Illicit cigarette trade in Metropolitan Santiago de Chile.

OBJECTIVE: To estimate with a rigorous statistical methodology and independent from the tobacco industry the prevalence and consumption of illicit cigarettes in Metropolitan Santiago de Chile, in addition to identifying the variables statistically associated with choosing to smoke illicit cigarettes. METHODS: Surveys of 851 smokers who reside in the Metropolitan Santiago were collected using a sampling design that combined a randomisation of high-traffic points and a quota sampling to approximate the smoking population. Photographs of packs along with questions on where they were bought were used to define whether cigarettes were licit or illicit. After this identification, the statistical association between the decision to smoke illicit cigarettes and sociodemographic variables and smoking habits was estimated using probit models. RESULTS: The proportion of smokers smoking illicit cigarettes in Metropolitan Santiago was 10.9%. Adjusted by smoking intensity, 16.3% of cigarettes smoked in a month were illicit. Models show that the probability of smoking illicit cigarettes is inversely associated with employment status (ie, employed/inactive/unemployed), and smokers with lower levels of education are more likely to smoke illicit cigarettes. Though smokers' incomes are not directly measured, both employment status and educational levels are indicative that illicit cigarette consumption is more prevalent among low-income groups. CONCLUSIONS: The proportion of smokers consuming illicit cigarettes estimated in this research is less than half of the widely publicised claims of the tobacco industry. Furthermore, past and present pricing strategies by the tobacco industry indicate that, contrary to public statements, the tobacco industry is not concerned by illicit trade.

Price and expenditure elasticity of cigarette demand in El Salvador: a household-level analysis and simulation of a tax increase.

BACKGROUND: In El Salvador, 8.8% of adults 15 years and older smoke cigarettes. Little is known about the sensitivity of cigarette consumption among the adults in El Salvador to tax and price increases and income growth. METHODS: Elasticities are estimated using Deaton's Almost Ideal Demand System model applied to data from the National Household Income and Expenditure Survey 2005/2006 for the total population and separately for income groups. The estimates are then used to simulate the effects of a proposed change in tobacco tax policy on cigarette consumption and tax revenue. FINDINGS: The estimated price elasticities (-0.77 for the total population) are within the range of price elasticity estimates available for low and middle-income countries. Given the estimated elasticities, a tobacco tax increase is expected to reduce the number of smokers (by almost 20%) and increase tobacco tax revenue (by more than 50%). CONCLUSIONS: Increasing tobacco taxes has the potential to decrease consumption in El Salvador and raise fiscal revenues. The tobacco tax burden in El Salvador is one of the lowest in Latin America and the social costs of tobacco consumption largely exceed the tobacco tax revenues. An increase in tobacco tax could significantly decrease the number of smokers and reduce the burden of tobacco-related diseases and deaths.

Relationship between smoking and health and education spending in Chile.

OBJECTIVE: To estimate the degree to which tobacco consumption is associated with spending on a set of goods and services in Chile, especially health and education, for the total population as well as for specific subgroups. METHODS: A seemingly unrelated regression equation system was used to estimate the statistical relationship between having tobacco expenditures and the budget share allocated to other items for the total population and for specific subgroups in Chile (eg, households within the bottom/top 33% by total expenditures). The use of household-level data allows for the control of a number of sociodemographic characteristics. The nationally representative 2012 Chilean Household Expenditure Survey was used for the analysis. RESULTS: Tobacco consumption is associated with lower budget shares allocated to healthcare, education and housing expenses, especially for poorer households. In the case of health, not consuming tobacco is related to higher health expenditures: up to 32% for the total population. Similarly, in the case of education, not consuming tobacco is statistically related to higher education expenditures: up to 16% for the total population. For all groups, tobacco consumption is also related to a significantly higher budget share allocated to alcoholic beverages. CONCLUSIONS: The strong significant statistical relationship found between tobacco consumption and resources allocated to healthcare and education consumption may be indicative of the existence of a crowding out effect of tobacco. This effect, in turn, may increase the burden that the rest of society must bear for the increased healthcare that they require because of tobacco consumption.

