Seroprevalence of the cat lungworm Aelurostrongylus abstrusus in Central Italy

NTRODUCTION. Aelurostrongylus abstrusus (Metastrongyloidea, Angiostrongyliidae), i.e. the “cat lungworm” infects cats worldwide. The Baermann’s method is considered the gold standard for the diagnosis of A. abstrusus infection, although its sensitivity and specificity can be impaired by different factors (e.g. prepatency, intermittent larval shedding and low parasite burdens) (Traversa et al., 2010, Parasit. Vectors, 3:62). To overcome these limitations an enzyme-linked immunosorbent assay (ELISA) has recently been developed (Zottler et al., 2017, Vet. Parasitol., 235:75-82) as an alternative diagnostic tool. This is the first field study relying on this ELISA for the serological detection of antibodies vs the cat lungworm A. abstrusus in endemic areas. MATERIALS AND METHODS. Sera samples of 250 cats from two endemic regions of Italy were tested for the presence of antibodies vs A. abstrusus by the ELISA, i.e. 162 from Abruzzo (Site A) and 88 from Umbria (Site B). In particular, 20 serum samples of cats infected with A. abstrusus and 20 of cats negative for lungworms by Baermann’s and PCR were used to select an OD cut off value (Subset A). Sera of 210 cats scoring negative for lungworms at Baermann’s were also tested (Subset B). RESULTS AND CONCLUSIONS. A cut off value of 0.347 OD (sensitivity 95% and specificity 100%) was determined. Antibodies vs A. abstrusus were present in 45 samples (21.4%) from Subset B, in particular 28/142 (19.7%) and 17/68 (25%) from sites A and B respectively. These results show a higher prevalence of A. abstrusus if compared with those obtained in other surveys carried out in the same areas (Traversa et al., 2008, Parasitol. Res., 103:1191-1196; Di Cesare et al., 2011, Parasitol. Res., 1S87:96; Di Cesare et al., 2015, Parasitol. Res., 114:4463-4469) that used the Baermann’s test to diagnose the infection. This study confirms the endemicity of cat aelurostrongylosis in Italy, and shows that the newly developed ELISA represents a potential alternative for future large-scale epidemiological studies and for the clinical diagnosis of the infection, being able to detect even subclinical non patent infections and therefore overcoming the existing difficulties of copromicroscopic examinations.