Diagnostic and clinical implications of a nested PCR specific for the ribosomal DNA of feline lungworm Aelurostrongylus abstrusus (Nematoda, Strongylida)

Department of Comparative Biomedical Sciences, Faculty of Veterinary Medicine, Teramo, Italy; Department of Public Health and Zootechny, Faculty of Veterinary Medicine, Valenzano, Bari, Italy

^* To whom correspondence should be addressed. Email: dtraversa{at}unite.it.

	Abstract

Aelurostrongylus abstrusus (Nematoda, Strongylida, Metastrongyloidea) is a cosmopolitan parasite of cats causing severe respiratory distress. Information on the biology and epidemiology of feline aelurostrongylosis is fragmentary, mainly due to the limits inherent in the classical diagnosis. In the present work a two-step nested PCR, based on the use of genetic markers in the second Internal Transcribed Spacer (ITS2) of ribosomal DNA (rDNA), was established for A. abstrusus in different biological samples. Characterization of the ITS2 (321 bp of length) revealed G+C contents of 39.5%. Exploiting the sequence difference between the ITS2 of A. abstrusus and other common feline endoparasites, specific primers were designed and tested by PCR for their specificity and sensitivity. The PCR assay was validated on a panel of fecal (i.e. feces, floatation supernatant, Baermann sediment) and pharyngeal swab samples from cats with a known history of lungworm infection, and it showed a specificity of 100% and a sensitivity of up to 96.6%. Also, the nested PCR was able to reveal cats actually infected but negative at the classical diagnostic methods. This PCR method showed to be a powerful tool for the molecular diagnosis of feline aelurostrongylosis, overcoming the constraints of the classical diagnosis. The implications of such a molecular tool for further bio-epidemiological studies in both intermediate and definitive hosts have been discussed.