Serological Comparison of Native Antigen ELISAs with Rapid ICT Test Kits for the Diagnosis of Human Alveolar and Cystic Echinococcosis in China

Shu-Kun Yang; Wei Zhang; Na Zhu; Donald P McManus; Darren J Gray; Archie C A Clements; Angela M Cadavid Restrepo; Gail M Williams; Ting Zhang; Guo-Rong Ma; Yan-Hui Yang; Yu-Rong Yang

doi:10.3390/tropicalmed9020044

Serological Comparison of Native Antigen ELISAs with Rapid ICT Test Kits for the Diagnosis of Human Alveolar and Cystic Echinococcosis in China

Trop Med Infect Dis. 2024 Feb 7;9(2):44. doi: 10.3390/tropicalmed9020044.

Authors

Shu-Kun Yang¹, Wei Zhang², Na Zhu², Donald P McManus³, Darren J Gray^{3

4

5}, Archie C A Clements^{4

6}, Angela M Cadavid Restrepo⁵, Gail M Williams⁵, Ting Zhang⁷, Guo-Rong Ma², Yan-Hui Yang², Yu-Rong Yang²

Affiliations

¹ Department of Radiology, The Second Affiliated Hospital of Ningxia Medical University, The First People's Hospital of Yinchuan City, Yinchuan 750001, China.
² Department of Pathogenic Biology & Medical Immunology, School of Basic Medical Science, Ningxia Medical University, Yinchuan 750004, China.
³ Molecular Parasitology Laboratory, Global Health & Tropical Medicine, QIMR Berghofer Medical Research Institute, Brisbane, QLD 4006, Australia.
⁴ Department of Global Health, Research School of Population Health, Australian National University, Acton, ACT 2600, Australia.
⁵ Infectious Disease Epidemiology Unit, School of Public Health, University of Queensland, Brisbane, QLD 4006, Australia.
⁶ Faculty of Health Sciences, Curtin University, Perth, WA 6102, Australia.
⁷ NHC Key Laboratory of Parasite and Vector Biology, National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention (Chinese Center for Tropical Diseases Research), Shanghai 200025, China.

Abstract

Background: The aim of this study was to compare the diagnostic performance of native antigen ELISAs and ADAMU-AE/CE commercial ICT test kits in subjects either exposed to Echinococcus infection or with clinically diagnosed alveolar (AE) or cystic (CE) echinococcosis.

Methods: A total of 370 subjects with a previous clinical confirmation of CE or AE from northwestern China were recruited. Serum samples were also obtained from 3923 children/teenagers during a community survey. All sera were tested using native antigen ELISAs. The ADAMU-AE/CE test kits were subsequently used for the serology of the 370 clinically confirmed individuals and of 251 children/teenagers that were ELISA antibody-positive for both Echinococcus species but ultrasound-negative during baseline survey. An analysis of the association between the serological tests and ultrasound classification was carried out amongst 89 AE and 164 CE cases. A Kappa consistency analysis was undertaken to compare the diagnostic performance of the native antigen ELISAs and the ADAMU kits and the ultrasound imaging results. The χ² test was also used for a comparison of the different seropositivity rates between the groups.

Findings: There was poor consistency (Kappa = 0.26 and 0.28 for AE and CE respectively) between the native antigen ELISAs and the ADAMU kits for the diagnosis of AE and CE among the cases and the surveyed children/teenagers, but a relatively good consistency (Kappa = 0.63) between the ADAMU-AE kit and ultrasound observations for the AE cases. Additionally, of the 251 teenagers co-positive for both AE and CE antibodies by the native antigen ELISAs, only one was found positive by the ADAMU-AE kit, verified as a new AE case on subsequent ultrasound follow-up. The remainder (N = 250) were negative by serology using the ADAMU-AE/CE kits and by ultrasound examination. The two native antigen ELISAs did not discriminate well between cases of clinically diagnosed AE and CE. In contrast, ADAMU-AE and ADAMU-CE commercial ICT test kits readily differentiated cases of AE from CE with specificities of 99% for AE and 100% for CE.

Conclusions: The ADAMU-AE/CE kits proved reliable, accurate, and amenable diagnostic tools in the clinical setting for confirmation of suspected AE/CE cases. The native antigen ELISAs tests can provide useful information on the level of human exposure to Echinococcus infection.

Keywords: ADAMU-AE/CE kits; alveolar echinococcosis; cystic echinococcosis; egg exposure of Echinococcus granulosus and E. multilocularis; native antigen ELISAs; serological diagnosis.

Grants and funding

This study was funded by the National Natural Science Foundation of China (No. 81460311; 81960604) and the Australian National Health and Medical Research Council (NHMRC, APP1009539).