2016–2022 Yemen cholera outbreak

As of 2017, Yemen had a population of 25 million and was geographically divided into 22 governorates. Houthi forces controlling the capital Sanaʽa, and allied with forces loyal to the former president Ali Abdullah Saleh, have clashed with forces loyal to the government of Abdrabbuh Mansur Hadi, based in Aden. A Saudi Arabian-led intervention in Yemen was launched in 2015, with Saudi Arabia leading a coalition of nine countries from the Middle East and Africa, in response to calls from President Abdrabbuh Mansur Hadi for military support. Cholera is an infection of the small intestine by strains of the bacterium Vibrio cholerae. It is spread mostly by unsafe water and unsafe food that has been contaminated with human feces containing the bacteria. Diarrhea can be so severe that it leads, within hours, to severe dehydration and electrolyte imbalance. In severe cases, shock and seizures may occur. Cholera vaccines that are given by mouth provide reasonable protection for about six months. Two oral killed vaccines are available: Dukoral and Shanchol. Total cost, including delivery costs, of oral cholera vaccination is under US$10 per person. ==Outbreak==

Following "on the heels of civil conflict between Houthi rebels and the internationally recognized Yemeni regime", By the end of October, cases had been reported in the governorates of Al-Bayda, Aden, Al-Hudaydah, Hajjah, Ibb, Lahij and Taiz and, by late November, also in Al-Dhale'a and Amran. By mid-December, 135 districts of 15 governorates had reported suspected cases, but nearly two-thirds were confined to Aden, Al-Bayda, Al-Hudaydah and Taiz. By mid-January 2017, 80% of cases were located in 28 districts of Al-Dhale'a, Al-Hudaydah, Hajjah, Lahij and Taiz. A total of 268 districts from 20 governorates had reported cases by 21 June 2017; over half are from the governorates of Amanat Al Asimah (the capital Sana'a), Al-Hudaydah, Amran and Hajjah, which are all located in the west of the country. In particular, 77.7% of cholera cases (339,061 of 436,625) and 80.7% of deaths from cholera (1,545 of 1,915) occurred in Houthi-controlled governorates, compared to 15.4% of cases and 10.4% of deaths in government-controlled governorates. Using genomic sequencing, researchers at the Wellcome Sanger Institute and Institut Pasteur concluded the strain of cholera originated in eastern Africa and was carried to Yemen by migrants. ==Morbidity and mortality==

Yemen authorities announced the cholera outbreak on October 7, 2016. and by mid-March 2017, the outbreak was in decline after a wave of cold weather. The number of cholera cases resurged in a second wave that began on 27 April 2017. The two agencies stated that it was then "the worst cholera outbreak in the world". On 14 August 2017 the WHO updated the number of suspected cholera cases to 500,000. Oxfam said in 2017 the outbreak would become the largest epidemic since record-keeping began, overtaking the 754,373 cases of cholera recorded after the 2010 Haiti earthquake. In six months, more people were ill with cholera in Yemen than in seven years after the earthquake in Haiti, and the situation in Yemen was made worse by hunger and malnutrition. On 22 December 2017, WHO reported the number of suspected cholera cases in Yemen had surpassed one million. By October 2018, there were more than 1.2 million cases reported, and more than 2,500 people—58% children—have died in the Yemen cholera outbreak, which is the worst epidemic in recorded history and was, according to the United Nations (UN), the worst humanitarian crisis in the world. Between 1 January 2018 to 31 May 2020, the cumulative total number of suspected cases was 1,371,819 with 1566 associated deaths. The case fatality rate for the outbreak was 0.11% as of 2020, having declined from a high of 1% when the outbreak first began. ==Causes and challenges==

