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New Publication: ITNs on Vanuatu

Today, in Malaria Journal, a new publication appeared with my name on it (though I am not the main author). This will be a record of one of the most challenging experiences of my life.

In 2012, my friend Akira and I went hiking in the mountains outside Osaka. It was a pretty easy hike, but on the way down Akira twisted his ankle and sort of lumbered down the rest of the trail. After a few days, the pain got worse and he had to cancel an upcoming research trip to Vanuatu. He asked me to go in his place and offered to pay my expenses. I was due to go on a couple of other research trips that summer so I couldn’t commit, but the only other gringo on the trip begged me and at the last minute I decided to go.

Long story short, it was a crazy set of interpersonal dynamics, we suffered bacterial infections, got stuck on an island for ten days because a plane needed to be repaired, one of us didn’t eat or drink water for ten days, much fish was eaten (but the people who ate), much kava was drank and stories were told. Our diet alternated between delicious seafood and fresh fruits to ramen noodles over rice.

It was a surreal experience. I lost ~16 pounds, down from 175 to 159, came back with numerous skin infections and was a general physical wreck for months, more so than usual. It was challenging, but an experience I am unlikely to forget. I hope to go back one day.

The paper can be found here.

Pictures from Vanuatu (back when I took pictures) are here.

“Background
Insecticide-treated nets (ITNs) are an integral piece of any malaria elimination strategy, but compliance remains a challenge and determinants of use vary by location and context. The Health Belief Model (HBM) is a tool to explore perceptions and beliefs about malaria and ITN use. Insights from the model can be used to increase coverage to control malaria transmission in island contexts.

Methods
A mixed methods study consisting of a questionnaire and interviews was carried out in July 2012 on two islands of Vanuatu: Ambae Island where malaria transmission continues to occur at low levels, and Aneityum Island, where an elimination programme initiated in 1991 has halted transmission for several years.

Results
For most HBM constructs, no significant difference was found in the findings between the two islands: the fear of malaria (99%), severity of malaria (55%), malaria-prevention benefits of ITN use (79%) and willingness to use ITNs (93%). ITN use the previous night on Aneityum (73%) was higher than that on Ambae (68%) though not statistically significant. Results from interviews and group discussions showed that participants on Ambae tended to believe that risk was low due to the perceived absence of malaria, while participants on Aneityum believed that they were still at risk despite the long absence of malaria. On both islands, seasonal variation in perceived risk, thermal discomfort, costs of replacing nets, a lack of money, a lack of nets, nets in poor condition and the inconvenience of hanging had negative influences, while free mass distribution with awareness campaigns and the malaria-prevention benefits had positive influences on ITN use.

Conclusions
The results on Ambae highlight the challenges of motivating communities to engage in elimination efforts when transmission continues to occur, while the results from Aneityum suggest the possibility of continued compliance to malaria elimination efforts given the threat of resurgence. Where a high degree of community engagement is possible, malaria elimination programmes may prove successful.”

(Mostly) Vindicated: Euclidean measures of distance are just as good as high priced, fancy measures

DistancePlotsITNIn my seminal paper, “Distance to health services influences insecticide-treated net possession and use among six to 59 month-old children in Malawi,” I indicated that Euclidean (straight line) measures of distance were just as good as more complicated, network based measures.

I didn’t include the graph showing how correlated the two were, but I wish I had and I can’t find it here my computer.

Every time I’ve done presentations of research of the association of distances to various things and health outcomes, someone inevitably asks why I didn’t use a more complex measure of actual travel paths. The idea is that no one walks in a straight line anywhere, but rather follows a road network, or even utilizes a number of transportation options which might be lost in a simple measure.

I always respond that a straight line distance is as good as any other when investigating relationships on a coarse scale. Inevitably, audiences are never convinced.

A new paper came out today, “Methods to measure potential spatial access to delivery care in low- and middle-income countries: a case study in rural Ghana” which compared the Euclidean measure with a number of more complex measurements.

The conclusion confirmed what I already knew, that the Euclidean measure is just as good in most cases, and the pain and cost of producing sexy and complicated ways of calculating distance just isn’t worth it.

It’s a pretty decent paper, but I wish they had put some graphs in to illustrate their points. It would be good to see exactly where the measures disagree.

Background
Access to skilled attendance at childbirth is crucial to reduce maternal and newborn mortality. Several different measures of geographic access are used concurrently in public health research, with the assumption that sophisticated methods are generally better. Most of the evidence for this assumption comes from methodological comparisons in high-income countries. We compare different measures of travel impedance in a case study in Ghana’s Brong Ahafo region to determine if straight-line distance can be an adequate proxy for access to delivery care in certain low- and middle-income country (LMIC) settings.

