New device from China can detect Cryptosporidium in 10 minutes: study

Chinese researchers said Tuesday they have developed a lab-on-a-chip device that can diagnose Cryptosporidium infections in just 10 minutes by using a finger-prick of blood, potentially bringing point-of-care diagnosis to remote, at-risk rural areas in order to improve treatment outcomes.

In most cases, an infection of Cryptosporidium parvum means nothing more than a few days of bad diarrhea, but for someone with a compromised immune system, it can mean death, following an excruciating, protracted bout of watery diarrhea.

Worldwide, treatment for the parasitic infection consists largely of oral rehydration and managing symptoms until the body clears the infection, something that may take far longer for people with HIV infections.

But poor sensitivity and a short window of spore secretion both limit the viability of acid-fast staining, a standard diagnostic assay in use today. More advanced immunoassays, such as enzyme- linked immunosorbent assays (ELISA), are difficult to use because they require relatively advanced lab settings and skilled technicians.

In the U.S. journal Biomicrofluidics, Xunjia Cheng and Guodong Sui, both professors at Fudan University, described how they developed a new microfluidic device using a widely used silicon- based organic polymer known as PDMS to address this need.

"The microfluidic device tests for the presence of the parasites' P23 antigen, a major molecular target of host antibody responses against the pathogen's infective stages," the researchers said in a statement.

"The chip itself is small -- 3 cm by 2 cm -- and only costs about a dollar to manufacture," they said.

According to Sui and Cheng, the device is easy to use, allowing just about anybody to operate it. It can process up to five samples at a time, and the entire detection process can be completed in 10 minutes with only two microliters of blood.

They tested the device's efficacy at diagnosing Cryptosporidium infections in 190 HIV-infected patients in Guangxi, China and found that it's as effective as ELISA with huge potential reductions in cost, time and the amount of training needed to operate.

Next, Sui and Cheng planned to expand the chip's sample processing capacities to include other infectious diseases, as well as increase the device's sensitivity and specificity. Endite