[Cystic echinococcosis in dogs and children in the province of Río Negro, Argentina]. / Vigilancia de la equinococosis quística en perros y niños en la provincia de Río Negro, 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.

Off-premises demand elasticities for pure alcohol in five Latin American countries: The case of Argentina, Chile, Costa Rica, Honduras, and Uruguay.

BACKGROUND AND AIMS: There is ample evidence from high-income countries that fiscal policies such as alcohol taxes can affect the consumption of alcohol by increasing alcohol prices. In the case of Latin American countries, much less is known about how sensitive alcohol demand is to alcohol price changes. This study aims to expand the evidence base on the sensitivity of off-premises pure alcohol demand to price and expenditure increases in five Latin American countries: Argentina, Chile, Costa Rica, Honduras, and Uruguay, which have different socioeconomic profiles and alcohol consumption patterns. DESIGN AND SETTING: Cross-sectional study MEASUREMENTS: The price and expenditure elasticities were estimated using an Almost Ideal Demand System (AIDS). Own price and expenditure elasticities for off-premises pure alcohol were estimated using representative household surveys, which collect data on households' expenses to construct the consumer basket of goods and services used to calculate the consumer price index (CPI) for the country. FINDINGS: Own price elasticities of off-premises pure alcohol for all countries were negative, inelastic, and significant at 1 %. They were -0.418 for Argentina; -0.656 for Chile; and for Costa Rica, Honduras, and Uruguay, they were equal to -0.608, -0.509, and -0.32, respectively. Expenditure elasticities were positive and significant at 1 %, except for Costa Rica, which was significant at 10 %. They were equal to 0.865 in Argentina; 0.943 in Chile; 1.182 in Costa Rica; 0.874 in Honduras; and 0.857 in Uruguay. Elasticities for Costa Rica should be interpreted cautiously, as there is insufficient geographical price variability to identify the demand correctly. CONCLUSIONS: Results were consistent with previous literature for countries from other regions. Governments should expand this study to measure total demand elasticities to improve the design of alcohol tax policies.

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.

Prevalence of human cystic echinococcosis in the towns of Ñorquinco and Ramos Mexia in Rio Negro Province, Argentina, and direct risk factors for infection.

BACKGROUND: Cystic echinococcosis (CE) is a parasitic zoonosis caused by infection with the larval stage of Echinococcus granulosus (s.l.). This study investigated the prevalence and potential risk factors associated with human CE in the towns and rural areas of Ñorquinco and Ramos Mexia, Rio Negro province, Argentina. METHODS: To detect abdominal CE cysts, we screened 892 volunteers by ultrasound and investigated potential risk factors for CE using a standardized questionnaire. Prevalence ratio (PR) with 95% confidence intervals (CI) was used to measure the association between CE and the factors investigated, applying bivariate and multivariate analyses. RESULTS: Abdominal CE was detected in 42/892 screened volunteers (4.7%, 95% CI 3.2-6.1), only two of whom were under 15 years of age. Thirteen (30.9%) CE cases had 25 cysts in active stages (CE1, CE2, CE3a, according to the WHO Informal Working Group on Echinococcosis [WHO-IWGE] classification). The most relevant risk factors identified in the bivariate analysis included: living in rural areas (P = 0.003), age > 40 years (P = 0.000), always drinking water from natural sources (P = 0.007), residing in rural areas during the first 5 years of life (P = 0.000) and having lived more than 20 years at the current address (P = 0.013). In the multivariate final model, the statistically significant risk factors were: frequently touching dogs (P = 0.012), residing in rural areas during the first 5 years of life (P = 0.004), smoking (P = 0.000), age > 60 years (P = 0.002) and living in rural areas (P = 0.017). CONCLUSIONS: Our results point toward infection with CE being acquired since childhood and with constant exposure throughout life, especially in rural areas with a general environmental contamination.

