Detection of Echinococcus granulosus G3 in a Wild Boar ( Sus scrofa ) in Central Italy using PCR and Sequencing

Echinococcus granulosus complex infection in wild boar hunters and auxiliary hunting dogs

Cystic echinococcosis (CE) caused by Echinococcus granulosus sensu lato (s.l.) is a zoonotic neglected tropical disease endemic in Italy, which perpetuates in several intermediate hosts, including wild boars, and dogs as definitive hosts. People living in rural and livestock-raising areas are exposed to E. granulosus s.l. infection, as well as people leading outdoor activities in endemic regions. Therefore, this study was designed to assess the exposure to Echinococcus spp. in wild boar hunters, the role of their hunting dogs as parasite reservoirs, along with hunter's knowledge on the infection risk. From December 2022 to May 2023, wild boar hunters (n = 122) from southern Italy were recruited on volunteer basis for blood and serum sampling and a questionnaire enquiring socio-demographic, anamnestic data and knowledge on CE was also filled out. Sera were tested for Echinococcus spp. IgG by a commercial enzyme-linked immunosorbent assay (Euroimmun ELISA®, Germany). In addition, faecal samples from their hunting dogs (n = 208) were screened for Taeniidae eggs by parasitological and molecular approaches. Overall, six (4.9 %) hunters scored either positive or borderline for IgG anti-Echinococcus spp., of which one presented a calcified hepatic cyst at abdominal ultrasonography. In addition, 6.3 % Taeniidae prevalence was recorded in faecal samples (13/208) of hunting dogs, and E. granulosus sensu stricto (s.s.) was molecularly identified in two samples. The statistical analysis revealed the risk factors (odds ratio > 1, p < 0.05) associated with parasitic exposure, including the hunter geographical provenience, and the presence of animals around or in the house. The E. granulosus s.l. exposure of hunters herein detected, coupled with the parasite molecular positivity of their hunting dogs and the limited awareness on Echinococcus spp. life cycle/infection risk, highlight the relevance to promote health surveillance and educational programs within the hunting category, for minimizing the cestode circulation in the wildlife-urban premises.

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.

Molecular Screening of Echinococcus spp. and Other Cestodes in Wild Carnivores from Central Italy

Tapeworm infections are among the most relevant parasitic diseases in humans and animals. Tapeworms from the Genus Echinococcus are particularly important as they can cause cystic or alveolar echinococcosis. A molecular screening was performed on 279 fecal samples collected from carcasses of wild carnivores from Central Italy using PCR targeting diagnostic fragments of nad1, rrnS, and nad5 genes. Samples positive for either Taenia spp. or Echinococcus granulosus were sequenced to taxonomically identify the parasitic DNA. Of the 279 samples, 134 (48.0%) gave positive results in the multiplex PCR. Only one (0.4%) sample from an Apennine wolf tested positive for Echinococcus granulosus sensu stricto (genotype G3), whereas no sample tested positive for E. multilocularis. The most frequently detected tapeworms were: Mesocestoides corti (syn M. vogae) (12.9%), M. litteratus (10.8%), Taenia serialis (9.3%), and T. hydatigena (6.5%), other tapeworms were rarely detected. The results suggest that Echinococcus infections in Central Italy do not seem to be sustained by sylvatic cycles, confirming the absence of E. multilocularis in Central Italy. The survey corroborates, yet again, the importance of passive surveillance of wild animals that can serve as reservoirs for zoonotic pathogens, especially on wild canids that in other areas are strongly implicated in the transmission of E. granulosus and E. multilocularis.

Parasitic cysts in wild boars hunted in Central Italy: The sanitary controls in the wild game meats chain

Seven hundred sixty-five (765) adult wild boars were examined during the 2016/2017 hunting season for the research of parasites. Post mortem inspection was carried out at the slaughterhouse by the Official Veterinarian on the plucks (heart, tongue, lungs, diaphragm, and liver) of the killed animals presented by hunters. Of these, 0.8% (6/765) were positive for Echinococcus granulosus sensu lato (s.l.), and 2.6% (20/765) were positive for the metacestode stage of Taenia hydatigena (Cysticercus tenuicollis), while 0.5% (4/765) animals showed a mixed infection (Echinococcus granulosus s.l. and Taenia hydatigena). Sixty-three (63) cystic lesions were found. Of these 25,4% (16/63) were caused by Echinococcus granulosus s.l. and 74,6% (47/63) were caused by Cysticercus tenuicollis. The more involved organs were liver and lungs, in a less extension omentum and diaphragm. Parasitological analyses showed an overall prevalence of 3.9% for metacestodes in the hunted animals examined (Paoletti et al., 2018). Hydatids were molecularly characterized as E. granulosus sensu stricto. Trichinella spp. examination results showed no evidences of parasitic cysts. The products of hunting used for own consumption and direct sale to the final consumer or retailer, according to Regulation (EC) No 853/2004, lack of overall control by the Competent Authority. This is a critical point in the food chain of the game meat. The data obtained show the importance of the post mortem inspection and the central role of the Competent Authority to ensure not only the food safety of game meat but also to collect data for extensive epidemiological investigations on live-stocks wildlife settings having a direct impact on public health.

