Vacinação com EG95 contra a equinococose cística ovina na província de Río Negro: análise de 12 anos de trabalho

Equinococosis quística (EQ) es una enfermedad zoonótica causada por el estadío larval del complejo Echinococcus granulosus sensu lato. En el año 2009 en la Provincia de Rio Negro se agregó la vacunación de corderos con EG95, la desparasitación de perros con praziquantel lográndose disminuir la prevalencia de la infección en los diferentes hospederos. Sin embargo, los estudios de impacto señalaron la necesi-dad de mejorar la comprensión de la epidemiologia local.Objetivo: identificar causas que pueden generar aun infección en los perrosMateriales y métodos: se determinó la prevalencia de EQ en capri-nos y ovinos adultos mediante necropsia y por serología (ELISA). El análisis epidemiológico se completó con una encuesta a los producto-res sobre hábitos de faena para consumo.Resultados: Mediante serología. las diferencias en la tasa de in-fección entre ovinos vacunados y no vacunados resulto significativa (p=0.0004); entre ovinos no vacunados y cabras no vacunadas resulto significativa (p= 0.0013) y entre ovejas vacunadas y cabras no vacu-nadas resultaron no significativas (p= 0.254). Mediante necropsia las diferencias en la tasa de infección entre ovinos vacunados y no vacu-nados resulto significativa (p=0.0016); entre ovinos no vacunados y cabras no vacunadas resulto significativa (p= 0.0016 y entre ovejas va-cunadas y cabras no vacunadas resultaron no significativas (p= 0.23). El relevamiento de la faena de animales para consumo en 41 produc-tores mostro que 21 faenan en promedio 18 cabras mensuales y entre 36 faenan 35 ovejas viejas mensuales.Conclusión: El diseño y la implementación del programa resultaron costo – efectivas, en tanto ha podido sostenerse a través del tiempo demostrando impacto en la disminución de la prevalencia en los dis-tintos hospedadores.Cystic echinococcosis (CE) is a zoonosis caused by species of the complex Echinococcus granulosus, sensu lato in their larval stage. It is an endemic disease in the province of Río Negro, where lamb vaccination with EG95 was incorporated in 2009 with very good results: in fact, it contributed to a significant drop in prevalence of infection in diverse hosts. However, impact studies have revealed the need to improve understanding of local epidemiology. The objective was to identify causes which can still generate infection in dogs. In indigenous reserves comprised within the area of lamb vaccination with 3 doses of EG95, prevalence in adult caprines and ovines was determined by necropsy and serology (ELISA). Through serology, infection rates in vaccinated and non-vaccinated ovines were significantly different (p= 0.0004), as well as between non-vaccinated ovines and goats (p= 0.0013); on the other hand, infection rate differences between vaccinated sheep and non-vaccinated goats turned out non-significant (p= 0.254). Through necropsy, such difference between vaccinated and non-vaccinated ovines turned out significant (p= 0.0016); between non-vaccinated ovines and non-vaccinated goats, it proved non-significant (p= 0.23). With reference to epidemiology and control along the period 2018- 2022, vaccination strategy was maintained, and 2 extra deworming tasks were introduced, performed by the vaccination team. Assessment of animal slaughter for consumption in 41 producers showed that 21 of them slaughter a monthly average of 18 goats, and 36 in all slaughter 35 old sheep. Design and implementation of programme resulted cost-effective, since it was possible to maintain them over time, with clear impact on prevalence decrease in diverse hosts.A equinococose cística (EQ) é uma zoonose causada pela fase larval do complexo Echinococcus granulosus sensu lato. Em 2009, na Província de Rio Negro, foram