Being presently bored with Patrick White, I went in search of the sequel to Sea of Poppies in the UNSW Library. It seems they haven't gotten around to buying it yet, though it has been out for almost two years now, and so I came away with this sci fi pulp from 1996 instead. I read it over just a couple of days.
The central conceit of this book is contained in perhaps three pages sprayed amongst three hundred, so forgive me if I hurried on past it. (Given a hefty edit this might have been a decent short story.) Roughly the plot sways between the (still) near future, Ghosh's time of writing, and a fictionalised recounting of the discovery of how mosquitos transmit malaria back in the late 1890s by Sir Ronald Ross. This got Ross a Nobel Prize. He also riffs on the use of malaria to treat tertiary-stage syphilis which later got Julius Wagner-Jauregg a Nobel. Somehow this adds up to a mechanism for transferring character traits.
The latter use of malaria to treat another disease is clearly ethically dodgy. This pyrotherapy came up in a different guise while talking to the Persians over the weekend: in contrast to the Judaic religions, Zoroastrianism holds that fire is the strongest purifying element.