Introduction
The Brazilian Cerrado, the country’s second-largest biome after the Amazon, is located in the states of Goiás, Distrito Federal, part of Minas Gerais, Rondônia, Mato Grosso, Mato Grosso do Sul, Bahia, Tocantins, Maranhão, Piauí and Pará. This biome occupies around 23% of the national territory and is home to one-third of Brazil’s biodiversity (Santos et al., Reference Santos, Barbieri, Carvalho and Machado2010; Resende, Reference Resende2012). Emphasizing the importance of conserving this biome, despite the fact that deforestation for agricultural activities, the advancement of cities under native fauna and uncontrolled fires threaten its integrity (Alves-Junior et al., Reference Alves-Junior, Taveira, Evangelista, Casaroli and Barbosa2013). The same problems affect the Pantanal biome located in Mato Grosso and Mato Grosso do Sul, which contains the largest floodplain in the world (Souza and Souza, Reference Souza and Souza2010). In addition, the abundance of wild species in the Cerrado and Pantanal, for example, is constantly threatened by the increasing number of cattle every year (IBGE, Instituto Brasileiro de Geografia, 2022). Some human activities, such as cattle breeding and hunting, can increase the contact between wild animals, domestic animals and humans. The cattle occupy lands that were once occupied by wild animals; hunters use dogs to sniff and assist during the hunt (Arana et al., Reference Arana, Ponce-Noguez, Reyes-Rodríguez, Vega-Sánchez, Zepeda-Velázquez, Martínez-Juárez and Gómez-De-Anda2021). These practices narrow the relationship among wild and domestic animals; these environments can be disturbed when parasites from wild animals infect domestic animals and humans due to the closer relations between these groups (Campos et al., Reference Campos, Barbosa, Oliveira, Tavares, Cravo and Ostermayer2017; Souza et al., Reference Souza, Silva-Assis, Alves-Rieiro, Moraes, Alves-Sobrinho, Saturnino, Ferraz, Machado, Braga and Ramos2023).
Parasites are commonly found in wild animals, since they are not treated as frequently as domestic animals. Although parasites may be a burden to their individual hosts, they are essential for ecosystem dynamics (Gómez and Nichols, Reference Gómez and Nichols2013) and play an important role in population control (Leclaire and Faulkner, Reference Leclaire and Faulkner2014). Therefore, understanding the dynamics and parasitic constituents of wildlife is a valuable tool for predicting and assessing zoonotic risks (Gałęcki et al., Reference Gałęcki, Sokół and Koziatek2015). Despite the knowledge about the relevance of parasites to wildlife dynamics and their implications for human health, there are many gaps to be explored and understood regarding parasitic fauna that infect wild mammals, especially those in tropical climates (Hewavithana et al., Reference Hewavithana, Wijesinghe and Udagama2021).
The order Artiodactyla includes 2 separate families of swine: Tayassuidae and Suidae. The Brazilian Midwest shelters specifically Tayassu pecari, Dicotyles tajacu and Sus scrofa (wild boar), which have particular prominence related to their interactions with the wild fauna. The peccary (T. pecari), native to Brazil, can range from tropical forests to the Cerrado and Caatinga biomes, as well as subtropical areas such as prairies (Castro et al., Reference Castro, Brombila, Bersano, Soares, Silva, Minervino, Ogata, Gennari and Richtzenhain2014). The collared peccary (D. tajacu), also native to Brazil, is widely distributed from the southern United States to northern Argentina (Pereira-Junior et al., Reference Pereira-Junior, Sousa, Oliveira, Valadares, Hoppe and Almeida2016). The wild boar S. scrofa arrived in South America as an invasive species, introduced by humans in 1904 for hunting (Piórkowska and Ropka-Molik, Reference Piórkowska and Ropka-Molik2021; IBAMA, Instituto Brasileiro do Meio Ambiente e dos Recursos Naturais Renováveis, 2025). They are now largely distributed in Brazilian territory, being present in 22 of the 27 states of the federation (Brasil, 2024b). They originate from Eurasia and northern African, and thus, without natural predators that can control their population in South America, their population only increases (Oliveira, Reference Oliveira2012).
