[Development of colloidal gold immunochromatography assay strip for schistosomiasis diagnosis in domestic animals].

OBJECTIVE: To develop a quick and easy colloidal gold immunochromatography assay (GICA) strip for schistosomiasis diagnosis in domestic animals.

METHODS: The reconstruction of Streptococcal Protein G (SPG) was designed and its gene was subcloned into plasmid pET-28a(+) to express in Escherichia coli. The recombinant SPG was purified and labeled with colloidal gold. The Schistosoma japonicum soluble egg antigen (SEA) and rSPG were blotted on the nitrocellulose membrane for the test line and control line respectively. The specificity, sensitivity and cross-reaction of the strip method were detected.

RESULTS: The rSPG was successfully expressed and purified to label with colloidal gold. The colloidal gold immunochromatography assay strips were assembled and they could detect the sera of S. japonicum infected BALB/c mice, New Zealand white rabbits, buffalo and sheep successfully. Besides, the sensitivity of GICA strip was 100% in the sera of mice and the serum of rabbits with S. japonicum infection. The specificity was 100% in the serum of mice and the sera of rabbits with free of infection. The sensitivity was 100% in the sera of sheep with miracidia of S. japonicum hatching from the stool and the specificity was 88.46% in the sera of sheep without that. The sensitivity was 94.44% in the sera of buffalo with miracidia hatching from the stool and the specificity was 100% in the sera of buffalo without that. The cross-reaction rate was 5.88% in Paramphistomum.

CONCLUSION: The GICA strip can successfully detect a variety of S. japonicum infected domestic animals and may be a useful tool for screening on a large scale in the endemic areas.