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Homologous P. vivax malarial recurrences are not necessarily relapses

November 26, 2021 - 10:29 -- Miles Markus

It was pointed out a decade ago that non-reinfection recurrences of Plasmodium vivax malaria caused by parasites that are closely related to those from an earlier time point are highly suggestive of a merozoite origin [1,2].

This would make them recrudescences (in an unknown proportion of cases), not relapses. In other words, hypnozoites [3] have nothing to do with such a recurrence.

Some recurrences that take place after 28 days post infection are also recrudescences (not relapses), as has recently been explained [2].

 

 

REFERENCES

1. Markus MB. Source of homologous parasites in recurrent Plasmodium vivax malaria. J. Infect. Dis. 2012;206(4):622–623. Available from: https://doi.org/10.1093/infdis/jis393

2. Markus MB. Safety and efficacy of tafenoquine for Plasmodium vivax malaria prophylaxis and radical cure: overview and perspectives. Ther. Clin. Risk Manag. 2021;17:989–999. Available from: https://doi.org/10.2147/TCRM.S269336

3. Markus MB. The malarial hypnozoite. Lancet. 1980;315(8174):936. Available from: https://doi.org/10.1016/s0140-6736(80)90871-5

Comments

Submitted by Miles Markus on

Genetically, this is a clonal parasite (as opposed to meiotic siblings) explanation for the origin of some or many non-reinfection homologous recurrences of P. vivax malaria.

The explanation does not apply only to short-term recurrences. This is elucidated in reference 2 in the above blog.