Epidemiologia de Triatominos en la Provincia de Río Negro

Chagas is an endemic epidemic disease of vector transmission in the Province of Rio Negro caused by Trypanosoma cruzi, transmitted by triatomines. The Chagas control program in the province of Rio Negro certified, through serological and entomological indicators, the interruption of vector transmission throughout the province. However, in recent years, conditions have been generated that may allow the re-emergence of the disease, such as the eventual domiciliation of wild vinchucas such as T patagonico. The objective was to evaluate the epidemiological situation of the vector through studies of home and peri-home infestation by triatomines and to carry out resistance analyzes to insecticides that were applied for many years in control. As a result, 143 homes were evaluated and 66 light traps were placed. In the intra-domicile all the dwellings were negative, with 3 being positive in the peri-domicile (2.1%) with captures of T-infestans and T. patagonica. No triatomines were captured with the light traps. The captured triatomines were T. infestans and T. patagonica, which were all negative for T. cruzi. Insecticide resistance studies showed that the colonies are still susceptible to deltamethrin.colonies are still susceptible to deltamethrin.Chagas es una enfermedad endemoepidémica de transmisión vectorial en la Provincia de Rio Negro causada por Trypanosoma cruzi, transmitido por insectos vectores denominados triatominos (vinchucas). El programa de control de Chagas de la provincia de Rio Negro certifico, a través de indicadores serológicos y entomológicos, la interrupción de la transmisión vectorial en todo el territorio provincial. Sin embargo, en los últimos años se han generado condiciones que pueden posibilitar la reemergencia de la enfermedad, tal como la eventual domiciliación de vinchucas silvestres, tal el caso de Triatoma patagónica. El objetivo fue evaluar la situación epidemiológica del vector mediante estudios de infestación domiciliaria y peri domiciliaria por triatominos y efectuar análisis de resistencia al principal insecticida que fue aplicado durante muchos años en control. Como resultado se evaluaron 143 viviendas y se colocaron 66 trampas de luz. En el intradomicilio todas las viviendas resultaron negativas, resultando 3 positivas en el peri-domicilio (2.1%) con capturas de T- infestans y T. patagonica. Con las trampas de luz no se capturaron triatominos. Los insectos capturados fueron T. infestans y T. patagonica los que resultaron todos negativos a T. cruzi. Los estudios de resistencia a insecticidas mostraron que las colonias siguen siendo susceptibles a deltametrina

Cystic echinococcosis in dogs and children in the province of Río Negro, Argentina

Fil: Larrieu, Edmundo. Ministerio de Salud, Provincia de Río Negro, Viedma, Argentina; Facultad de Ciencias Veterinarias, Universidad Nacional de Río Negro; Argentina.  Fil: Seleiman, Marcos. Ministerio de Salud, Provincia de Río Negro; Argentina.Fil: Herrero, Eduardo. Ministerio de Salud, Provincia de Río Negro; Argentina.Fil: Mujica, Guillermo. Ministerio de Salud, Provincia de Río Negro; Argentina.Fil: Labanchi, Jose Luis. Ministerio de Salud, Provincia de Río Negro; Argentina.Fil: Araya, Daniel. Ministerio de Salud, Provincia de Río Negro; Argentina.Fil: Grizmado, Claudia. Ministerio de Salud, Provincia de Río Negro; Argentina.Fil: Sepulveda, Luis. Ministerio de Salud, Provincia de Río Negro; Argentina.Fil: Calabro, Arnoldo. Ministerio de Salud, Provincia de Río Negro; Argentina.Fil: Talmon, Gabriel. Ministerio de Salud, Provincia de Río Negro; Argentina.Fil: Crowley, Pablo. Ministerio de Salud, Provincia de Río Negro, Viedma, Argentina; Facultad de Ciencias Veterinarias, Universidad Nacional de Río Negro; Argentina.Fil: Albarracin, Silvina. Ministerio de Salud, Provincia de Río Negro; Argentina.Fil: Arezo, Marcos. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Parasitología; Argentina.Fil: Volpe, Marcela. Ministerio de Salud, Provincia de Río Negro; Argentina.Fil: Avila, A. Ministerio de Salud, Provincia de Río Negro; Argentina.Fil: Perez, Alicia. Ministerio de Salud, Provincia de Río Negro; Argentina.Fil: Uchiumi, Leonardo. Ministerio de Salud, Provincia de Río Negro; Argentina.Fil: Salvitti, Juan Carlos. Ministerio de Salud, Provincia de Río Negro; Argentina.Fil: Santillan, Graciela. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Parasitología; Argentina.Cystic echinococcosis (CE) is an endemic disease in the province of Río Negro, Argentina. The control program against CE has developed monitoring surveillance systems. Currently, the coproELISA/Western blot (WB) test is used to determine transmission in livestock farms (epidemiological units or EU) from collected dry field-dispersed dog feces. The objective was to evaluate the prevalence of CE on livestock farms and its relationship with CE cases in children aged 0-14 years. Canine fecal samples were obtained from randomly selected livestock farms and processed by the coproELISA/WB test. Furthermore, new cases in children in the same age group mentioned above were identified. In 278 EU, 571 samples of canine feces were obtained. There were 37 positive samples for coproELISA/WB (6.5%) and the presence of transmission was demonstrated in 37 EU (13.3%). There were no significant differences (p=0.9) with the survey conducted in the period 2003-2004 while there were significant differences (p=0.02) with the EU survey of native populations conducted in 2009-2010. With respect to animal density in the work area, the EU yielding negative results had an average of 2 dogs (SD 2.1) per EU while in the EU having positive results the average was 3 dogs (SD 4.2), showing statistically significant differences (p=0.02). In children under 15 years of age, 12 cases were diagnosed. This study has identified, on average, that the cases of hydatid disease are closer in the positive fields than in the negative fields (p=0.00307).The coproELISA/WB test allowed to identify the dispersion of CE on livestock farms and its relationship with the occurrence of cases in children in 2009-2010