UNICEF and the WHO attributed the outbreak to malnutrition, collapsing sanitation and clean water systems due to the country's ongoing conflict, and the approximately 30,000 local health care workers who had not been paid for almost a year. These factors resulted in a delayed vaccination program, which was not started until more than one million people were already ill. Pre-civil war conditions Even before civil war affected Yemen, it was "beset by circumstances that made it ripe for cholera". Ongoing conflict Because of the ongoing conflict in Yemen, and resulting displacement of people who do not have adequate food, water, housing or sanitation, pre-existing conditions were exacerbated. Shortages have been made worse by naval and air blockades. Grant Pritchard, Save the Children's interim country director for Yemen, stated in April 2017, "With the right medicines, these [diseases] are all completely treatable – but the Saudi Arabia-led coalition is stopping them from getting in." Wastewater and solid waste management systems Yemen's wastewater and solid waste management systems are the least developed among Middle Eastern countries, which has been a major contributor to the cholera outbreak. With 16 functional sewage treatment plants (STPs) and a growing population, the country's sewage systems are ill-equipped to meet the needs of citizens and serve just 7% of the population. High concentrations of Escherichia coli, Streptococcus faecalis, Klebsiella pneumoniae, Enterobacter aerogenes, Salmonella  typhi, S. typhimurium, and Shigella sonnei - among other harmful fecal coliforms - are present in this wastewater, and transmit to humans when they consume foods irrigated by it. Official dumping sites for solid waste are being created increasingly close to communities, which has increased the risk of infection and general health issues among citizens. For example, in East Africa, there was an upsurge in cholera cases in areas with increased rainfall, along with an increase in cases in areas with decreased rainfall. This alludes to a possible connection between cholera in East Africa and Yemen. A months-long strike of sanitation workers over unpaid wages contributed to the accumulation of garbage The geography of Yemen means that the Western mountainous plateau sees more rainfall, and has therefore an increased risk of high cholera incidence due to water precipitations. The request for vaccine was retracted. The WHO and UNICEF delivered oral vaccines to 540,000 individuals in August 2018. The COVID-19 pandemic has further burdened the already overwhelmed healthcare system in Yemen fighting a number of diseases including cholera, dengue fever, and malaria. Only half of existing health facilities are fully functioning while more than 17.9 million people of a total population of 30 million need health care services in 2020. == Humanitarian activity ==

Through 2018, several humanitarian healthcare organizations had reported activity to contain the cholera outbreak. The International Committee of the Red Cross have supported 17 treatment centers with supplies including IV fluids, oral rehydration therapy supplies, antibiotics, chlorine tablets, in addition to sending engineers to help restore water distribution in Yemen. The International Rescue Committee (IRC) supplied seven hospitals with medicine and supplies, deployed health teams and trained volunteers, delivered health and nutrition services, and facilitated referrals of malnourished children. The World Health Organization coordinated the Yemen Health Cluster with 40 member organizations, and together with Health and Water Sanitation and Hygiene (WaSH) units, explored the use of oral cholera vaccines (OCVs). The WHO reported operating 414 facilities using 406 teams active in 323 districts in Yemen, which included 36 treatment centers for cholera. In the management of cholera, they stated that they trained 900 health workers and ran 139 oral rehydration locations, to treat 700,000 reported cases of the illness. UNICEF reported that they ran awareness campaigns with 20,000 promoters, provided water to more than one million individuals, served as the WaSH lead, and delivered "40 tons of medical equipment including medicine, oral rehydration solution, IV fluids and diarrhea kits". Médecins Sans Frontières (Doctors Without Borders) said it treated at least 103,000 individuals in 37 locations. == Global responses ==

Canada As of June 2, 2020, Canada has pledged $40 million in humanitarian aid for Yemen to help the politically unstable country cope with cholera, malaria, dengue fever, and diphtheria along with COVID-19. This brings Canada's total contributions to Yemen since 2015 to $220 million, which contributes towards the goal of US$2.4 billion for underfunded humanitarian programs run by UN agencies and humanitarian organizations in Yemen. On 23 June 2017, Saudi Arabia's crown prince, Mohammed bin Salman, authorized a donation in excess of $66 million for cholera relief in Yemen. Mohammed al-Jaber, the Saudi ambassador to Yemen, has announced half a billion dollars from Saudi Arabia to support UN programs in 2020. As of July 8, 2019, the UN and partners are running 1200 cholera treatment facilities around the country, however, funding is an issue. The 2019 Yemen Humanitarian Response Plan required $4.2 billion to deliver assistance, but they ended up receiving $3.6 billion. This money will be used for food assistance, safe drinking water, emergency shelter, and medical supplies. The U.S. officials were concerned that the assistance was directed to fighters instead of civilians. The UK has partnered with organizations including UNICEF and the International Organisation for Migration (IOM) to combat the cholera disease in Yemen. DFID Secretary Priti Patel has urged the international community to follow the UK government's steps to curb the cholera outbreak. This money is being used to strengthen the country's health, water, and sanitation systems. == Statistics ==

The WHO provided regular outbreak updates for the epidemic in Yemen up until August 2020. Since then the epidemic has declined in numbers of cases and deaths, with 2020 seeing a total of 230,540 suspected cases and 84 deaths and 5,676 suspected cases with two deaths between January 1 and March 6 of 2021 Furthermore, UNICEF reports that in 2021 over 190,000 children received a cholera vaccine, achieving 94% coverage. == See also ==