New Publication (from me): “Insecticide-treated net use before and after mass distribution in a fishing community along Lake Victoria, Kenya: successes and unavoidable pitfalls”
This was was years in the making but it is finally out in Malaria Journal and ready for the world’s perusal. Done.
Insecticide-treated net use before and after mass distribution in a fishing community along Lake Victoria, Kenya: successes and unavoidable pitfalls
Peter S Larson, Noboru Minakawa, Gabriel O Dida, Sammy M Njenga, Edward L Ionides and Mark L Wilson
Insecticide-treated nets (ITNs) have proven instrumental in the successful reduction of malaria incidence in holoendemic regions during the past decade. As distribution of ITNs throughout sub-Saharan Africa (SSA) is being scaled up, maintaining maximal levels of coverage will be necessary to sustain current gains. The effectiveness of mass distribution of ITNs, requires careful analysis of successes and failures if impacts are to be sustained over the long term.
Mass distribution of ITNs to a rural Kenyan community along Lake Victoria was performed in early 2011. Surveyors collected data on ITN use both before and one year following this distribution. At both times, household representatives were asked to provide a complete accounting of ITNs within the dwelling, the location of each net, and the ages and genders of each person who slept under that net the previous night. Other data on household material possessions, education levels and occupations were recorded. Information on malaria preventative factors such as ceiling nets and indoor residual spraying was noted. Basic information on malaria knowledge and health-seeking behaviours was also collected. Patterns of ITN use before and one year following net distribution were compared using spatial and multi-variable statistical methods. Associations of ITN use with various individual, household, demographic and malaria related factors were tested using logistic regression.
After infancy (<1 year), ITN use sharply declined until the late teenage years then began to rise again, plateauing at 30 years of age. Males were less likely to use ITNs than females. Prior to distribution, socio-economic factors such as parental education and occupation were associated with ITN use. Following distribution, ITN use was similar across social groups. Household factors such as availability of nets and sleeping arrangements still reduced consistent net use, however.
Comprehensive, direct-to-household, mass distribution of ITNs was effective in rapidly scaling up coverage, with use being maintained at a high level at least one year following the intervention. Free distribution of ITNs through direct-to-household distribution method can eliminate important constraints in determining consistent ITN use, thus enhancing the sustainability of effective intervention campaigns.
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.
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.
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.
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.
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.”
In 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.
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.
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.
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).
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.
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.
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?
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.