EG95 VACCINE MONITORING OF INTERMEDIATE HOSTS. ANALYSIS AND INCLUSION OF THE SOCIO-CULTURAL CONTEXT IN VACCINATION PROGRAMS.

JENSEN, OSCAR; KELLER, LETICIA; POGGIO, THELMA VERONICA; LARRIEU EDMUNDO; GOMEZ, J. M.; SERAFINO JUAN JAVIER; BOADO, LORENA ANALIA; HEATH, DAVID

Congreso; XXVIII WORLD CONGRESS ON ECHINOCOCCOSIS; 2019

Introduction: Hydatidic disease is linked to symbolic and social considerations and responds to a cultural logic that interacts with a set of traditional knowledge and practices that need to be understood.Vaccination of intermediate hosts contributes to reduce the level of transmission of E. granulosus and thus, reduce the incidence of human infections, even when control programs address many practical difficulties.In order to validate a model supporting the One Health approach, that might be reproducible successfully in different regions of South America, we raise the socio-cultural understanding and the analysis of the environment and the operational conditions, looking for a mediation according to the context and using a special vaccination methodology in each level of difficulty.Materials and Methods:. In controlled trials immunization of sheep (0, 30 days and annual booster) with EG95 vaccine available in South America were carried out. After experimental challenge with E. granulosus eggs, subsequent necropsy, and the percentage of reduction of the viable cysts versus EG95 antibodies level were calculated. Control Programs included: Chubut 2007-2013-Río Negro 2009-2015- Alto Bio-Bio, Chile 2016-2020.Results: Sheep immunized with two doses, an annual booster and experimentally challenged, showed a protection ranging from 84.2 to 100%. Immunization with 4 doses (1405 dpv) and challenge showed a reduction of live cysts of 94.7%. The initial evaluation (2007) in El Chalia community (Chubut) showed that 25% of the dogs carried E. granulosus and 72% of the farms were exposed to the parasite. In 2015, it was found that only 2% of the dogs had parasitic infection belonging to 11% of the farms. In Rio Negro, a decrease in the prevalence in adult sheep from 56.3% (2009) to 21.1% (2015) was observed. The number of farmers with at least one infected sheep decreased from 94.7% to 23.5%.Discussion: Vaccination of intermediate hosts allows programs to reduce the time control of the hydatidic disease. The possibility of contextualizing the experience being able to define a comprehensible description of the environment is key to validate a methodological model applicable to different regions of South America.