Tag Archive | malaria

Is malaria prevalence really declining?

Malaria study areas. Note the non presence of the DRC and  Angola.. along with all of the other areas that are missing. Do we really know what's going on with malaria?

Malaria study areas. Note the non presence of the DRC and Angola.. along with all of the other areas that are missing. Do we really know what’s going on with malaria?

The development community (and the world) has been celebrating dramatic and unprecedented reductions in the number of malaria cases around the world throughout the past decade and a half. Billions of dollars have been thrown at the disease, which is a major killer of children and an incredible hindrance to development.

A new study which just appeared in Malaria Journal, however, calls this optimism into question.

This review presents two central arguments: (i) that empirical studies measuring change are biased towards low transmission settings and not necessarily representative of high-endemic Africa where declines will be hardest-won; and (ii) that current modelled estimates of broad scale intervention impact are inadequate and now need to be augmented by detailed measurements of change across the diversity of African transmission settings.

So, our ability to accurately determine whether transmission intensity has declined is hampered by the fact that most studies of the disease occur in areas of low transmission. This would make sense. It is much easier for us to evaluate the malaria situation in Kenyan context than in the Democratic Republic of Congo due to availability of surveillance infrastructure, official mechanisms which allow research projects to move forward, and security issues.

The obvious problem with this, is the relationship of governance, economy an instability to malaria itself. People in the poorest countries are at the highest risk for malaria and people in the poorest parts of the poorest countries are at the highest risk of all. The trouble is, despite being the populations we are most concerned about, they are the hardest to reach, and the hardest to help.

Worse yet, the estimates of malaria prevalence found in a number of studies were considerably lower than estimates for the entire African continent.

The combined study area represented by measurements of change was 3.6 million km2 (Figure 1), approximately 16% of the area of Africa at any risk of malaria [9]. The level of endemicity within these studied areas (mean PfPR2-10 = 16%) was systematically lower than across the continent as a whole (mean PfPR2-10 = 31%) (Figure 2). While 40% of endemic Africa experienced ‘high-endemic’ transmission in 2010 (PfPR2-10 in excess of 40%) [9], only 9% of the studied areas were from these high transmission settings.

This is a huge issue and one that shouldn’t be limited to malaria. While it is helpful to hear good news of malaria declines in formerly afflicted areas, we need to be careful about overstating the impact of interventions. Funding for malaria projects such as the distribution of insecticide treated bed nets was incredibly high throughout the 00’s but it is unlikely that trend will continue. Offering an positive picture can show that our efforts are valuable, but might also lead policy makers and donors to suggest that money be put toward other goals. If Sri Lanka is any indication, where malaria was nearly eliminated at one time but experienced a rapid and devastating resurgence, even a brief relaxation of malaria control efforts could erase current gains completely.

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Malaria eradication makes the Economist

Not that the Economist has ever made a habit of ignoring tropical diseases. Far from it, the Economist as a British magazine is quite good at reporting on the Isles former colonies.

Here they’ve written on the issues of mass drug administrations as a tool in malaria eradication. Specifically, they focus on a Chinese group seeking to ramp up efforts to create a successful regimen of artemisinin and piperaquine to eliminate the disease by prophylacticly preventing infection, and interrupting the cycle of transmission long enough to eliminate the parasite entirely.

Dr Li’s approach is to attack not the mosquito, but the disease-causing parasite itself. This parasite’s life cycle alternates between its insect host (the mosquito) and its vertebrate one (human beings). Crucially, as far as is known, humans are its only vertebrate host. Deny it them and it will, perforce, wither away—an approach that worked for the smallpox virus, which had a similarly picky appetite. In the case of smallpox, a vaccine was used to make humans hostile territory for the pathogen. Since there is no vaccine against malaria, Dr Li is instead using drugs.

To date, the group has been running trials in the Comoros islands off the coast of Mozambique and had some success, but haven’t come close to full elimination. Elimination on islands surrounded by salt water (mosquitoes which transmit malaria breed in fresh water) should be a fairly easy proposition, but the issue of human mobility from the African continent guarantees reintroduction.

I’m personally involved in an island malaria elimination project in Kenya, but am under no illusions that results from an island are in the least bit generalization to the continent. Falciparum malaria is far too efficient and the lack of a winter renders transmission far too consistent to allow easy elimination. Add the issue of the intense mobility of Africans and one can’t help but be discouraged.

Dr. Li from the Guangzhou group seems to be optimistically under the mistaken impression that all it will take to eradicate malaria is the right combination of magic pills, but he’s gravely mistaken. The only thing that will consistently control malaria on the continent will be a full on, sustained assault using every tool known, along with intense economic development. The continent has only seen gains in malaria control during the 00’s, when incredible amounts of money and effort was thrown at the disease and, not coincidentally, when African economies finally started to take off. Eradicating malaria won’t be about a few pills.

