Polycystic echinococcosis in Pacas, Amazon region, Peru

The establishment of a collaborative surveillance program with indigenous hunters to characterize primate health in Southern Guyana

The consumption of primates is integral to the traditional subsistence strategies of many Indigenous communities throughout Amazonia. Understanding the overall health of primates harvested for food in the region is critical to Indigenous food security and thus, these communities are highly invested in long-term primate population health. Here, we describe the establishment of a surveillance comanagement program among the Waiwai, an Indigenous community in the Konashen Amerindian Protected Area (KAPA). To assess primate health in the KAPA, hunters performed field necropsies on primates harvested for food and tissues collected from these individuals were analyzed using histopathology. From 2015 to 2019, hunters conducted 127 necropsies across seven species of primates. Of this sample, 82 primates (between 2015 and 2017) were submitted for histopathological screening. Our histopathology data revealed that KAPA primates had little evidence of underlying disease. Of the tissue abnormalities observed, the majority were either due to diet (e.g., hepatocellular pigment), degenerative changes resulting from aging (e.g., interstitial nephritis, myocyte lipofusion), or nonspecific responses to antigenic stimulation (renal and splenic lymphoid hyperplasia). In our sample, 7.32% of individuals had abnormalities that were consistent with a viral etiology, including myocarditis and hepatitis. Internal parasites were observed in 53.66% of individuals and is consistent with what would be expected from a free-ranging primate population. This study represents the importance of baseline data for long-term monitoring of primate populations hunted for food. More broadly, this research begins to close a critical gap in zoonotic disease risk related to primate harvesting in Amazonia, while also demonstrating the benefits of partnering with Indigenous hunters and leveraging hunting practices in disease surveillance and primate population health assessment.

Echinococcus species in wildlife

Transmission of Echinococcus spp. in life cycles that involve mainly wildlife is well recognized for those species with small mammals as intermediate hosts (e. g. E. multilocularis), as well as for E. felidis and the 'northern' genotypes of E. canadensis (G8 and G10). In contrast, the remaining taxa of E. granulosus sensu lato are best known for their domestic life cycles, and the numerous wild mammal species (mainly ungulates) that have been recorded with cystic echinococcosis in the past were mainly considered a result of spill-over from the dog-livestock transmission system. This view was challenged with the advent of molecular characterization, allowing discrimination of the metacestodes, although the contribution of wild mammals to various Echinococcus life cycles has remained uncertain for scarcity of wildlife studies. Numerous records of cysts in wild ungulates date back to the 20th century, but cannot with certainty be allocated to the Echinococcus species and genotypes that are recognized today. This means that our current knowledge is largely restricted to studies of the past two decades that kept adding gradually to our concepts of transmission in various geographic regions. In particular, new insights were gathered in the past years on E. granulosus s.l. in wildlife of sub-Saharan Africa, but also on transmission patterns of E. multilocularis in previously neglected regions, e. g. North America. Here, an update is provided on the current state of knowledge on wild mammals as hosts for all Echinococcus species, listing >150 species of wild hosts with references, as well as estimates on their epidemiological impact and our current gaps of knowledge.

Climate determines transmission hotspots of Polycystic Echinococcosis, a life-threatening zoonotic disease, across Pan-Amazonia

Polycystic Echinococcosis (PE), a neglected life-threatening zoonotic disease caused by the cestode Echinococcus vogeli, is endemic in the Amazon. Despite being treatable, PE reaches a case fatality rate of around 29% due to late or missed diagnosis. PE is sustained in Pan-Amazonia by a complex sylvatic cycle. The hunting of its infected intermediate hosts (especially the lowland paca Cuniculus paca) enables the disease to further transmit to humans, when their viscera are improperly handled. In this study, we compiled a unique dataset of host occurrences (~86000 records) and disease infections (~400 cases) covering the entire Pan-Amazonia and employed different modeling and statistical tools to unveil the spatial distribution of PE's key animal hosts. Subsequently, we derived a set of ecological, environmental, climatic, and hunting covariates that potentially act as transmission risk factors and used them as predictors of two independent Maximum Entropy models, one for animal infections and one for human infections. Our findings indicate that temperature stability promotes the sylvatic circulation of the disease. Additionally, we show how El Niño-Southern Oscillation (ENSO) extreme events disrupt hunting patterns throughout Pan-Amazonia, ultimately affecting the probability of spillover. In a scenario where climate extremes are projected to intensify, climate change at regional level appears to be indirectly driving the spillover of E. vogeli. These results hold substantial implications for a wide range of zoonoses acquired at the wildlife-human interface for which transmission is related to the manipulation and consumption of wild meat, underscoring the pressing need for enhanced awareness and intervention strategies.

