In 2012, the following remark appeared in the Journal of Travel Medicine (reference 44 in the publication for which the link is provided below):
"Malariologists need to reassess the conventional view that plasmodial habitats in humans are only liver and blood and be more open to the concept of there perhaps being additional parasite reservoirs."
This philosophy elicited some peculiar knee-jerk reactions of long duration (a phenomenon certainly not unprecedented in malariology), although mainly just straightforward disbelief. Now, almost a decade later, it has become apparent that Plasmodium vivax is primarily a non-peripheral bloodstream parasite. In the interim, we have routinely continued to stare down microscopes at blood films, especially in rural areas, in order to try and detect infection. But not having seen parasites does not necessarily mean that the patients were not infected. The number of chronic P. vivax infections that are sub-patent might be large.
The bottom line is that non-reinfection, recurrent P. vivax malaria is not only about hypnozoites (ignore what textbooks say). There is more to the story than meets the eye, so to speak, requiring a paradigm shift in thinking.
The paper that comes up via the following link contains (despite the article’s title) some of the latest commentary relating to P. vivax biology, etc.: