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

Canine parasitoses in north Patagonia (Argentina): comparison between different social and environmental factors

In many countries, urban areas are commonly contaminated with canine feces that spread parasites, a situation related to the natural and social environment. Dogs having free access to public areas therefore constitutes a health risk. Because in Patagonia there are no records of city comparisons that consider the number of free-roaming dogs and the local environmental and socioeconomic characteristics, in this study we analyse and compare canine parasitoses in two cities of Rio Negro province, Argentina. Canine feces were collected from public areas of El Bolsón and Cipolletti cities and examined using enrichment methods, Kinyoun stain and immunoassay (Copro-Elisa). The total percentage of positive feces in El Bolsón was 68.95% and 16 parasite taxa being identified, whereas in Cipolletti the total positive feces was 41.1%, with 11 taxa. Both cities presented more helminth species than protozoans. The variables that explained the occurrence of all parasites were rainfall and socioeconomic stratum with the highest values being found in low-income areas.Soil moisture is conditioned by rainfall. This study highlights the presence of the zoonotic Echinococcus sp. in dogs in urban areas of the Rio Negro province. The occurrence of this parasite in Cipolletti is unexpected, given that this city is not considered an endemic zone for this disease, which is not included in local monitoring and control plans.

A cross-sectional study of free-roaming dogs in a Patagonian city: Their distribution and intestinal helminths in relation to socioeconomic aspects of neighborhoods

Human and dog health are inextricably linked, and although our relationship with dogs brings numerous benefits for our well-being, it is known that they can transmit disease. Bariloche is a Patagonian tourist city with heterogeneous social composition. This cross-sectional study evaluates the population of free-roaming dogs and their intestinal parasites in relation to the socioeconomic level of the city's human population. Census areas were used as survey units, stratified in three levels according to socioeconomic status. The free-roaming dog population was estimated by walking around each census area. Eight fresh feces per census count area were collected and analyzed using coproparasitological flotation tests, and CoproELISA was used to detect Echinococcus sp. A total of 858 free-roaming dogs were registered along 40.9 km, with significant differences between socioeconomic strata: the highest numbers were found in the lowest income strata. Of the feces collected, 39.2% tested positive for parasites, those associated with a lower socioeconomic level having higher percentages of positive feces and a greater number of species. Eight species of helminths were found, some of which were zoonotic, such as Echinococcus sp., Toxocara canis, and Dibothriocephalus latus. The presence of parasites can be explained by the number of free-roaming dogs per census count area. The free-roaming dogs generally have owners, and their parasitic infection is strongly associated with the socioeconomic level of the population. The main problem is irresponsible pet care, which generates healthy conditions for both dogs and humans. Thus, both dogs and humans deserve effective ethical public policies.

Cystic Echinococcosis: An Impact Assessment of Prevention Programs in Endemic Developing Countries in Africa, Central Asia, and South America

Background. Cystic echinococcosis (CE), caused by the tapeworm species, Echinococcus granulosus sensu stricto (G1), is one of many primary neglected zoonoses worldwide. Within endemic developing countries, CE has multiple effects on animal and human health and well-being. To address such effects, veterinary and human medical sector collaboration on prevention program delivery is essential. To begin preliminary evaluations of county specific prevention programs, a critically appraised topic (CAT) was conducted. It sought to answer: What impact do CE prevention programs have on human and animal disease prevalence, in populations living in endemic developing countries within Africa, Central Asia, and South America? Methodology. The aim was to assess the ability of prevention and control program outputs to produce measurable differences in health, social, and economic outcomes (e.g., improved access to medical services, positive behavioral change, or reduced treatment costs, respectively). Included articles were obtained using predefined inclusion/exclusion criteria from the four databases (CAB Abstracts and Global Health; the National Library of Medicine (PubMed); ScienceDirect; and WHO Institutional Repository of Information Sharing (IRIS)). The articles were appraised using three checklists: the Royal College of Veterinary Surgeons (RCVS), the Critical Appraisals Skills Programme (CASP), and the Joanna Briggs Institute checklists. Results. Ten articles were selected. Geographically, 20% of studies were conducted in South America, 30% in Africa, and 50% in Central Asia. For definitive hosts, dogs, CoproELISA antigen testing, before and after Praziquantel (PZQ) de-worming, was a primary focus. For humans, who are intermediate hosts (IH), disease surveillance methods, namely ultrasound (US), were commonly assessed. Whilst for sheep, also acting as IH, disease prevention methods, such as the EG95 livestock vaccine and de-worming farm dogs, were evaluated. Common to all studies were issues of program sustainability, in terms of regular human US screening, dog de-worming, and annual sheep vaccination. This was attributed to transient and remote human or animal populations; limited access to adequate roads or hospitals; few skilled health workers or veterinarians; an over-reliance on communities to administer preventatives; and limited resources. Conclusion. Despite variations in result validity and collection periods, useful comparisons of CE endemic countries produced key research and program recommendations. Future research recommendations included testing the significance of multiple program outcomes in relation to prevalence (e.g., the social outcome: behavioral change), further research on the impact of livestock vaccinations, and the CE transmission role of waterways and sanitation. Program recommendations included calculating and distinguishing between stray versus owned dog populations; formal representation of internal and external stakeholder interests through institutional organization; establishing sustainable guidelines around the frequency of PZQ and vaccination administration; improved veterinary-human medical training and resource sharing; and combined prevention methods and multiple canine disease management.

