Conjugated silver nanoparticles as a diagnostic tool for circulating hydatid antigens

Cystic hydatid disease is one of the most significant worldwide zoonotic diseases. The causative agent is the larval stage of Echinococcus granulosus. The diagnosis of cystic echinococcosis by clinical symptoms and scanning alone is often difficult and confusing. The definite diagnosis needs sensitive and reliable serological tests. This study aimed to evaluate a nano silver-based enzyme linked immunosorbent assay (ELISA) in the detection of circulating hydatid antigen in human serum samples. The study included 66 human serum samples (36 hydatidosis confirmed cases, 15 cases infected with other parasites, and 15 normal subjects as negative control). The circulating protoscolices antigen was assayed by the nano-silver dot ELISA, nano-silver sandwich ELISA and the traditional methods (dot ELISA and sandwich ELISA). Our study revealed that the sensitivity and specificity of the nano-silver dot ELISA were 97.2% and 93.3%, respectively. The sensitivity and specificity of nano-silver sandwich ELISA were 94.4% and 96.7% respectively. The nano-silver-based ELISA showed higher sensitivity, specificity, positive predictive value, negative predictive value, and diagnostic accuracy than the traditional ELISA. In conclusion, the nano-silver-based ELISA can be proposed as a confirmatory test in the diagnosis of cystic echinococcosis.