adicionadas a vacinação de cordeiros com EG95 e a desparasitação de cães com praziquantel, obtendo-se uma redução na prevalência da infecção nos diferentes hospedeiros. No entanto, os estudos de impacto apontaram para a necessidade de melhorar o entendimento da epidemiologia local. Objetivo: identificar causas que ainda podem gerar infecção em cães. Materiais e métodos: a prevalência de EQ em caprinos e ovinos adultos foi determinada por necropsia e por sorologia (ELISA). A análise epidemiológica foi completada com um levantamento dos produtores sobre os hábitos de abate para consumo. Resultados: Por sorologia. as diferenças na taxa de infecção entre ovinos vacinados e não vacinados foram significativas (p=0,0004); entre ovinos não vacinados e caprinos não vacinados foi significativo (p= 0,0013) e entre ovinos vacinados e caprinos não vacinados não foi significativo (p= 0,254). Pela necropsia, as diferenças na taxa de infecção entre ovinos vacinados e não vacinados foram significativas (p=0,0016); entre ovinos não vacinados e caprinos não vacinados foi significativa (p= 0,0016 e entre ovinos vacinados e caprinos não vacinados não foi significativa (p= 0,23). O levantamento do abate de animais para consumo em 41 produtores mostrou que 21 abates em média 18 cabras mensais e entre 36 abatem 35 ovelhas velhas mensalmente. Conclusão: O desenho e a implementação do programa foram custo-efetivos, pois se manteve ao longo do tempo, mostrando impacto na diminuição da prevalência em diferentes acolhimentos.Fil: Labanchi, Jose Luis. Ministerio de Salud ; Gobierno de la Provincia de Rio Negro;Fil: Poggio, Thelma Veronica. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Ciencia y Tecnología "Dr. César Milstein". Fundación Pablo Cassará. Instituto de Ciencia y Tecnología "Dr. César Milstein"; ArgentinaFil: Mujica, Guillermo Bernardo. Ministerio de Salud ; Gobierno de la Provincia de Rio Negro;Fil: Gutierrez, Ariadna. Dirección Nacional de Instituto de Investigación.Administración Nacional de Laboratorios e Institutos de Salud "Dr. Carlos G. Malbrán"; ArgentinaFil: Araya, Daniel. Ministerio de Salud ; Gobierno de la Provincia de Rio Negro;Fil: Grizmado, Claudia. Ministerio de Salud ; Gobierno de la Provincia de Rio Negro;Fil: Calabro, Arnoldo. Ministerio de Salud ; Gobierno de la Provincia de Rio Negro;Fil: Crowley, Pablo Ernesto. Universidad Nacional de Río Negro; ArgentinaFil: Arezo, Marcos. Ministerio de Salud ; Gobierno de la Provincia de Rio Negro;Fil: Seleiman, Marcos. Ministerio de Salud ; Gobierno de la Provincia de Rio Negro;Fil: Herrero, Eduardo. Ministerio de Salud ; Gobierno de la Provincia de Rio Negro;Fil: Sepulveda, Luis. Ministerio de Salud ; Gobierno de la Provincia de Rio Negro;Fil: Talmon, Gabriel. Ministerio de Salud ; Gobierno de la Provincia de Rio Negro;Fil: Diaz, Oscar. Ministerio de Salud ; Gobierno de la Provincia de Rio Negro;Fil: Larrieu, Edmundo Juan. Universidad Nacional de La Pampa. Facultad de Ciencias Veterinarias; Argentina. Universidad Nacional de Río Negro; Argentin

Analysis of vaccination strategy against cystic echinococcosis developed in the Province of Río Negro, Argentina: 12 years of work

Cystic echinococcosis (CE) is a zoonosis caused by species of the complex Echinococcus granulosus, sensu lato in their larval stage. It is an endemic disease in the province of Río Negro, where small farmers generally have both sheep and goats. Lamb vaccination with EG95 was incorporated in 2009 with very good results: in fact, it contributed to a significant drop in prevalence of infection in both sheep and goats, when determined by necropsy and serology in 2018. In the design of the activity, it was decided not to vaccinate goats in order to minimize the operational requirements of vaccination and comments from producers about the