Early Diagnosis, Treatment and Follow-Up of Cystic Echinococcosis in Remote Rural Areas in Patagonia: Impact of Ultrasound Training of Non-Specialists

Cystic echinococcosis (CE) is an important and widespread disease that affects sheep, cattle, and humans living in areas where sheep and cattle are raised. CE is highly endemic in rural sections of Rio Negro, Argentina, where our group is based. However, it requires continuous monitoring of both populations with human disease best assessed by means of ultrasound (US) screening. This is challenging in remote rural areas due to the shortage of imaging specialists. To overcome this hurdle, we set up a two-day training program of Focused Assessment with Sonography for Echinococcosis (FASE) on CE for family medicine practitioners with no previous experience in US. After the course, they were equipped with portable US scanners and dispatched to remote rural areas in Rio Negro where they screened patients, located and staged the cysts and decided on the treatment with the help of surgeons and radiologists in local tertiary care centers

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

Vigilancia de la equinococosis quística en perros y niños en la provincia de Río Negro, Argentina

La equinococosis quística (EQ) es una enfermedad endémica en la provincia de Río Negro, Argentina. El programa de control de esta afección desarrolla sistemas de vigilancia epidemiológica basados en las técnicas de coproELISA/Western blot (WB) en muestras de heces de perros recolectadas del suelo, a fin de determinar establecimientos ganaderos (unidades epidemiológicas o UE) con transmisión presente. El objetivo de esta investigación fue evaluar la prevalencia de EQ en establecimientos ganaderos y su relación con la presencia de casos de EQ en niños de 0 a 14 años. Se seleccionaron aleatoriamente UE donde se obtuvieron muestras de materia fecal canina, las que fueron procesadas mediante coproELISA/WB. Asimismo, se identificaron casos nuevos ocurridos en niños del rango etario señalado. Se obtuvieron 571 muestras de 278 UE; 37 (6,5 %) fueron positivas a coproELISA/WB de 37 (13,3 %) UE con transmisión presente. Las diferencias con el relevamiento efectuado en el período 2003-2004 resultaron no significativas (p = 0,9), mientras que las diferencias con el relevamiento efectuado en UE de poblaciones originarias en 2009-2010 resultaron significativas (p = 0,02). Con relación a la densidad animal en el área de trabajo, las UE que dieron un resultado negativo tuvieron un promedio de 2 (DE: 2,1) perros por UE, en las UE con infección presente el promedio fue de 3 (DE 4,2), esta diferencia fue estadísticamente significativa (p = 0,02). Se diagnosticaron 12 casos en niños menores de 15 años. Se estableció que los casos de hidatidosis, en promedio, se situaron a menor distancia de los campos positivos a coproELISA/WB que de los campos negativos (p= 0,00307). La prueba de coproELISA/WB permitió identificar la dispersión de EQ en establecimientos ganaderos y analizar su relación con la ocurrencia de casos en niños

