New publication! Snakebite victim profiles and treatment-seeking behaviors in two regions of Kenya: results from a health demographic surveillance system in Tropical Medicine and Health (BMC)
Permanent injury from a puff adder bite, Kenya, 2016
Back in 2016 or so, I nearly stepped on a headless and very dead spitting cobra on an island in Homa Bay, Kenya. The locals apparently weren’t satisfied with simply decapitating it, but smashed the head to bits presumably so it couldn’t come back to life and bite someone. That gave me a hair brained idea to do a research project on snakebites and I’m proud to say that the results of that work have been published today.
This work was a team effort under the auspices of the Nagasaki University Institute of Tropical Medicine. It couldn’t have happened without the incredible contributions of researchers, students and local partners,in Kenya, Japan and the United States.
Snakebites are a major cause of permanent injury and death among poor, rural populations in developing countries, including those in East Africa. This research characterizes snakebite incidence, risk factors, and subsequent health-seeking behaviors in two regions of Kenya using a mixed methods approach.
As a part of regular activities of a health demographic surveillance system, household-level survey on snakebite incidence was conducted in two areas of Kenya: Kwale along the Kenyan Coast and Mbita on Lake Victoria. If someone in the home was reported to have been bitten in the 5 years previous to the visit, a survey instrument was administered. The survey gathered contextual information on the bite, treatment-seeking behavior and clinical manifestations. To obtain deeper, contextual information, respondents were also asked to narrate the bite incident, subsequent behavior and outcomes.
8775 and 9206 households were surveyed in Kwale and Mbita, respectively. Out of these, 453 (5.17%) and 92 (1.00%) households reported that at least one person had been bitten by a snake in the past 5 years. Deaths from snakebites were rare (4.04%), but patterns of treatment seeking varied. Treatment at formal care facilities were sought for 50.8% and at traditional healers for 53.3%. 18.4% sought treatment from both sources. Victims who delayed receiving treatment from a formal facility were more likely to have consulted a traditional healer (OR 8.8995% CI [3.83, 20.64]). Delays in treatment seeking were associated with significantly increased odds of having a severe outcome, including death, paralysis or loss of consciousness (OR 3.47 95% CI [1.56; 7.70]).
Snakebite incidence and outcomes vary by region in Kenya, and treatment-seeking behaviors are complex. Work needs to be done to better characterize the spatial distribution of snakebite incidence in Kenya and efforts need to be made to ensure that victims have sufficient access to effective treatments to prevent death and serious injury.”
New publication: Ambient air pollution and non-communicable respiratory illness in sub-Saharan Africa: a systematic review of the literature
New publication from our Air Pollution and Health team out today in BMC Environmental Health:
Aerosol pollutants are known to raise the risk of development of non-communicable respiratory diseases (NCRDs) such as asthma, chronic bronchitis, chronic obstructive pulmonary disease, and allergic rhinitis. Sub-Saharan Africa’s rapid pace of urbanization, economic expansion, and population growth raise concerns of increasing incidence of NCRDs. This research characterizes the state of research on pollution and NCRDs in the 46 countries of Sub-Saharan Africa (SSA). This research systematically reviewed the literature on studies of asthma; chronic bronchitis; allergic rhinitis; and air pollutants such as particulate matter, ozone, NOx, and sulfuric oxide.
We searched three major databases (PubMed, Web of Science, and Scopus) using the key words “asthma”, “chronic bronchitis”, “allergic rhinitis”, and “COPD” with “carbon monoxide (CO)”, “sulfuric oxide (SO)”, “ozone (O3)”, “nitrogen dioxide (NO2)”, and “particulate matter (PM)”, restricting the search to the 46 countries that comprise SSA. Only papers published in scholarly journals with a defined health outcome in individuals and which tested associations with explicitly measured or modelled air exposures were considered for inclusion. All candidate papers were entered into a database for review.
We found a total of 362 unique research papers in the initial search of the three databases. Among these, 14 met the inclusion criteria. These papers comprised studies from just five countries. Nine papers were from South Africa; two from Malawi; and one each from Ghana, Namibia, and Nigeria. Most studies were cross-sectional. Exposures to ambient air pollutants were measured using spectrometry and chromatography. Some studies created composite measures of air pollution using a range of data layers. NCRD outcomes were measured by self-reported health status and measures of lung function (spirometry). Populations of interest were primarily schoolchildren, though a few studies focused on secondary school students and adults.
The paucity of research on NCRDs and ambient air pollutant exposures is pronounced within the African continent. While capacity to measure air quality in SSA is high, studies targeting NCRDs should work to draw attention to questions of outdoor air pollution and health. As the climate changes and SSA economies expand and countries urbanize, these questions will become increasingly important.”
