How genotyping is aiding in the fight against malaria

mosquitoe-1548975_19203.2 billion people across 106 countries and territories, live in areas at risk of malaria transmission. The serious and sometime fatal mosquito-borne disease is caused by the Plasmodium parasite – in 2015, malaria caused 212 million clinical episodes, and 429,000 deaths.

Malaria has been a public health problem in Brazil ever since it was brought to the region during its colonization. By the 1940s it is estimated that six to eight million infections and 80,000 malaria-related deaths occurred every year in the country.

Due to a concerted series of malaria control policies, Brazil has recorded a 76.8% decrease in malaria incidence between 2000 and 2014 – and effort which the country was praised by the WHO.  In 2014, there were 143,910 of microscopically confirmed cases of malaria and 41 malaria-related deaths.

Part of Brazil’s malaria control policy involves the use of primaquine – a medication first made in 1946, to treat and prevent malaria. It is particularly effective against the Plasmodium vivax parasite that is prevalent in the Brazil.

Unfortunately primaquine can induce haemolytic anaemia in glucose-6-phosphate dehydrogenase (G6PD)-deficient individuals and may lead to severe and fatal complications. 330 million people worldwide are affected with G6PD deficiency, with recent studies suggesting the prevalence of the deficiency could be as high as 10% in Brazil.

Recently, molecular biologists from LGC enabled a cutting edge study in collaboration with researchers from Brazil and the London School of Hygiene and Tropical Medicine.

The researchers looked for mutations in a sample of 516 male volunteers that could be used as clinical indicators for G6PD deficiency that could lead to complications in people prescribed with primaquine.

Blood samples were collected from around Brazil at hospitals during surgeries, as well as using the local Brazilian radio stations to ask people to come and submit blood.

Needing a fast and efficient way to generate results in high throughput, the team turned to LGC’s integrated genomics toolkit to facillitate the research. Each sample was screened against 24 KASP assays to assess the genetic bases of G6PD deficiency. In combination with the IntelliQube®,a fully automated point and click PCR system;  the team collected the data in roughly three hours of instrument time and one hour hands on time.

KASP is a flexible, highly specific genotyping technology, which can be used to determine SNPs and InDels.  KASP uses unlabelled oligonucleotide primers, which gives the technology a cost advantage and allows more data to be generated, increasing data quality.

The data indicates that approximately one in 23 males from the Alto do Juruá could be G6PD deficient and at risk of haemolytic anaemia if treated with primaquine. The authors conclude that routine G6PDd screening to personalize primaquine administration should be considered – particularly as complete treatment of patients with vivax malaria using chloroquine and primaquine, is crucial for malaria elimination.

The teams are continuing their collaboration to help further research in to treatments for malaria, and we can’t wait to see more!

To access the paper, please click here, or to see the IntelliQube in action and learn more about this automated PCR instrument click here.

 

 

Sources:

Malaria. (2017, July 13). Retrieved August 8, 2017, from https://www.cdc.gov/malaria/about/index.html

Maia, U. M., Batista, D. C., Pereira, W. O., & Fernandes, Thales Allyrio Araújo de Medeiros. (n.d.). Prevalence of glucose-6-phosphate dehydrogenase deficiency in blood donors of Mossoró, Rio Grande do Norte. Retrieved August 8, 2017, from http://www.scielo.br/scielo.php?pid=S1516-84842010000500017&script=sci_arttext&tlng=en

 

This blog post was originally published on the Biosearch Technologies blog.

Delivering impact to support AIDS research

LGC is helping to ensure that research into a cure for HIV is based on sound fundamental measurements.

Over 36 million people currently live with HIV, with approximately 2 million becoming infected each year (WHO 2015). Although HIV can be successfully managed with combination antiretroviral therapy (cART), the therapy must be continued indefinitely as no cure presently exists. This can be challenging in regions with high HIV prevalence and long-term use can potentially have toxic side effects.

One barrier to curing HIV is the presence of infected host cells that are not targeted by current therapies but lay dormant (so-called ‘viral reservoir’). These cells have the potential to become re-activated so novel strategies to cure HIV aim to target this reservoir. To determine whether these new approaches are successful, accurate and robust, methods for measuring HIV DNA are required.

The Molecular and Cell Biology team at LGC perform research to support accurate and reliable measurement as part of our National Measurement Laboratory (NML) role. Recent work by NML scientists comparing different molecular methods (qPCR, digital PCR) for quantification of HIV DNA has raised some concerns around the current popular choice of calibrator used to compare results between HIV clinical studies (8E5, ATCC® CRL-8993). It appears to lose HIV DNA copies during cell growth, potentially producing misleading estimates of how much HIV DNA is present and affecting whether novel strategies towards curing HIV are deemed successful or not.

Based in part on our work, the NIH AIDS Reagent Program, which provides critical reagents and resources to support research in the areas of AIDS therapeutics and vaccine development, has recently highlighted the potential instability of the standard on its reagent database to support the research community and enable the best chances of success.

 

 

Citation:

Busby E et al. Instability of 8E5 calibration standard revealed by digital PCR risks inaccurate quantification of HIV DNA in clinical samples by qPCR (2017) Sci Rep 7(1):1209. doi:10.1038/s41598-017-01221-5