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Concentration of Plasmodium falciparum gametocytes in whole blood samples by magnetic cell sorting enhances parasite infection rates in mosquito feeding assays

By Pierre Bush, PhD Moderator | 06 Aug, 2017

Dear Colleagues,
Here is the news in malaria methodologies
Abstract:
Background
Mosquito-feeding assays are important tools to guide the development and support the evaluation of transmission-blocking interventions. These functional bioassays measure the sporogonic development of gametocytes in blood-fed mosquitoes. Measuring the infectivity of low gametocyte densities has become increasingly important in malaria elimination scenarios. This will pose challenges to the sensitivity and throughput of existing mosquito-feeding assay protocols. Here, different gametocyte concentration methods of blood samples were explored to optimize conditions for detection of positive mosquito infections.
Methods
Mature gametocytes of Plasmodium falciparum were diluted into whole blood samples of malaria-naïve volunteers. Standard centrifugation, Percoll gradient, magnetic cell sorting (MACS) enrichment were compared using starting blood volumes larger than the control (direct) feed.
Results
MACS gametocyte enrichment resulted in the highest infection intensity with statistically significant increases in mean oocyst density in 2 of 3 experiments (p = 0.0003; p ≤ 0.0001; p = 0.2348). The Percoll gradient and standard centrifugation procedures resulted in variable infectivity. A significant increase in the proportion of infected mosquitoes and oocyst density was found when larger volumes of gametocyte-infected blood were used with the MACS procedure.

Conclusions
The current study demonstrates that concentration methods of P. falciparum gametocyte-infected whole blood samples can enhance transmission in mosquito-feeding assays. Gametocyte purification by MACS was the most efficient method, allowing the assessment of gametocyte infectivity in low-density gametocyte infections, as can be expected in natural or experimental conditions.

Replies

 

NIRMAL GHIMIRE Replied at 6:36 AM, 8 Aug 2017

Thanks Bush. ...but 1 querry from my side? Any drug which can interrupt
the sexual cycle of malaria. ..

Pierre Bush, PhD Moderator Replied at 12:33 PM, 9 Aug 2017

Hello Nirmal, we had a discussion three months ago about disrupting mosquito reproduction using steroid hormones disrupters, but the referenced study was conducted targeting female Anopheles gambiae (see Childs et al. 2016). Otherwise, Ivermectin is another product that has been in consideration for this purpose (see Chaccour & Rabinovich,2017).
Highest Regards.

Attached resources:

NIRMAL GHIMIRE Replied at 11:00 PM, 9 Aug 2017

Thanks mate

dr.hanifa mbithe Replied at 5:22 AM, 13 Feb 2018

Hi thanks very informative article

Kamiludeen Hassan Replied at 1:19 PM, 13 Feb 2018

Thanks a lot.

Ahishakiye Alain Replied at 12:09 AM, 14 Feb 2018

Very interesting!

Mbonea Yonazi Replied at 1:25 AM, 14 Feb 2018

Interesting!

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