Tuesday, March 31, 2009

Malariffic!

The classic model for malaria is rural and tropical. That model is changing with recent demographic and ecological shifts, as malaria is becoming more and more an urban disease, with the expected alteration in required prevention tactics. Unfortunately, the urban lifestyle dictates less time spent at home and more time out-and-about in the city, meaning traditional and proven control mechanisms such as insecticide treated nets lose some of their effectiveness. In addition, traditional agricultural development that has been shown to be effective in curtailing malaria propagation is less relevant in urban centres (I suggest Randall Packard's great book on the history of malaria for more information on this). Therefore, new techniques are mandatory, mostly through mosquito control. While we wait for genetically engineered mosquitoes, good old fashioned mosquito killers will have to do.

The larvicides used in this study (Geissb├╝hler Y, Kannady K, Chaki PP, Emidi B, Govella NJ, et al. (2009) Microbial Larvicide Application by a Large-Scale, Community-Based Program Reduces Malaria Infection Prevalence in Urban Dar Es Salaam, Tanzania. PLoS ONE 4(3): e5107. doi:10.1371/journal.pone.0005107) published this week in PLOS One, are bacteria distributed in pellets that larval mosquitoes ingest. These bacteria release toxins that are toxic to the mosquito digestive tract, resulting in mosquito death. The pellets are effective for a few weeks after distribution, and there has been no documented side-effect of human danger from their dissemination. One of the challenges is the development of larval resistance to their toxins, something not seen yet, but potentially present in the future.

The researchers showed a fairly significant decrease in malaria incidence, and a decreased number of mosquito bites in general (with the rigorous bites/night methodology used by frequently-tested volunteers). A nice population level intervention, though it was relatively top-heavy with staff and infrastructure - for an urban centre, however, the cost-effectiveness is probably reasonable, given the huge economic effects of malaria incidence upon a population. The next step is to replicate this in another city - perhaps in Asia where the mosquitoes are slightly different, to see if this can be effectively scaled up for global dissemination.

Friday, March 27, 2009

Babies with bad guts

The first post of many, hopefully.

I'll try and focus upon research that may not otherwise get the press that it deserves, either because of the obscurity of the topic or the location of the researchers. Here's an interesting article performed by researchers in Kolkata, randomizing premature babies to prophylactic probiotics or placebo, and finding a fairly significant response rate with the outcomes of necrotizing enterocolitis, hospital stay, and time to full gut feeding. Not revolutionary stuff, since prior studies have backed this up, including a well-performed Cochrane analysis, which showed that by giving little babies probiotics, you reduce the incidence of this serious gut disease. This has been slow to disseminate into practice, however, since people seem to be still afraid of giving little babies, with their immature little immune systems, more microorganisms. None of the data says that this is a concern, with no significantly increased rates of new blood infections or other serious adverse events in the babies that received the probiotic.

What's more notable than just the direct clinical application of this study, however, is just how crucial our endogenous bacterial flora is in our physiology. Premature infants are premature in everything, including the establishment of an appropriate microbial environment, and by artificially inducing something akin to that, as the researchers have done through providing organisms that are commensal in breast milk, they have reduced the incidence of a disease. Bacteria have long gotten a bad rap, and only recently their multi-varied function in the developing infant has been realized: from digestion to vitamin production to immune regulation
to many more, emphasizing the complex host-microbial relationship. Some exciting stuff is being performed looking at the long-term incidence of disease and the neonatal gut flora, and most exciting is the human microbiome project, with the potential to seed the gut with specific disease-preventing/treating bacteria and add even more complexity to the gene-environment interactability discussions. Exciting times.

An initiation

I've tried blogging numerous times before. It's fairly straightforward, though my attention span doesn't seem to be conducive to maintaining and sustaining a coherent theme to one specific blog. Hence, my blogger profile is littered with the corpses of blogs-that-were-but-are-no-longer-active, although this time will be different (I swear). Instead of nonsensical ramblings about the state of the world, this will be a structured, weekly compilation of published scientific literature that I find the most interesting and relevant to the world at large. Yes, there will be digressions into discussing the latest Ig-Nobel worthy feline gender identity research, but hopefully I'll maintain my focus on the studies that really matter, leaning towards my tripartite passion of infectious diseases, child health, and critical care.

Today, as an intro, one of my favourite TED talks of the past few years, not necessarily because of its debatable content, but moreso because of its effective use of data visualization to convey a complicated message.