Records of Human Deaths from Echinococcosis in Brazil, 1995–2016

Simple Summary

Echinococcosis is a zoonotic disease relevant to public health in many countries. The disease is present in Brazil; however, it is often underreported due to the lack of mandatory notification of cases across all Brazilian states. The records of two national databases were accessed during the period of 1995–2016 to describe the registered cases and deaths from echinococcosis in the country. Demographic, epidemiological, and health care data related to the occurrence of disease, and deaths attributed to echinococcosis are described. During the study period, 7955 hospitalizations were recorded due to echinococcosis, with 185 deaths. In a second database recording just mortality, a further 113 deaths were documented. Deaths were observed in every state of Brazil. When comparing between states, there was great variability in mortality rates, possibly indicating differences in the quality of health care received by patients and reinforcing the need to expand the compulsory notification of the disease across the country.

Abstract

Echinococcosis is a zoonotic disease relevant to public health in many countries, on all continents except Antarctica. The objective of the study is to describe the registered cases and mortality from echinococcosis in Brazil, from 1995 to 2016. The records of two national databases, the Hospital Information System (HIS) and the Mortality Information System (MIS), were accessed during the period of 1995–2016. Demographic, epidemiological, and health care data related to the occurrence of disease and deaths attributed to echinococcosis in Brazil are described. The results showed that 7955 records of hospitalizations were documented in the HIS, during the study period, with 185 deaths from echinococcosis, and 113 records of deaths were documented in the MIS Deaths in every state of Brazil in the period. When comparing between states, the HIS showed great variability in mortality rates, possibly indicating heterogeneity in diagnosis and in the quality of health care received by patients. Less severe cases that do not require specialized care are not recorded by the information systems, thus the true burden of the disease could be underrepresented in the country. A change in the coding of disease records in the HIS in the late 1990s, (the integration of echinococcosis cases with other pathologies), led to the loss of specificity of the records. The records showed a wide geographic distribution of deaths from echinococcosis, reinforcing the need to expand the notification of the disease in Brazil. Currently, notification of cases is compulsory in the state of Rio Grande do Sul.

Update of Cestodes Parasitizing Neotropical Hystricomorphic Rodent

This review aims at identifying cestodes that are present in hunted rodent species in the neo-tropical region. The rodent species that was investigated were the capybara (Hydrochoerus hydrochaeris, Linnaeus, 1766), lappe (Cuniculus paca, Linnaeus, 1766), agouti (Dasyprocta leporina, Linnaeus, 1758), chinchilla (Chinchilla chinchilla, Lichtenstein, 1829), Trinidad spiny rat (Proehimys trinitatus, Allen and Chapman, 1893), nutria (Myocastor coypus, Molina, 1782), and vizcacha (Lagostomus maximus, Desmarest, 1817). These rodent species are utilized for their meats in many rural communities in the Caribbean and South America. These rodents belong to the hystricomorphic group. Raillietina demerariensis Daniels, 1895 was commonly found in the gastrointestinal tract of D. leporina, C. paca and P. trinitatus. Similarly, in the liver, muscle and subcutaneous tissue the metacestodes on Echinococcus vogeli Daniels, 1895 and Echinococcus oligarthrus was found in the lappe and agouti. The capybara was found to have the most species of cestodes in its gastrointestinal tract when compared to the agouti and lappe. However, metacestodes were not recorded in the tissues of the capybara. This surprising feature shows the effect of the difference in feeding habits between the capybara and the agouti and lappe. The literature reviewed in this study includes scientific publications on cestodes and metacestodes of Hystricomorphic rodents. An exhaustive search was performed using the digital repositories in Google Scholar, Scielo, Redalyc, Scopus and Pubmed. Literature searched spanned the years 1970-2021. Cestodes of zoonotic significance were E. vogeli and E. oligarthrus, with humans becoming infected when consuming eggs of contaminated food and water. The agouti and lappe act as intermediate host in the life cycle of E. vogeli and E. oligarthrus, the definitive host (canids and felids) become infected by consuming of tissue infected with metacestodes. Humans become infected through the ingestion of eggs from the definitive host where cystic lesions develop in the liver, lungs and other abdominal organs.

