduced into Haiti by the UN’s Nepalese peacekeepers. The Nepalese UN base was located upstream of the Artibonite River, which supplied most of the country with fresh drinking water. Improper sanitation practices at the base, including open dump pits and leaky latrine pipes, allowed human feces infected with Vibrio cholerae O1, serotype Ogawa, a strain found in cholera cases in Nepal to enter the river. By March 2011, more than 500,000 cholera infections were reported with approximately 5,000 deaths. Since its introduction, several subsequent cholera outbreaks have been reported in Haiti [16].
A total number of suspected cholera cases in Yemen in 2017 had risen to 500,000, and nearly 2,000 people had died.
Demonstrating that cholera epidemics do not respect geography or history, a major cholera outbreak occurred in Yemen in 2017. The WHO reports a total number of suspected cholera cases in Yemen in 2017 had risen to 500,000, and nearly 2,000 people had died since the outbreak began to spread rapidly at the end of April 2017 [17]. Yemen’s cholera epidemic was the largest in the world in 2017. The epidemic spread rapidly due to deteriorating hygiene and sanitation conditions and disruptions to the water supply across the country. Millions of people were cut off from clean water, and waste collection had ceased in major cities as a consequence of civil war in Yemen. Later, a restored water treatment plant dramatically reduced a local cholera epidemic. Al Barzakh is one of around 10 water treatment centers in Yemen, and it serves four different districts in Aden, in southern Yemen, as well as the Lahij and the Abyan governorates. As a contribution to public health, UNICEF undertook the plant’s restoration, while also analyzing the infrastructure needs of the region. The plant became fully operational in September 2017, and by January 2018, cholera reports had decreased to 164 cholera cases and zero deaths, which was a 92% decrease in new cholera cases [18].