If there’s only one disease, the transmission of which is controlled by just the observation of good hygiene, it’d be cholera. This assertion is solidly supported by the famous 19th century well documented successful control of the transmission of cholera in a certain area in London just by changing the head of a contaminated public water tap. More to this, looking at the current epidemiology of cholera, it is easily seen that the incidence of cholera is almost non-existent in societies that have progressed from having poor hygiene in the past, to being the epitomes of hygiene today. In essence, cholera is a disease of poor hygiene.
A research done to ascertain the global burden of cholera between 2008-2012 indicates that there are 1.3 – 4 million cases of cholera annually, with 21,000 to 143,000 deaths. The sub-Saharan Africa accounted for 60% of all the cases, with South-east Asia taking 29%. Between 2020-2021, there were 93,598 cases in Nigeria with 3,298 deaths. As at the time of writing this article, there’s an ongoing cholera outbreak in Lagos, Nigeria.
In this article, we will be looking at cholera, what it is, what symptoms and signs an individual who is infected comes down with, how to go about it, and how to prevent it.
What is cholera?
Cholera, according to the World Health Organization (WHO) is an acute darrhoeal infection caused by ingestion of food or water contaminated with the bacterium Vibrio cholerae. The bacteria infect the intestine, causing loss of fluid, electrolytes and severe dehydration. Cholera continues to remain a threat to global health.
Causes
As stated above, cholera is caused by a bacterium called Vibrio cholerae. The bacteria are found in shallow, salty water, on crustaceans. They also exist as biofilms that coat the surface of water, plants, stones, shells.
Human beings get them from drinking contaminated water or food, consuming undercooked seafood. They are only transmitted feco-oral. There is no transmission by any other form of contact.
The bacteria produce toxin, which interferes with sodium and chloride flow through the walls of the intestine. This leads to secretion of sodium and chloride into the intestine and water naturally follows. Large amount of water and electrolytes are then lost from the body via copious diarrhoea and vomiting.
Risk factors
These are conditions that make an individual more likely to develop the disease, but they may or may not develop the disease despite having or living in such conditions. They include:
- Unclean conditions: Living in an environment with poor sanitation and contaminated water.
- Achlorhydria: This is a condition in which the stomach does not produce gastric acid. As the bacteria do not survive in acidic environment, this condition gives them the perfect opportunity to thrive.
- Sick household members: close contact with people who have cholera may predispose one to the disease as there is a chance for the contamination of the household’s food and water.
- Eating raw shellfish: As they may be contaminated with the bacteria from the source
- Type “O” blood group: although the exact mechanism is still not known, but studies have demonstrated an enhanced response of cells that express the ‘O’ blood group to the cholera toxin.
Symptoms and signs
It is worthy of note that not all people who are infected with the bacteria come down with the signs and symptoms of the disease. In fact, according to the Centre for Disease Control (CDC), only 1 in 10 people come down with symptoms of severe illness. The symptoms usually begin to manifest between 12 hours to 5 days of infection. They include:
- Large volumes of explosive watery diarrhoea, called “rice water stools” because it typically looks like water that has been used to wash rice.
- Vomiting
- Cramps in the legs
- As the disease is more devastating in children, it may come with fever, convulsions and even coma.
Since the hallmark of this disease is the loss of fluid and electrolytes, dehydration and ultimately shock may result. The features of dehydration include:
- Sunken eyes
- Dry mouth
- Decreased secretions; less sweating, less urination.
- Fast heartbeat
- Rapid weight loss
- Dizziness or light-headedness
- Low blood pressure
- Shock, and if not addressed, ultimately death.
Making diagnosis
Since cholera usually occurs in epidemics, it is easy to make diagnosis clinically by analysing the presenting symptoms and signs. Further, stool culture or a swab of the rectum may be taken to identify the organism in the laboratory.
Treatment
The mainstay of treatment of this disease is replacement of the fluid lost. Rehydration is the aim of treatment. It may be:
- Oral Rehydration Solution (ORS) for those able to take orally.
- For those unable to take orally, intravenous fluid replacement should be done using specific intravenous fluids, and the best here is Ringer’s Lactate.
- Zinc may also be given to help with the reformation of the intestinal lining.
- Antibiotics are also given to help to contain the organism and reduce the duration of illness.
Complications
Cholera is a very fatal disease. It can kill an individual within few hours if not treated. The severest complications are shock and severe dehydration. Others include:
- Acute kidney injury due to hypovolemia
- Hypoglycemia which is low blood sugar
- Hypokalemia
Prevention
As we stated from the beginning, cholera is a disease of poor hygiene. The prevention of this disease is anchored to the observance of good personal and environmental hygiene. There are several ways of achieving this, and some of them include:
- Hand washing – washing of one’s hands before and after using the toilet, before and after meals. Using hand sanitizers where available.
- Drinking water should be boiled, or should come from a trusted clean piped supply.
- Food should be cooked thoroughly, thorough enough for the microbes to get killed in case the food is contaminated.
- Street food, especially from vendors who do not cover their foods should be avoided.
- Flies that may carry the organisms around on their bodies must be denied access to food.
- Peel fruits before eating them or wash them thoroughly.
- Vegetables must be thoroughly washed before consumption.
- During epidemics, the public must be educated about the disease, there must be improvement in sanitation and access to clean water, and control of population movement.
Vaccination
The World Health Organization has approved 3 oral vaccines for use as part of its pre-qualification programme. They are: Dukoral, Euvichol and Shanchol. The last two are those frequently used for people in endemic areas. Two doses of this vaccine are given, with at least 14 days interval between them. This is also the case in guidelines followed by the Medecins Sans Frontieres (MSF). It is advisable to administer this vaccine to children from 2 years of age and adults. The two doses confer protection for at least 3 years.
Cholera is a disease of poor hygiene, and therefore outbreaks frequently happen in developing countries especially those belonging to the sub-Saharan region.
It is a rapidly fatal disease and kills within hours if not treated.
The mainstay of treatment of cholera is replacement of lost fluids.
It is responsive to prompt treatment.
References
Ali, M., Nelson, A. R., Lopez, A. L., & Sack, D. A. (2015). Updated Global burden of cholera in endemic countries. PLoS Neglected Tropical Diseases, 9 (6), e0003832. https://doi.org/10.1371/journal.pntd.0003832
Elimian, K., Yennan, S., Musah, A., Cheshi, I. D., King, C., Dunkwu, L., Mohammed, A. L., Ekeng, E., Akande, O. W., Ayres, S., Gandi, B., Pembi, E., Saleh, F., Omar, A. N., Crawford, E., Olopha, O. O., Nnaji, R., Muhammad, B., Luka-Lawal, R., . . . Adetifa, I. (2022). Epidemiology, diagnostics and factors associated with mortality during a cholera epidemic in Nigeria, October 2020–October 2021: a retrospective analysis of national surveillance data. BMJ Open, 12 (9), e063703. https://doi.org/10.1136/bmjopen-2022-063703
Kuhlmann, F. M., Fleckenstein, J. M., Santhanam, S., Kumar, P., Luo, Q., & Ciorba, M. A. (2016). Blood group O–Dependent cellular Responses to cholera toxin: parallel clinical and epidemiological links to severe cholera. The American Journal of Tropical Medicine and Hygiene, 95(2), 440–443. https://doi.org/10.4269/ajtmh.16-0161
Oral Cholera Vaccine O1 and O139 | MSF Medical guidelines. (n.d.).
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