An Ethnographic Approach to Characterizing Potential Pathways of Zoonotic Disease Transmission from Wild Meat in Guyana

The hunting, butchery, and consumption of wild meat is an important interface for zoonotic disease transmission. Despite this, few researchers have used ethnography to understand the sociocultural factors that may increase zoonotic disease transmission from hunting, particularly in Amazonia. Here, we use ethnographic methods consisting of structured, semi-structured and unstructured interviews, and participant observation to address questions pertaining to wild meat consumption, pathways of zoonotic disease transmission, food security, and the cultural identity of indigenous Waiwai in the Konashen Community Owned Conservation Area, Guyana. Our data revealed that the majority of Waiwai eat wild meat two to three times/week and 60% of respondents reported butchery-related injuries. However, semi-structured and unstructured interviews, and participant observation data indicate that the Waiwai do not perceive most cuts from butchery as injuries, despite being a potential route of pathogen exposure. Additionally, participant observation revealed that hunting is integral to Waiwai identity and the Waiwai exhibit a cultural aversion to domestic meats. These findings provide valuable insights into the interplay of hunting and wild meat consumption and disease in Amazonia and demonstrate how an ethnographic approach provides the contextual data necessary for identifying potential pathways of zoonotic transmission from wild meat.

Endoparasites of Selected Native Non-Domesticated Mammals in the Neotropics (New World Tropics)

In this review, information was summarized on endoparasites found in six non-domesticated neotropical animals. These mammals have the potential to be domesticated. The animals included three rodents, agouti (Dasyprocta leporina), lappe (Agouti paca), and capybara (Hydrochoerus hydrochaeris); a marsupial, manicou (Didelphis marsupialis insularis); and an artiodactyl, the collared peccary (Tayassu tajacu/Peccari tajacu) and a ruminant (the red brocket deer, Mazama americana). While there are many descriptions of the parasites present, the majority of publications failed to note the effect of them on the animals. Most information is available on endoparasites of capybara, while the endoparasites of the red brocket deer were the least reported. The manicou was reported to have had the most number of endoparasites, 44 species of parasites were reported, while there were only 24 endoparasites reported in the lappe. The most common parasites found in these neotropical animals were Paraspidodera uncinata, Strongyloides spp., Eimeria spp., Moniezia benedeni, Trichuris spp., Physocephalus spp., and Giardia spp. A large majority of the studies concluded that these animals were reservoirs for parasites that could affect domesticated livestock. Endoparasites of zoonotic significance were Echinoccocus spp., Trichuris spp., Giardia spp., and Cryptosporidium spp.

Genetic diversity of Echinococcus vogeli in the western Brazilian Amazon

Human polycystic echinococcosis is a parasitic infection caused by the larval stage of Echinococcus vogeli, which occurs in rural areas of Central and South America. Until now, little information on the genetic variability of E. vogeli is available. Here, 32 samples from human-excised E. vogeli cysts had a 396-bp sequence of the mitochondrial cytochrome oxidase I (COI) gene sequenced and compared to another 17 COI sequences representing nine Echinococcus species. A Bayesian COI tree revealed that all E. vogeli sequences formed a monophyletic and well-supported clade with an E. vogeli reference sequence. The occurrence of geographically restricted E. vogeli COI haplotypes suggests retention of ancestral polymorphisms with little migration in Acre, Brazil.

