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Multilocus genotyping of Giardia duodenalis in lambs from Spain reveals a high heterogeneity

Gómez-Muñoz, María Teresa, Cámara-Badenes, Carmen, Martínez-Herrero, María del Carmen, Dea-Ayuela, María Auxiliadora, Pérez-Gracia, María Teresa, Fernández-Barredo, Salceda, Santín, Mónica, Fayer, Ronald
Research in veterinary science 2012 v.93 no.2 pp. 836
Giardia lamblia, feces, genes, genetic heterogeneity, genotyping, glutamate dehydrogenase, lambs, loci, mixed infection, polymerase chain reaction, ribosomal RNA, triose-phosphate isomerase, Spain
Fecal specimens from 120 lambs in Valencia (Spain) were analyzed for Giardia duodenalis by IFA and nested-PCR using the beta giardin (bg), glutamate dehydrogenase (gdh), triose phosphate isomerase (tpi) and small subunit ribosomal RNA (ssurRNA) genes. The highest prevalence was obtained using the ssurRNA gene (89.2%), whereas values from other techniques ranged from 64.1% to 69.2%. Sequences of the ssurRNA showed a high proportion of assemblage A or mixed assemblage A/E samples (55.1% and 25.2%, respectively). When the other 3 loci were analyzed, between 6.5% and 15.4% were found to be assemblage A or A/E, respectively. Nested PCR for the tpi gene was the most variable of the targets employed. Twelve new sequences of gdh and tpi for G. duodenalis from sheep were found. Multilocus genotyping resulted in 63 patterns from the 71 samples sequenced at the four loci. This high variability among isolates possibly reflects the high frequency of mixed infections.