Methods
We created a geospatial database, mapping population location in both compounds and village centroids, service locations for all health facilities offering delivery care, land-cover and a detailed road network. Six different measures were used to calculate travel impedance to health facilities (straight-line distance, network distance, network travel time and raster travel time, the latter two both mechanized and non-mechanized). The measures were compared using Spearman rank correlation coefficients, absolute differences, and the percentage of the same facilities identified as closest. We used logistic regression with robust standard errors to model the association of the different measures with health facility use for delivery in 9,306 births.

Results
Non-mechanized measures were highly correlated with each other, and identified the same facilities as closest for approximately 80% of villages. Measures calculated from compounds identified the same closest facility as measures from village centroids for over 85% of births. For 90% of births, the aggregation error from using village centroids instead of compound locations was less than 35 minutes and less than 1.12 km. All non-mechanized measures showed an inverse association with facility use of similar magnitude, an approximately 67% reduction in odds of facility delivery per standard deviation increase in each measure (OR = 0.33).

Conclusion
Different data models and population locations produced comparable results in our case study, thus demonstrating that straight-line distance can be reasonably used as a proxy for potential spatial access in certain LMIC settings. The cost of obtaining individually geocoded population location and sophisticated measures of travel impedance should be weighed against the gain in accuracy.

Development as unfreedom….

Was reading Chris Blattman’s list of books that development people should read but don’t and found this in the Amazon description of “The Anti-Politics Machine: Development, Depoliticization, and Bureaucratic Power in Lesotho.”

Development, it is generally assumed, is good and necessary, and in its name the West has intervened, implementing all manner of projects in the impoverished regions of the world. When these projects fail, as they do with astonishing regularity, they nonetheless produce a host of regular and unacknowledged effects, including the expansion of bureaucratic state power and the translation of the political realities of poverty and powerlessness into “technical” problems awaiting solution by “development” agencies and experts.

Note that I do not harbor any ill will toward development or even, as a general rule, “technical solutions.” Having been involved with bed net distributions and having watched the outcomes of reproductive health interventions, for example, I can say that there are many positive outcomes of development projects. In my area, fewer kids are dying and women are becoming pregnant a whole lot less, decreasing the risk of maternal mortality.

Disclaimers aside, there is no doubt that development projects often fail for a number of reasons, the first of which is that leaders have no interest in seeing that they succeed. While leaders are indifferent to the outcomes, they happily take on the power that comes with them, embracing bureaucratic reforms, which are mostly just expansions of power at all levels of government.

This wouldn’t necessarily be a bad thing, except that African countries never embraced many of the protections of individual rights which restrict the powers of the state. Independence movements in much of Africa was predicated on an eventual return of power to the majority. Not many (none?) of these movements sought to protect the rights of the minority, much less the individual. Thus, there is little restriction on the types of rules which may be created and since many of these development projects influence policy, development projects unwittingly feed into the autocracy machine.

Can the use of technology in surveys change the nature of responses?

In the past, surveys were done on paper, either through a designed questionnaire or by someone frantically writing down interview responses. When computers came around, people would be hired to type in responses for later analysis.

Nowadays, with the advent of cheap and portable computing, research projects are rapidly moving toward fully digital methods of data collection. Tablet computers are easy to operate, can be cheaply replaced, and now can access the internet for easy uploading of data from the field.

Surveyors like them because large teams can be spread out over a wide space, data can be completely standardized and the tedious process of data entry can be avoided.

Of interest to me, however, is whether the technology is influencing the nature of the responses given. That is, will someone provide that same set of responses in a survey using digital data collection methods as in a paper survey?

Recently, we attempted using a tablet based software for a small project on livestock possession and management on Mbita Point in Western Kenya. I intended it as a test to see if a particular software package might be a good fit for another project I`m working on (the one that`s paying the bills).

We had only limited success. The survey workers found the tablets clunky and a number of problems with the Android operating system made it more trouble than the survey was actually worth. Of interest, though, was how the technology distracted the enumerators from their principle task, which was to collect data.

Enumerators would become so wrapped up in trying to navigate the various buttons and options of the software that they couldn`t effectively concentrate on performing the survey. Often they appeared to skip questions out of frustration or would just frantically select one of the many options in the hope of moving on to the next one.

In a survey of more than 100 questions, the process started taking far more time than households were willing to give. We eventually had to abandon the software and revert to a paper based method.

Surveys went from lasting more than one hour, to taking under 30 minutes. Workers were more confident and had more time to interact with the respondents. Respondents had more of an opportunity to ask questions and consider the meaning of what they were being asked. They offered far more information than we expected and felt that they were participating in the survey as a partner and not just as a passive victim.