Identification of potential 'hot spots' of cystic echinococcosis transmission in the province of Río Negro, Argentina.

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.

[Pathophysiology and immune response in sheep experimentally infected with Echinococcus granulosus]. / Fisiopatología y respuesta inmune de ovinos experimentalmente infectados con Echinococcus granulosus.

The immune response to Echinococcus granulosus in sheep has not been extensively investigated. The objective of this study was to increase the information on the physiopathology of E. granulosus and the immune response elicited in sheep. Animals were experimentally inoculated with three different doses of E. granulosus eggs and the immune response was evaluated over 500 days using enzyme immunoassay with three antigenic preparations: total hydatid fluid, purified fraction of hydatid fluid and purified lipoprotein fraction. Sheep were slaughtered at different intervals to observe the macroscopic and microscopic development of the parasite. Immune response was detected at 10 days and was maintained throughout the observation period, being initially proportional to the load of inoculated eggs and then decreasing over time. Fertile cysts were identified 10 months after inoculation and live onchosphere 500 days after inoculation. Antibody response to E. granulosus in sheep preceded hydatid fluid formation and was generated by the mobility of the onchosphere. Early histological identification of fertile cysts indicates that feeding dogs with viscera of young sheep can produce cycles of infection. Furthermore, the presence of live onchosphere in the liver here found contributes to a better knowledge of the pathogenesis of this disease it could be hypothetically considered as a cause for the repeated surgeries necessary in man after the extirpation of a hydatid cyst.

The association between flavor capsule cigarette use and sociodemographic variables: Evidence from Chile.

PURPOSE: The objective of this article is to examine the factors associated with smoking of flavor capsule cigarettes in Chile, where the popularity of these products has increased dramatically, a trend increasingly observed across the world. METHODS: A representative poll of 851 smokers in Metropolitan Santiago de Chile, which comprises 40% of the country's total population, was implemented in mid-2017. Smokers were given a questionnaire that collected socio-demographic information and information on smoking patterns. Four discrete-choice models were estimated on the decision to smoke flavor capsule cigarettes to better understand the statistical relationships between traits of smokers and the consumption of flavor capsule cigarettes. RESULTS: The results of these models show that each year less in a smoker's age increases the likelihood of preferring flavor capsule cigarettes by, on average, between 0.8 and 0.9 percentage points. If the smoker is a woman, the likelihood of preferring flavor capsule cigarettes increases between 13.4 and 13.5 percentage points. Results also reveal a positive relationship between the price paid and the consumption of flavor capsule cigarettes, indicating that these cigarettes tend to be more expensive. There is no statistical relationship between participation in the labor market and smoking these products. CONCLUSIONS: Chile has the world's highest prevalence of flavor capsule cigarette smoking, which is concentrated among young people (25 years and younger) and females. No relationship between socioeconomic status and use of these products is found, though there are indications that such relationship may exist, as they were at the time of study 14% more expensive, on average, than conventional non-flavored cigarettes. As in most countries, the tobacco industry appears to be deliberately promoting these products with the goal of halting or slowing the decline in cigarette consumption in Chile. Thus, to reduce cigarette consumption (especially among youth), restricting or forbidding cigarette flavorings of all types, including flavor capsules, would be an effective strategy.

Epidemiology, diagnosis, treatment and follow-up of cystic echinococcosis in asymptomatic carriers.

