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Monday, January 11, 2016

A piece of kit that quickly multiplies the DNA of parasitic worms could detect infections by schistosome species more than six times faster than the most accurate existing method.

Test results published in PLOS Neglected Tropical Diseases last week show that the device can detect infections by Schistosoma mansoni in mice with high accuracy from a drop of blood — and it can do so after only a week of infection.

This parasite is the main cause of the neglected tropical disease schistosomiasis (bilharzia).

The same kit can also detect infection with other schistosome parasites and helminths such as filarial worms, says Robert Greenberg, a parasite researcher at the University of Pennsylvania in the United States, who was part of the research team.

The kit works by multiplying the parasite’s DNA, using a process known as loop-mediated isothermal amplification, or LAMP, which previous studies had shown can detect schistosome DNA in infected samples. The amplified DNA is tagged with a fluorescent molecule and its presence confirmed using a smartphone camera.

Greenberg and the team found that the kit could diagnose infection withS. mansoni much earlier than the existing gold standard, which involves detecting parasite eggs in urine and stool samples through a microscope. “[Current tests] require production of eggs, which means a lag for schistosomiasis of at least six weeks,” he says.