Here is something of fundamental malariological interest:
A past suggestion is that both early and late homologous recurrences of Plasmodium vivax malaria can have a non-circulating merozoite origin [1–4].
There is now revealing new (February 2021) evidence which supports this idea. Some post-28-day recurrences that took place during a recent study appeared to be recrudescences rather than relapses . Thus, it seems likely that a combination of the two types of recurrence can occur after 28 days.
What remains to be determined is how many longer-term P. vivax malarial recurrences are relapses (hypnozoite origin) and what proportion are recrudescences (merozoite origin).
1. “Origin of recurrent Plasmodium vivax malaria – a new theory”. https://www.researchgate.net/publication/221827340_Origin_of_recurrent_P...
2. “Source of homologous parasites in recurrent Plasmodium vivax malaria”. https://doi.org/10.1093/infdis/jis393
3. “Dormancy in mammalian malaria”. https://doi.org/10.1016/j.pt.2011.10.005
4. “Malaria eradication and the hidden parasite reservoir”. https://doi.org/10.1016/j.pt.2017.03.002
5. “High proportion of genome-wide homology and increased basal pvcrt levels in Plasmodium vivax late recurrences: a chloroquine therapeutic efficacy study”. https://doi.org/10.1101/2021.01.22.21250265