rarity of observing hydatid cysts in goat viscera were considered. Objective: To identify causes which can still generate infection in dogs, and to detect species/genotypes in circulation in the province of Río Negro. Materials and methods: In indigenous reserves comprised within the area of lamb vaccination with 3 doses of EG95, (dose 1 in December, dose 2 in January and dose 3 in December of the year following, at the time of application of dose 1 to the new lambs). Prevalence in adult goats and sheep was determined by necropsy and serology (ELISA). Infective species/genotypes present in the work area and in the rest of the province of Río Negro were identified by Cox1 mitochondrial gene sequencing. Epidemiological analysis was completed with surveys among farmers about slaughter habits for human consumption. Results: Through serology and necropsy, infection rates in vaccinated and nonvaccinated sheep were significantly different (21% versus 66%). Non-vaccinated sheep and non-vaccinated goats were also significantly different in that there was less infection in goats compared to sheep (7% versus 66% for necropsy, 30% versus 61% for serology); After many years of sheep vaccination the infection positives were low, and differences between vaccinated sheep and non-vaccinated goats turned out non-significant (21% versus 7%). With reference to epidemiology and control along the period 2018–2022, PZQ dosing of dogs 4 times a year was maintained, and 2 extra deworming tasks were introduced together with dose 1 and 2 of EG95, performed by the veterinary vaccination team, ensuring the ingestion of PZQ by dogs. Assessment of animal slaughter for consumption in 41 producers showed that 21 of them slaughter a monthly average of 18 goats (an average of 0.43 goat per month per farm) and 36 in all slaughter 35 old sheep in a year (average of 0.85 sheep per month per farm). With respect to identification of species/genotypes as from 2010, genotypes G1 have been found in 11 sheep (out of which 6 belong to vaccination zone) and genotypes G7, in one pig. A goat cyst within vaccination zone turned out unfertile and it was not possible to sequence it. Conclusion: Design and implementation of a vaccine programme combined with the use of PZQ resulted as cost-effective, since it was possible to maintain the vaccine over time, with clear impact on prevalence decrease in sheep and goats.Fil: Labanchi, Jose Luis. Universidad Nacional de Río Negro; ArgentinaFil: Poggio, Thelma Veronica. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Ciencia y Tecnología "Dr. César Milstein". Fundación Pablo Cassará. Instituto de Ciencia y Tecnología "Dr. César Milstein"; ArgentinaFil: Gutiérrez, Ariana. Dirección Nacional de Instituto de Investigación.Administración Nacional de Laboratorios e Institutos de Salud "Dr. Carlos G. Malbrán"; ArgentinaFil: Mujica, Guillermo Bernardo. Ministerio de Salud de la Nación; ArgentinaFil: Araya, Daniel. Ministerio de Salud de la Nación; ArgentinaFil: Grizmado, Claudia. Ministerio de Salud de la Nación; ArgentinaFil: Calabro, Arnoldo. Ministerio de Salud de la Nación; ArgentinaFil: Crowley, Pablo Ernesto. Universidad Nacional de Río Negro; ArgentinaFil: Arezo, Marcos. Ministerio de Salud de la Nación; ArgentinaFil: Seleiman, Marcos. Ministerio de Salud de la Nación; ArgentinaFil: Herrero, Eduardo. Ministerio de Salud de la Nación; ArgentinaFil: Sepulveda, Luis. Ministerio de Salud de la Nación; ArgentinaFil: Talmon, Gabriel. Ministerio de Salud de la Nación; ArgentinaFil: Diaz, Oscar. Ministerio de Salud de la Nación; ArgentinaFil: Larrieu, Edmundo Juan. Universidad Nacional de La Pampa. Facultad de Ciencias Veterinarias; Argentina. Universidad Nacional de Río Negro; Argentin

Pilot field trial of the EG95 vaccine against ovine cystic echinococcosis in Rio Negro, Argentina: Humoral response to the vaccine

