topnaman | Malaria blog

The American Journal of Public Health published a terrific account (hat tip: Steven Meshnick) of a bizarre event from the 1950s where:

DDT spraying to control malaria allegedly resulted in cats being poisoned in some areas, which led to increased rodent populations and, in turn, the parachuting of cats into the highlands of the island of Borneo to kill the rodents.

Of course, why not? Everyone knows the rationale response to a rodent menace must involve flying felines – and in large numbers! Another source suggests that in “Operation Cat Drop” some 14000 live cats were parachuted into Borneo. In any case I am indebted to Patrick O’Shaughnessy for his entertaining and meticulous research.

An example of a poor use of facility-based data to claim the anti-malaria impact of interventions:

In 2007 the Millennium Village Project published early results related to agriculture, health, and economic development in their three research villages in Kenya, Ethiopia, and Malawi. I am not commenting on their work as a whole but their malaria claims were disproportionate to the evidence (especially given the bias of self-evaluation). The group does note some of their limitations but they also unequivocally state to “have reduced malaria prevalence”. It is an interesting use of the term prevalence, which usually refers to the proportion of parasitemic people in a survey, whereas they used facility based data and measured changes in the proportion of clinical malaria cases against total clinic visits. Regardless, even if prevalence or incidence decreased any credit due is unsubstantiated. Some of the obstacles in interpreting their data include the use of clinical malaria cases (which is problematic as discussed here), no demographic comparisons of facility controls, displaying a reduction in diagnostically confirmed cases without any context of testing trends, and only one year of follow up in the absence of any discussion of pre-intervention trends. To be frank the malaria portion of the paper is rather bad science. I am surprised the Proceedings of the National Academy of Sciences endorsed it.

About a year and a half ago I briefly discussed a WHO report (see comments here) claiming the success of scale-up of malaria control interventions. Now a group of CDC/ex-CDC scientists have published a superb commentary (Malaria Journal – open access) on the same evaluation and on using facility-based data more broadly (hat tip: Matt Price). The authors focus on technical pitfalls, which were aplenty, but these are often exacerbated by the incentives of the evaluators. In act of terrific political deftness, Rowe et al. avoid any discussion of possible conflicts of interest.

On an unrelated note, I found the first sentence of the abstract to be curiously phrased:

The global health community is interested in the health impact of the billions of dollars invested to fight malaria in Africa.

First,  the prima facie concern regarding the impact of malaria control is with endemic countries. They have skin in the game. It is unclear what “the global health community” really means – while it could be inclusive of endemic nations the connation of the phrase seems more aligned with a donor perspective. Thus, the rationale of this paper reads “accurate program evaluations are needed because donors want to assess their impact.” This is wrong. Quality evaluations are important first and foremost because they allow country programs to track and improve their progress in minimizing the suffering of their citizens.  Anything else is secondary and subjugate to this concern. The framing of the sentence reflects a subtle, and likely unintentional, appropriation of responsibility which may not impact practice but devalues local decision makers. Second, why “in Africa”? Neither malaria, large investments, nor the cautions highlighted in the commentary are specific to that continent.

Tales of malaria fascinate me, how could they not? It is a dangerous, exotic, haphazard, and hopelessly romantic history. No other disease is as entwined with colonialism, war, and agricultural industry. Also, the basics haven’t changed much. Little in the past few decades has altered the underlying rationale and means of practical malaria control. Thus, along with fascinating stories there is a lot we can learn. A wise man (Dr J Kevin Baird) once told me:

A malariologist troubles himself to understand all of the gathered science of malaria, without regard to what technology has been applied to gather it. This means reading the old literature, a lot. The more I read it and understand it, a clear and somewhat disturbing message sinks in. There are very few malariologists actively publishing today. And the malaria scientists of today do not read or understand malariology. We make fundamental errors of strategy and strategic thinking.

In my readings thus far, this rings true. What the old literature provides is a rare element of perspective – a vantage point of clarity in an increasingly complex landscape. And the lens of history need not restrict our ambitions but can inform and temper our methods. So, where to look? In addition to your standard archived articles at the BMJ, JAMA, and other journals, two fantastic resources are:

1) Google Books – many incredible texts such as The Prevention of Malaria by Ronald Ross (1910) and The Practical Study of Malaria and Other Blood Parasites by JWW Stephens and SR Christophers (1904)

2) The National Library of Scotland – an entire collection of rare public health reports on plague, cholera, kala-azar, and malaria from the British era of India including the classic data of devastating malaria epidemics in the Punjab

Last week in Kolkata I vaguely recalled reading about a school of tropical medicine somewhere in the city. Scouring around one afternoon, I found a majestic old building attached to the Calcutta Medical College. The Calcultta School of Tropical Medicine was started by Sir Leonard Rogers, one of the founders of the Royal Society of Tropical Medicine who made important contributions in kala-azar (visceral leishmaniasis) and cholera research in the Bengal. In its heyday the school was one of the few key centers for such research in the world.

