Rapid and sensitive detection of feline herpesvirus-1 using fluorescent microspheres as labels for immunochromatographic test strips.

Feline herpesvirus-1 is a local contact-infectious pathogen that causes acute upper respiratory tract infections in cats. This virus exclusively affects felines, with a clinical incidence rate of nearly 100%, particularly in young cats. To address this health concern, this study aimed to develop a rapid fluorescence microsphere immunochromatography assay (FM-ICA) for the direct detection of Feline herpesvirus-1 (FHV-1) antigen. This method utilizes a fusion protein and fluorescent nanoparticle-labelled monoclonal antibody to detect FHV-1 within 10 min, achieving a detection limit of 2.5 × 102 TCID50/mL. Critically, the assay exhibited excellent specificity with cross-reactivity against canine distemper virus, canine parvovirus, canine adenovirus, canine coronavirus, feline plague virus, feline calicivirus, or feline infectious peritonitis virus. The field and clinical applicability of the method was evaluated using 100 clinical samples, including 30 faecal samples and 70 nasopharyngeal secretion samples from cats. The coincidence rate between the FM-ICA test results and the polymerase chain reaction (PCR) test results of the clinical samples was 99%.