Genetic variation and epidemiology of Echinococcus granulosus in Argentina

Polymerase chain reaction-ribosomal ITS-1 DNA (rDNA) restriction fragment l ength polymorphism (PCR-RFLP) analysis and sequencing of the mitochondrial cytochrome c oxidase subunit 1 (CO1) and NADH dehydrogenase 1 (ND1) genes w ere used to characterize 33 Echinococcus granulosus isolates collected from different regions and hosts in Argentina, and to determine which genotypes occurred in humans with cystic hydatid disease. The results of the study d emonstrated the presence of at least 4 distinct genotypes; the common sheep strain (G1) in sheep from Chubut Province and in humans from Rio Negro Pro vince, the Tasmanian sheep strain (G2) in sheep and 1 human from Tucuman Pr ovince, the pig strain (G7) in pigs from Santa Fe Province and the camel st rain (G6) in humans from Rio Negro and Buenos Aires Provinces. The finding that pigs harboured the pig strain and the occurrence of the Tasmanian shee p strain has considerable implications for the implementation of hydatid co ntrol programmes due to the shorter maturation time of both strains in dogs compared with the common sheep strain. Furthermore, this is the first repo rt of the presence of the G2 and G6 genotypes in humans which may also have important consequences for human health.