Epidemiology and spatial distribution of Echinococcus granulosus in sheep and goats slaughtered in a hyperendemic European Mediterranean area

Background

Cystic echinococcosis (CE) is a worldwide parasitic zoonosis caused by the larval stage of Echinococcus granulosus sensu lato affecting livestock, particularly sheep and goats. However, often this parasitosis is underestimated. For this reason, this study aimed to evaluate the epidemiological features and spatial distribution of CE in sheep and goats slaughtered in a hyperendemic Mediterranean area.

Methods

A survey was conducted in the Basilicata region (southern Italy) from 2014 to 2019. A total of 1454 animals (1265 sheep and 189 goats) from 824 farms were examined for hydatid cyst detection by visual inspection, palpation and incision of target organs. All the CE cysts were counted and classified into five morphostructural types (unilocular, multiseptate, calcified, caseous and hyperlaminated). Molecular analysis was performed on 353 cysts. For spatial analysis, a kriging interpolation method was used to create risk maps, while clustering was assessed by Moran’s I test.

Results

CE prevalence of 72.2% (595/824) and 58.4% (849/1454) was observed at the farm and animal levels, respectively, with higher values in sheep (62.9%) than goats (28.0%). The liver and lungs were the most frequently infected organs in both sheep and goats. Most of recovered cysts were of the calcified and multiseptate morphotypes. All the isolates were identified as E. granulosus sensu stricto (genotypes G1–G3). Spatial distribution showed a moderate clustering of positive animals.

Conclusion

The findings of this study can be used to better understand the eco-epidemiology of echinococcosis and to improve CE surveillance and prevention programs in regions highly endemic for CE.

Graphical abstract

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.

Graphic Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13071-021-04753-y.

Integration of animal health and public health surveillance sources to exhaustively inform the risk of zoonosis: An application to echinococcosis in Rio Negro, Argentina

The analysis of zoonotic disease risk requires the consideration of both human and animal geo-referenced disease incidence data. Here we show an application of joint Bayesian analyses to the study of echinococcosis granulosus (EG) in the province of Rio Negro, Argentina. We focus on merging passive and active surveillance data sources of animal and human EG cases using joint Bayesian spatial and spatio-temporal models. While similar spatial clustering and temporal trending was apparent, there appears to be limited lagged dependence between animal and human outcomes. Beyond the data quality issues relating to missingness at different times, we were able to identify relations between dog and human data and the highest ‘at risk’ areas for echinococcosis within the province.

This work focuses on utilizing animal disease data to try and inform our understanding of the spread of diseases in humans. We implement predictive models to estimate the relationship between the distribution of disease in animal populations and the distribution of disease in human populations. Development of a better understanding of this relationship could inform animal and public health interventions aiming to mitigate against human disease before it spreads. Missing data and limited data resources made discovery of these relationships difficult, but we fit multiple model types to try and identify any connection between these two populations. We found specific areas with elevated risk of human disease and changes in disease risk over time. Finally, there was some indication of an association between previous years’ levels of animal disease and human disease when using animals as covariables.

Intestinal parasites in canine feces contaminating urban and recreational areas in Ushuaia (Argentina)

Wild and domestic dogs are important reservoir hosts of numerous intestinal parasites that represent potential infection sources for both humans and wild or other domestic animals. The aim of this study was to determine the presence, diversity, and contamination potential of intestinal parasites in dog feces contaminating urban and recreational areas in Ushuaia (Tierra del Fuego province, Argentina). A total of 80 canine fecal samples were collected from urban (playgrounds, streets, sidewalks, squares and coastal walks) and recreational areas (winter centers for raising and training sled dogs) in 2018. Samples were preserved in 5% formalin and processed using formalin-ethyl acetate sedimentation and FLOTAC dual Pellet techniques. Data were analyzed using the R software. At least one parasite species was recovered in 32.5% of the total samples examined. Of the seven parasite species detected, infection by protozoan species was higher than helminth infections (28.8% versus 8.8%). Sarcocystis sp. (20.0%), Giardia sp. (8.8%) and Cystoisospora spp. (7.5%) were the most frequent species, followed by Toxocara canis (5.0%), Echinococcus spp./Taenia spp. (2.5%), Trichuris vulpis and Uncinaria sp. (1.3% for both). Single infections (69.2%) were more frequent than coinfections with two (19.2%) and three parasite species (11.5%). This study provides the first description of the diversity and frequency of intestinal parasite species in dog feces from Ushuaia, the southernmost city in the world. The unfavorable environment of Ushuaia, characterized by low temperatures and winter snowfall, is likely to reduce parasite survivability, decreasing contamination potential. Some parasite species found are potentially zoonotic and represent an important risk for the human population and a source of infection to free-roaming pets. The results of this study revealed the need to strengthen the prevention, surveillance and control of these infections in pets, as well as to implement programs for public health education, control measures for the free-roaming canine population, and responsible pet ownership in the study area.