First Report of Echinococcus ortleppi in Free-Living Wild Boar (Sus scrofa) from Portugal

Cystic echinococcosis (CE) is a zoonosis that is prevalent worldwide. It is considered endemic in Portugal but few studies have been performed on Echinococcus granulosus sensu lato and their hosts. In this study, CE cysts are reported for the first time in a free-living wild boar (Sus scrofa) in Portugal. The presence of the metacestodes in the liver of the wild boar was identified by morphological features, microscopic examination and molecular analysis. The sequencing of part of the DNA nuclear ribosomal internal transcribed spacer-1 (ITS-1) region revealed a G5 genotype that presently corresponds to Echinococcus ortleppi. This is the first report of E. ortleppi in Portugal and to the best of the authors’ knowledge, in Europe. These results suggest that wild boar may be a host of CE, namely, crossing the livestock–wildlife interface, which has important public health implications. Wildlife reservoirs must be taken into account as CE hosts and surveillance of game as well as health education for hunters should be implemented using a One Health approach, with implementation of feasible and tailor-made control strategies, namely, proper elimination of byproducts in the field.

Taeniid cestodes in a wolf pack living in a highly anthropic hilly agro-ecosystem

The Italian wolf population in human-modified landscapes has increased greatly in the last few decades. Anthropisation increases the risk of transmission of many zoonotic infections and in this context, control of taeniid cestode species needs to be addressed from a One Health perspective. Predator-prey interactions are at the root of taeniid cestode transmission, and the wolf plays a key role in the maintenance and transmission of taeniids. To date, all available data on the taeniids of wolves in Italy refer to populations living in a wild habitat. Between 2018 and 2019, we investigated taeniids in a wolf pack living in a highly anthropic hilly agro-ecosystem. Thirty-eight faecal samples were collected and analysed, 4 of which were also genetically characterised for individual wolves and belonged to three different animals. Samples collected were analysed microscopically and by molecular analysis in order to identify the taeniid species. Taeniid eggs were detected in 34.2% (13/38) of samples. Within samples positive to taeniid eggs only Echinococcus granulosus s.s. and Taenia hydatigena were identified in 26.3% and 10.5% of the samples, respectively. On microscopic examination, Capillaria spp., Ancylostomatidae and Toxocara canis eggs, Crenosoma vulpis larvae, and coccidian oocysts were also found. The combination of low biodiversity of taeniid species with a high occurrence of E. granulosus s.s. recorded in this study could be the consequence of a deeper link occurring between wolves and livestock in human-modified landscapes than in wild settings.

Dispersal and molecular characterisation of the Echinococcus granulosus (Batsch, 1786) complex isolated from various intermediate hosts in the Calabria region, southern Italy

Cystic echinococcosis (CE) is a zoonotic disease caused by the tapeworms of the Echinococcus granulosus sensu lato complex, which have worldwide distribution. No data on the circulation of genotypes of the E. granulosus complex in intermediate hosts in endemic areas in Calabria are available. The aims of our study were to evaluate the dispersal of genotypes of the E. granulosus complex in Calabria and to characterise parasite isolates by Sanger sequencing and phylogenetic analysis. We collected 71 animal samples from pigs, wild boars, sheep, cattle and goats. The first PCR screening analysis targeted three partial genomic regions: the cytochrome c oxidase subunit 1 (cox1), calreticulin protein (cal) and NADH dehydrogenase subunit 1 (nad1); this identified 28 parasitic cysts. Bidirectional sequencing of cox1 amplicons and phylogenetic analysis allowed us to characterise all isolates. Molecular analyses of 28 newly generated cox1 sequences revealed that most wild boars (n = 16) and three pigs were parasitised by the larval stage of Taenia hydatidena Pallas, 1766, called cysticercus tenuicollis. Two isolates from wild boars were identified as Echinococcus canadensis Webster and Cameron, 1961 (G7), while five sheep and two goats were infected with E. granulosus G1 (sheep strain) and G1 microvariant (previously reported as G2 genotype or Tasmanian sheep strain), respectively. These molecular findings should prompt further and more extensive studies, to elucidate regional transmission patterns and to guide control programs.

