An immunochromatographic device to detect antibodies for rapid diagnosis of human angiostrongyliasis in whole-blood and cerebrospinal fluid samples.

BACKGROUND

Human angiostrongyliasis is caused by the rat lung worm, Angiostrongylus cantonensis and is often a cause of eosinophilic meningitis (EOM) or meningoencephalitis. Humans are infected by consuming infective larvae from intermediate hosts (snails and slugs), paratenic hosts or contaminated vegetables. Here, a simple and rapid antibody-detection lateral-flow immunochromatographic test (ICT) was developed as a point-of-care tool for supporting diagnosis of human angiostrongyliasis. We also tested the ICT with cerebrospinal fluid (CSF) samples.

METHODS

We evaluated a new ICT format using a recombinant A. cantonensis galectin-2 (rAcGal2) protein as a target for anti-A. cantonensis IgG antibodies in simulated whole-blood samples (WBSs) and compared results with those obtained using corresponding serum samples.

RESULTS

The sensitivity and specificity values for IgG antibody detection in simulated WBSs were 82.0 (95 % CI 73.1-89.0) and 97.1 (95 % CI 93.3-99.0), while in serum samples these were 92.0 (95 % CI 84.8-96.5), and 97.1 (95 % CI 93.3-99.0), respectively. Results between simulated WBSs and serum samples did not differ significantly with a concordance of 96.3 % (Cohen's kappa 0.9177). Anti-Angiostrongylus antibodies were also detected in CSF samples: 12 out of 16 EOM cases were positive while all 10 CSF samples from control cases were negative.

CONCLUSION

The ICT is easy to implement and can provide supportive diagnosis at the bedside or in local and remote hospitals with limited facilities. An additional benefit is that it can be used with CSF samples obtained by lumbar puncture for management of high intracranial pressure of EOM patients in intensive care units.