The expansion of wild boar populations, along with the increasing anthropization of natural habitats, has led to a rise in conflicts or perhaps encounters between humans and both native and domestic animals (Sütő et al., Reference Sütő, Heltai and Katona2020). The contact between wild boars and local species is of zoonotic importance, because wild boars act as hosts for different infectious agents and parasites, such as brucellosis and ascariasis (Dodangeh et al., Reference Dodangeh, Azami, Daryani, Gholami, Sharif, Mobedi, Sarvi, Soleymani, Rahimi, Pirestani, Gohardehi and Bastani2018; Severo et al., Reference Severo, Werlang, Mori, Baldi, Mendes, Surian, Coldebella, Kramer, Trevisol, Gomes and Silva2021). Invasive species represent a risk to local biodiversity by transmitting pathogens to endemic species, a process known as spillover. In contrast, invasive species can act as amplifiers for endemic parasites, promoting the dispersion and increase in abundance of these species in a process called spill-back (Lapera, Reference Lapera2020). The invasive species also compete with local species due to sharing an ecological niche, which occurs mainly due to dietary overlap, leading to competition (Oliveira, Reference Oliveira2012; Lima et al., Reference Lima, Butti, Miotto, Silva and Berlinck2022).
The species S. scrofa, D. tajacu and T. pecari were used in this study. Most of the research involves S. scrofa because of its worldwide distribution (Dodangeh et al., Reference Dodangeh, Azami, Daryani, Gholami, Sharif, Mobedi, Sarvi, Soleymani, Rahimi, Pirestani, Gohardehi and Bastani2017; Arana et al., Reference Arana, Ponce-Noguez, Reyes-Rodríguez, Vega-Sánchez, Zepeda-Velázquez, Martínez-Juárez and Gómez-De-Anda2021; Belov et al., Reference Belov, Tabakaeva, Pankratov, Shchelkanov, Surovyi, Popov, Tabakaev, Zheleznova and Galkina2022). The other 2 species are native to America and are being devastated by the presence of wild boars and food competition (Lapera, Reference Lapera2020; Lima et al., Reference Lima, Butti, Miotto, Silva and Berlinck2022). Another problem about study of this species is that scientific names can change during the time which hinders the collection of information, D. tajacu, for example, was used to be Pecari tajacu (Pereira-Junior et al., Reference Pereira-Junior, Sousa, Oliveira, Valadares, Hoppe and Almeida2016). The same helminths described in D. tajacu include Moniezia benedeni, Dirofilaria acutiuscula, Eucyathostomum dentatum, Gongylonema baylisi, Monodontus semicircularis, Nematodirus molini and Oesophagostomum dentatum (Vicente et al., Reference Vicente, Henrique, Gomes and Roberto1997; Pereira-Junior et al., Reference Pereira-Junior, Sousa, Oliveira, Valadares, Hoppe and Almeida2016; Justo et al., Reference Justo, Fernandes, Knoff, Cardenas and Cohen2017). In T. pecari, the parasites include Monoecocestus decrescens, Ascaris sp., Paragonimus sp., Trypanosoma cruzi, Toxoplasma gondii, and Oligacanthorhynchus major (Gomez-Puerta, Reference Gomez-Puerta2011; Justo et al., Reference Justo, Fernandes, Knoff, Cardenas and Cohen2017; Morais et al., Reference Morais, Domingues, Oliveira, Paula, Listoni and Ribeiro2017).
The development of research related to wild animals is a challenge in Brazil. Most of the resources are destined for the agriculture sector: being birds, ruminants and fishes the ranking of animals used for teaching and research (CONCEA, Conselho Nacional de Controle de Experimentação Animal, 2024). Working with wild animals comes up against several ethical and legal aspects. Brazilian legislation is quite rigid about the use, manipulation and displacement, even of corpses, being necessary licenses and authorizations specific to study and area (Brasil, Ministério da Justiça, 2008; Nomura, Reference Nomura2012; IBAMA, 2013). Moreover, some species are threatened with extinction or considered vulnerable, which makes it difficult to get permission to manipulate the animal (Gongora et al., Reference Gongora, Reyna-Hurtado, Beck, Taber, Altrichter and Keuroghlian2011; Keuroghlian et al., Reference Keuroghlian, Desbiez, Reyna-Hurtado, Altrichter, Beck, Taber and Fragoso2013).
