Tuesday, June 5, 2012

Kenya Diaries: Day 14, Part 2 - Malaria and the Climate Crisis

I spent my only full day in Kisumu learning about how the climate crisis is allowing malaria to move to areas where it previously could not survive. And I had the privilege of learning from Andrew Githeko, a world-renowned Kenyan expert on malaria who is on the Intergovernmental Panel on Climate Change.

Here's our interview:

Andrew Githeko: My area of research of malaria. I study the ecology, the epidemiology, transmission, control, but now the emphasis is on climate-driven malaria - not so driven but modulated - that causes epidemics in the highlands. See, before we used to focus our attention on the lowlands where, in those days, it was so bad we had prevalences of up to 80 percent. Virtually everybody had infections, particularly the kids.

JR: I know there are different varieties of malaria. Which one was common here?

[The four human varieties are Plasmodium falciparum, P.vivax, P. ovale and P.malariae. The worst is P. falciparum]

AG: The nastiest one, called Falciparum. It's really nasty, because one gets sick very fast and can get very sick and can kill very fast. Everybody had it here, but most of them were fairly immune. You'd be carrying the parasite, but not much disease. But what you'd be seeing a lot is anemia cuz the parasite eats the blood and eventually they run out of blood and that's what kills them.

But in the highlands, it's a different form of the disease. Cuz people are not immune, they get what you call severe disease. Severe disease includes the cerebral malaria, you can't get enough oxygen in your brain, then your brain chokes, then you get a lot of abortions [miscarriages] from pregnant women, kids dying, basically everybody's affected. It's very dramatic and very severe. But that's... The number of people infected is very low, so the number of people immune is very low. So the large population is naive, so when you get a disease, you get a very severe form of the disease.

JR: Do people in the highlands take the same precautions that they do here? Or are they on their guard?

AG: What used to happen is, say in the 80s, there was virtually no control. So you got sick and you went to the hospital, or you got sick and you bought tablets but then the tablets were quite cheap. The chloroquine. Very effective. It was available everywhere and you could take it. But then the parasites developed resistance and you couldn't cure the disease, so a lot of people died.

So they came up with another one called [inaudible], mid-90s, but before long, the bug became resistant again to this drug. So the disease got so bad they decided that now, the only way is to kill the mosquitoes, or prevent the mosquitoes from biting people, because every time they brought a new drug, the bug became resistance.

So they started giving, selling bednets, subsidized price, but still not many people could afford them. Because people are too poor. So this went on and then they said ok, the next thing we are going to do is to give virtually free bednets to very young children and pregnant mothers, and they did that. But still, only about 20 percent of the people were protected against the disease. So then they changed the policy again and decided they were going to give free bednets to pregnant women and young children. And that too, was not working very well. So recently they changed the policy and decided that they are going to give one free bednet for every two people in the house. So now, what's happening is about 80 percent of poeple have bednets, or 80 percent of houses have bednets. So as soon as they did that, the disease has really declined. It's declined by about 50 percent.

And actually, in the highlands now, we have areas where we used to see 10 percent of people carrying the parasite and now we are seeing only one percent. Other areas, we used to see 60 percent of the people with the parasite, and now it's down to 10 percent. So what's going on now with money, and particularly money from the U.S, from - you know, Bush, one of the great things Bush did was to come up with his Presidential Malaria Initiative - the U.S. government gives a lot of money for malaria control in Africa, and they give money to buy bednets, money to spray insecticides, and money to buy drugs. So now people can get virtually free medication. If you're sick, you go to the hospital, and you get the best available medicine. You only pay for being tested, which is maybe 20 shillings [$0.24]. Because this drug it was about US$50, for an adult, and that's a lot of money. Most people simply couldn't afford it. And it was the only drug that could be used. So if you didn't get it, you were gonna die.

The other thing now we are doing is, once in a while we awful epidemics. They come in - the cases would go up by anything up to 600 percent, hospitals would be having three times, four times as many patients as it could handle. No drugs. They'd have to do blood transfusions. And now, with HIV, this is very bad. And see, these epidemics would catch healthy people by surprise.

JR: When did they start?

AG: Late 80s to the 1990s

JR: And are they in the highlands or lowlands?

AG: Highlands. So we had to try and figure out a way of detecting these epidemics, of predicting these epidemics, well ahead before they happened. Everybody has been trying to do this and nobody's done it. Except for one group which did it in Botswana. They were able to predict flooding, and once you can predict flooding... because after you get floods, you get epidemics.

