Parasitic disease has always been a problem ever since the ancient time. Different people living in different region suffers from various kinds of parasitic disease. As one of the common genus of parasites, tapeworms of the genus Echinococcus can cause human echinococcosis.cystic echinococcosis, also known as hydatid disease or hydatidosis,caused by infection with a species complex centred on Echinococcus granulosus;alveolar echinococcosis, caused by infection with E. multilocularis;two forms of neotropical echinococcosis: polycystic caused by infection with E. vogeli; and unicystic caused by E. oligarthrus.
The two most important forms, which are of medical and public health relevance in humans, are cystic echinococcosis (CE) and alveolar echinococcosis (AE). The most common one is cystic echinococcosis (CE), it is globally distributed and found in every continent except Antarctica. Alveolar echinococcosis is confined to the northern hemisphere, in particular to regions of China, the Russian Federation and countries in continental Europe and North America.[1]
Through out the life span on echinococcus, different stages play different roles in the pathogeny of the disease.
Adult worm living inside the bodies of definitive hosts can lay eggs or shed pregnancy section and contaminate the environment. By accidental ingestion of the eggs (mostly by drinking contaminated water and consuming contaminated vegetables), people can get infected with the worm.
Worms ingested can travel in the blood vessels and find an ideal organ or tissue for them to reside, mostly lung, liver, sometimes brain, bone or other tissue and form a echinococcosis cyst.
When the parasite infect the liver, abdominal pain, jaundice, nausea, and vomiting are the most common symptoms. When it comes to the lung, dyspnea, chronic cough and chest pain can be observed.
Unfortunately, people infected with echinococcus are usually herdsmen living on the prairie, which makes it troublesome for them to go to the hospital and get the diagnosis. Furthermore, hospitals in those regions usually do not own personnel skilled enough or qualified equipment to run the tests and conduct the examination for echinococcosis diagnosis.
To solve this problem and make it easier for potential patients to get the diagnosis, we designed our diagnostic system.
As parasites living inside human body, there's constant necrosis and apoptosis of cells. As cells die, cell-free DNA is released into the circulating peripheral blood through the cyst wall.
We can detect the cfDNA in the peripheral blood to determine whether there re parasites inside a patient’s body or not.
The releasing of the cfDNA is random, Therefore, we designed our system with multi-primer and multi-sgRNA to target a larger range of different cfDNA segments released from the echinococcos.
Then the amplification product was used to activate the trans-cleavage activities of CRISPR-Cas12a system, cut the nucleic acid probe we designed and synthesized.
We used the Recombinase Polymerase Amplification（RPA） amplify cfDNA in blood.
Then the colloidal gold test papers were used to detect product.
Compared with traditional antibody tests and PCR tests, our kit can complete the test without time consuming and expensive
equipment necessary for PCR or antibody tests, makes it more convenient for people living on the prairie to get the diagnosis.