First parasitological, histopathological and molecular characterization of Echinococcus vogeli Rausch and Bernstein, 1972 from Cuniculus paca Linnaeus, 1766 in the Cerrado biome (Mato Grosso do Sul, Brazil)

Polycystic echinococcosis (PE) is caused by Echinococcus vogeli metacestodes (larval stage) in Neotropical countries. E. vogeli is trophically-transmitted between predators bush dogs (Speothos venaticus) and prey pacas (Cuniculus paca). In Brazil, reported PE cases are restricted to the Amazon biome. In this study, metacestodes from a paca hunted in Mato Grosso do Sul state (Cerrado biome) were identified morphological and histopathological techniques and further confirmed by molecular testing (sequencing of cytochrome C oxidase subunit I (cox1) gene) for the first time. Images of the whole liver showed superficial bubble-like hepatic masses. The parasitological analysis revealed large hooks (41.3 ± 1.2 μm length/12.8 ± 0.8 μm width) and small hooks (33.0 ± 1.5 μm length/11.1 ± 1.2 μm width), consistent with E. vogeli. Microscopically, the liver showed protoscoleces, a thick laminated layer, fibrosis, and inflammatory infiltrate in the adventitial layer. The DNA sequencing confirmed E. vogeli with 99% homology with sequences deposited in the GenBank. In addition, this finding greatly extends the geographic range of animal polycystic echinococcosis into the Cerrado. It is likely to occur in new biomes, where bush dogs and pacas share a given area in a trophic relationship.

Assessment of mammal reproduction for hunting sustainability through community-based sampling of species in the wild

Wildlife subsistence hunting is a major source of protein for tropical rural populations and a prominent conservation issue. The intrinsic rate of natural increase. (r_max ) of populations is a key reproductive parameter in the most used assessments of hunting sustainability. However, researchers face severe difficulties in obtaining reproductive data in the wild, so these assessments often rely on classic reproductive rates calculated mostly from studies of captive animals conducted 30 years ago. The result is a flaw in almost 50% of studies, which hampers management decision making. We conducted a 15-year study in the Amazon in which we used reproductive data from the genitalia of 950 hunted female mammals. Genitalia were collected by local hunters. We examined tissue from these samples to estimate birthrates for wild populations of the 10 most hunted mammals. We compared our estimates with classic measures and considered the utility of the use of r_max in sustainability assessments. For woolly monkey (Lagothrix poeppigii) and tapir (Tapirus terrestris), wild birthrates were similar to those from captive populations, whereas birthrates for other ungulates and lowland-paca (Cuniculus paca) were significantly lower than previous estimates. Conversely, for capuchin monkeys (Sapajus macrocephalus), agoutis (Dasyprocta sp.), and coatis (Nasua nasua), our calculated reproductive rates greatly exceeded often-used values. Researchers could keep applying classic measures compatible with our estimates, but for other species previous estimates of r_max may not be appropriate. We suggest that data from local studies be used to set hunting quotas. Our maximum rates of population growth in the wild correlated with body weight, which suggests that our method is consistent and reliable. Integration of this method into community-based wildlife management and the training of local hunters to record pregnancies in hunted animals could efficiently generate useful information of life histories of wild species and thus improve management of natural resources.

First molecular identification of Echinococcus vogeli and Echinococcus granulosus (sensu stricto) G1 revealed in feces of domestic dogs (Canis familiaris) from Acre, Brazil

Background

Echinococcus granulosus (sensu lato) (s.l.) and Echinococcus vogeli are causative agents of chronic zoonotic diseases such as cystic and polycystic echinococcosis, respectively. In Brazil, polycystic echinococcosis has a restricted geographical distribution in the North Region, while cystic echinococcosis is observed in the South Region. Domestic dogs (Canis familiaris) fed with raw viscera represent a risk factor for E. granulosus (s.l.) infection in the South Region. Although this practice is frequent, it remains unclear whether domestic dogs are infected with E. vogeli in the state of Acre, located in the Amazon basin in the North Region of Brazil. The aim of this study was to investigate this gap in the polycystic echinococcosis epidemiology.