One of our enumerators noted that people react differently to a surveyor collecting data on the tablets than with paper. She described collecting data with technology as being “self absorbed” and alienating to the respondents. Collecting data on paper, however, was seen as a plus. “They can see me writing down what they say and feel like their words are important.”

I`m thinking that the nature of the responses themselves might be different as well. Particularly with complex questions of health and disease, often the surveyors will have to explain the question and give a respondent a chance to ask for further clarification. Technology appears to inhibit this process, perhaps compromising the chance for a truly reasoned response.

While I am absolutely not opposed to the use of technology in surveys, I think that the survey strategy has to be properly thought through and the challenges considered. At the same time, however, data collection is a team effort and requires a proper rapport between community members and surveyors who often know each other.

Is technology restricting our ability to gather good data? Could the use of technology even impact the nature of the response by pushing them in ways which really only tell us what we want to believe rather than what actually exists?

Today is World Malaria Day

Kenya (23 of 26)I was supposed to give a presentation, but instead I’m in the Delta SkyClub writing a blog post.

I’m not exactly sure what we’re all supposed to be doing on World Malaria Day that we shouldn’t be doing every day, but at least we have a day! There’s no such thing as “World Helminth Day,” unfortunately.

What I think we should be doing on World Malaria Day:

1. Reducing ridiculous bureaucracy in developing countries which inflates the price of goods at the border.
2. Eliminate ridiculous protectionist policies in wealthy countries which selectively hobbles imports from developing countries.
3. Encourage true democracy in African States (where it doesn’t already exist) and eliminate unproductive authoritarian dead weight.
4. Guarantee rights to representation, legal fairness, political expression and property.
5. Create a global tax on capital and reinvest monies fairly in locally developed infrastructure projects in developing countries.
6. Encourage deep state investments in health care and health delivery in malarious countries while creating conditions favorable for the private sector to meet health needs.
7. Invest in the development of new pharmaceutical tools to prepare for the day when ACTs are no longer effective.

Wait, only points 6 and 7 had anything to do with malaria, you say, but I say they all do. Malaria is a complex disease, the root cause of which is poverty, the root cause of which is politics and economics. We will never be able to eliminate malaria unless we take care of all of the other problems which create the context that allows it to exist.

Do malaria interventions cause human suffering through population growth?

041614_1200_Theimpactof3People often ask me this. I mostly find the question annoying since a dead kid is, well, a dead kid.

The thinking, however, isn’t entirely illogical and can, of course, even be traced back to Malthus himself. Malthus believed that helping the poor would only increase their misery through worsening conditions of crowding and starvation. If Malthus had lived in 2013 and were concerned with welfare policy, he’d probably be a card carrying member of the Republican Party.

For the record, I despise Malthus (and his spawn, Paul Ehrlich). I can’t think of a more cynical and heartless thinker. It’s disturbing to me that his ideas continue to permeate today, despite being wrong at best and simply hateful, at worst. More disturbing is how eagerly his ideas are absorbed by even otherwise well meaning people.

“It’s obvious,” I’ve heard people say while implicitly suggesting the some lives (ours) are worth more than others (theirs). As cliched as it may sound, I think that every human has both a right to live and the right to a life that is healthy and meaningful. Not saving kids from malaria compromises the ability to do either.

So far, though, no one really knows whether life saving interventions in developing countries fuel population growth. Does saving a child’s life simply increase the number of mouths to feed, thereby straining resources and insuring misery for everyone? David Roodman, a public policy consultant working on behalf of GiveWell, a group which does analyses on the effectiveness of charity programs, has searched the published literature to find the answer.

I think the best interpretation of the available evidence is that the impact of life-saving interventions on fertility and population growth varies by context, above all with total fertility, and is rarely greater than 1:1. In places where lifetime births/woman has been converging to 2 or lower, family size is largely a conscious choice, made with an ideal family size in mind, and achieved in part by access to modern contraception. In those contexts, saving one child’s life should lead parents to avert a birth they would otherwise have. The impact of mortality drops on fertility will be nearly 1:1, so population growth will hardly change.

He goes through the available data and finds evidence to suggest that averted child deaths are associated with a decrease in the number of births over the lifetime of a woman. This is somewhat non-controversial. It has long been noticed that economic development and increased access to medical care is associated with decreased lifetime fertility.

Where things become controversial is in the case of developing countries, where saving a child’s life might not have the same effect on reducing births overall. This might be true in the short term, and Roodman finds evidence to suggest this. A short term reduction in child mortality might not yield immediate results.

The issue might be more nuanced, however. Merely providing malaria interventions such as insecticide treated nets to prevent disease without increasing access to quality health services might lead to a situation where population increases quite rapidly. I would think that this might explain why some of the most malarious countries in the world are experience the most rapid population growth. Malawi would be an example.

