Pre-erythrocytic Stage in Mammalian Malaria Parasites

Shortt, H. E.; Garnhám, P. C. C.

doi:10.1038/161126a0

Cited by 109 publications

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“…inoculation of sporozoites of P. cynomologi into rhesus monkeys (2). In addition to reporting fully mature parasites inside hepatocytes, the authors also documented the persistence of immature and dormant forms of the parasite in the liver several months after the initial inoculation, which they proposed to be the cause of relapses (5), and were later called hypnozoites (6).…”

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Development of the malaria parasite in the skin of the mammalian host

Gueirard

Tavares²,

Thiberge³

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

122

109

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The first step of Plasmodium development in vertebrates is the transformation of the sporozoite, the parasite stage injected by the mosquito in the skin, into merozoites, the stage that invades erythrocytes and initiates the disease. The current view is that, in mammals, this stage conversion occurs only inside hepatocytes. Here, we document the transformation of sporozoites of rodentinfecting Plasmodium into merozoites in the skin of mice. After mosquito bite, ∼50% of the parasites remain in the skin, and at 24 h ∼10% are developing in the epidermis and the dermis, as well as in the immunoprivileged hair follicles where they can survive for weeks. The parasite developmental pathway in skin cells, although frequently abortive, leads to the generation of merozoites that are infective to erythrocytes and are released via merosomes, as typically observed in the liver. Therefore, during malaria in rodents, the skin is not just the route to the liver but is also the final destination for many inoculated parasites, where they can differentiate into merozoites and possibly persist.intravital imaging | Plasmodium | schizogony M alarial infection starts with the inoculation of Plasmodium sporozoites by mosquitoes probing the vertebrate skin for blood. The highly motile sporozoites eventually invade host target cells where they differentiate and divide into numerous merozoites, the parasite form that invades erythrocytes and initiates the pathogenic phase of malarial infection. The host cell type in which sporozoites transform into merozoites, however, differs between Plasmodium species. In species that infect birds, sporozoites differentiate inside macrophages primarily in the skin but also in the spleen, liver, and bone marrow (1). In species that infect mammals, sporozoites are known to differentiate only inside hepatocytes in the liver (2-4).The first demonstration that sporozoites of mammal-infecting Plasmodium species develop inside hepatocytes was made in 1948 after i.v. inoculation of sporozoites of P. cynomologi into rhesus monkeys (2). In addition to reporting fully mature parasites inside hepatocytes, the authors also documented the persistence of immature and dormant forms of the parasite in the liver several months after the initial inoculation, which they proposed to be the cause of relapses (5), and were later called hypnozoites (6). Subsequent work indicated that sporozoites of species that infect humans (7) also undergo complete development inside hepatocytes.Since these early studies, P. berghei and the related P. yoelii species, which infect rodents, have been used as practical and safe models for studying the pre-erythrocytic phase of malaria. These parasites were shown to differentiate in the liver of laboratory rodents (8), and the P. berghei/rodent system was used to demonstrate that the majority of sporozoites were inoculated by mosquitoes in the skin rather than directly into the blood circulation (9), as traditionally assumed. More recently, the generation of fluorescent P. berghei parasites, alo...

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confidence: 99%

“…In species that infect birds, sporozoites differentiate inside macrophages primarily in the skin but also in the spleen, liver, and bone marrow (1). In species that infect mammals, sporozoites are known to differentiate only inside hepatocytes in the liver (2)(3)(4).…”

mentioning

confidence: 99%

Development of the malaria parasite in the skin of the mammalian host

Gueirard

Tavares²,

Thiberge³

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

122

109

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“…6 British parasitologists Percy Cyril Claude (P.C.C.) Garnham and Henry E. Shortt, of the London School of Hygiene and Tropical Medicine, had uncovered this ''exoerythrocytic cycle'' while studying a rhesus macaque infected by Plasmodium cynomolgi (Shortt and Garnham, 1948). 5 In 1935, only a few years after Coatney isolated a plasmodium from a pigeon, chicken malaria, P. gallinceum, was isolated and identified and it soon became an extremely common model (Slater, 2009, p. 53), although, according to Coatney, the USDA would not allow the importation of this parasite until the advent of World War II made it imperative (Schmidt, 1979, at 13:52).…”

Section: Modeling Parasitic Disease: Monkeys Malaria and Men In Thementioning

confidence: 99%

Patterns of Infection and Patterns of Evolution: How a Malaria Parasite Brought “Monkeys and Man” Closer Together in the 1960s

Dentinger

2015

J Hist Biol

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Abstract. In 1960, American parasitologist Don Eyles was unexpectedly infected with a malariaparasite isolated from a macaque. He and his supervisor, G. Robert Coatney of the National Institutes of Health, had started this series of experiments with the assumption that humans were not susceptible to ''monkey malaria.'' The revelation that a mosquito carrying a macaque parasite could infect a human raised a whole range of public health and biological questions. This paper follows Coatney's team of parasitologists and their subjects: from the human to the nonhuman; from the American laboratory to the forests of Malaysia; and between the domains of medical research and natural history. In the course of this research, Coatney and his colleagues inverted Koch's postulate, by which animal subjects are used to identify and understand human parasites. In contrast, Coatney's experimental protocol used human subjects to identify and understand monkey parasites. In so doing, the team repeatedly followed malaria parasites across the purported boundary separating monkeys and humans, a practical experience that created a sense of biological symmetry between these separate species. Ultimately, this led Coatney and his colleagues make evolutionary inferences, concluding ''that monkeys and man are more closely related than some of us wish to admit.'' In following monkeys, men, and malaria across biological, geographical, and disciplinary boundaries, this paper offers a new historical narrative, demonstrating that the pursuit of public health agendas can fuel the expansion of evolutionary knowledge.

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“…Reproduction sexuée [1]. Dans ces lignées, ce n'est pas le niveau d'activité enzymatique de la SOD1 qui est en cause, mais un gain de fonction toxique encore mal élu-cidé.…”

Section: Derme Cycle Chez L'anophèleunclassified

“…La phase pré-érythrocytaire du cycle de vie de Plasmodium, découverte en 1948 [1], soit 68 ans après la découverte de la forme érythrocytaire du parasite par Alphonse Laveran, reste encore mal connue [2]. Seuls quelques parasites contenus dans les glandes salivaires du moustique, appelés sporozoïtes, sont injectés dans le derme durant une piqûre.…”

unclassified

Paludisme : une nouvelle vie pourPlasmodium

Ménard

2006

Med Sci (Paris)

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Pre-erythrocytic Stage in Mammalian Malaria Parasites

Cited by 109 publications

References 0 publications

Development of the malaria parasite in the skin of the mammalian host

Development of the malaria parasite in the skin of the mammalian host

Patterns of Infection and Patterns of Evolution: How a Malaria Parasite Brought “Monkeys and Man” Closer Together in the 1960s

Paludisme : une nouvelle vie pourPlasmodium

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