Larrieu Edmundo, Mujica Guillermo, Gauci Charles G, Vizcaychipi Katherina, Seleiman Marcos, Herrero Eduardo, Labanchi José Luis, Araya Daniel, Sepúlveda Luis, Grizmado Claudia, Calabro Arnoldo, Talmon Gabriel, Poggio Thelma Verónica, Crowley Pablo, Cespedes Graciela, Santillán Graciela, García Cachau Mariela, Lamberti Roberto, Gino Lilia, Donadeu Meritxell, Lightowlers Marshall W
Facultad de Ciencias Veterinarias, Universidad Nacional de La Pampa, General Pico, Argentina; Escuela de Veterinaria, Universidad Nacional de Río Negro, Choele Choel, Argentina.
Ministerio de Salud, Provincia de Río Negro, Viedma, Argentina.
PLoS Negl Trop Dis. 2015 Oct 30;9(10):e0004134. doi: 10.1371/journal.pntd.0004134. eCollection 2015.
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.
Evaluate the impact of EG95 vaccination in sheep on the transmission of Echinococcus granulosus in a field environment.
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.
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.
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.
囊型包虫病（CE）是由绦虫寄生虫细粒棘球绦虫引起的一种重要的人畜共患病。该病发生在世界上许多以牧业活动为主的地区，包括阿根廷的内乌肯省。尽管在内乌肯省西部地区已经开展了二十多年的CE防控活动，但该病在人类和牲畜群体中仍然普遍存在。用EG95疫苗对CE的动物中间宿主进行疫苗接种可能为提高CE防控措施的有效性提供新的机会，不过目前缺乏该疫苗现场应用的数据。
评估在野外环境中，用EG95疫苗给绵羊接种对细粒棘球绦虫传播的影响。
在内乌肯省西部的土著社区设立了两个试验点。对一个试验点出生的羔羊进行疫苗接种，并持续了6年。在试验开始前和试验结束时，通过尸检确定绵羊中CE的流行情况。断奶羔羊接受两次EG95疫苗注射，间隔约一个月，一年后进行一次加强注射。第二个试验点未实施疫苗接种。第一年共有2725只动物接种了疫苗。对该队列中的动物以及来自对照区的年龄匹配的绵羊进行尸检评估。
与引入疫苗之前的情况相比，或者与未应用疫苗的对照区的CE流行情况相比，疫苗的引入导致棘球蚴囊肿的数量和大小在统计学上有显著变化。与再次干预水平相比，接种疫苗地区的感染率也显著降低了62%，低于对照区的感染率，不过由于用于尸检的动物数量有限，干预后与对照区的差异不显著。
用EG95疫苗给绵羊接种提供了一种有价值的新工具，可提高CE防控活动 的有效性。即使在困难、偏远的环境中，疫苗接种也是有效的，在这些社区出生的羔羊中只有大约一半完全接种了疫苗。
