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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.

Cystic echinococcosis (CE) is a parasitic zoonosis caused by Echinococcus granulosus. The control program of CE of Rio Negro province, Argentina, involves annual surveillance using ultrasound (US) screening in school children, and five-year cross-sectional surveys to detect livestock farms with parasitized dogs by coproELISA with confirmation tests (Western Blot or PCR). Control program is based on deworming of dogs with praziquantel and the aim is to identify areas at risk of Cystic echinococcosis transmission to humans, using all available data sources. The information was spatially distributed in 13 program areas and, at a smaller geographical scale, in 80 Primary Health Care Centers. CoproELISA surveys involved three randomized sampling periods (2003-05, 2009-10, 2017-18), with 1790 canine fecal samples. The US surveys were conducted in 2003-08, 2009-16 and 2017-18 in 34,515 children. Heat maps were created at the smallest geographic scale with QGIS 3.4.6. For the consecutive sampling periods, prevalence of positive canine fecal samples from livestock farms were 14.7, 12.1 and 7.8%, respectively, and children prevalence was 0.4, 0.2 and 0.1%, respectively. The study has been developed on a scale according to which the temporal-spatial distribution of CE allows to adjust control strategies in those areas of potential transmission of the zoonosis to humans.

Although cystic echinococcosis (CE) is an important public health problem in Rio Negro Province, current epidemiological data for CE, in this region of Argentina, are not available. Therefore, a community-based study, which incorporated diagnostic imaging and a questionnaire, was conducted in Ingeniero Jacobacci, a small town in southern Rio Negro Province. This study sought to assess the prevalence of human CE, in the study population, and to evaluate epidemiologic factors associated with CE transmission within the study area. Of the 560 individuals who volunteered to participate in the study, 189 (34%) were children and 371 (66%) were adults. All study participants were screened for CE using abdominal ultrasound scanning, with CE-positive or suspect individuals also receiving thoracic radiographs. The overall prevalence of CE was 7.1% (40/560), with 1.6% (3/189) of children, and 10% (37/371) of adults diagnosed as CE-positive. Although 92.5% (37/40) of the CE-positive individuals had only hepatic lesions, two participants had both hepatic and pulmonary lesions, and one participant had a single renal lesion. Approximately 92% (340/371) of the adult study participants completed the questionnaire, which was used to identify factors associated with an increased risk for human infection. Age, level of education, dog ownership, and contact with sheep were found to be significantly associated with CE status. This study demonstrated that CE continues to be highly endemic in this region of Rio Negro Province, Argentina. In addition, community-based ultrasound screening surveys are a noninvasive, effective approach to case detection at the community level.

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.

Cystic echinococcosis is an endemic disease in the Province of Rio Negro, Argentina. Ultrasound surveys carried out in 1984 found prevalence rates of 5.6% in children between 6 and 14 years of age. Objective To describe and to evaluate the results of the strategy applied in school children by hospital services of the Province of Rio Negro with regard to diagnosis, treatment and monitoring of cystic echinococcosis and to evaluate simultaneously the results of the control program against cystic echinococcosis. Materials and methods In 1997 ultrasound was chosen to carry out population surveys and the medical treatment criteria for the detected cases were standardized. The population under study involved 5745 students in the first survey and 22,793 in subsequent studies. The detected cases were classified according to Gharbi's scheme. A treatment algorithm was defined based only on monitoring (“watch and wait”), albendazole, surgery (open or laparoscopic) or mini-invasive procedures, according to type, location and size of the cyst. Information was also obtained on cases notified to the Health System between 1980 and 2008. Results In the first survey, 70 carriers (1.2%) were detected; of these, 25 started albendazole treatment (35.7%) and only 3 (4.3%) underwent surgery. Ten years after treatment, 60.1% of 42 cases, presented Types IV and V cysts and 14.5% presented total involution of their cysts. In subsequent studies, 87 (0.4%) cases were detected, 49 of which started albendazole treatment (56.3%) and 9 underwent surgery (10.3%). The incidence rate of cystic echinococcosis cases decreased from 38 × 100,000 in 1980 to 3.7 × 100,000 in 2008. Discussion A strong decrease in cystic echinococcosis was obtained although persistent levels of transmission were maintained. The cases produced under these conditions are diagnosed by means of ultrasound surveys and are treated using a plan based on albendazole and monitoring by the Health System during a period of 10 years.

Hydatidosis or cystic echinococcosis (CE) caused by Echinococcus granulosus is endemic in the Province of Rio Negro, Argentina. The objective of this investigation was to evaluate the results of a program carried out in endemic areas of the Province of Rio Negro, Argentina, in the years 1997-2002. Abdominal ultrasonography was used, classifying the cases detected according to WHO guidelines. A treatment algorithm was defined which included observation, albendazol therapy, PAIR or surgery, according to cyst type and size. A total of 5745 schoolchildren were evaluated, detecting hydatid cyst carriers in 70 (1.2%). Of these; 40 (57.1%) were included in follow-up protocol, 25 (35.7%) in treatment protocol with albendazol, 2 (2.9%) with PAIR and 3 (4.3%) with conventional surgery. After a mean of 44 months, among 25 cases treated with albendazol, in 2 (8%) cysts underwent total involution, in 17 (68%) they presented positive changes, in one (4%) they remained unchanged and in 4 (16%) they progressed to type II, while 1 (4%) displayed negative evolutionary changes. Out of 39 cases under observation alone protocol, in 8 cases (21%) cysts underwent total involution, in 7 (18%) they presented positive changes, in 11 (28%) they remained unchanged, in 2 (5%) they progressed to Type II and in 11 (28%) they presented negative evolutionary changes and had to be included in the other protocol types. In this study, conventional surgery, was applied to 10% of detected cases. The combination of ultrasonographic screening and albendazol treatment showed promising results.

Epidemiological surveillance for hydatidosis is based on initial determination and follow-up of the infestation rate in man, sheep and dogs. The use of ultrasonography (US) as a screening method has demonstrated its usefulness in detecting asymptomatic human carriers of abdominal hydatidosis. To evaluate the contribution of US to epidemiological surveillance within the framework of disease control programs, we performed 719 US studies in school children from 7 to 13 years of age, in rural areas of Rio Negro, Argentina, subjected to canine deparasitization during 1984/1986 and 1997/1998. In the first period, 15/268 (5.6%), while in the second, 5/451 (1.1%) carriers were detected (P < 0.0004). The average diameter of the cysts was 4.71 cm in 1984/1986 and 2.14 in 1997/1998. US as a mass screening method allows evaluation of early changes in human prevalence rates, closely related to infestation rates in sheeps and dogs, thus providing a sensitive indicator of the evaluation of control programs.