More troubling to me are the ethical issues. Mass drug administrations require the participation. If even a small group of people refuse the medication, the entire effort might be for naught. Obtaining full, informed consent, however, is near impossible in these areas. While most people are willing to participate once the benefits are explained to them, the risks are often glossed over. Moreover, as communities will often follow the behavior of their neighbors or community leaders, it is difficult to judge whether people participate of their own volition or whether they are merely bowing to community pressure. Educational barriers might also compromise the ability to obtain truly informed consent.

Further, I don’t doubt the intent of the Guangzhou group, but I do wonder if Chinese institutions truly have the same level of ethical review and monitoring that United States’ institutions have (which isn’t even perfect and sometimes ill suited to developing countries). I’m sure that China would love to claim a success like malaria elimination, but I worry that a zeal for victory might lead to a violation of basic ethics and even a masking of failures, complicating the issue in the long term. I hope that I’m wrong.

Does malaria facilitate the development of exploitative agricultural estates? Interview with Dr. Luis Chavez

905237_334159403372948_183902807_oMy friend Luis just published a paper in PlosOne on land consolidation or the formation of “latifundia” in Spain. Latifundia were large agricultural estates owned by the Romans, often dependent on slave labor, the growth of which has been implicated in Rome’s fall.

Luis creates a mathematical model to describe the formation of these large estates. He then tests the hypothesis that malaria transmission exacerbated the situation, by forcing land owners to sell cheaply to opportunistic land owners in less malarious areas.

Luis, an ecologist who works on issues of disease transmission (and all around great guy), is somewhat unique in the world of quantitative sciences. He took a few minutes to talk to me so that you can see why.

Who are you and what’s your background?

If you ask the japanese they might say: O gata no hen na gaijinsan. As to my academic background, I studied biology/parasitology as an undergraduate, then mathematical ecology for a M.Sc. and then was granted a Ph.D. in ecology and evolutionary biology (note: at the University of Michigan).

Nevertheless, I have always been interested in the humanities, especially history since it gives the best vantage point to understand the present. I grew up in a household where mixing things/topics was usual. Both my father and grandfather went to grad school, something unusual in Latin America, and since i was child lunch time talk was heavy on the side of human rights and solidarity, science and the need for change. When Nelson Mandela died i remembered that a lovely family activity during my childhood was going to a cultural/educational event in solidarity with Nelson Mandela and the South African people to end the apartheid.

For lay people, what’s the paper about and what motivated you to explore it?

The paper presents a mathematical model that can explain the formation of latifundia (large estates) when the profitability of land varies across landowners in a landscape. The model is also used to show that when such differences are not present latifundia still can emerge if there are differences in the risk of acquiring an infectious diseases. I built the model based on historical records to show that both patterns have been observed in societies as different as “latin” Europe (Italy and Spain) and China.

What’s a “latifundium” in Spain? I dug around a bit and could find some things about Rome and Latin America, but not so much about Spain. Why choose Spain?

A latifundium is a large estate, which requires the labor of people that do not own the land. I chose Spain because a essay by Chantal Beauchamp presented a couple of striking maps showing that places where malaria was common were those where Latifundia were common during the 1930s (Fig. 2): http://www.persee.fr/web/revues/home/prescript/article/ahess_0395-2649_1988_num_43_1_283483

The pattern of association between malaria and latifundia was not new, but only Beauchamp had data amenable for a quantitative analysis.

Are you trying to say that malaria helped enable capitalist land appropriation?

It might be the case. The hypothesis that malaria helped to enable land appropriation was put forward by the great italian malariologist, Angelo Celli. He has a book on the topic [reference 8 in the paper, available at the UMICH SPH library]. Celli was probably the most advanced malaria epidemiologist at the turn of the 20th century.

Unfortunately, he and other italians [most notably Grassi] were blackbolded in the Anglo-Saxon world because they threatened the ego of Ronald Ross by saying malaria was not just due to a parasite transmitted by the bite of a mosquito [a biological fact that, nevertheless, they independently showed and published in Italian]. If you are interested just check the oldest records for malaria in the Nature archives.

Though issues of land tenure are very different in the US (given that we killed all the natives and stole it all), we did have some big and awful land plantations in the South along with a serious malaria problem. Might we also try to apply this to the United States, and, if so, how?

I think it might have helped to the consolidation of large estates in the south. Interestingly in the Midwest you never had the latifundia observed in the south, but you had malaria in Michigan (the midwest) at some point (See Humphreys M. 2001. Malaria: Poverty, Race, and Public Health in the United States. Baltimore (MD): Johns Hopkins University Press.).