New publication: “Long-Term PM2.5 Exposure Is Associated with Symptoms of Acute Respiratory Infections among Children under Five Years of Age in Kenya, 2014”
In early December, I was asked to submit a paper to a special issue on “Air pollution and health in Africa and the African Diaspora” which is great! But the deadline was Dec 31st, which is absolutely crazy. I pulled an amazing team together and somehow we made the deadline and now, here we are…. published!
Here’s the “video abstract.”
Introduction: Short-term exposures to air pollutants such as particulate matter (PM) have been associated with increased risk for symptoms of acute respiratory infections (ARIs). Less well understood is how long-term exposures to fine PM (PM2.5 ) might increase risk of ARIs and their symptoms. This research uses georeferenced Demographic Health Survey (DHS) data from Kenya (2014) along with a remote sensing based raster of PM2.5 concentrations to test associations between PM2.5 exposure and ARI symptoms in children for up to 12 monthly lags. Methods: Predicted PM2.5 concentrations were extracted from raster of monthly averages for latitude/longitude locations of survey clusters. These data and other environmental and demographic data were used in a logistic regression model of ARI symptoms within a distributed lag nonlinear modeling framework (DLNM) to test lag associations of PM2.5 exposure with binary presence/absence of ARI symptoms in the previous two weeks. Results: Out of 7036 children under five for whom data were available, 46.8% reported ARI symptoms in the previous two weeks. Exposure to PM2.5 within the same month and as an average for the previous 12 months was 18.31 and 22.1 µg/m3, respectively, far in excess of guidelines set by the World Health Organization. One-year average PM2.5 exposure was higher for children who experienced ARI symptoms compared with children who did not (22.4 vs. 21.8 µg/m3, p < 0.0001.) Logistic regression models using the DLNM framework indicated that while PM exposure was not significantly associated with ARI symptoms for early lags, exposure to high concentrations of PM2.5 (90th percentile) was associated with elevated odds for ARI symptoms along a gradient of lag exposure time even when controlling for age, sex, types of cooking fuels, and precipitation. Conclusions: Long-term exposure to high concentrations of PM2.5 may increase risk for acute respiratory problems in small children. However, more work should be carried out to increase capacity to accurately measure air pollutants in emerging economies such as Kenya.
New publication: An urban-to-rural continuum of malaria risk: new analytic approaches characterize patterns in Malawi
12 years in the making! Our new paper from partners at the University of Michigan and the #Malawi College of Medicine on new approaches to defining urban and rural environments in the context of malaria risk is now out in #Malaria Journal.
It was the last chapter in my dissertation to be published (all the rest were published when I was still in grad school.)Short version: malaria is complicated and really local. Malaria transmits poorly in urban and environments and well in rural environments. There’s urban like spaces in “rural” areas and rural-like spaces in “urban” areas, demanding a more nuanced view of what those terms really mean.
We know that malaria is a “rural” problem, but not all “rural” spaces are the same. Even in the country, there are “urban like” spaces and in “rural like” spaces even in the largest cities in Sub-Saharan Africa. Could those spaces impact malaria risk? If so, shouldn’t we redefine what we mean by urban vs. rural to inform intervention strategies to better target resources?
Here, we combine GIS and statistical methods with a house to house malaria survey in Malawi to create and test a new composite index of urbanicity and apply that to create a more nuanced risk map.
The urban–rural designation has been an important risk factor in infectious disease epidemiology. Many studies rely on a politically determined dichotomization of rural versus urban spaces, which fails to capture the complex mosaic of infrastructural, social and environmental factors driving risk. Such evaluation is especially important for Plasmodium transmission and malaria disease. To improve targeting of anti-malarial interventions, a continuous composite measure of urbanicity using spatially-referenced data was developed to evaluate household-level malaria risk from a house-to-house survey of children in Malawi.
Children from 7564 households from 8 districts in Malawi were tested for presence of Plasmodium parasites through finger-prick blood sampling and slide microscopy. A survey questionnaire was administered and latitude and longitude coordinates were recorded for each household. Distances from households to features associated with high and low levels of development (health facilities, roads, rivers, lakes) and population density were used to produce a principal component analysis (PCA)-based composite measure for all centroid locations of a fine geo-spatial grid covering Malawi. Regression methods were used to test associations of the urbanicity measure against Plasmodium infection status and to predict parasitaemia risk for all locations in Malawi.
Infection probability declined with increasing urbanicity. The new urbanicity metric was more predictive than either a governmentally defined rural/urban dichotomous variable or a population density variable. One reason for this was that 23% of cells within politically defined rural areas exhibited lower risk, more like those normally associated with “urban” locations.
Mark WilsonDon MathangaVeronica Berrocal#malaria#globalhealth#publichealth#GIS#spatialanalysis#maps#Malawi#Africa#Plasmodium#surveys#health#medicine#environmental#data
Why malaria? Over-researched, over-funded, diminishing returns? Rambling on the need for student mentorship.
