New Urine Test Capable of Detecting Disease that Causes Blindness

A team of researchers from Scripps Research have recently created a urine test that can detect Onchocerca, a parasitic worm that cause river blindness. This tropical disease, referred to as onchocerciasis, affects 18 to 120 million people in the world and causes aggressive loss of vision.

As described in ACS Infectious Diseases, this new noninvasive test could provide an affordable means of real time diagnosis for the infection. Onchocerciasis occurs when the parasitic worm volvulus invades the host’s skin. The mature worm than undergoes rapid proliferation, producing a large number of offspring. These offspring are eventually spread via bites from blackflies and can spread to the hosts eyes. Once dead in the eye, the parasite releases toxins, causes inflammation, and eventually causes blindness without medical intervention.

“River blindness affects individuals both in Africa and Latin America, and because many of these endemic regions are difficult to access, what is needed in the field is an inexpensive point-of-care means to monitor the disease,” says Dr. Kim Janda, Ely R. Callaway Jr. chemistry professor and researcher at the Skaggs Institute for Chemical Biology at Scripps Research.

Janda stresses monitoring and evaluation as mandatory steps for epidemiologists leading efforts to eliminate onchocerciasis. With the current method of detecting these parasitic worms being a biopsy of the skin, but this diagnostic technique is not very sensitive. As the concentration of parasite in the skin decreases, the skin snipping method loses potency. These tests cannot distinguish between new and lingering infections.

As for medical intervention, patients with onchocerciasis are commonly given high dose therapy of Ivermectin to hinder and eliminate transmission of the Onchocerca volvulus. Though effective, without a proper means of detecting ongoing disease it is difficult to see whether the treatment is working or when to cease drug administration. The device uses antibodies to bind a biomarker that is only detectable after the human host has broken down the tyramine neurotransmitter from the parasite, and the biomarker is secreted in the urine.

After undergoing a 10-year development phase, this urine diagnostic is finally ready to enter the manufacturing process. Differing from the biopsy test, this diagnostic is the first to utilize one of the metabolites of the worm, says Janda. With its inexpensive delivery, and use with smartphone applications, this device could lead to a huge improvement in the monitoring and treating of river blindness.

Source: ScienceDaily