Background: Río Negro Province is endemic for cystic echinococcosis (CE). A CE control program includes early diagnosis in humans. During 1980-1996, screening was done with serology and surgery was the unique choice of treatment. Since 1997, ultrasound (US) has been the method of choice for screening, and new choices of treatment for asymptomatic carriers are discussed in the CE guidelines. Methods: Between 1997 and 2016, 42 734 abdominal USs were performed, 192 new asymptomatic cases were diagnosed and underwent a protocol according to the size, location and type of cyst. Treatment options included active surveillance (US monitoring, 83 [43.3%]), antiparasitic (albendazole, 92 [47.9%]) and surgery (17 [8.8%], including percutaneous treatment). Results: After 7.7 y of follow-up, of the cases under active surveillance, 28 (33.7%) had to change treatment: 5 (6%) to surgery and 22 (26.5%) to albendazole. Of the patients treated with albendazole, 3 (3.2%) were operated on and 13 (14%) were treated with a second cycle of albendazole. Conclusion: As a result of the present study, resolution of CE in a non-surgical way with albendazole is confirmed to be effective in asymptomatic carriers with CE1 or CE3a cysts. An update eliminates the strategy of active surveillance in type CE1 cysts <3 cm and is replaced by treatment with antiparasitic in all asymptomatic cases with CE1 or CE3a cysts <10 cm. The update also limits follow-up to 12-18 months to evaluate those cases with non-response to antiparasitic and switch to a surgical option.

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

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.

The impact of prices on alcoholic beverage consumption in Chile.

INTRODUCTION AND OBJECTIVE: Chile is among the countries with the highest alcohol consumption per capita in Latin America, but little has been done in the way of public policy and policy research to overcome this problem. The objective of the present study is to estimate demand elasticities (own-price, cross-price, expenditure and quality) for three groups of alcoholic beverages in Chile: spirits, wines, and beers. DATA AND METHODS: The study uses data from the VII Encuesta de Presupuestos Familiares (Family Budget Survey) 2011-2012 conducted by the National Institute of Statistics. Because of problems with the quality of the measurement units, hot-deck imputation method was used with the alcohol purchases that presented problems. To estimate the demand elasticities, the Almost Ideal Demand System (AIDS) method proposed by Deaton was used. Quality decisions were estimated for each beverage separately using an equation proposed by Deaton in the three-step AIDS. RESULTS: The estimated elasticities were more inelastic for spirits (-0.14, P<0.01), followed by wines (-0.77, P<0.01) and beers (-0.93, P<0.01). Spirits reported less sensitivity to changes in the total budget, while wines reported the most sensitivity to changes in the total budget (expenditure elasticity). Wines also reported the most sensitivity related to quality for changes in the total budget (0,20, meaning that a 10% increase in a household's total expenditure increases the "quality" of purchased wines by 2%). CONCLUSIONS: Own-price elasticities reported for spirits, wines and beers are consistently negative, and inelastic, in line with international evidence. Although own-price elasticities for spirits is more inelastic than found in most studies, its quality-elasticity is more positive and greater. This could be explained by the greater price dispersion of spirits, as well as spirits (and wine) being consumed more than beers in Chile. This in turn may be because consumers have the option of switching to cheaper, Chilean-produced spirits such as pisco and wines when prices rise. The existence of these relatively broad quality-elasticities points to the need for a change in the alcohol tax structure from the current ad-valorem tax to a specific tax that could reduce price dispersion and curb total consumption.

Ovine echinococcosis I. Immunological diagnosis by enzyme immunoassay.

Immunodiagnosis in sheep presents problems of sensitivity and specificity, limiting its applicability in surveillance systems. The objective of this study was to develop a sensitive, specific and accessible technique for diagnosing cystic echinococcosis in naturally infected sheep and to evaluate the validity of necropsy as a reference test. A total of 247 sheep were studied at slaughterhouses, confirming the parasitological diagnosis with histology. Serum was processed with enzyme immunoassay (EIA) using three antigen preparations: total hydatid liquid (LHT), purified fraction of LHT (S2B) and purified lipoprotein (B). Western Blot (WB) was used as a control. EIA proved effective for differentiating Echinococcus granulosus from larval stage of Taenia hydatigena and intestinal cestodes in all three antigen preparations. Serums from macroscopically negative sheep were reactive to EIA and positive with WB. In the whole flock, sensitivity was 89.2% for LHT, 80.0% for S2B and 86.4% for B. Sensitivity in lambs was 78.6% for LHT, 75.0% for S2B and 64.3% for B. Macroscopic diagnosis at the time of slaughter was found to have limitations as a reference test for immunodiagnosis of cystic equinococcosis in sheep, so it was necessary to include histology and WB as reference tests. LHT was the antigen preparation of greatest value and EIA proved to be a sensitive and specific technique, adequate for surveillance systems and for evaluating control programmes.