But here it is much more complicated, it's not flooding. It's warm temperatures and a lot of rainfall. So we developed before they what's called epidemic detection. That means, you have to wait until there's an epidemic. Then you see it creeping up. And mind, you that's during the rainy season, so the roads are impossible, inaccessible, you couldn't spray the houses, it's too complicated, and there's not much you can do.

So we were looking for a method that could predict an epidemic two to three months ahead of this. And we actually managed to do that. We noticed that before every epidemic there was a spike in temperatures. You'd get between two to five degrees above the average, and each time it was followed by heavy rainfall. This was, you were going to get an epidemic. So now we've developed a system that tracks temperatures, and if it starts showing this anomalous departure from average and we know that there's a rainy season coming, then we tell the authorities there's a big risk of an epidemic. And the bigger the departure and the more the rains, the greater the chance.

So we can see these things well ahead of time and these guys can warn people, spray the places, give medication. But fortunately, after they started giving free bednets, this has actually stopped the epidemics. But as I told you earlier, the bug is going to become resistant to the insecticide.

JR: Which insecticides are being used?

AG: These are pyrethroids. Synthetic pyrethroids. Permethrin, deltamethrin, and these kind of stuff. So, the drug is pretty good because it's two drugs in one. It's quite good. But already we are seeing resistance coming up to the insecticides so we are - it's a matter of time. Then we are back.

JR: And then will you have to use something more toxic?

AG: Maybe. So we will have to choose between two evils.

JR: You mentioned high temperatures and rainfall affecting malaria epidemics. Are the rainy seasons less predictable than they used to be?

AG: Yeah, yeah, yeah. Particularly, the short rains. And these things, substantially, El Nino. Most epidemics have something to do with El Nino. So once you predict El Nino, and then we start seeing how hot is it getting, how much rain are we getting, then the system will raise a red flag.

JR: Is it a simple matter of El Nino vs. climate change?

AG: There are those two things. Well, climate change, it only has two things. One component is climate variability, spikes of extreme weather, extreme heat, extreme rainfall. That's one thing. But then there is also the gradual warming. So the mean temperature, long term is increasing, very slowly, but nevertheless, it's increasing. So what this one does is to, you see, below 18 degrees [Celsius] mean annual temperature, you cannot get transmission, because the mosquito dies before the parasite can mature and be transmitted.

So now what's going is the areas, particularly the highlands, the mean annual temperature used to be just below 18 - 17.5, 17.6, 17.8, now a very small change, 0.2 degrees has raised it just above the threshold. And that's what's going on. Like Central Kenya, there was no [malaria] transmission before. 1993 the threshold was crossed. So now those areas are suitable for transmission.

JR: Are you talking about Central Province?

AG: Yeah, Central Province. Nyeri, Murang'a. So now, the disease is now there. So that was climate change's doing. Certain areas are now suitable for transmission. But some other areas as well become too hot and too dry, so you might see less disease, or no disease at all. But we are worried more about areas where the disease is moving into.

JR: Because the people don't have resistance?

AG: Yeah. They don't have resistance and they are not familiar with the disease. So sometimes they think it's just a flu and they just stay in bed and take stuff for headaches and before long, they are in a coma.

JR: What's the usual rate of death if somebody gets malaria?

AG: It depends. Down here, it might be 3 percent. But when you go in the highlands - well, it changes depending on which drug is being used. In the earlier days it used to be about 8 percent in the highlands, but during epidemics it can go as high as 15 percent, 20 percent.

JR: Does it tend to take out people who are very young and very old, or any life stage?

AG: In the highlands, everybody. But mostly young children. The highlands it's everybody. Here, it's just young children. Up to age three. Once you pass three years, it doesn't kill as fast as young children.

JR: So when you're looking at statistics for mortality under age five, a lot of that is malaria?

AG: Yeah. Most of it is malaria. But you know, it's not just malaria that is going on. You have other diseases. Now that's just Kenyan diseases. If you look at Africa as a whole, we've recently done a review, a scientific review, and noticed we have other diseases that are spreading from their original range. You have diseases like Rift Valley fever spreading in areas in Kenya. It's also linked to mosquitoes and rainfall.

Then we have another disease called chikungunya. Now it's spreading as well. But this one, it's not just climate change. This one has got something to do with the Asian Tiger Mosquito that has brought to Africa through second-hand tires importation. When you import tires from Japan or from Southeast Asia, they come with eggs of this mosquito. So when they get here, they start breeding. Now that mosquito is already established in Africa, throughout Africa, and that's a vector of two diseases: dengue and chikungunya. Dengue is spreading in Africa also because of this new mosquito.