The current ecological scenario in the Brazilian Cerrado, resulting from habitat sharing with wild species, has allowed the entry of new hosts into established parasitic cycles. This study aims to (1) report the occurrence of helminths in wild boars and peccaries in the Cerrado and Pantanal biomes of Brazil’s Midwest region and (2) assess the zoonotic potential of the identified helminth species, helping to address existing knowledge gaps regarding parasitic infections in these animals.
Materials and methods
Animals and ethical statement
Four gastrointestinal tracts of S. scrofa slaughtered by hunters under the population control measures of the Brazilian Defense Ministry (concession No. 7479935) were analysed. The carcasses of 5 T. pecari and 1 D. tajacu, which were killed in fires or by being run over on highways in the Midwest, were collected and assessed for parasites, with permission from SISBIO (approval No. 84201-3) between 2021 and 2024. Seven animals were referred by the Wildlife Triage Center after death to necropsy in the laboratory of pathology in Mato Grosso, Brazil.
Parasitological assessments in intestinal loops
Each animal intestinal loop was inspected during a parasitological necropsy divided in 2 stages: (1) parasites that were visible to the naked eye in the loops and faecal contents were removed and (2) the intestinal contents were washed and filtered through a 0.075-mm sieve, and the retained material was inspected in a Petri dish under a stereoscopic light microscope to obtain any microscopic parasites. The collected parasites were preserved in 70% ethanol (v/v), and the helminths were identified on temporary slides with either 50% glycerol (v/v) or lactophenol solution (Dinâmica) or 90% phenol solution (v/v, Dinâmica) according to the thickness of the helminth (Hoffmann, Reference Hoffmann1987). The parasites were identified using the taxonomic keys of Vicente et al. (Reference Vicente, Henrique, Gomes and Roberto1997), Anderson et al. (Reference Anderson, Chabaud and Willmott2009), Gibbons (Reference Gibbons2010) and Richardson and Barger (Reference Richardson and Barger2006). The mean intensity (MI) of each helminth species in each host was calculated, as described by Bush et al. (Reference Bush, Lafferty, Lotz and Shostak1997).
Host–parasite network analysis
Two node centrality statistics (degree and betweenness) were calculated to infer species roles and estimate their importance in the host–parasite network structure (Newman, Reference Newman and Newman2018). Degree centrality refers to the number of direct connections a node has with other nodes in the network and betweenness centrality refers to the number of times a node is on the shortest path between all other nodes, being important to determine how much a species intermediates the connection between all other species (Newman, Reference Newman and Newman2018). These centrality metrics were calculated using the igraph package (Csardi and Nepusz, Reference Csardi and Nepusz2006) in the software R version 4.5.0 (R Core Team, 2025).
A host–parasite interaction network was constructed to describe the interaction patterns between species, considering abundance values of each parasite species in a given host species. The nodes represent the host and parasite species, and the links between the nodes represent the observed interactions between the species. The network representation was built using the software Gephi 0.9.2 (Bastian et al., Reference Bastian, Heymann and Jacomy2009).
Results
Pecarie and wild boars in the Brazilian Cerrado are highly parasitized
The parasitological necropsies revealed the presence of at least 1 parasite species in >70% of the 17 intestinal loops assessed in this study (3 S. scrofa, 12 T. pecari and 1 D. tajacu). Three specimens of S. scrofa were positive for Ascaris suum (n = 2; MI = 4) and Monodontus rarus (n = 1; MI = 66). Eight T. pecari were positive for A. suum (n = 2; MI = 1), Lagochilascaris minor (n = 1; MI = 1), Strongyloides spp. (n = 1; MI = 15), Monodontus semincircularis (n = 3; MI = 1,37), Eucyathostomum dentatum (n = 1; MI = 5) and Oligacanthorhynchus major (n = 3; MI = 2). The distribution of parasitized and non-parasitized animals is shown in Figure 1. The single D. tajacu assessed was positive for Ascarops strongylina (n = 1; MI = 1). Representative examples of morphological characteristics of the specimens: L. minor, M. semicircularis, A. strongylina and M. rarus are shown in Figure 2.