Cystic echinococcosis is endemic in the Rio Negro province of Argentina and, for this, a control program using praziquantel in dogs was developed from 1980. The transmission rate to humans and sheep has decreased significantly, however transmission persists. In 2009 the vaccination of sheep with EG95 was incorporated in some areas of the province. The objective of the study was to evaluate the humoral responses to the vaccine EG95. Lambs received two vaccinations with the EG95 vaccine followed by a single booster injection when the animals were 1-1.5 years of age. Blood samples from 6 vaccinated groups and 4 no vaccinated sheep were obtained for determination of antibody titles against EG95 protein. Anti-EG95 responses were determined as described by Heath and Koolaard, 2012. Responses were evaluated from 331 animals. Median ELISA absorbance values in vaccinated group was 0.828, and in non-vaccinated groups was 0.218. EG95 antibody responses in sheep from different cohorts of non-immunized control groups and vaccinated groups reveal the sustained increase in response seen in animals following the third immunization. (p< 0.0001). Significant differences are also evidenced in ANOVA test (p< 0.001). An anti-EG95 antibody response was induced in all groups of immunized sheep, 4 times higher (0.828) than the mean observed in the control groups (0.218). Data described here indicate that following a third vaccination with the EG95 vaccine at 1 year of age the specific IgG responses detected in the serum of sheep increased to a level greater than that seen following the second immunization and that this response was maintained longitudinally over time, for at least 5 years.Fil: Larrieu, Edmundo Juan. Universidad Nacional de La Pampa. Facultad de Ciencias Veterinarias; Argentina. Universidad Nacional de Río Negro; ArgentinaFil: Poggio, Thelma Veronica. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Ciencia y Tecnología "Dr. César Milstein". Fundación Pablo Cassará. Instituto de Ciencia y Tecnología ; ArgentinaFil: Mujica, Guillermo. Provincia de Río Negro. Ministerio de Salud; ArgentinaFil: Gauci, Charles G.. University of Melbourne; AustraliaFil: Labanchi, Jose Luis. Provincia de Río Negro. Ministerio de Salud; ArgentinaFil: Herrero, Eduardo. Provincia de Río Negro. Ministerio de Salud; ArgentinaFil: Araya, Daniel. Provincia de Río Negro. Ministerio de Salud; ArgentinaFil: Grizmado, Claudia. Provincia de Río Negro. Ministerio de Salud; ArgentinaFil: Calabro, Arnoldo. Provincia de Río Negro. Ministerio de Salud; ArgentinaFil: Talmon, Gabriel. Provincia de Río Negro. Ministerio de Salud; ArgentinaFil: Crowley, Pablo Ernesto. Universidad Nacional de Río Negro; ArgentinaFil: Santillán, Graciela. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud "Dr. C. G. Malbran". Departamento de Parasitología; ArgentinaFil: Vizcaychipi, Katherina. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud "Dr. C. G. Malbran". Departamento de Parasitología; ArgentinaFil: Seleiman, Marcos. Provincia de Río Negro. Ministerio de Salud; ArgentinaFil: Sepulveda, Luis. Provincia de Río Negro. Ministerio de Salud; ArgentinaFil: Arezo, Marcos. Provincia de Río Negro. Ministerio de Salud; ArgentinaFil: García Cachau, Mariela Alejandra. Universidad Nacional de La Pampa. Facultad de Ciencias Veterinarias; ArgentinaFil: Lamberti, Roberto. Universidad Nacional de La Pampa. Facultad de Ciencias Veterinarias; ArgentinaFil: Molina, Leonardo. Universidad Nacional de La Pampa. Facultad de Ciencias Veterinarias; ArgentinaFil: Gino, Lilia Mabel. Universidad Nacional de La Pampa. Facultad de Ciencias Veterinarias; ArgentinaFil: Donadeu, Meritxell. University of Melbourne; AustraliaFil: Lightowlers, Marshall W.. University of Melbourne; Australi