Pilot Field Trial of the EG95 Vaccine Against Ovine Cystic Echinococcosis in Rio Negro, Argentina: Second Study of Impact

Cystic echinococcosis (CE) is an important zoonotic disease caused by the cestode parasite Echinococcus granulosus. It occurs in many parts of the world where pastoral activities predominate, including the Rio Negro province of Argentina. Although CE control activities have been undertaken in the western regions of Rio Negro for more than two decades, the disease continues to remain prevalent in both the human and livestock animal populations. Vaccination of animal intermediate hosts of CE with the EG95 vaccine may provide a new opportunity to improve the effectiveness of CE control measures, although data are lacking about field application of the vaccine. Aims: Evaluate the impact of EG95 vaccination in sheep on the transmission of Echinococcus granulosus in a field environment. Methodology: Two trial sites were established in western Rio Negro province within indigenous communities. Vaccination of lambs born into one trial site was introduced and continued for 6 years. Prior to initiation of the trial, and at the end of the trial, the prevalence of CE in sheep was determined by necropsy. Weaned lambs received two injections of EG95 vaccine, approximately one month apart, and a single booster injection one year later. Vaccination was not implemented at the second trial site. A total of 2725 animals were vaccinated in the first year. Animals from this cohort as well as age-matched sheep from the control area were evaluated by necropsy. Key results: Introduction of the vaccine led to a statistically significant in the number and size of hydatid cysts in comparison to the situation prior to the introduction of the vaccine, or compared to CE prevalence in the control area where the vaccine was not applied. The prevalence of infection in the vaccinated area was also significantly reduced by 62% compared to the re-intervention level, being lower than the prevalence seen in the control area, although the difference from the control area after the intervention was not significant possibly due to limitations in the numbers of animals available for necropsy. Conclusions: Vaccination of sheep with the EG95 vaccine provides a valuable new tool which improves the effectiveness of CE control activities. Vaccination was effective even in a difficult, remote environment where only approximately half the lambs born into the communities were fully vaccinated.Fil: Larrieu, Edmundo Juan. Universidad Nacional de La Pampa; Argentina. Universidad Nacional de Río Negro; ArgentinaFil: Mujica, Guillermo. Provincia de Río Negro, Ministerio de Salud; ArgentinaFil: Gauci, Charles G.. University of Melbourne; AustraliaFil: Vizcaychipi, Katherina. Instituto Nacional de Enfermedades Infecciosas; Argentina. Provincia de Río Negro, Ministerio de Salud; ArgentinaFil: Seleiman, Marcos. Provincia de Río Negro, Ministerio de Salud; ArgentinaFil: Herrero, Eduardo. Provincia de Río Negro, Ministerio de Salud; ArgentinaFil: Labanchi, José Luis. Provincia de Río Negro, Ministerio de Salud; ArgentinaFil: Araya, Daniel. Provincia de Río Negro, Ministerio de Salud; ArgentinaFil: Sepúlveda, Luis. 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: 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: Crowley, Pablo. Universidad Nacional de Río Negro; ArgentinaFil: Cespedes, Graciela. Dirección Nacional de Institutos de Investigación. Administración Nacional de Laboratorios e Institutos de Salud. Instituto Nacional de Enfermedades Infecciosas; ArgentinaFil: Santillán, Graciela. Dirección Nacional de Institutos de Investigación. Administración Nacional de Laboratorios e Institutos de Salud. Instituto Nacional de Enfermedades Infecciosas; ArgentinaFil: García Cachau, Mariela. Universidad Nacional de La Pampa; ArgentinaFil: Lamberti, Roberto. Universidad Nacional de La Pampa; ArgentinaFil: Gino, Lilia. Universidad Nacional de La Pampa; ArgentinaFil: Donadeu, Meritxell. University of Melbourne; AustraliaFil: Lightowlers, Marshall W.. University of Melbourne; Australi

Impacto de la vacuna EG95 contra la hidatidosis ovina en el programa de control de la provincia de Río Negro, Argentina. Ocho años de trabajo (informe preliminar) /Pilot field trial of the EG95 vaccine against ovine cystic echinococcosis in Rio Negro, Ar

