A follow-up on recent posts: plague & HIV

In early September I blogged about a modelling study linking the incidence of plague with climate change in Kazakhstan. Donald McNeil Jr. of the New York Times took a look at the analysis of US data that I referred to in the blog (I didn’t have the full text) and writes that according to that research, climate change has led to a reduction in the cases of bubonic plague in the US – the opposite trend to that suggested by the study in Central Asia.

I thought it important to point this out because the last paragraph of my blog can give a different message depending on how it’s read. It’s also interesting in the larger picture. It underscores that the evidence emerging (from other studies as well) suggests that there is a correlation between climatic changes and the incidence of plague. Which way it will drive incidence seems to vary from place to place. I should note that searching for ‘plague and climate change’ in PubMed comes up with just 12 hits, so there isn’t that much to go on at the moment. I can’t avoid ending by saying more research is needed.

…Moving on to HIV: the papers on early spread of the virus in Africa that I blogged about a couple of weeks ago ended up getting some attention. A story by Frederik Joelving titled Did doctors jumpstart the HIV pandemic?, published on Reuters.com and picked up widely, adds a counter-point – the “traditional line of argument”, as Joelving points out – with comment from biologist Michael Worobey. Worobey is not so convinced by the idea that HIV spread with unsterilised syringes and says the evidence in these two papers don’t settle the question.

I’d say that’s true, a single piece of research hardly ever does settle a question in public health. The debate will undoubtedly continue. But I think the research is significant, even if all it does is provide evidence that backs a less popular argument.