Pilot field trial of the EG95 vaccine against ovine cystic echinococcosis in Rio Negro, Argentina: 8 years of work.

Autor: Larrieu E; Facultad de Ciencias Veterinarias, Universidad Nacional de La Pampa, General Pico, Argentina; Escuela de Veterinaria, Universidad Nacional de Rio Negro, Choele Choel, Argentina. Electronic address: ejlarrieu@hotmail.com., Mujica G; Ministerio de Salud, Provincia de Río Negro, Viedma, Argentina., Araya D; Ministerio de Salud, Provincia de Río Negro, Viedma, Argentina., Labanchi JL; Ministerio de Salud, Provincia de Río Negro, Viedma, Argentina; Escuela de Veterinaria, Universidad Nacional de Rio Negro, Choele Choel, Argentina., Arezo M; Ministerio de Salud, Provincia de Río Negro, Viedma, Argentina; Escuela de Veterinaria, Universidad Nacional de Rio Negro, Choele Choel, Argentina., Herrero E; Ministerio de Salud, Provincia de Río Negro, Viedma, Argentina., Santillán G; Instituto Nacional de Microbiología 'ANLIS-MALBRAN', Buenos Aires, Argentina., Vizcaychipi K; Instituto Nacional de Microbiología 'ANLIS-MALBRAN', Buenos Aires, Argentina., Uchiumi L; Ministerio de Salud, Provincia de Río Negro, Viedma, Argentina., Salvitti JC; Ministerio de Salud, Provincia de Río Negro, Viedma, Argentina., Grizmado C; Ministerio de Salud, Provincia de Río Negro, Viedma, Argentina., Calabro A; Ministerio de Salud, Provincia de Río Negro, Viedma, Argentina., Talmon G; Ministerio de Salud, Provincia de Río Negro, Viedma, Argentina., Sepulveda L; Ministerio de Salud, Provincia de Río Negro, Viedma, Argentina., Galvan JM; Ministerio de Salud, Provincia de Río Negro, Viedma, Argentina., Cabrera M; Instituto Nacional de Microbiología 'ANLIS-MALBRAN', Buenos Aires, Argentina., Seleiman M; Ministerio de Salud, Provincia de Río Negro, Viedma, Argentina., Crowley P; Escuela de Veterinaria, Universidad Nacional de Rio Negro, Choele Choel, Argentina., Cespedes G; Instituto Nacional de Microbiología 'ANLIS-MALBRAN', Buenos Aires, Argentina., García Cachau M; Facultad de Ciencias Veterinarias, Universidad Nacional de La Pampa, General Pico, Argentina., Gino L; Facultad de Ciencias Veterinarias, Universidad Nacional de La Pampa, General Pico, Argentina., Molina L; Facultad de Ciencias Veterinarias, Universidad Nacional de La Pampa, General Pico, Argentina., Daffner J; Escuela de Veterinaria, Universidad Nacional de Rio Negro, Choele Choel, Argentina., Gauci CG; University of Melbourne, Veterinary Clinical Centre, 250 Princes Highway, Werribee, Victoria, 3030, Australia., Donadeu M; University of Melbourne, Veterinary Clinical Centre, 250 Princes Highway, Werribee, Victoria, 3030, Australia., Lightowlers MW; University of Melbourne, Veterinary Clinical Centre, 250 Princes Highway, Werribee, Victoria, 3030, Australia.
Jazyk: angličtina
Zdroj: Acta tropica [Acta Trop] 2019 Mar; Vol. 191, pp. 1-7. Date of Electronic Publication: 2018 Dec 18.
DOI: 10.1016/j.actatropica.2018.12.025
Abstrakt: Cystic echinococcosis (CE) 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 was to assess the inclusion of the EG95 for sheep in the control program and to determine the vaccine's operative feasibility in field conditions. An intervention study was defined in Rio Negro Province in Argentina comprising, in total, an area of 5820 Km2. Lambs received two vaccinations with the EG95 vaccine followed by a single booster injection when the animals were 1-1.5 years of age. Vaccination of lambs born into one trial site was introduced and continued for 8 years. Evidence for Echinococcus granulosus transmission was monitored before and after vaccination by coproantigen ELISA in faecal samples of dog, purgation of dogs to detect E. granulosus worms, necropsy on adult sheep and by ultrasound screening in children of 6-14 years old. 29,323 doses of vaccine were applied between 2009 and 2017, which a vaccination coverage of 80.1%/85.7% (57.3% average for fully vaccinated). Before the introduction of the vaccine 56.3% of the 6-year-old sheep were infected with E. granulosus at necropsy and 84.2% of the farms had infected sheep; 4.3% of the dogs were positive for E. granulosus infection using the arecoline test, and with coproELISA 9.6% of dog fecal samples were positive and 20.3% of the farms had infected dog.After the vaccine was introduced, 21.6% of sheep older than 6 years were found to be infected at necropsy and 20.2% of the farms were found to be infected; in dogs, 4.5% were found positive for E. granulosus using arecoline purgation and with coproELISA 3.7% of samples were positive, with 8.9% of farms having a positive dog. In 2016 only one case of E. granulosus infection was diagnosed by US screening in a 6-14 years old child. Included in the analysis are discussions of difficulties experienced in the field which affected correct vaccine administration as well as social features and practices that may impact on echinococcosis control and the EG95 vaccination program in Rio Negro. 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.
(Published by Elsevier B.V.)
Databáze: MEDLINE
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