Detection and molecular characterization of ascarid nematode infection (Toxascaris leonina and Toxocara cati) in captive Asiatic lions (Panthera leo persica)

The objective of this study was to investigate the ascarid infection in Asiatic lions using scat samples, based on microscopic analysis, PCR amplification of the ITS-2 region of ribosomal DNA and sequence analysis of the amplicons. Microscopic analysis indicated the presence of eggs of Toxascaris leonina in eleven of the sixteen scat samples analysed and in one of these eleven scats eggs of Toxocara cati were also detected. In five of the scats eggs were not detectable. The presence of T. leonina in all the infected samples was also confirmed by PCR amplification of the ITS-2 of ribosomal RNA gene and five of these also showed amplicons corresponding to T. cati, respectively. Toxocara canis infection was not observed in any of the scat samples. Nucleotide sequence analysis of the ITS-2 region indicated 97% to 99% similarity with T. leonina and T. cati, respectively. To our knowledge, this is the first molecular characterization of ascarid infection in captive Asiatic lions from a zoological garden of India. This study also indicates that Asiatic lions are more prone to infection either with T. leonina or T. cati and the parasite is not host specific.