The close link between colonial industries and tropical diseases is apparent in this plaque dedicating research laboratories. The last scholarship for filariasis is even funded by a local Maharajah (king).

They have two dusty museums (I would not be surprised if I was the first visitor in months). One is maintained by the pathology department with a great set of clinical photographs, anatomical specimens ranging from enlarged spleens, amebic abscess ridden livers, and data on conditions from former times like black water fever (ie. intense hematuria precipitated by malaria infection in someone undertaking quinine prophylaxis).

The other museum in the department of helminthology is filled with jars of worms, flukes, and other parasites. Below is a photo of Dracunculus medinensis (better known as guinea worm) which has not plagued India since its elimination in 1996. It’s amazing how far we’ve come in just a generation given that my mother remembers hearing about guinea worm in her childhood.

The school is unfortunately a pale shadow of its former self. While it still has some great faculty who conduct tropical disease research when they can,  inclusion of the school into the general health services precipitated its decline. The pressing healthcare needs of the population the school serves and a large number of staff vacancies overwhelm the remaining staff with clinical duties. It is a story well-known in research institutions the world over.

Sometimes I hate advocates. Anything which smacks of “my disease is more important than yours” is a great way for me to stop listening. Nicholas Kristoff’s blog post on pneumonia importantly highlights the large disease burden and the relatively scant public attention. However, the solution is not to have a world pneumonia day. Nor do we need to justify schistosomiasis control with tenuous evidence on its association with HIV prevalence. I understand what Hotez et al. are trying to accomplish since the latter is a hot issue, but I wonder whether we will be undermined by such messaging in the long run. As a friend of mine said, “Treat schisto to treat schisto.  Anything else is icing on the cake.”

We need to move beyond unilateral thinking and organize around broader public health platforms. Unfortunately, this is not as tangible as a single topic, and it doesn’t make a good bumper sticker.

How do we do it?

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So this is what I’ve been writing about. Courtesy of Wordle.

Everyone likes to talk about DDT and malaria, and a friend of mine asked me to post about the topic. No way! I am not walking into that mess.

Suffice to say, I am frustrated with both sides of the debate. My personal views probably lie closest to those eloquently expressed here.

I really have to hand it to Paul Chinnock and his team at Tropika. Paul has turned the site into what I think is the best source of groundbreaking and offbeat  malaria news on the web (the site covers tropical diseases in general). I like his editorial input as well – he’s not afraid delve into substantive comments or share doubts and criticism. However, changing the comment system to not require a log-in would be my one suggestion for them. Here are some of my recent favorites from Tropika:

• MalERA – The malaria eradication research agenda – it’s arranged according to programmatic areas with all relevant documents made available, lists upcoming events, and has a forum to provide feedback! Well thought, transparent and progressive, I’m impressed.
• Every day is Malaria Day – a gem of an article. With a brilliant tongue-in-cheek first paragraph lamenting single disease and the stifling positivity of today’s adovacy, Paul goes on to guard against magic bullets, creating false hopes, and the consequences of failure.
• Gates, Lancet, priority setting in global health – a random hodgepodge of topics but noteworthy for not only mentioning that Ranbaxy plans to move forward with an antimalarial trial (which many news sources carried) but pointing out that Medicines for Malaria Ventures pulled out of that project after previous trial results.
• Sharing experiences in vivax control – a) it is news on vivax b) I simply did not see this conference covered anywhere else
• China and malaria elimination in the Solomons – a fascinating story about an scaled up malaria control effort and the controversy it has generated. The tone of the discussion (in the original news source, not the Tropika article) is disturbing and I hope to write more about this soon.

Note: Posts have been sparse but this will likely continue with USMLE exams and work in India coming up

Today is World Malaria Day.

Many more people are aware of this fact in 2009 with the increase in advocacy, particularly  in the Western world. Some would say malaria is now “hip”. For others, that’s as much a cause for concern as it is for celebration. In any case I’ll certainly take a minute today to reflect on how far we’ve come, and where we’ll go.