Blood group O has been linked with severe cholera illness — Ogunbosi

Dr. Babatunde Ogunbosi, a paediatric infectious disease expert at the University College Hospital (UCH), Ibadan, speaks in this interview with SADE OGUNTOLA on cases of cholera in Nigeria and what individuals need to know regarding the recurrence of the deadly infection.

WhAT is the cause of cholera and what are the predisposing factors for it?

Cholera is caused by an organism, a bacterium called Vibrio cholerae. And then different types of the cholera germ can cause infection. Now, it is transmitted through the faecal-oral route, which occurs between faeces; its effluents get to the mouth. People that have the organism pass it out in the faeces, and when that organism is in the faeces and comes into contact with anything people put in the mouth, then they get cholera. That means it’s unlike measles or tuberculosis, contracted through the air. These come from people coughing out these germs, and then they remain airborne.

So, cholera is a water-borne disease to a large extent. The places where you see cholera are where you have poor sanitary conditions. That means waste disposal is not optimal. Currently, Nigeria has one of the largest populations of people that openly defecate all over the world. Data tells us that about 48 million Nigerians still practiced open defecation in 2023. According to the National Bureau of Statistics, 24.4 percent of household members in Nigeria still practice open defecation, one of the top 10 in the world. It is highest in the North Central with 53.9%, followed by the South West with 28.0%, while the North West had the least with 10.3%.

When you have open defecation, the faeces that are let out just anyhow find their way back into body waters. And then those body waters come back into our water sources. And so, in the early rains, when you have open defecation all over the place, the early rains are going to wash all those faeces that have not been properly disposed into surface waters. And you know, we don’t have good water supply in most parts of our country. Only about 18 million people have access to pipe-borne water supply in this country, less than 10% of the population.

So, people get water from ordinary streams, from wells that might be contaminated with surface and underground water. Even the boreholes, often times, are not properly treated. When you have poor sanitary conditions and a poor water supply source, then you are going to have cholera.

And so, you have cholera in most low- and middle-income countries, which are mainly sub-Saharan Africa, South America, and Southeast Asia, and especially in places where they don’t have good pipe-borne water. Unfortunately, Nigeria is not doing so well. So, when somebody asked me about cholera recently, I said it’s just a failure of government and basic infrastructure. Water supply and sewage disposal are basic infrastructure. Problems around these two things have been solved over 100 years ago. We have the technology and resources to fix it, but we haven’t. And that’s why we keep having cholera episodes all the time. Everybody is at risk, young and old, because we all take water; we all take food. So, anybody that does not have good access to potable water is at risk. But some factors increase the risk of having cholera. Blood group O has been linked with severe illness. Also, conditions that reduce acid in the gut, those that use antacids that reduce the acid in the gut, people with peptic ulcer disease on drugs like H-2 receptor blockers and proton pump inhibitors—all of these will cause reduced acid in the gut. That’s what they do because we use all those medications for patients with ulcers. Close contact with infected persons also increases the risk of having cholera.

The people that have had previous infections will have some degree of protection against that particular serogroup.

Does it mean that we have different strains of cholera germ, and each with a different severity of infectivity?

I imagine that the amount you take in will determine whether you get the infection or not. But the type is mainly tied to epidemics and where they occur but not to their severity.

What exactly is the problem? Is it the germ that causes the problem or the toxins that it generates in the body that cause the problem?

A: Usually when there’s an infection, it goes through the small intestine, and it has to survive the acid environment of the intestine when it ends up in the small intestine and producing toxins that activate a pathway inside the gut that leads to massive waste secretion in the small intestine. And so, people come down with a large volume of stools that contain a lot of electrolytes, and they can also have vomiting. So, death in patients with cholera is usually due to massive fluid and electrolyte loss both through the vomiting and the stool. It is this that causes the deaths that we have seen in cases of cholera.

Aside from water, are there other means or routes of contracting cholera?

Anything that goes into the mouth, water, and food can be sources for contracting cholera. Also, through poor sanitation. For example, if somebody is taking care of a patient with cholera and does not ensure proper hand hygiene and issues like that, they can get the bugs on their hands and put it in their mouth unknowingly, and that can transmit the infection.

What are the risk factors for cholera spreading in a particular household or community?

