Serological investigation on Sarcocystis spp. infection and associated risk factors in South American camelids in Italy

Protozoa of the genus Sarcocystis have an obligate two-host-prey-predator life cycle, in which South American Camelids (SAC) are among the intermediate hosts for certain species. Sarcocystis spp. infection has been well documented in SAC in endemic areas of the South America, while data from Europe are absent. This study assessed the seroprevalence of Sarcocystis spp. in SAC in Italy investigating related risk factors. A total of 506 SAC sera (486 alpacas and 20 llamas) from 38 sampling sites were analysed to detect antibodies to Sarcocystis spp. using the Indirect Fluorescent Antibody Test (IFAT). A seropositivity of 15.2% (77/506) was found, corresponding to 14.4% (70/486) in alpacas and 35.0% in llamas (7/20). Risk factor analysis showed that Sarcocystis spp. seropositivity increased with age, while no statistically significant association was found with regard to sex. Access to stables and/or pasture by dogs was identified as a putative risk factor, particularly as the number of dogs increased. Further association was found between seropositivity to Sarcocystis spp. and N. caninum. Although the life cycles of Sarcocystis spp. in SAC are not fully elucidated, these findings highlight the need for further studies to clarify the potential role of dogs as definitive hosts for Sarcocystis species infecting SAC in Europe. This study provides for the first time data on specific antibodies for Sarcocystis spp. in SAC in Europe, highlighting the need of improving the surveillance of this protozoan in camelids, particularly given the growing interest in camelid meat production.