A rapid microassay for dirofilarial antibodies by using antigen-coated nitrocellulose paper

This study describes an enzyme (horseradish peroxidase)-linked immunosorbent assay using nitrocellulose (NC) paper (Dot-ELISA) for the detection of antibodies against Dirofilaria immitis in dogs. Dirofilarial antigens prepared were directly bound on NC paper set into a microfiltration apparatus to ensure their uniformity. Of the 23 infected dogs tested, 21 were determined positive by visual observation of brown-colored spots on NC paper. The positive and negative readings were further confirmed by using a densitometer. Sera from 15 non-infected and 17 other parasite-infected dogs were all negative, i.e. no false positive readings and low cross-reactivities were found using this technique. Also, a large number of samples could be assayed simultaneously within 1.5 h. The Dot-ELISA technique reported here may be useful to veterinarians and also may be a means of field surveying human filariasis.