Most human cystic echinococcosis (CE) cases worldwide are attributed to Echinococcus granulosus sensu stricto (s.s), followed by the G6 and G7 genotypes. While E. granulosus s.s. has a cosmopolitan distribution, the G6 genotype is restricted to areas where camels and goats are present. Goats are the primary livestock in the Neuquén province in Argentina where the G6 genotype has been reported to be responsible for a significant percentage of CE human cysts genotyped. In the present study, we genotyped 124 Echinococcus cysts infecting 90 CE-confirmed patients. Echinococcus granulosus s.s. was identified in 51 patients (56.7%) with 81 cysts and the G6 genotype in 39 patients (43.3%) harbouring 43 cysts. Most CE cases ≤18 years were male suggesting pastoral work could be a risk factor for the infection. Echinococcus granulosus s.s. was significantly found more frequently in the liver (32/51 patients) and the G6 genotype in the lungs and extrahepatic localizations (27/39). The patients infected with E. granulosus s.s., presented up to 6 cysts while patients infected with G6 presented a maximum of 2. The diameter of lung cysts attributed to E. granulosus s.s. was significantly larger compared to lung cysts from G6. Following the WHO ultrasound classification of liver cysts, we observed inactive cysts in 55.6% of G6 cysts and only 15.3% of E. granulosus s.s cysts. In conclusion, we provide evidence of differences in clinical aspects of CE caused by E. granulosus s.s. and the G6 genotype of E. granulosus s.l. complex infecting humans.

Cystic echinococcosis (CE) is one of the most common zoonotic diseases worldwide, particularly in rural areas. This study aimed at the identification of the genotype/species belonging to Echinococcus granulosus sensu lato (s.l.) specimens in retrieved percutaneously from the human host and to investigate their relationship with cyst characteristics. The genetic identification of cyst material was performed by mt-CO1 gene polymerase chain reaction, and confirmed via sequencing. A total of 110 CE cysts were identified as E. granulosus s.l. In detail, 104 belonged to E. granulosus sensu stricto (G1 and G3) and six isolates were in the E. canadensis cluster (G6/7). All clusters were tested for the relationship between demographics, cyst features and genetic diversity. The relationship between genetic variation and certain clinical characteristics such as cyst volume and location were statistically significant for G6/7 cluster. Further studies are required with a larger sample set to investigate the relationship between the genetic variability of E. granulosus s.l. and cyst features.

This study describes, for the first time, the characterization of excretory–secretory antigens (ES-Ag) from Echinococcus granulosus protoscoleces, evaluating their usefulness in the immunodiagnosis of human cystic echinococcosis. ES-Ag were obtained from the first 50 h maintenance of protoscoleces in vitro. This preparation contained over 20 major protein components which could be distinguished by 1-dimensional SDS–PAGE with apparent masses between 9 and 300 kDa. The culture of of protoscoleces from liver produced a greater variety of excretory–secretory protein components than those from lung. Determination of enzymatic activities of secreted proteins revealed the presence of phosphatases, lipases and glucosidases, but no proteases. These findings were compared to those obtained from somatic extracts of protoscoleces and hydatid cyst fluid products. Immunochemical characterization was performed by immunoblotting with sera from individuals infected by cystic echinococcosis (n=15), non-hydatidic parasitoses (n=19), various liver diseases (n=24), lung neoplasia (n=16), and healthy donors (n=18). Antigens with apparent masses of 89, 74, 47/50, 32, and 20 kDa showed specificity for immunodiagnosis of human hydatidosis. The 89 and 74 kDa components corresponded to antigens not yet described in E. granulosus, whereas proteins of 41–43 kDa and 91–95 kDa were recognized by the majority of the non-hydatid sera studied.