Last week I gave an informal lecture on survey sampling to a small group of graduate students from a number of countries. With only one exception, all of the students were working on various aspects of malaria, primarily in basic sciences. The lone non-malaria student was from Vietnam and is interested in Dengue fever.
I praised her for working on Dengue. Dengue presents a serious threat to human health in all countries where the vectors exist, but the burden of disease will be particularly felt in rapidly urbanizing areas of developing countries.
Developing countries are ill equipped to deal with Dengue, and the antiquated nature of their health care systems, leftover by the colonialists, means that diagnostics are mostly non-existent and drugs wholly unavailable. Any fever in most of Sub-Saharan Africa is diagnosed simply as malaria, drugs administered and the patient left on their own.
We have extensive experience, however, with malaria. While there are numerous challenges to reducing malaria incidence, preventing recrudescence and postponing drug resistance, the basic fact is that the best way to eliminate or control malaria is to simply make people less poor. Even countries with holoendemic transmission, wealthier people get malaria less often than poor people, and poor people who live in wealthier areas get sick less than wealthier people in poor areas. This is known (in Game of Thrones parlance).
So, as we discussed the topic during lecture, I softly tried to encourage the students to look at other areas where they might be able to better apply their skills. They were mostly unresponsive, which is fine. Someone has to tell them, it might as well be me.
One of the students, however, indicated that “malaria is where the money is.” I couldn’t disagree. The reason that we put so much money and effort into diseases like malaria and HIV is simply because they yield marketable products. Medications for diseases like tungiasis (jiggers) are so simple as to not be profitable, customers too poor to buy them, and governments and donors too distracted by big diseases like malaria, HIV and TB to be concerned with dumping money to provide them for free.
And this is where the problem lies. We have a self propagating system of companies, researchers and donors, which simply float money between one another with little regard for the needs of the poorest of the poor. Breaking the cycle is difficult, but it starts with academics who need to push students to do work with neglected, overlooked or under-researched diseases. Even small grants can support small, but meaningful projects.
We have reached a point where malaria funding for malaria research is yielding ever diminishing returns. Money needs to be put into programs to deliver the tools we have and make ITNs, ACTs and IRS available to the people who need them, who often have trouble getting them. Moreover, we need economic development to make people less poor in developing coutnries so that fewer of their babies die. Human resources in developed countries need to start focusing on emerging (or already emerged but ignored) threats lke antibiotic resistance, Dengue fever, emerging zoonotics and others. That starts with us as mentors.
New Publication: “First Report of a Foodborne Providencia alcalifaciens Outbreak in Kenya.”
I’m only a middle author, but I have a new publication out. After being involved in this, I will never eat mukimo (Kenyan mashed potato dish) ever again. Ever again.
First Report of a Foodborne Providencia alcalifaciens Outbreak in Kenya.
Shah MM, Odoyo E, Larson PS, Apondi E, Kathiiko C, Miringu G, Nakashima M, Ichinose Y.
Am J Trop Med Hyg. 2015 Jun 29. pii: 15-0126.
Providencia alcalifaciens is an emerging bacterial pathogen known to cause acute gastroenteritis in children and travelers. In July 2013, P. alcalifaciens was isolated from four children appearing for diarrhea at Kiambu District Hospital (KDH) in Kenya. This study describes the outbreak investigation, which aimed to identify the source and mechanisms of infection. We identified seven primary and four secondary cases. Among primary cases were four mothers who had children and experienced mild diarrhea after eating mashed potatoes. The mothers reported feeding children after visiting the toilet and washing their hands without soap. P. alcalifaciens was detected from all secondary cases, and the isolates were found to be clonal by random amplified polymorphic DNA (RAPD) fingerprinting. Our study suggests that the outbreak was caused by P. alcalifaciens, although no fluid accumulation was observed in rabbit ileal loops. The vehicle of the outbreak was believed to be the mashed potato dish, but the source of P. alcalifaciens could not be confirmed. We found that lack of hygiene, inadequate food storage, and improper hand washing before food preparation was the likely cause of the current outbreak. This is the first report of a foodborne infection caused by P. alcalifaciens in Kenya.
© The American Society of Tropical Medicine and Hygiene.
PMID: 26123962 [PubMed – as supplied by publisher]
Eid in Kwale, Kenya
I traveled out to Kwale on the Kenyan Coast and celebrated Eid (the end of Ramadan) with my friend Juma and his family in Mwachinga. It was a great time for everyone (except the goat). It rained on and off, but the ladies made up some great Pilau and the men had some conversations about Islam and witch doctor Senators. Juma even gave us a detailed family history. Finally, everyone had a serious discussion on the impacts of social media on family relations.
