So today we want to talk about the disease human schistosomiasis and fairly briefly it's just and, and maybe my task is to give a little brief overview of the, what we call the burden of the disease. In other words, how big is it and how do we see it as as as a clinician or a doctor working at let's say a teaching hospital in, in an African country. In this case we're in Northern Tanzania. We're in East Africa. And then, more or less, wha, what happens to the, to the patients? What goes wrong? In other words. How does the disease affect humans essentially. And a little bit then about how we make the diagnosis of the disease and then our management. So going back to the disease itself it's a very old disease and, and they found evidence, evidence of it in, in, in fair times. So it is one of the classical, old diseases. And it's we call it a disease of, of, of, of worms basically they're called trematodes I think. And they have an intermediate host. A big, and the intermediate host is the snail. And then they the human is the is the what we call the definitive host. And they, the life cycles is very important because the life cycle of is, is, is the way, the understanding of that is how we prevent it. So, what happens there are different types of schistosomiasis that's less important. And it's a very common disease worldwide. I think it's estimated that globally there are 200 million infected, of which 150 million are in Sub Saharan Africa. And if we consider, we, we have a population of 800 million. Then that's a huge burden. And it exists right throughout Sub-Saharan Africa. Of course, it has a predilection for certain areas which we'll talk about. And the intermediate host is a snail and the snail likes to live near water. Particularly water that has an edge whereby it can occupy land and water. So therefore you find an intermediate host. The snail. The one we see here is Bulinus, that is the one that transmits Schistosoma mansonii which is our common type here and anywhere where you have got irrigation, lakes, water, what they call stagnant water that is not flowing. The snail will inhabit. And, very simple, very simply, the the humans come and either defecate or pass urine. And when they do that they pass the eggs from the adult worm, which is inside of them, into the ,. Feces and urine of course goes into the water. The, the eggs hatch out and become intermediate phase, I think they're called mericidae. They actually go to the snail and they have a second life cycle in the snail, which they eventually hatch our and become cercaria. And then, when the humans walk in the water, the cercaria go in through your skin. Usually on your legs. And inside of you, they migrate. They migrate, the larval form migrates, depending on the type you have, either to your small in, to your intestine, to the veins in your intestine we call the mesenteric veins, or to your bladder vein. With haematobium or your intestinal things with mansoni. They are the two common types we have here. And, I always teach the students that, on average, you become infected with about seven adult pairs. Now, they live in your mesenteric veins, and the, the female is three times as big as the male. She apparently lies on her back with the male on top of her, and their entire job is to produce eggs for all their life. They can live up to 17 or 20 years. And unless they are killed off, they will continuously secrete eggs, and it's the eggs that do the damage. The eggs are very, what we call, inflammatory producing, and the eggs go with the flow of the vein, and in this case. In the case of they go with the veins, and the veins go to the liver. They join with a vein coming from the spleen, go to the liver. What happens is they, the veins get, inflamed, the bigger veins around them as the eggs try to migrate up to the tissues. So the surrounding area, what we call the portal system, becomes inflamed, then thicken. And eventually the blood is not able to get through. So the pressure goes up an inch, and that pressure is transmitted back through what we call the portal system. The spleen enlarges but the worst effect is actually the the, the veins in the portal system do have a, a joining. With things that come from the other system. And one area is the lower part of your gullet, or your esophagus. They, essentially you get piles, or hemorrhoids or varices in your lower end of your esophagus. They bleed and you die. And of course, that is the big complication of, of, of, of schistosomiasis. And that's the one we see. The way we make the diagnosis of course, is relatively easy because the patient will present with vomiting large amounts of blood. When we examine them we inevitably find a spleen, the liver may or may not be slightly enlarged. They may have some free fluid in their abdomen, because of the back pressure. And in, in, in a place like we can do a gastroscopy or esophagoscopy look down and confirm them. The management is extraordinary difficult because here you have a young person now who has a major complication which will kill him eventually unless something is done about it. And the something done about it is almost impossible in Africa. Because it means we can kill off the other worms, but by then they have done their damage and in other words we're dealing with a complication. We manage that by putting on medication for life, try to drop their blood pressure, we call them beta blockers. We sometimes inject the varices with a sclerosing agent to try to to try to make the sides come together and promote lack of bleeding. You can use elastic bands if you have them, but technically, that procedure needs five, at least, five. Five separate looking down in your stomach and that's not cheap and very time consuming and for a disease that is as common as I have just said I would like to emphasize that of course not everybody with schistosomiasis develops portal hypertension. But the type we have here, the is the most common type. That's the major complication, and that's the one. And of course, even a small percentage of a common disease will produce a high burden. In terms of case KCMC in our experience here, I would say it's safe to say that we will see somebody bleeding from schistosome varices. On average we'll see two, maybe three a week. And it, it's, it has become one of our leading causes of death, in, in our inpatients. Because, where does it all come from? Well it comes from the irrigation of rice fields, which was promoted in the last 30 years for, to produce food. And of course, with that it carries the, the danger of, of a disease. So, that brings up the question then of how you manage it. Well, the management at the moment is, is, is primarily based on, on what we call primary prevention. We try to prevent the. The people who are infected with the adult worms, either in their intestine, intestine, which is mansoni, or haematobium goes to bladder, so they're excreted in your urine. Mansoni is in your stool. So it's excreted that way. The eggs. We encourage them to defecate or urinate in a controlled manner, like a toilet. Now you, you and I, you can imagine it's impossible to put toilets for every right field, rice field is. And, so that effectively fails. Another way would be to get rid of the snail. Mao Tse Tung did that and stopped schistosomiasis in parts of China, but it's come back again. I think the only way we have here now, that's, that is probably effective is mass chemotherapy for younger generations, who are exposed. By that, I mean, you would give a drug that would kill off the other prawn. In say school children, every 12 months right up till the time they're I think young adults, probably 18 19, would be ideal. And to be effective you'd have to treat everybody as if they were infected in areas of high exposure. That I think is the main target for the future. Because it's, it seems almost impossible to, to, to promote the hygienic method that I’ve said. You can encourage it of course and of course looking for complications is late. So by the time the patients are presenting you with bleeding disorder. Like we see them. There is another group of complications which I didn't mention that comes from hematobium where the bladder can get stones. You can get malignancy and complications in what we call the genital urinary system. Which can present with kidney failure later on in life. So there's a serious, another serious group of complications that. So all in all we also see eggs in places they shouldn't be. In the nervous system I see them, and if you go to an endemic area where schisto is actually endemic in the population, i.e. like malaria, if more than a significant percent of the population is infected, say 20, 30, 40%. Carry the adult worms. If you go to areas like that, you will find rare complications like paralysis in the legs in about, it's supposed to account for something like, up to 5% of all paralysis of the legs in areas that were endemic for So it carries a very high burden, medically, that's my point. And it's a big disease either based on, on, on I think it's probably our biggest protozoal disease now with the relative demise of malaria and of course it's dwarfed by HIV and by tuberculosis but of course in the pecking order for for what we call, disease, it's probably our biggest one. It is our biggest one. Thank you.