Nevertheless, in the south due, for example, to Jim Crow laws there might have been a differential risk of malaria infection not observed in the Midwest. However, i found no data to go beyond speculation, well other that in the Canal Zone the Jim Crow housing organization showed the differential malaria risk: http://www.jstor.org/stable/10.1086/529265

I find these quantitative approaches to historical problems fascinating (I also started work on a paper on malaria in post-conflict Angola, maybe I should publish it). Do you think applying these methods to history as informative to present day problems? If so, how?

I think so, history probably gives the best vantage point to understand the present (Rendering history a tinker damn’s is a good strategy to sell things no matter if they are useful or even safe, Henry Ford was clear about this). In theory failures can be highly educational, something the model suggests is that equity in land tenure is an unstable equilibrium that could only be maintained by an external policy as the Chinese did before the An Lushan rebellion, and that any kind of unfair land redistribution could only be expected to not work (latifundia will be eventually formed), as observed over and over in most Latin American nations.

The mix of methods is rather novel. However, in the discipline focused and partitioned environment of academia, do you find that its hard to get an audience for this kind of work? Is there a future in it?

I can tell you this stuff is only suitable for publication on the Arxiv.org or PLoS One/ Springer Plus, if you want it to be peer reviewed and you don’t sign your paper with an address in Princeton or Oxford. I think the audience does not belong in any department, though scholars working on the diverse fields of ecology, health, sociology, maths, economics and even history might find it interesting. I think there is some future, there is the emerging field of cliodynamics that looks at historical dynamics and there is even a journal for cliodynamics where they, every once on a while, publish good food for thought like this paper: http://escholarship.org/uc/item/1ks0g7dr#page-1

I thought my data was not dynamical enough, so I didn’t try there.

This work is heavily political. Do you think there is a place for politics in science?

I think everything gets embedded in politics. Otherwise there would have been no shutdown in the CDC and other US government agencies few months ago, etc. I don’t think my work is more or less political than a risk factor analysis for lung cancer and smoking. I think i might be blackbolded by some of the references I cited, but to understand Capitalism even the Catholic Church is studying Marx [Funny the leading scholar is the Munich Bishop, whose last name is Marx]:

http://www.catholicherald.co.uk/news/2012/06/01/cardinal-marx-urges-europe-to-move-beyond-capitalism/

Kenya Day 3: Malaria Journal

Girl with a motorcycle, Homa Bay, Kenya

Girl with a motorcycle, Homa Bay, Kenya

As part of our research in Kenya, we have hired a couple of local people to keep journals on malaria. Basically, we give them a notebook, they observe people in the community, watch for conversations about malaria or malaria related things, and write down what they hear.

Called “hearsay ethnography,” it makes ethnographers out of non-professional folks who are already embedded within the community. To date, it has been used in understanding the cultural understanding of HIV in Malawi.

We are turning local young people into anthropologists.

Through this technique, we can minimize the observer effect, i.e. the problem of influencing the data collection environment by being the odd, linguistically challenged white people of ambiguous intent. The writers have to write in English, in a manner assumed to be understood by educated folks, which presents problems of its own, but it’s a somewhat more flexible methodology.

It’s a valuable tool for medical anthropology. Through this study, we hope to begin to understand how people in this area conceptualize malaria, malaria treatment and health delivery.

I hired these guys last May, the money ran out, and I thought that the project was just a bust. To my surprise and delight, the data collectors are still writing in their journals and I was finally able to see the results.

Here’s a sample:

I attended the funeral of a child below five years old at Kamyeri. There were so many people who attended irrespective of their age or gender. The discussion about malaria broke out when the child’s father was narrating the cause of her death. He said that many people may think that his daughter had been bewitched but according to him, her death was as a result of his wife’s negligence.

He went on saying that he wasn’t at home when he received the news about her daughter’s illness. He told his wife to take the child to the hospital. However, he arrived home after two days to find out that the child had not been taken to hospital and have not received any kind of medication. He rushed her to the hospital but it was too late because the child died dew hours after the doctor had confirmed that she had serious malaria.

He went on saying if she would have diagnosed early enough, maybe she could have not died.

He added that before someone make or jump to any conclusions about the cause of any illness, he/she should go to the hospital and get tested in order to know the real cause of a disease he/she must be suffering from.

Then an old woman who was just in front of me said that she had informed the child’s mother to take to her the child so that she could treat her through “frito” and “suro.” ”Frito” means a method in which powder traditional herbs are administered to a patient through snifting, while “suro” means a method in which herbs in a powdered form is put on small cuts made using a knife. However, the woman did not turn up instead she went to a preacher to seek divine healing.

The old woman continued saying that the shivering and headache could have been treated using traditional herbs.

God is the source of human needs. Why Christianity is at odds with Buddhism

God is the source of human needs. Why Christianity is at odds with Buddhism

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