After a grueling 12 hour bus ride from Nairobi to Mombasa, the highlight of the trip was a two hour tuk tuk ride across the ferry and all the way out to Kwale Town. I’m still not sure how it made it up all the hills.
Infectious disease transmission dynamics and the ethics of intervention based public health research
I think a lot about ethics and ethical issues. Research in Sub-Saharan Africa presents unique risks for ethical breaches. Given income and power disparities between individuals and foreign researchers and even between individuals and local political leaders the possibility of coercive research is ever present. Pressure to produce can lead to unrealistic assumptions of risks and benefits to very poor individuals. Inadequate knowledge or willful ignorance of local political issues can compromise future research activities, both by international and domestic groups.
Recently, though, an interesting situation came across my desk that included an intersection of ethics and the dynamics of infectious disease transmission.
As everyone knows, not all infectious diseases are the same. Some, like measles, impart full immunity upon exposure, whereas diseases such as malaria impart only partial immunity, requiring repeated exposures to acquire full or adequate immunity to prevent death or serious injury. Moreover, as immunity and immune reactions change over the life course, the time (age) of exposure are sometimes crucial to prevent serious disease. Polio is a great example. Exposure in infancy leads merely to diarrhea, where exposure at older ages can lead to debilitating paralysis.
I was thinking of an population based intervention study which provides some sort of malaria medication to a small population in a holo-endemic area. Given the year round nature of malaria transmission in this area, we would expect that even with a depression in symptomatic and asymptomatic cases, active transmission in the surrounding areas would lead to recrudescence within a very short time. Given the short time frame, we would assume very little interruption in the development of immunity in small children and might even see a short term reduction of childhood mortality. Assuming that this medication presented little or no risk of serious side effects, I believe that there is little reason to assume an ethical breach. A short term reduction in malaria would suggest that the benefits far outweigh the risks.
However, conducting the same study on a very large population in the same area might have very different outcomes. Delivering a malaria medication to, say, an entire county surrounded by other areas of extremely high transmission would indicate that recrudescence is also inevitable but that the time required to return to pre-intervention levels is extended. Infectious disease transmission requires a chain of hosts. The longer that chain, the longer it will take for new hosts to become newly infected.
Theoretically, this could delay infections in small children and it is theoretically possible that we might see a spike in childhood mortality, since the timing of initial malaria infection and frequency of infections are crucial to preventing the worst outcomes.
Of course, I’m not suggesting that people should just get infected to induce immunity, but I am suggesting that a study which seeks to reduce transmission through pharmaceuticals given only intermittently (as opposed to prophylactically) consider all possible implications. Insecticide treated nets (ITNs) provide protection over time and are a form of vector control. A medication given at a single time point merely clears the parasite, but does nothing to prevent bites or kill mosquitoes.
Though I could be overthinking the issue, my worry is that ethical approvals approach the issue of mass distributions of pharmaceuticals as a one size fits all issue without taking other factors such as population size and acquired immunity into account. Malaria, as a complex vector borne disease introduces complexities that, say, measles does not. Researchers, IRBs and ethics board would do well to consider this complexity.
Pictures from the Gambia
Not much else to post, so I’ll add a few pictures of a bird watching trip in the Gambia. Turns out the Gambia has an incredible bird diversity. Unfortunately, my camera couldn’t capture it but we play with the cards we are dealt with…
Photography in developing country research: we’re essentially journalists anyway
I just found this short article on the LSE blog from Professor Sylvia Chant, who does work on female genital mutilation in Sub-Saharan Africa:
“Opportunities for taking one’s research beyond textbooks and journal articles are critical for teaching at LSE, where students at all levels and from an extensive range of geographical and disciplinary backgrounds are eager to see theory translated into practice, and to engage with impact. From my experience, it is the anecdotes about the lives of people who have formed part of one’s research which help to make ideas and arguments more accessible; how one went about fieldwork in different localities, or the stories of what you, as lecturer, have done in the public and policy domain (whether acting as an expert witness in court cases for asylum seekers, or playing an advisory or consultant role for international agencies). These really grab students’ attention, with photographs and video clips adding more value still!”
I completely agree. Graphs and tables are great for making specific points of interest to researchers, but photos and videos humanize the results and make our research accessible to regular folks and policy makers. People have a real hard time with numbers, which are essentially about communities, countries and institutions, but are used to listening to stories of the struggles and challenges of individuals. Providing plenty of interesting visuals and stories is essential to what we do.
Public health work is about people. Our mission is to be an advocate for the sick and those at risk of becoming sick, who are often marginalized, poor or lack a political voice. Telling their stories simply in a way that non-experts can understand helps us to draw support for what we do.
I have long taken the position that we are essentially journalists. Though we, as scientists, follow a strict set of protocols and rules, our job is to tell stories of particular groups of people and provide information which is often difficult to obtain.