First case of cholera in Spain since 1979? What you should know

Indeed, from cholera, from that disease that most of us will only remember from old movies or history books, the cause of multiple pandemics in times past or in countries without much access to drinking water. In fact, the last time someone in Spain was locally infected with cholera was in the North African enclave of Melilla in July 1979. From there, it spread throughout the country, affecting 264 people.

What happened?

Last week, a girl drank water from a farm in the province of Toledo. Shortly thereafter he fell ill and tested positive for the bacterium Vibrio cholerae , the bacteria responsible for cholera . It was diagnosed in the Community of Madrid by the Carlos III Institute, which sounded the alarm and caused the farm to be sealed.

What exactly is cholera?

Cholera is an intestinal infection caused by the bacteria Vibrio cholerae . The hallmark of the disease is profuse secretory diarrhea . Cholera can be endemic, epidemic or pandemic. Despite all the great advances in research, the disease remains a challenge to the modern medical world. Although the disease may be asymptomatic or mild, severe cholera can cause dehydration and death within hours of onset.

Cholera is transmitted by the fecal-oral route , that is, through ingestion of the bacteria, often through contaminated food or water. In developed countries, due to advanced water and sanitation systems, cholera is not a common problem. However, the disease is still prevalent in other parts of the world, such as India or sub-Saharan Africa.

How is it treated?

Definitive diagnosis is not a prerequisite for treatment of patients with cholera. The priority in treating any watery diarrhea is to replace lost fluid and electrolytes and provide an antimicrobial agent when indicated.

A Vibrio cholerae infection does not equate to cholera

Although it is true that cholera is a disease caused by this bacterium, not every infection caused by this bacterium leads to the development of cholera. Let me explain.

Bacteria are divided into five basic groups based on their shape: spherical ( cocci ), rod ( bacilli ), spiral ( spirilla ), comma ( vibrios ), or corkscrew ( spirochetes ).

In this case, we are talking about a bacterium of the Vibrio group. This name also refers to the fact that organisms in this group seem to vibrate when they move.

The second name is no longer “the house” to which they belong, but “their proper name”, in our case, cholerae . However, this is where another important concept comes into the picture. You see, if you have 100,000 children all with the same name, you will have to refine a little more to differentiate them, that is where the particularities of each one come in, such as hair color, eye color, the number of freckles, etc. Or, in the case of bacteria, their serotype .

A serotype is an infectious microorganism classified according to the antigens (proteins) present on its cell surface. Serotypes allow organisms to be differentiated at the subspecies level , something of great importance in epidemiology.

Thus, a given serotype is a subpopulation of an infectious organism that is distinguished from other subpopulations of the same species by serological tests . Therefore, the body’s immune responses against a serotype of a microorganism, such as those provided by vaccines (such as influenza or SARS-CoV-2) may not protect against another serotype of the same species.

Serotypes can be established according to virulence factors, presence of exotoxins or other characteristics that differentiate two elements of the same species through various tests.

Thus we understand that not all Vibrio cholerae bacteria cause cholera. Specifically, the serotypes identified as the main cause are O1 and O139 (these are just two “labels” to help us differentiate between them).

A little history…

Cholera is a very old disease. Throughout history, populations around the world have been sporadically affected by devastating outbreaks of cholera. Records from Hippocrates (460-377 BC) and from the Indian peninsula describe a disease that could have been cholera.

Although not the first description, the discovery of the cholera organism is attributed to German bacteriologist Robert Koch, who independently identified V. cholerae in 1883 during an outbreak in Egypt.

Since 1817, there have been seven cholera pandemics . The pandemics originated in the endemic cholera reservoir on the Indian subcontinent. Of these six pandemics, five affected Europe and four reached the United States, causing more than 150,000 deaths in 1832 and 50,000 in 1866. It is thought that the first six were probably the result of the Vibrio cholerae O1 subtype.

The seventh cholera pandemic, and the first of the 20th century, began in 1961; by 1991, it had affected 5 continents. The pandemic continues today. This seventh pandemic was the first recognized as being caused by the El Tor biotype of V. cholerae O1 (yes, we can subclassify bacteria even beyond their serotype ). The pandemic originated in the Sulawesi Islands, Indonesia, and affected more countries and continents than the previous 6 pandemics.

A new strain of cholera, V. cholerae serogroup O139 (Bengal), emerged in the fall of 1992 and caused outbreaks in Bangladesh and India in 1993. Disease from this strain has become endemic in at least 11 countries.

What are the symptoms?

V. cholerae produces a powerful toxin that, in the cells of the intestinal mucosa, causes the chloride channels to remain open and, therefore, these channels open and the ion comes out massively from the intestine, dragging with other ions and causing an excessive intestinal secretion of water with sodium, bicarbonate and potassium, which exceeds its absorption capacity. That is, we lose chlorine massively, which causes the massive loss of other ions and water. Thus, we dehydrate in a few hours. Therefore, it is understood that, after a short incubation period (between 2 hours and 5 days), the symptoms are varied, such as:

• Abdominal pain due to mucosal irritation
• Watery diarrhea with a high number of stools (up to 30-40 in 24 hours). This is perhaps the most important fact.
• Whitish stools.
• Diarrhea can be accompanied by vomiting, which further contributes to rapid dehydration .
• It does not usually cause fever , because the disease, remember, is caused by the toxin of the bacteria, not the bacteria itself.

So… do we have cholera in Spain?

Now that we know what the disease consists of, and the difference between a Vibrio cholerae infection and suffering from cholera, we can understand the statement made by the Spanish Ministry of Health last Wednesday.

On Wednesday, the director of Public Health of Madrid, Elena Andradas, said that a case of cholera had been detected in the Spanish capital last week. However, the Ministry of Health has clarified that his illness should have been diagnosed as Vibrio gastroenteritis, not cholera .

This is because, although the one detected in Spain was part of serogroup O1, the ministry said that this particular bacterium lacked the toxin that causes the infection .

References:

Cholera (2018). MedlinePlus. https://medlineplus.gov/spanish/ency/article/000303.htm

‌Govan, F. (2022). Spain’s Health Ministry denies report of first local cholera infection since 1979. Olive Press News Spain. https://www.theolivepress.es/spain-news/2022/06/23/spains-health-ministry-denies-report-of-first-local-cholera-infection-since-1979/

Handa, S. (2021). Cholera. Medscape. https://emedicine.medscape.com/article/962643-overview

McMurtry, A. (2022). Spain denies report of 1st local cholera case since 1979. Anadolu Agency. https://www.aa.com.tr/en/europe/spain-denies-report-of-1st-local-cholera-case-since-1979/2620768

‌Spain denies regional report of first local cholera infection since 1979 (2022). Reuters. https://www.reuters.com/business/healthcare-pharmaceuticals/spain-detects-first-local-infection-with-cholera-since-1979-2022-06-22/