Drought-related Cholera Outbreaks in Africa

Throughout its history, Africa has seen several periods of prolonged and extreme droughts across the continent that, along with malnutrition, poor access to water, sanitation and hygiene, and population displacement, cause food insecurity, exacerbate social inequity, boost mortality rates, and, perhaps most significantly, encourage disease outbreaks. Cholera is one such disease, and Africa has the highest global cholera burden. It is also a continent with many drought-prone regions. Despite this, research on cholera and droughts in Africa is lacking.

Vibrio cholerae is a water-borne bacterial pathogen, with symptomatic cholera causing profuse watery diarrhea and sudden onset dehydration [1]. The annual cholera burden is estimated at 1.3–4 million cases and 21,000–143,000 deaths annually [2,3], with >94% of these reported in Africa [4]. Several countries are beginning to show signs of endemicity and there is currently a Global Task Force on Cholera Control that aims to reduce cholera deaths by 90% by 2030 and eliminate cholera in 20 countries [5].

Less well understood is the impact of drought on cholera [1,2]. Droughts are a complex hazard and involve meteorological, hydrological, agricultural, and societal changes [3]. Africa has seen several periods of extreme and extended drought [14]. Despite some studies suggesting links between drought and cholera outbreaks [3], this link, especially in Africa, has been widely under-studied in isolation. One suggested mechanism through which drought may catalyze cholera outbreaks is via increasing concentrations of V. cholerae in groundwater. For example, in Bangladesh cholera concentrations were 13-49% higher in dry weather drainage flow samples compared to wet weather samples from floodwater [5].

Environmental factors may only be influential in cholera outbreaks to a certain extent, after which socio-economic conditions are key drivers for outbreaks. Eight hundred and forty-four million people worldwide lack access to basic drinking water and a further 2.4 billion are without basic sanitation [5], putting many people at risk for diarrheal diseases. Human-induced factors may therefore be of equal importance for cholera dynamics with environmental factors due to a range of risk factors and potential cascades including poverty, sanitation, drainage, water quality, poor healthcare, malnutrition, and human behavior such as eating practices, all of which could be exacerbated by drought [3].

There is a need for the involvement of people in water-related democratic dialogues at all levels to identify some of these challenges and their solutions. Democratizing water helps in bringing all stakeholders—governments, local governments, communities, private sectors, and non-profits—towards a common understanding of challenges to water quality and encourages looking for locally relevant solutions together.

Citations

[1] Ali M, Lopez AL, You Y, et al. The global burden of cholera. Bull World Health Organ. 2012;90(3):209–218.

[2] Germani Y, Quilici ML, Glaziou P, et al. Emergence of cholera in the Central African Republic. Eur J Clin Microbiol Infect Dis. 1998;17(12):888.

[3] World Health Organization. Cholera. [On-line]; 2020. Available from: https://www.who.int/health-topics/cholera#tab=tab_1

[4] Nkoko DB, Giraudoux P, Plisnier PD, et al. Dynamics of cholera outbreaks in Great Lakes region of Africa, 1978–2008. Emerg Infect Dis. 2011;17(11):2026.

[5] World Health Organization. Ending cholera a global roadmap to 2030. In: Ending cholera a global roadmap to 2030. Geneva: World Health Organization; 2017, pp.4.

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