Use of bio-sensors to detect Cryptosporidium-parvum bacteria

It may be tiny, but the parasite known as Cryptosporidium certainly packs a punch. Several summers ago, the microscopic, single-celled protozoan infected hundreds of Utah pools with the swimming pool virus, leaving thousands of residents with deadly flu-like symptoms. After pools in 20 Utah counties were forced to close, swimmers were left with fewer options to keep cool in the sweltering summer heat.

In 1993, the protozoan parasite had infected over 400,000 Milwaukee, Wis. residents with the throes of a deadly outbreak of very similar flu-like symptoms. After weeks of severe stomach cramping, fever, vomiting, and diarrhea, 104 people died, and Cryptosporidium made its mark as a force to be reckoned with. Literally meaning hidden germ, Cryptosporidium is a deadly, waterborne protozoan parasite that wreaks gastrointestinal havoc on its victims.

Usually found in drinking water, Cryptosporidium sneaks its way into the body through the digestive tract. Once inside, Cryptosporidium wastes no time in spawning its microscopic offspring into the intestines, creating a debilitating and sometimes life-threatening illness. Cryptosporidium has been recognized by the World Health Organization as a significant global health threat, said Anhong Zhou, assistant professor of biological engineering at Utah State University. It causes dehydration and malnutrition that is responsible for the deaths of 11,000 children each day and 5 million people a year worldwide, making it the second leading cause of death, behind cardiovascular disease.

However, cryptosporidium will have finally met its match in DNA-based biosensors. So what exactly are biosensors? Put simply, a biosensor is a device that monitors changes in environmental conditions. Even something as simple as a canary in a mine used to detect gas could technically be considered a biosensor. Blood glucose monitors, familiar to most people, are used by diabetics and are the most widespread biosensor.

By using organisms that are super sensitive to chemicals, biosensors alert people to the presence of hazardous materials, like Cryptosporidium, long before humans could recognize them. DNA biosensors are a recently developed, rapid, and ultra-sensitive technique that are widely used for biomedical diagnosis and environmental microorganism detection. Zhou has found that these DNA-based biosensors are especially helpful in detecting Cryptosporidium. "The known unique genetic information of Cryptosporidium has inspired me to develop specific biosensors that will possibly detect its different genotypes of Cryptosporidium," said Zhou. Because the 22 different strains of Cryptosporidium have similar genomes, some only differing by a single base, a DNA-based biosensor will allow us to more readily detect Cryptosporidium, as well as the source in an epidemic.

Zhou hopes to use his research to create a portable biosensor that can be used to detect species-specific genes of Cryptosporidium. He plans to work with the Utah Department of Environmental Quality to validate this new sensor in the field. Zhou is also working to get patents for his biosensors so he can commercialize his new technology. There is no doubt about the potential for the application of this biosensor technique in human healthcare, said Zhou. Success of this research would be directly beneficial to finding effective treatment of Cryptosporidiosis and related water and food safety issues resulting from this protozoan parasite.