Methods

Sixty-five fecal samples were collected from the ground in five municipalities (Sena Madureira, n = 14; Rio Branco, n = 06; Bujari, n = 06; Xapuri, n = 30; and Epitaciolândia, n = 09) located in the state of Acre, northern Brazil. The samples were screened for parasites by copro-PCR using the cox1 gene associated with automated sequencing.

Results

Echinococcus vogeli was molecularly confirmed in a sample from Sena Madureira and E. granulosus (sensu stricto) (s.s.) (G1) in a sample from Rio Branco.

Conclusions

These findings indicate that molecular assays are useful in typing Echinococcus taxa from fecal samples of dogs in northern Brazil. The present study is the first molecular record of E. vogeli in domestic dogs found in the state of Acre, reinforcing their role as a source of infection for humans. Because E. granulosus (s.s.) (G1) was detected for the first time in the North Region, from the epidemiological standpoint this finding is highly relevant, because it expands the known geographical distribution, which was previously restricted to the South Region of Brazil.

Ecology and Life Cycle Patterns of Echinococcus Species

The genus Echinococcus is composed of eight generally recognized species and one genotypic cluster (Echinococcus canadensis cluster) that may in future be resolved into one to three species. For each species, we review existing information on transmission routes and life cycles in different geographical contexts and - where available - include basic biological information of parasites and hosts (e.g., susceptibility of host species). While some Echinococcus spp. are transmitted in life cycles that involve predominantly domestic animals (e.g., dog - livestock cycles), others are wildlife parasites that do or do not interact with domestic transmission. In many cases, life cycle patterns of the same parasite species differ according to geography. Simple life cycles contrast with transmission patterns that are highly complex, involving multihost systems that may include both domestic and wild mammals. Wildlife transmission may be primary or secondary, i.e., resulting from spillovers from domestic animals. For most of the species and regions, existing information does not yet permit a conclusive description of transmission systems. Such data, however, would be highly relevant, e.g., for anticipation of geographical changes of the presence and frequency of these parasites in a warming world, or for initiating evidence-based control strategies.

Neotropical Zoonotic Parasites in Bush Dogs (Speothos venaticus) from Upper Paraná Atlantic Forests in Misiones, Argentina

Wildlife remains an important source of zoonotic diseases for the most vulnerable groups of humans, primarily those living in rural areas or coexisting with forest. The Upper Paraná Atlantic forest of Misiones, Argentina is facing ongoing environmental and anthropogenic changes, which affect the local biodiversity, including the bush dog (Speothos venaticus), a small canid considered Near Threatened globally and Endangered locally. This project aimed to expand the knowledge of zoonotic parasites present in the bush dog and the potential implications for human health and conservation medicine. From May to August 2011, a detection dog located 34 scats that were genetically confirmed as bush dog and georeferenced to northern Misiones. Of these 34 scats, 27 had sufficient quantity that allowed processing for zoonotic parasites using morphological (sedimentation and flotation) and antigen (coproantigen technique) analyses. Within these 27 scats, we determined that the parasitic prevalence was 63.0% (n = 17) with 8 (47.1%) having mixed infections with 2-4 parasitic genera. No significant differences (p > 0.05) between sampling areas, sex, and parasite taxa were found. We were able to summarize the predominant nematodes (Ancylostoma caninum, Toxocara canis, and Lagochilascaris spp.), cestodes (Taenia spp. and Spirometra spp.), and apicomplexa (Cystoisospora caninum) found in these bush dogs. With the copro-ELISA technique, 14.8% (n = 4) of the samples were positive for Echinococcus spp. This study represents the first comprehensive study about parasitic fauna with zoonotic potential in the free-ranging bush dog. This information combined with the innovative set of techniques used to collect the samples constitute a valuable contribution that can be used in control programs, surveillance of zoonotic diseases, and wildlife conservation, both regionally and across the bush dog's broad distribution.