Clinical, Chemotherapeutic and Immunological Studies on Induced Malaria

Covell, G.; Nicol, W. D.

doi:10.1093/oxfordjournals.bmb.a074054

Cited by 47 publications

(22 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

Section: Discussioncontrasting

confidence: 52%

“…The paper gives no details about the "particular procedure" of mosquito and blood inoculations but claims that it led to infections with higher fevers, higher mortality (if untreated), and more consistent transmission to Anopheles, changes "evidenced not only by an increase in the number of asexual parasites but particularly by the earlier appearance and greater number of gametocytes." We are wary of the discrepancies between this account and reports on the same strain in the same facility during the same period that were published 5 yr earlier (James, 1931) and 15 yr later (Covell and Nicol, 1951), however.Decades of experience with the common malariatherapy "strains" seemed to confirm the presence and persistence of characteristic differences between primary infections with each of them (Boyd, 1940a;Kaplan et al, 1946), e.g., between the El Limon, McLendon, and SanteeCooper strains of P. falciparum (Collins and Jeffery, 1999). Several citations in the first paragraph of this paper are generalizations from the authors' extensive experience, each predominantly with 1 strain of P. vivax: Chesson (Whorton et al, 1947), McCoy (Kitchen, 1949), or Madagascar (Shute, 1958 Chesson infections and so may not apply to the authors' experience with St. Elizabeth infections.…”

mentioning

confidence: 56%

See 1 more Smart Citation

Plasmodium vivax Blood-Stage Dynamics

McKenzie¹,

Jeffery²,

Collins³

2002

The Journal of Parasitology

View full text Add to dashboard Cite

We examine the dynamics of parasitemia and gametocytemia reflected in the preintervention charts of 221 malaria-naive U.S. neurosyphilis patients infected with the St. Elizabeth strain of Plasmodium vivax, for malariatherapy, focusing on the 109 charts for which 15 or more days of patency preceded intervention and daily records encompassed an average 98% of the duration of each infection. Our approximations of merogony cycles (via "local peaks" in parasitemia) seldom fit patterns that correspond to "textbook" tertian brood structures. Peak parasitemia was higher in trophozoiteinduced infections than in sporozoite-induced ones. Relative densities of male and female gametocytes appeared to alternate, though without a discernably regular period. Successful transmission to mosquitoes did not depend on detectable gametocytemia or on absence of fever. When gametocytes were detected, transmission success depended on densities of only male gametocytes. Successful feeds occurred on average 4.7 days later in an infection than did failures. Parasitemia was lower in homologous reinfection, gametocytemia lower or absent.Plasmodium vivax asexual blood-stage cycles are authoritatively cited as displaying a period of 48 hr (Cox, 1993;Reisberg, 1997). Hence, a single-brood P. vivax infection would be expected to produce peaks of asexual parasitemia (in the form of merozoites) and corresponding fevers on alternate days and a 2-brood infection to produce daily (quotidian) peaks of parasitemia and fever. Whorton et al. (1947) attributed their observations of irregular or steady fevers to irregular parasite segmentation. Kitchen (1949) agreed, noting that the earliest phases of patent P. vivax infections might be marked by "continuous fever caused by more or less constant sporulation," but argued that "the great majority of the vivax plasmodia are segregated into two pyrogenic broods … whose corresponding developmental stages are separated by approximately twenty-four hours." Coatney et al. (1971) found P. vivax as often tertian as quotidian and remarked that "if the infection is allowed to run, it is not unusual for multiple broods to get-in-step resulting in a tertian fever pattern; likewise, tertian patterns, sometimes, become quotidian for a time, only to revert to tertian again." Garnham (1966) reported that "the process of schizogony in P. vivax is never of clockwork regularity." According to Shute (1958), "the true explanation is that the cycle depends on the patient and not on the parasite," meaning, in particular, that quotidian behavior marks the initial infection in a malaria-naive patient, whereas tertian behavior typifies relapses and subsequent infections.A companion paper on trophozoite-induced P. malariae infections addressed some of these phenomena (McKenzie et al., 2001). With the P. vivax charts, they can be addressed in the context of sporozoite-as well as trophozoite-induced infections. Inoculation modes may influence subsequent events: sporozoite-induced infections will show longer prepatency and incuba...