Then, of course, there's cholera around this region. We've had small epidemics but we've had two very nasty ones. 1983, I think, or 82. During a very strong El Nino and during 1997-98, was the strongest El Nino and we had a massive outbreak. The whole region around this lake [Lake Victoria], there were huge epidemics, also along the coast, Somalia, Kenya, Tanzania, big outbreaks. That's cuz of what you call climate variability.

JR: Do you think that part of the reason there haven't been more drugs developed is the lack of profit incentive?

AG: Yeah, they say in America, you make more money by developing antidepressants. That sells a lot more. This stuff, here, you know, this.. they don't make money. But now there are organizations that actually make special drugs for malaria which are given free. Subsidized. Somebody else is paying for it. Otherwise, this drug is 50 bucks, nobody is going to pay 50 bucks. So these organizations are given money to buy these drugs and together with the manufacturers they give it free.

Cholera, we can cure cholera no problem, but the trouble is they go to the hospital when it's too late. And that could be just, maybe, lack of transport. They're too far deep in the rural areas and they are trying to take local medicines. And by the time they start to go to the hospital, they are so dehydrated they just die.

But then you have these other diseases like dengue, there's simply not medication. Same with Rift Valley Fever. There are no drugs. West Nile, no drugs. They have West Nile in the U.S. now.

JR: Is it depressing? Is it hard to deal with?

AG: The exciting thing is when you get a solution. But it's tough if you fail, that's depressing. And it's just that we do all kind of things. You say, what if the bug, the mosquito develops resistance to drugs [insecticides], what are you going to do? So we are looking at other ways of controlling the mosquitoes, like modify village houses. Put a ceiling that has vents and confuse the mosquito. Instead of coming in the house it's above the ceiling and gets killed. Because we understand the behavior of the mosquito.

JR: Do you know - it seems like some people are more attractive to mosquitoes.

AG: Oh yeah.

JR: Do you know why?

AG: It's got something to do with, there's some bacteria that live on the human skin. That's what these mosquitoes sniff. That's how they know there's a human being. The body heat, the CO2, coming out... but any mammal will produce heat, and any mammal will produce carbon dioxide. But it's these bacteria actually live in the feet, that's what tells the mosquito this is human. So the more bacteria you have, the more human you are.

JR: So wash your feet?

AG: Wash your feet. That helps a lot. In fact, if you wear socks for a couple days and you hang it in your room, mosquitoes will try to bite it.

JR: What if I have permethrin coated socks and I hang those?

AG: That would be great. That would be a good mosquito trap. Actually, they've been trying to work on this, I don't know how far they've got. They are doing this huge experiment. They've taken an island and they are putting these traps. They either have CO2 or special odors, and the mosquitoes are going to go to these traps and get killed. That's high tech.

JR: Yeah, I've seen stuff about genetically engineered mosquitoes and releasing sterile males...

AG: Yeah, but the wild mosquito is just too strong. The normal mosquito. It can out-mate all these GMOs.

JR: Really? Maybe a pet frog would be the key.

AG: A pet frog?

JR: To kill them.

AG: A lizard, actually. Very useful.

We ended the conversation there, but as we chatted throughout the day, he told me two more very important factoids:

1. The thing about the bacteria on your feet only applies to malarial mosquitoes, not all kinds. So you can have the world's cleanest feet and non-malarial mosquitoes will still bite you.

2. Papyrus leaves produce an oil toxic to malarial mosquitoes, so where you have a papyrus swamp, you don't have malaria. This is important because there's a papyrus swamp in Kenya that is being turned into rice farm by an American corporation. There are still mosquitoes that bite and itch, but not malarial mosquitoes. Andrew said, "But the minute you open up a swamp. Because the swamp has shade and also you have a plant like papyrus, which produce toxic oil for malarial mosquitoes and it kills malarial mosquitoes. But the minute you remove this plant, you remove the oil, you get clear water, there's sunlight, it's warmer, it's cleaner, and that's what the malarial mosquitoes love. So you're going to produce loads of mosquitoes and transmit the disease, so there's a health risk. I mean, we have one area south of Kisumu - I can't remember the exact figures - I think it was in the sugar growing area which was adjacent to the rice irrigation system, we had something like 80 infectious bites per person per year. In the rice fields, it was 409 infectious bites per person per year. And the distance between the two is something like 10 km. It's cuz they were irrigating - flooding - the rice fields. It was a swamp before." He added that you can reduce the malaria with a good control program using bednets.

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