CHOLERA spread across the world during the 19th Century, from its original reservoir in the Ganges Delta in India.
Six subsequent cholera pandemics have killed millions of people across all continents.
The current (seventh) pandemic started in South Asia in 1961; reached Africa in 1971 and the Americas in 1991.
Cholera is now endemic in many countries, including Zimbabwe.
The number of cholera cases reported to WHO, over the last few years, has continued to increase.
During 2020, 323 369 cases and 857 deaths from 24 countries were notified.
Latest cholera hotspots in Zimbabwe:Source: Ministry of Health and Child Care Cholera Situation Report, May 4 2023.
In epidemiology, cholera can be defined as endemic or epidemic.
A cholera-endemic area is an area where confirmed cholera cases have been detected during the last three years with evidence of local transmission (that is, the cases are not imported from elsewhere).
A cholera outbreak in endemic countries can be seasonal (as in Zimbabwe) or sporadic and represents a greater than expected number of cases.
In a country where cholera does not occur regularly, an outbreak is defined by the occurrence of at least one confirmed case of cholera with evidence of local transmission in an area where cholera is not usually present.
A cholera epidemic/outbreak can occur in both endemic countries and in countries where cholera does not regularly occur.
The disease was studied during an epidemic in Egypt by Robert Koch (1843-1910), a German bacteriologist, and found a bacterium in the intestines of those who had died of cholera, but could neither isolate the organism nor infect animals with it.
The v. cholera bacteria, the cause of cholera infection, was discovered later in 1883 when Koch went to India, where he succeeded in isolating the bacteria.
There are many serogroups of v. cholerae, but only two – O1 and O139, cause outbreaks of cholera.
V. cholerae O1 caused all recent outbreaks.
While v. cholerae O139 — first identified in Bangladesh in 1992 — caused outbreaks in the past, more recently it has been identified in sporadic cases in Asia only.
Toxic strains of cholera bacteria produce a poison that triggers violent diarrhoea in humans.
A person with cholera can quickly lose body fluids — up to 20 litres a day — resulting in severe dehydration while shock can occur.
This can lead to the collapse of the circulatory system.
It is a life-threatening condition and a medical emergency.
Dehydration usually leads to death; so the most important treatment is to give to a patient oral hydration solution (ORS), also known as oral rehydration therapy (ORT).
Home-made ORS recipes are often used in developing countries, where commercially pre-packaged mixtures are limited by cost. Common household ingredients consist large volumes of water mixed with a blend of sugar and salts.
Many of us old-timers will remember using the iconic Zimbabwean 2-litre Mazoe bottle as a standard measure for this purpose.
The WHO/UNICEF ORS standard sachet is dissolved in one litre of clean water.
Adult patients may require up to six litres of ORS to treat moderate dehydration on the first day.
Severe cases of cholera require intravenous fluid replacement. For an adult weighing 70 kg, at least seven litres of intravenous fluids will be required.
While antibiotics are available, WHO does not recommend the mass use of antibiotics for cholera because of the growing risk of bacterial resistance.
Cholera remains a global threat to public health and an indicator of inequity and lack of social development.
In Zimbabwe, the quality of water for both urban and rural communities has deteriorated over the recent years due to several factors which include but are not limited to: over population pressure; cultivation and construction on watercourses and wetlands (home to 40 percent of all biodiversity); pollution from agriculture, industry and mining and, lastly, climate fluctuations.
The deplorable water supply situation in Zimbabwe has led to increased health hazards, and contributed to the increase in diarrhoeal water-borne disease outbreaks since the 2008/2009 cholera outbreak.
The prevalence of diarrhoea, often a result of poor water for sanitation and hygiene (WASH) practices, is significantly higher in urban areas (6,9 percent) than rural areas.
Diarrhoea increases the risk of malnutrition as it hampers nutrient absorption.
The high incidence of diarrhoea in children under five years is mainly due to the poor quality of water sources in urban areas. The high incidence of waterborne diseases, such as diarrhoea, typhoid and cholera, in urban areas in Zimbabwe is an indication of high contamination in water from tap and boreholes in urban areas in Zimbabwe, especially Harare.
Adequate water supply and sanitary facilities are of the utmost importance in reducing infectious diseases, but are severely lacking in both rural and urban areas.
Water for sanitation and hygiene (WASH) is most challenged in Matabeleland North, where open defaecation in the area is high and sources of clean drinking water poor.
The long-term solution for cholera control lies in economic development and universal access to safe drinking water and adequate sanitation.
Actions targeting environmental conditions include the implementation of long-term sustainable WASH solutions to ensure use of safe water, basic sanitation and good hygiene practices in cholera hotspots.
In addition to cholera, such interventions prevent a wide range of other water-borne illnesses, as well as contributing to achieving goals related to poverty, malnutrition and education.
The WASH solutions for cholera are aligned with those of the Sustainable Development Goals (SDG 6).
The provision of safe water is a basic human right.
The Government of Zimbabwe, Municipal authorities, Urban Planning Council and other relevant national water and sanitation departments must be pro-active in preventing the spread of waterborne disease in Zimbabwe.
Additionally, public health education needs to be made more accessible through various media platforms to educate the populace about the prevention of the spread of cholera.
They owe it to the people.
Dr Tony Monda is currently conducting medical epidemiology research on urban disease control and public health issues in Zimbabwe. For views and comments, email: tonym.MONDA@gmail.com