Veterinary Research Communications, 31 (2007) 297–303 DOI: 10.1007/s11259-006-3428-8 C  Springer 2007 Short Communication Survey of Feline Giardiasis by ELISA Test in Italy R. Papini 1,∗ , G. Giuliani 2 , G. Gorini 3 and G. Cardini 1 1 Dipartimento di Clinica Veterinaria, Facolt` a di Medicina Veterinaria, Pisa; 2 Unit` a Sanitaria Locale 10, Florence; 3 U.O. Epidemiologia Ambientale Occupazionale, Centro per lo Studio e la Prevenzione Oncologica (CSPO), Istituto Scientifico della Regione Toscana, Florence, Italy ∗ Correspondence: E-mail: rpapini@vet.unipi.it Keywords: ELISA, cat, Giardia, giardiasis, prevalence, Italy Abbreviations: ELISA enzyme-linked immunosorbent assay; EIA enzyme immunoassay; GSA Giardia- specific antigen INTRODUCTION Giardia is a cosmopolitan enteric flagellated protozoan that can affect a wide range of hosts, including humans, livestock, dogs, cats and numerous species of wild mammals and birds. Owing to its increasing role in human outbreaks of diarrhoea, Giardia is now referred to as a re-emerging infectious agent and is the most commonly diagnosed parasite of the human intestinal tract. Giardiasis is also the most frequently diagnosed waterborne disease, and is thus one of the major public health concerns of water utilities in both developed and developing countries (Thompson, 2004). Acute signs of giardiasis in animals and humans include those expected from maldigestion and malabsorption of nutrients, including pale and malodorous faeces, steatorrhoea, diarrhoea, and weight loss or poor weight gain, some- times despite a normal appetite. Infection with Giardia may also be asymptomatic. Chronic infection can occur with or without an acute phase, is often associated with treatment failure, and may result in recurrent symptoms. In efforts to improve diagnostic testing in recent years, Giardia-specific antigens and monoclonal antibodies have been developed and the sensitivity of Giardia diagnosis has been improved through the development of immmunological tests. Various antigen detec- tion assays have been developed and evaluated for their ability to detect Giardia under a variety of conditions. Most of these tests have used the enzyme-linked immunosorbent assay (ELISA) format, such as coproantigen-capture ELISAs. Among them, the ProspecT Giardia Microplate Assay is a solid-phase immunoassay which uses monoclonal antibod- ies for the qualitative detection of a soluble Giardia-specific antigen (GSA 65) in aqueous extract of faeces. According to the package insert, GSA 65 is a 65 000 Da molecular weight glycoprotein, common to all known isolates, that is constantly produced in great quantities by Giardia spp. protozoa as they multiply within the host intestinal tract, independently of the shedding rate of trophozoites and cysts. The antigen is stable during passage through the 297