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Mosquito transmission, growth phenotypes and the virulence of malaria parasites.

Pollitt LC, Mackinnon MJ, Mideo N, Read AF - Malar. J. (2013)

Bottom Line: A series of elegant experiments was recently published which demonstrated that transmission of malaria parasites through mosquitoes elicited an attenuated growth phenotype, whereby infections grew more slowly and reached peak parasitaemia at least five-fold lower than parasites which had not been mosquito transmitted.The effect of mosquito transmission varied among strains, but did not lead to pronounced or consistent reductions in parasite growth rate.Mosquito-induced attenuated growth phenotype is sensitive to experimental conditions.

View Article: PubMed Central - HTML - PubMed

Affiliation: Center for Infectious Disease Dynamics, Millennium Science Complex, Pennsylvania State University, University Park, State college, Pennsylvania 16801, USA. laura.pollitt@googlemail.com.

ABSTRACT

Background: A series of elegant experiments was recently published which demonstrated that transmission of malaria parasites through mosquitoes elicited an attenuated growth phenotype, whereby infections grew more slowly and reached peak parasitaemia at least five-fold lower than parasites which had not been mosquito transmitted. To assess the implications of these results it is essential to understand whether the attenuated infection phenotype is a general phenomenon across parasites genotypes and conditions.

Methods: Using previously published data, the impact of mosquito transmission on parasite growth rates and virulence of six Plasmodium chabaudi lines was analysed.

Results: The effect of mosquito transmission varied among strains, but did not lead to pronounced or consistent reductions in parasite growth rate.

Conclusions: Mosquito-induced attenuated growth phenotype is sensitive to experimental conditions.

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Related in: MedlinePlus

Comparison of infection protocol between (A) Spence et al. [5]and (B) Mackinnon et al. [6]. Dashed boxes indicate the hosts from which data for the different types of infections (SBP, serially blood-passaged; MT, mosquito transmitted; recently MT) were generated.
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Figure 1: Comparison of infection protocol between (A) Spence et al. [5]and (B) Mackinnon et al. [6]. Dashed boxes indicate the hosts from which data for the different types of infections (SBP, serially blood-passaged; MT, mosquito transmitted; recently MT) were generated.

Mentions: Their study has two important implications. Firstly, demonstrating the effect of parasite expression profiles on host immunity and disease progression sheds light on the mechanisms of protective immunity in malaria infections. Secondly, these results call into question the standard methodology used in model rodent malaria systems. For convenience, and because it is the blood stage infection which causes disease, the majority of laboratory studies examining the interactions between malaria parasites and their host bypass the vector and initiate infections with direct serial passage of blood stage parasites. The study by Spence et al.[5] suggests that this non-natural route of infection may alter parasite phenotypes and infection outcomes. To assess the implications of these results for future research in this area, understanding whether the attenuated infection phenotype is a general phenomenon across a broader range of parasites genotypes and conditions is crucial. This paper seeks to address this question by reanalysing a previously published dataset of parasite densities and measures of virulence from experimental malaria infections initiated with parasites that differed in their transmission histories. The experimental design differs in subtle ways from that of Spence et al.[5] (FigureĀ 1), but this is the best existing dataset for the task.


Mosquito transmission, growth phenotypes and the virulence of malaria parasites.

Pollitt LC, Mackinnon MJ, Mideo N, Read AF - Malar. J. (2013)

Comparison of infection protocol between (A) Spence et al. [5]and (B) Mackinnon et al. [6]. Dashed boxes indicate the hosts from which data for the different types of infections (SBP, serially blood-passaged; MT, mosquito transmitted; recently MT) were generated.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC3924181&req=5

Figure 1: Comparison of infection protocol between (A) Spence et al. [5]and (B) Mackinnon et al. [6]. Dashed boxes indicate the hosts from which data for the different types of infections (SBP, serially blood-passaged; MT, mosquito transmitted; recently MT) were generated.
Mentions: Their study has two important implications. Firstly, demonstrating the effect of parasite expression profiles on host immunity and disease progression sheds light on the mechanisms of protective immunity in malaria infections. Secondly, these results call into question the standard methodology used in model rodent malaria systems. For convenience, and because it is the blood stage infection which causes disease, the majority of laboratory studies examining the interactions between malaria parasites and their host bypass the vector and initiate infections with direct serial passage of blood stage parasites. The study by Spence et al.[5] suggests that this non-natural route of infection may alter parasite phenotypes and infection outcomes. To assess the implications of these results for future research in this area, understanding whether the attenuated infection phenotype is a general phenomenon across a broader range of parasites genotypes and conditions is crucial. This paper seeks to address this question by reanalysing a previously published dataset of parasite densities and measures of virulence from experimental malaria infections initiated with parasites that differed in their transmission histories. The experimental design differs in subtle ways from that of Spence et al.[5] (FigureĀ 1), but this is the best existing dataset for the task.

Bottom Line: A series of elegant experiments was recently published which demonstrated that transmission of malaria parasites through mosquitoes elicited an attenuated growth phenotype, whereby infections grew more slowly and reached peak parasitaemia at least five-fold lower than parasites which had not been mosquito transmitted.The effect of mosquito transmission varied among strains, but did not lead to pronounced or consistent reductions in parasite growth rate.Mosquito-induced attenuated growth phenotype is sensitive to experimental conditions.

View Article: PubMed Central - HTML - PubMed

Affiliation: Center for Infectious Disease Dynamics, Millennium Science Complex, Pennsylvania State University, University Park, State college, Pennsylvania 16801, USA. laura.pollitt@googlemail.com.

ABSTRACT

Background: A series of elegant experiments was recently published which demonstrated that transmission of malaria parasites through mosquitoes elicited an attenuated growth phenotype, whereby infections grew more slowly and reached peak parasitaemia at least five-fold lower than parasites which had not been mosquito transmitted. To assess the implications of these results it is essential to understand whether the attenuated infection phenotype is a general phenomenon across parasites genotypes and conditions.

Methods: Using previously published data, the impact of mosquito transmission on parasite growth rates and virulence of six Plasmodium chabaudi lines was analysed.

Results: The effect of mosquito transmission varied among strains, but did not lead to pronounced or consistent reductions in parasite growth rate.

Conclusions: Mosquito-induced attenuated growth phenotype is sensitive to experimental conditions.

Show MeSH
Related in: MedlinePlus