Comparative performance of ELISA and lateral flow immunoassay for distinguishing Cucumovirus CMV strains in Iraqi field samples

Abstract

Pandemic and epidemic plant infections with Cucumovirus (CMV) poses a continuing threat to agricultural stability. Therefore, diagnostic tools that are both accurate and expedient have become an urgent need. This study compared the performance of Enzyme-Linked Immunosorbent Assay (ELISA) and Lateral Flow Immunoassay (LFIA) for detecting CMV in symptomatic plant hosts in the middle of Iraq. A total of 200 field samples were collected from tomato, pepper, eggplant, datura, cucumber, and zucchini squash across Baghdad Governorate and neighboring territories during the 2024 growing season. Comparative analysis demonstrated a clear difference in diagnostic sensitivity. ELISA outperformed LFIA in successfully detecting the virus in samples that tested negative by LFIA. This high-level sensitivity is likely due to enzymatic amplification in the ELISA, which enables detection of lower viral titers that might not be captured by the direct antigen-antibody binding mechanism of standard LFIA. Geographical distribution data showed that CMV infection was common in Al-Jadiriya but not in Khan Bani Sa’ad. Despite the apparent CMV-like symptoms observed in cucumber samples collected from Khan Bani Sa’ad, the samples tested negative by both diagnostic methods. This might be due to varietal resistance to CMV or the presence of divergent CMV strains not detected by commercial immunodiagnostic kits. Generally, the better sensitivity and quantitative competency of ELISA makes it suitable for comprehensive CMV surveillance, whereas LFIA remains a valuable rapid, on-site screening tool. Further molecular characterization of local CMV isolates is recommended to improve understanding of genetic diversity and regional detection strategies.