Baylisascaris
larva migrans is an important
zoonotic disease caused by Baylisascaris procyonis, the raccoon roundworm, and is being increasingly considered in the differential diagnosis of eosinophilic
meningoencephalitis in children and young adults. Although a B. procyonis excretory-secretory (BPES)
antigen-based
enzyme-linked
immunosorbent assay (ELISA) and a Western blot assay are useful in the immunodiagnosis of this
infection, cross-reactivity remains a major problem. Recently, a recombinant B. procyonis
antigen, BpRAG1, was reported for use in the development of improved serological assays for the diagnosis of Baylisascaris
larva migrans. In this study, we tested a total of 384 human patient serum samples in a BpRAG1 ELISA, including samples from 20 patients with clinical Baylisascaris
larva migrans, 137 patients with other
parasitic infections (8 helminth and 4 protozoan), and 227 individuals with unknown/suspected
parasitic infections. A sensitivity of 85% and a specificity of 86.9% were observed with the BpRAG1 ELISA, compared to only 39.4% specificity with the BPES ELISA. In addition, the BpRAG1 ELISA had a low degree of cross-reactivity with
antibodies to Toxocara
infection (25%), while the BPES
antigen showed 90.6% cross-reactivity. Based on these results, the BpRAG1
antigen has a high degree of sensitivity and specificity and should be very useful and reliable in the diagnosis and seroepidemiology of Baylisascaris
larva migrans by ELISA.