Cystic echinococcosis is endemic in the Rio Negro province ofArgentina. After 30 years of control using praziquantel in dogs,the transmission rate to humans and sheep has decreased significantly,however transmission persistsThe objective of the study is to assess the impact of the inclusionof the EG95 vaccine in sheep in the control program.The vaccine was applied to lambs from communities of nativepeoples which included 70 producers (Anecón Grande, MamuelChoique, Nahuel Pan y Río Chico Abajo).From 2009 on, lambs received two doses of the EG95 vaccinewhen they were 30 and 60 days of age, followed by a singlebooster injection when the animals were 1 year of age. Thetransmission of Echinococcus granulosus was assessed throughnecropsy in mature sheep, Arecoline test and coproantigen testin dogs and register of new clinical cases in inhabitants of thearea. A total of 29.323 doses of EG95 vaccine were applied tolambs in the 2009-2017 period, working with 4 groups of 2 veterinarieseach, covering 83.5% with one doses, 80.1% with twodoses and 85.7% with three doses. Before the vaccine was introduced,in necropsy of sheep of 6 years old showed that 45.7%were infected with E. granulosus. The rate decreased to 21.1% in2006. The number of cysts per animal decreased from 1.4% to0.3. The number of producers with infected animals decreasedfrom 84.2% to 22.2%. The humoral response to the vaccination,in field conditions, showed an increased in antibodies with thesecond dose, reaching its maximum after the booster at one yearof age for many years and keeping constant.In dogs, 4.7% was found positive using arecoline purgationand 20.3% of the farms were infected using coproantigen test.The impact assessment showed a 5.6% of dogs positive to thearecoline test. Only a new case of echinococcosis was detectedin kids with a 10 cm cyst, and its origin was probably before thevaccination. EG95 vaccine has been effective to prevent the infectionin ovines up to six years of age, in spite of the difficultiesof achieving better coverage. The transmission to dogs and humanbeings has to be determined.La Equinococosis quística es endémica en la provincia de Río Negro, Argentina. En esta región, después de 30 años de control usando praziquantel en perros, la velocidad de transmisión a los seres humanos se ha reducido significativamente, sin embargo, persiste la transmisión. El objetivo fue evaluar en los distintos hospederos el impacto de la introducción de la vacuna EG95 en el programa de control. La vacuna fue aplicada en corderos de comunidades de pueblos originarios que incluyeron a 79 productores (Anecón Grande, Mamuel Choique, Nahuel Pan y Río Chico abajo). Los corderos recibieron a partir de 2009 dos dosis de la vacuna EG95 a los 30 y 60 días de edad seguido de un refuerzo cuando los animales tenían 1 año de edad. La transmisión de Echinococcus granulosus fue evaluada mediante necropsia de  ovejas adultas, test de arecolina y test de coproantígenos en perros y registro de nuevos casos clínicos en pobladores del área, Un total de 29323 dosis de vacuna EG95 se aplicaron en corderos, en el período 2009-2017 trabajando con 4 equipos de 2 veterinarios cada uno, alcanzando una cobertura de 83.5% con una dosis, 80.1% con dos dosis y 85.7% con tres dosis. Antes de la introducción de la vacuna, el 45.7% de los ovinos de 6 años fueron positivos a la necropsia, valor que disminuyó a 21.1% en 2016. El número de quistes por animal disminuyó de 1.4 a 0.3. El número de productores con animales infectados disminuyó de 84.2% al 22.2%. La respuesta humoral a la vacunación, en condiciones de campo, mostro un aumento de títulos de anticuerpos con la aplicación de la segunda dosis, alcanzando su máximo luego del refuerzo al año y por varios años, manteniéndose constante. Los estudios iniciales en perros mostraron unaprevalencia al test de arecolina del 4.7% y 20.3% de productores con transmisión presente al test de coproantígenos. La evaluación de impacto mostro un 5.6% de perros positivos al test de arecolina. Solo se detectó un caso nuevo de equinococosis en niños con un quiste de 10 cm, cuyo origen fuera probablemente anterior a la introducción de la vacuna. La vacuna EG95 ha sido eficiente en prevenir la infección en ovinos de hasta 6 años de edad, a pesar de las dificultades operativas para alcanzar mejores coberturas, restando definir su impacto en la transmisión al perro y al hombre

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

Pilot field trial of the EG95 vaccine against ovine cystic echinococcosis in Rio Negro, Argentina: Early impact and preliminary data