Wherever you have overpopulation or overcrowding, then there’s a closer mixing of people and all of that. Now, if they also have poor water supply and sanitation, that will inevitably increase the possibility of a disease like cholera. So, individuals in poor socioeconomic settings will probably be at higher risk of those risk factors. Likewise, internally displaced people in camps with poor sanitation conditions, poor water supply, overcrowding, etc. Of course, travel to areas where there’s high endemicity of cholera will be a factor. Obviously, children that are less than five years old have a higher risk of infection and probably severity because of the poor immunity that they have.

In the past, it was said that eating things like fish products and leftover foods in Calabar was linked with cholera. How is this linked with cholera?

Basically, what we know about cholera is that poor hygienic situations and poor water supply is responsible for cholera. But all these other things, like eating fish and fish products and leftover foods, cannot cause cholera unless they have been contaminated by the germ responsible for the disease. But there’s a possibility of the transmission of the germ if such is eaten. Leftover food, especially when not properly stored at low temperatures, just allows the bacteria to multiply and increases the bacteria load.

However, the situation is unlike food poisoning, where things like that can happen. Cholera is basically from the contamination of the food. Whether it’s leftover or not, it’s really got to do with food being contaminated.

How do you see the level of antimicrobial resistance to common antibiotics affecting the current cholera epidemic in Nigeria?

For cholera, to a large extent, what you need to do in managing cholera is to replace the fluids and lost electrolytes. Yes, you can give antibiotics to reduce the shedding of the organism in the stool and also the duration of shedding, which puts them at higher risk of transmitting the bacteria and all of that.

Now, with antimicrobial resistance, treatment becomes even more challenging when you abuse drugs. And so, in that setting, available treatment options are compromised. But the most important intervention for cholera is to ensure electrolyte and water loss replacement.

Do we have cholera vaccines, and are they effective?

Certainly there are cholera vaccines. There are quite several cholera vaccines on the market, and they all have different degrees of efficacy, and the duration of coverage also differs.

Is the cholera vaccine available in Nigeria? Is it advisable to go for the vaccine, particularly now that we are recording cases of cholera in different parts of Nigeria?

In endemic areas like Nigeria, the use of vaccines is often not recommended, except for people travelling from non-endemic areas to endemic areas. That means they’re living in places where cholera is not a problem and then they’re going to areas where cholera is a problem. So, those are typically advised to take the vaccines based on their travel vaccination advisory. In essence, routine immunisation for cholera is not recommended.

Can the vaccine be administered now that we have pockets of cholera across Nigeria?

So, for some settings where there’s a large outbreak, there may be a role for active vaccination to curb and reduce the risk of those that will potentially be at risk, especially in conjunction with other interventions like improved sanitation and water supply. Then it can be given in settings where there are particularly high-risk populations, like those in IDP camps, where there will be overcrowding, poor water supply, and sanitation. So, it is not like the polio, diphtheria, or meningitis vaccine that is given to everyone.

What are the signs and symptoms that people should look out for to suspect a case of cholera? And which hospital are they supposed to go to?

Typically, cholera presents with the passage of large volumes of watery stool. Some may have vomiting as well. We typically describe the diarrhoea in cholera as spurious diarrhoea with a rice-water kind of stool. So, that means the patient is passing a lot of loose stools that are like rice water. That’s basically because of the flaking of the lining of the intestine that gets shed with the passage of the watery stool. The watery stool comes out a lot, with probably no faecal matter with it. Now, they might have a low-grade fever and abdominal pain.

But it happens so rapidly that the patient becomes very weak in a very short time because of the severe loss of water and electrolytes from the body at the same time. Some of them can present in shock. Shock in this setting leads to death. Early signs of shock include thirst, dry mouth, and decreased urination. Once a case of cholera is suspected, such should ideally go to an infectious disease hospital or a hospital that has resources or facilities for isolation such that they don’t spread the infection and where there is competence to put up an intravenous line to rehydrate them rapidly as well as run tests to check for electrolytes. Without this treatment, serious complications, including seizures and coma, can happen as a result of dehydration.

Q: What is your advice to mothers to ensure children are protected, particularly now from contracting cholera?

Particularly now, babies must be breastfed. Breastfeeding boosts babies’ immune systems while also eliminating the risks of consuming contaminated water. Likewise, hand hygiene and food and water safety precautions need to be taught to children.

Fruits and vegetables should be washed and peeled before eating. It is better to purchase already peeled fruits, as they may become contaminated after peeling. Also, in cases of diarrhoea, they should be given zinc and ORS and taken to the hospital. Children should also not be allowed to eat food from doubtful sources.

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