show abstract

Section: Discussioncontrasting

confidence: 52%

mentioning

confidence: 56%

Plasmodium vivax Blood-Stage Dynamics

McKenzie¹,

Jeffery²,

Collins³

2002

The Journal of Parasitology

View full text Add to dashboard Cite

show abstract

“…This question can be now further studied by using the Saimiri model, in which complex infections are reproduced with characteristics similar to those of natural infections in humans. 5,20,21,24 …”

Section: Discussionmentioning

confidence: 99%

Variant- and strain-specific immunity in Saimiri infected with Plasmodium falciparum.

Fandeur

Chalvet²

1998

The American Journal of Tropical Medicine and Hygiene

View full text Add to dashboard Cite

Abstract. Variant-and strain-specific immunity to malaria in Saimiri monkeys infected with homologous O and R variants of the Palo Alto strain (FUPSP) of Plasmodium falciparum or by various heterologous divergent strains were studied. Following homologous reinfections, the primary immune response in monkeys was effective only against the same variant type but not against the other variant, which differed only by antigens exposed at the surface of the infected red blood cell. In contrast, after two successive inoculations with a single variant type, a variant transcending immunity developed to both O and R parasite populations. The immunity against FUPSP in monkeys repeatedly infected with various combinations of heterologous strains, including Sal I, Tanzania, Camp, FUPCP, FCH4, FVO, and FUPCDC parasites was less effective, resulting at best in protecting the monkey against fulminating infection. However, in several cases, previous or concomitant heterologous infections modified the course of virulent infection by FUPSP parasites, indicating a significant degree of cross-protection between the strains. Therefore, in this model, while variant-and strain-specific antigens are important components of acquired immunity to malaria, the monkey immune response to infection transcends phenotypic antigenic variation and strain diversity.Immunity to malaria in humans is poorly protective and only acquired slowly after several years of exposure to intense transmission. It is a nonsterile immunity and requires frequent boosting if it is to last. 1 Malaria parasites exhibit an extensive antigenic polymorphism as a result of two major factors, allelic diversity and antigenic variation. While antigenic diversity and host adaptation to it are likely to be important parameters to naturally acquired immunity to malaria, little is known about the relationship between antigenic diversity and the protective immune response against infection. 2 It has been suggested that the various allelic forms of genes interfere with and hinder the development of an efficient immune response such that protection is only achieved after exposure to a large number of antigenically distinct parasite strains. 3,4 However, epidemiologic studies are not conclusive on this issue because of the complexity of natural parasite populations, host genetic diversity, and the possible presence of other immune evasion mechanisms such as antigenic variation. [5][6][7][8] It is important to determine the effect of phenotypic variation and antigenic diversity on the development of immunity. This question should be easier to address in experimental models in which the infection is well characterized and controlled. By using different approaches (parasitologic, immunologic, and molecular), we studied the relative importance of conserved and polymorphic antigenic determinants in inducing an effective immunity against Plasmodium falciparum in a monkey model. In this communication, we report the pattern of infections of Saimiri monkeys successively injected with various c...

show abstract

“…The clinical, chemotherapeutic, and immunologic aspects for infections with P. vivax, P. Ja lciparum, P. malariae, and P. ovale in some 2,500 patients observed at the Horton Hospital were reported. [6][7][8][9] Maiariatherapy in the United States. Malaria therapy was first used in the United States at St. Elizabeth's Hospital in Washington, DC in December 1922.…”

Section: Historical Perspectivementioning

confidence: 99%