[Epidemiological surveillance of cystic echinococcosis in dogs, sheep farms and humans in the Rio Negro Province]. / Vigilancia epidemiológica de la equinococcosis quística en perros, establecimientos ganaderos y poblaciones humanas en la provincia de Río Negro.

The surveillance of infection for Echinococcus granulosus in the Province of Rio Negro during 1980-2002 included serological and ultrasonographic screening in humans and arecoline test in dogs. In lieu of the limitations of the arecoline test the proposal was to supplant that test for the copro ELISA-copro/Western Blot complex applied to feces collected from the environment. The objective was to compare the pros and cons of the two tests and to evaluate the human and the canine infection prevalence. The working area encompassed 7 Departments with systematic canine parasiticide activities (Program Area) and 4 Departments, not endemic, as Control Area. The arecoline test was applied to the dogs in assembled groups with the voluntary participation of their owners (not randomized sampling). Samples for the detection of coproantigens were obtained from sheep farms selected at random and analyzed by the complex copro-ELISA /Western Blot. Prevalence in man was determined by screening the school population (6 to 14 years old) by ultrasound, and by means of the compulsory notification of cases from the official system. Dogs (416) were tested with arecoline, 365 of which belonged to the Program Area. Of these 19 (5.2%) resulted positive, while none of 51 dogs from the Control Area were positive. Samples (748) of feces were tested to detect coproantigens, obtaining 37 positive samples within the Program Area and 4 within the Control Area. Farms (271) from the livestock estate unit were evaluated, out of which 236 belonged to the Program Area, gave 32 (13.6%) positive results, while 4 (11.4%) of 35 from the Control Area resulted positive. Sonography tests (7421) were done in the Program Area detecting 40 (0.5%) carriers, while in the Control Area, over 1732 tests, 9 (0.5%) resulted positive. The arecoline test provides information about the dog prevalence while the detection of coproantigens in feces collected from the environment allowed to enhance the quality of the information, and the identification of environments where specific control activities focusing on risk must be concentrated. Also the study allowed to recognize new transmission areas.

Diagnosis of cystic echinococcosis on sheep farms in the south of Argentina: areas with a control program.

In 2000 Guarnera et al. proposed using ELISA in canine faeces collected from the ground to detect dogs infected with Echinococcus granulosus, thus determining sheep farms with active transmission. The objective was to evaluate the prevalence of E. granulosus infection in sheep farms of the Patagonia. Sheep farms were randomly selected in the Provinces of Río Negro, Chubut, Neuquén, Santa Cruz and Tierra del Fuego (areas with control programs) and La Pampa (comparison area). From one to three samples of fecal matter were obtained for each sheep farm, which were processed by means of copro-ELISA test with confirmation of positive samples by copro-Western blot. A total of 1042 samples were obtained from 352 sheep farms, 26 (7.3%) proving positive. Of these 5 (6.3%) were from La Pampa, 9 (13.8%) from Neuquén, 4 (4.7%) from Río Negro, 2 (2.9%) from Chubut, 1 (5.9%) from Santa Cruz and 5 (13.9%) from Tierra del Fuego. The identification of parasitized dogs is an essential activity upon which rests the strategy of control and surveillance. Arecoline tests or coproantigen test with fecal matter obtained directly from the dog contribute information on individual prevalence, while the use of coproantigens detected in ground-collected samples transfers the dog unit of observation to units of greater epidemiological value. In the present experience, the technique employed seems promising for its application in systems of epidemiological surveillance of cystic echinococcosis and in drawing a baseline on which to measure the progress of control programs in the Argentine Patagonia in subsequent years.

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

BACKGROUND: 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.

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

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.