Detection of selected pathogens in Apennine wolf (Canis lupus italicus) by a non-invasive GPS-based telemetry sampling of two packs from Majella National Park, Italy

In this study, a multi-pathogens survey was conducted to verify the sanitary status of two Italian wolf packs of Majella National Park. Twenty fecal samples (10/pack) were collected using a sampling protocol, based on the combining data from radio-collared wolves with geographic information system (GIS) analysis, allowing to mark off the home range of packs and to recover group-specific and high-quality specimens. Virological screening against the most prevalent canine viruses (protoparvovirus, distemper virus, adenoviruses, and coronaviruses) was carried out by molecular methods, while parasites were detected by means of copromicroscopic and molecular analysis. Canine parvovirus type 2b (CPV-2b) is the most prevalent virus in both packs (7/20), followed by canine adenovirus type 2 (CAdV-2), while no sequences of canine distemper virus and coronaviruses were detected. The sequence analysis of the viruses demonstrated the domestic origin of the infection, highlighting the importance of vaccination of local dogs in order to reduce the risk of exposure of wildlife to these pathogens. Fourteen samples resulted positive for parasites. Capillaria aerophila (sin. Eucoleus aerophilus), Ancylostoma/Uncinaria, Trichuris vulpis eggs, Sarcocystis spp., Cystoisospora canis, and Angiostrongylus vasorum larvae were identified. Echinococcus granulosus sensu stricto (ovine genotype G1) and Giardia duodenalis(canid-specific Assemblage C) were also characterized, providing insights into the wolves' diet and their effects on environmental contamination. The sampling protocol applied in this study, based on a multidisciplinary approach, represents an innovative tool for the survey of Apennine wolf, able to integrate sanitary data with the ecological and demographic features of this population.

Cystic echinococcosis in wild boars (Sus scrofa) from southern Italy: Epidemiological survey and molecular characterization

Cystic Echinococcosis (CE) caused by Echinococcus granulosus sensu lato (s.l.) is one of the most important parasitic zoonotic diseases in the world and it represents an important public health and socio-economic concern. In the Mediterranean basin, CE is widespread and it is endemic in Italy, with major prevalence in southern areas. Several studies have investigated CE in domestic pigs, however, such data in wild boars are scant. In the last decades the wild boar population in Italy has increased and this ungulate could play an important role in the spreading of CE in the wild. Here we report on the prevalence and fertility rate of hydatid cysts in wild boars that were shot during two hunting seasons (2016-2017) in the Campania region of southern Italy. For each animal, a detailed inspection of the carcass and organs (lungs, liver and spleen) was performed and when cysts were found, their number, morphology and fertility were determined by visual and microscopic examination. Cysts were classified morphologically as fertile, sterile, caseous and calcified. Protoscoleces and germinal layers were collected from individual cysts and DNA was extracted to identify different strains/genotypes of E. granulosus s.l. Out of a total of 2108 wild boars 93 (4.4%) were found positive for CE. Infected animals were 45 males and 48 females, aged between 1 and 8 years. The average number of cysts per wild boar was 1.3 (min 1 - max 13). The total number of cysts collected was 123, of which 118 (95.9%) in the liver, 4 (3.3%) in the lungs and 1 (0.8%) in the spleen. Of all analyzed cysts, 70 (56.9%) were fertile and 53 (43.1%) sterile/acephalous. The presence of fertile cysts in 19.4% of CE-positive animals is noteworthy. Overall, molecular diagnosis showed 19 wild boars infected with the pig strain (G7).

Epidemiological survey on cystic echinococcosis in wild boar from Central Italy

Despite the wide distribution of wild boar populations in Italy and the increase of its diffusion in urbanized areas, only one case report has described the occurrence of Echinococcus granulosus s.l. in a wild boar from Marche (Central Italy). The present study investigated the presence of E. granulosus sensu lato with an epidemiological survey on wild boars from central Italy that had been killed during hunting season. Seven hundred sixty-five (765) adult wild boars were examined during the 2016-2017 hunting season. Of these animals, 1.0% (8/765) were positive to E. granulosus s.l. with a fertility of 0.3% (2/765), and 2.9% animals (22/765) were positive for the metacestode stage of Taenia hydatigena (Cysticercus tenuicollis), while 0.5% (4/765) showed mixed infection (E. granulosus s.l. + T. hydatigena). Sixteen hydatids were found, of which 12.5% were fertile, 37.5% were sterile, 31.3% were caseous, and 18.8% were calcified. Eight hydatids (two fertile and six sterile cysts) were molecularly characterized by analysis of the mitochondrial gene, cytochrome c oxidase subunit 1 (cox1), and the NADH dehydrogenase subunit 1 (ND1). Hydatids found in wild boars were characterized as E. granulosus sensu stricto (G1 genotype). The present survey represents the first epidemiological study on cystic echinococcosis in wild boar in Italy which highlights the need for more extensive epidemiological investigations to determine the causal factors, economic impact, and public health importance of the disease in this livestock-wildlife setting.