The strategy, then, is incomplete and Roodman’s analysis might suggest that we need to take a holistic approach to include both malaria prevention and reproductive health services.

I would, however, suggest that the problem is more complicated, particularly when reflecting on Kenya, where the most effective method of reducing fertility has probably been the imposition of school fees. The issue then isn’t merely a matter of saving kids and Depo shots, it’s also a matter of finances. If people can’t afford kids, they won’t have them, but the only way to arrive at economic barriers to reproduction is to have an economy, which is exactly what a country like Malawi doesn’t have.

Did pathogens influence the course of human development?

Roman toilets

Roman toilets

I would say “it depends.” I was just reading an interesting article on the “pathogen stress theory” of the development of human societies, most often attributed to Randy Thornhill, an evolutionary biologist at the University of New Mexico.

According to the “pathogen stress theory of values,” the evolutionary case that Thornhill and his colleagues have put forward, our behavioral immune systems—our group responses to local disease threats—play a decisive role in shaping our various political systems, religions, and shared moral views.

If they are right, Thornhill and his colleagues may be on their way to unlocking some of the most stubborn mysteries of human behavior. Their theory may help explain why authoritarian governments tend to persist in certain latitudes while democracies rise in others; why some cultures are xenophobic and others are relatively open to strangers; why certain peoples value equality and individuality while others prize hierarchical structures and strict adherence to tradition. What’s more, their work may offer a clear insight into how societies change.

This is a reasonable view, and something I’ve long observed from working on infectious diseases in developing countries. The developmental trajectory of a country is influenced by the deliberate avoidance of illness. An example can be seen in the locations of African cities. Many African administrative capitals are located on isolated, cool hilltops, far away from rivers and lakes. Colonialists would intentionally set up shop in areas where they were unlikely to encounter malaria.

Developmentally, this has had major implications for trade within Africa. European cities are often placed along water ways amenable to domestic European trade. The lack of trade between African countries is one of the reasons the continent has developed so poorly. This is the direct result of not only colonial priorities of resource extraction to Europe, but also the unfortunate placement of economic centers in response to malaria.

Certainly, the nature of cities themselves have much to do with the control of infectious diseases. Public works often involve the management of sewage waste and the delivery of clean water. Thornhill might suggest that the development of democracy, citizen involvement and taxation to pay for urban improvements are in direct response to enteric diseases.

However, while it is interesting to try to apply this view, it can be taken to the extreme:

Fincher (a graduate student of Thornhill) suspected that many behaviors in collectivist cultures might be masks for behavioral immune responses. To take one key example, collectivist cultures tend to be both more xenophobic and more ethnocentric than individualist cultures. Keeping strangers away might be a valuable defense against foreign pathogens, Fincher thought. And a strong preference for in-group mating might help maintain a community’s hereditary immunities to local disease strains. To test his hypothesis, Fincher set out to see whether places with heavier disease loads also tended toward these sorts of collectivist values.

I’m not sure it’s that easy to boil down political differences between Asia and Europe to a need to manage infectious disease. Certainly, Sweden is more collectivist than England, but I wouldn’t say that their infectious disease profiles are all that different.

Worse yet, if taken to the extreme, this “hunt for significance” will provide one with evidence to support any crazy theory at all. Pathogens exist wherever humans do. Moreover, we risk attributing the contribution of pathogens to human development based on current conditions, assuming that the present is deterministically preordained centuries ago. Until very recently, nearly the entire world was at risk for malaria, but despite this, various societies have embarked on different social and political trajectories.

The biggest problem I have with the theory is in its basic in rational theory. It assumes that humans are making rational choices based on pathogen threats, when we know, and particularly those of us who work in the tropics, that humans often have poor conceptions of disease transmission and causes of illness. At times, despite very obvious threate, humans will act in manners which exacerbate that threat. The history of enteric disease is filled with tales of ignorance and folly.

If we are going to subscribe to a rational model of political and social development which includes pathogens, then we have to also address first, the ability of pathogens to hijack human behavior to create new opportunities for replication and survival and second, that social changes can exacerbate the worst effects of infection. For the first point, I would look to the development of international trade systems which allow pathogens such as influenza to move around the world quickly, increasing opportunities for mutation to avoid immune responses. For the second I would point to polio, a disease which becomes a problem on after the introduction of water sanitation practices.

Thornhill’s ideas are interesting, and certainly provide good material for the popular press and BBQ conversation, but they require that the reader suspend too much consideration of the details of the complex history of human social and political development. Taken with restraint, as in the example of the locations of African cities, they can provide interesting insights into how current conditions are impacted by past pathogenic threats.

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