Fil: Larrieu, Edmundo. Ministerio de Salud, Provincia de Río Negro; Argentina.Fil: Herrero, Eduardo. Ministerio de Salud, Provincia de Río Negro; Argentina.Fil: Mujica, Guillermo. Ministerio de Salud, Provincia de Río Negro; Argentina.Fil: Labanchi, Jose Luis. Ministerio de Salud, Provincia de Río Negro; Argentina.Fil: Araya, Daniel. Ministerio de Salud, Provincia de Río Negro; Argentina.Fil: Grizmado, Claudia. Ministerio de Salud, Provincia de Río Negro; Argentina.Fil: Calabro, Arnoldo. Ministerio de Salud, Provincia de Río Negro; Argentina.Fil: Talmon, Gabriel. Ministerio de Salud, Provincia de Río Negro; Argentina.Fil: Ruesta, Guillermo. Ministerio de Salud, Provincia de Río Negro; Argentina.Fil: Perez, Alicia. Ministerio de Salud, Provincia de Río Negro; Argentina.Fil: Gatti, Antonio. Ministerio de Salud, Provincia de Río Negro; Argentina.Fil: Santillan, Graciela Inés. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Parasitología; Argentina.Fil: Cabrera, Marta. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas. Departamento de Parasitología; Argentina.Fil: Arezzo, Marcos. Ministerio de Salud, Provincia de Río Negro; Argentina.Fil: Seleiman, Marcos. Ministerio de Salud, Provincia de Río Negro; Argentina.Fil: Cavagión, Laura. Universidad Nacional de La Pampa. Facultad de Ciencias Veterinarias; Argentina.Fil: García Cachau, Mariela. Universidad Nacional de La Pampa. Facultad de Ciencias Veterinarias; Argentina.Fil: Alvarez Rojas, Cristian A. University of Melbourne. Veterinary Clinical Centre; Australia.Fil: Gino, Lilia. Universidad Nacional de La Pampa. Facultad de Ciencias Veterinarias; Argentina.Fil: Gauci, Charles G. University of Melbourne. Veterinary Clinical Centre; Australia.Fil: Heath, David D. AgResearch New Zealand Limited; Nueva Zelanda.Fil: Lamberti, Roberto. Universidad Nacional de La Pampa. Facultad de Ciencias Veterinarias; Argentina.Fil: Lightowlers, Marshall W. University of Melbourne. Veterinary Clinical Centre; Australia.Cystic echinococcosis is endemic in the Rio Negro province of Argentina. After 30 years of control using praziquantel in dogs the transmission rate to humans and sheep has decreased significantly, however transmission persists. The objective of the study is to assess the impact of the inclusion of the EG95 vaccine for sheep in the control programme, including analysis of the vaccine's operative feasibility in field conditions. The vaccine was applied in an area comprising four communities of native people including 79 farms with 3146 lambs and 311 dogs in total. Seventy one farms were designated as control areas where no vaccinations were undertaken while vaccinations of lambs undertaken on 91 farms. Lambs received two vaccinations with the EG95 vaccine followed by a single booster injection when the animals were 1-1.5 years of age. Farm locations were defined using GPS coordinates for the houses. Evidence for Echinococcus granulosus transmission was monitored by coproantigen ELISA on samples of dog faeces, by E. granulosus-specific PCR using soil samples, and anti-E. granulosus antibody assessments in sera from 2 to 4 teeth lambs, purgation of dogs to detect E. granulosus worms and necropsy on adult sheep. Before the vaccine was introduced, 26.2% of sheep with 2-4 teeth were positive using ELISA/WB, the prevalence decreased to 7.8% at the third year following use of the vaccine. Necropsy of animals older than 6 years (not vaccinated) showed that 66.1% of animals were infected with E. granulosus. In dogs, 4% was found positive for E. granulosus using arecoline purgation and 24.7% of the farms were infected using coproELISA/WB. During the first year of vaccination 2721 lambs received the first vaccine dose and 2448 received a booster. In the second year 2138 lambs were initially vaccinated and 1745 received a booster, and 1308 animals received the third dose. During the third year 1110 lambs received the first dose from which 539 received a booster and 723 animals received the third dose. An analysis of advantages and limitations of the diagnostic techniques used and the ability of the geospatial analysis to detect risk area are included. Based in the immunodiagnostic techniques, the EG95 vaccine has been able to prevent the infection in animals up to 3 years old. Also, the difficulties in the field for the correct vaccine administration and the social features and habits that may impact on echinococcosis control are included in the analysis