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Research Article

A Systems-Based Analysis of Plasmodium vivax Lifecycle Transcription from Human to Mosquito

  • Scott J. Westenberger,

    Affiliation: Department of Cell Biology ICND 202, The Scripps Research Institute, La Jolla, California, United States of America

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  • Colleen M. McClean,

    Affiliation: Division of Infectious Diseases, Department of Medicine, University of California San Diego School of Medicine, La Jolla, California, United States of America

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  • Rana Chattopadhyay,

    Affiliation: Sanaria Inc., Rockville, Maryland, United States of America

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  • Neekesh V. Dharia,

    Affiliation: Department of Cell Biology ICND 202, The Scripps Research Institute, La Jolla, California, United States of America

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  • Jane M. Carlton,

    Affiliation: Department of Medical Parasitology, New York University Langone Medical Center, New York, New York, United States of America

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  • John W. Barnwell,

    Affiliation: Centers for Disease Control and Prevention, Division of Parasitic Diseases, Atlanta, Georgia, United States of America

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  • William E. Collins,

    Affiliation: Centers for Disease Control and Prevention, Division of Parasitic Diseases, Atlanta, Georgia, United States of America

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  • Stephen L. Hoffman,

    Affiliation: Sanaria Inc., Rockville, Maryland, United States of America

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  • Yingyao Zhou,

    Affiliation: Genomics Institute of the Novartis Research Foundation, San Diego, California, United States of America

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  • Joseph M. Vinetz,

    Affiliation: Division of Infectious Diseases, Department of Medicine, University of California San Diego School of Medicine, La Jolla, California, United States of America

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  • Elizabeth A. Winzeler mail

    winzeler@scripps.edu

    Affiliation: Department of Cell Biology ICND 202, The Scripps Research Institute, La Jolla, California, United States of America

    X

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THE HYPNOZOITE : HISTORICAL OMISSIONS

Posted by MILES206MARKUS on 01 Jun 2010 at 21:12 GMT

The novel and exciting hypnozoite-related life cycle research carried out in the late 1970s and 1980s by W.A. Krotoski and his colleagues is well known. Westenberger et al. point out in their very interesting paper that three decades after the malarial hypnozoite was discovered by Krotoski, its biology is still “poorly understood”; “little is known about what triggers a relapse”; and “almost nothing is known about metabolic activity in the hypnozoite”. The enigmatic aura that surrounds the hypnozoite extends to (inter alia) the origin of the term and its adoption for Plasmodium.

To clarify, the hypnozoite owes it name to non-malarial research that I carried out in the 1970s while a postgraduate student at Imperial College London in the United Kingdom. The following predictive remark (which has not been mentioned since in articles on the history of malaria or anywhere else) was made at the time [1]: “If sporozoites of Isospora can behave in this fashion, then those of related Sporozoa, like malaria parasites, may have the ability to survive in the tissues in a similar way.”

The term “hypnozoite” was coined by Markus [2,3], not by Garnham as has been stated in the literature. In a letter to me, the late Professor Garnham wrote: “I am sorry there should be even a misunderstanding on the origin of this word which as you … recognise from my remarks in Protozoology abstracts is clearly due to you.” He also commented: “… you found a very useful word to describe these stages.” A detailed explanation concerning the origin of the name “hypnozoite” has been submitted for publication elsewhere. Garnham’s letter will appear as a Figure.

Finally, something that has almost never been correct in publications on malaria is how the term “hypnozoite” first came to be used in relation to the disease. The name was applied at a time when the existence of dormant plasmodial liver forms was still a hypothetical notion. In adopting the word “hypnozoite” for malaria in 1978, Markus [3] wrote (in a relatively obscure journal) that it would “… describe any dormant sporozoites or dormant, sporozoite-like stages in the life cycles of Plasmodium …”. This adoption of the term is reflected similarly in the abstract of one of two international conference contributions [4] upon which the article [3] was based; and in the other abstract [5] by the wording: “A ‘hypnozoite’ … is a dormant sporozoite or sporozoite-like stage in the life-cycle of … Plasmodium.” Reprints of the full paper [3] are still available (contact e-mail address: medsynth@yahoo.co.uk).

The malarial hypnozoite is not merely of academic interest. Westenberger et al. express, as follows, the significant public health problem that is associated with it: “Because P. vivax produces latent liver forms, eradication of P. vivax malaria is more challenging than it is for P. falciparum.”

REFERENCES: 1. Markus MB (1976) Possible support for the sporozoite hypothesis of relapse and latency in malaria. Trans R Soc Trop Med Hyg 70: 535; 2. Markus MB (1976) A term for extra-intestinal stages of mammalian Isospora (Protozoa, Coccidia, Eimeriidae). S Afr J Sci 72: 220; 3. Markus MB (1978) Terminology for invasive stages of protozoa of the subphylum Apicomplexa (Sporozoa). S Afr J Sci 74: 105-106; 4. Markus MB (1978) Terminology for invasive stages of the subphylum Sporozoa (Apicomplexa). Proc IVth Int Congr Parasitol (Warsaw) B: 79-80; 5. Markus MB (1978) Terms for invasive stages of protozoa of the subphylum Sporozoa (Apicomplexa). Parasitology 77: vii-viii.

No competing interests declared.