Ministerio de Salud, Provincia de Río Negro, Argentina.
Acta Trop. 2013 Aug;127(2):143-51. doi: 10.1016/j.actatropica.2013.04.009. Epub 2013 Apr 28.
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.
泡型包虫病在阿根廷里奥内格罗省流行。经过 30 年使用吡喹酮控制犬感染，人类和绵羊的感染率显著下降，但传播仍在持续。本研究的目的是评估在绵羊中纳入 EG95 疫苗对控制计划的影响，包括分析该疫苗在野外条件下的操作性。该疫苗在四个原住民社区的一个区域内实施，共有 79 个农场，共 3146 只羔羊和 311 只狗。71 个农场被指定为对照区，没有进行疫苗接种，而在 91 个农场对羔羊进行了疫苗接种。羔羊在 1-1.5 岁时接受两次 EG95 疫苗接种，然后进行单次加强注射。使用全球定位系统坐标定义农场位置。通过对犬粪便样本进行粪抗原 ELISA、土壤样本进行 E. granulosus 特异性 PCR 以及对 2-4 齿羔羊血清进行抗 E. granulosus 抗体评估，监测 Echinococcus granulosus 传播的证据，对犬进行驱虫以检测 E. granulosus 蠕虫，并对成年绵羊进行剖检。在引入疫苗之前，使用 ELISA/WB，26.2%的 2-4 齿羔羊呈阳性，使用疫苗 3 年后，流行率下降至 7.8%。对年龄大于 6 岁（未接种疫苗）的动物进行剖检显示，66.1%的动物感染了 E. granulosus。用槟榔碱驱虫检测到犬中 4%为阳性，用 coproELISA/WB 检测到 24.7%的农场感染。在接种疫苗的第一年，2721 只羔羊接受了第一剂疫苗，2448 只接受了加强剂。第二年，2138 只羔羊最初接受了疫苗接种，其中 1745 只接受了加强剂，1308 只接受了第三剂。第三年，1110 只羔羊接受了第一剂疫苗，其中 539 只接受了加强剂，723 只接受了第三剂。包括对使用的诊断技术的优缺点和地理空间分析检测风险区域的能力的分析。基于免疫诊断技术，EG95 疫苗能够预防 3 岁以下动物的感染。还包括在野外正确接种疫苗的困难以及可能影响包虫病控制的社会特征和习惯。