Figure 1. Map of the distribution of Suidae and Tayassuidae positive and negative for helminths in the Central-West of Brazil. Municipalities and states: Po – poconé, Mato Grosso; Se – Serranópolis, Goiás; Cp – Caiapônia, Goiás; Ja – Jataí; Ca – Caçu.
Figure 2. Anterior part of nematodes found in Suidae and Tayassuidae in Central-West Brazil: (A) Lagochilascaris minor; (B) Monodontus semicircularis showing buccal capsule devoid of teeth or plates but with ventral blades according to Vicente et al. (Reference Vicente, Henrique, Gomes and Roberto1997); (C) esophagus of M. semicircularis; (D) Ascarops strongylina; (E) Monodontus rarus with 3 ventral blades according to Vicente et al. (Reference Vicente, Henrique, Gomes and Roberto1997); (F) esophagus of M. rarus.
All parasites were deposited in the helminthological collection of the Universidade Federal de Jataí, Brazil (CHUFJ). The number of samples is presented in Table 1, along with the data from positive animals and co-infections.
Table 1. Occurrence of helminths in wild boars (Sus scrofa), peccary (Tayassu pecari) and collared peccary (Dicotyles tajacu) from the Brazilian Cerrado and Pantanal biomes
Parasites sharing
We observed a greater diversity of parasite species in T. pecari. There is low sharing of parasites between hosts (Figure 3), indicating that parasites tend to be specialized in certain groups of hosts. Thus, there is less sharing of parasites between hosts. It is noted that the only species shared between the host species was A. suum. It was observed that the host species with the greatest importance in the network is T. pecari, and the parasite species with the greatest importance was A. suum (Figure 4). The higher values of network degree and betweenness centrality for T. pecari suggest that this species has greater potential to transmit parasites in the network compared to the other species. In turn, the greater degree of network and betweenness-centrality for A. suum suggests that this species has greater potential to disperse between hosts.
Figure 3. Distribution of parasite species in relation to hosts where 2 clades were identified with the sharing of parasite species between Tayassu pecari and Sus scrofa, and Dicotyles tajacu in a single clade. Thickness of the lines demonstrates a greater abundance of parasites found in the parasite–host interaction.
Figure 4. Network centrality. (A) Degree of species by host and by parasites; (B) centrality of species by hosts and by parasites.
Discussion
The geolocalization of wild hosts in this investigation and the parasitic helminths they are infected with are congruent with reports of same infections in domestic animals, namely dogs and cats, thereby reinforcing the zoonotic aspects of these parasites (Souza et al., Reference Souza, Silva-Assis, Alves-Rieiro, Moraes, Alves-Sobrinho, Saturnino, Ferraz, Machado, Braga and Ramos2023). In certain regions of Brazil, including in the Cerrado, animals such as pigs and tayassuids are bred and kept close to humans. This close interaction between humans and these animals increases the opportunities for parasite transmission (Andrade et al., Reference Andrade, Silva, Duarte, Canto, Costa, Oliveira, Monteiro, Bomfim, Oliveira-Pereira, Pereira-Filho, Oliveira, Rodrigues and Sousa2009).
Free-living animals such as S. scrofa, T. pecari and D. tajacu are continually exposed to a diverse range of parasites in both natural and anthropogenic environments. The nematode A. suum was first reported in Brazilian peccaries in the 1940s, and it is widely distributed throughout South America (Carlos et al., Reference Carlos, Tantaleán, Leguía, Alcázar and Donadi2008; Quiñajo et al., Reference Quiñajo, Nallar-Gutierrez and Alandia-Robles2014). It is commonly found in domestic pigs and can damage the economy of pork production systems (Fausto et al., Reference Fausto, Oliveira, Fausto, Carvalho, Valente, Campos and Araújo2015). Ascaris suum has been found in S. scrofa and T. pecari (Belov et al., Reference Belov, Tabakaeva, Pankratov, Shchelkanov, Surovyi, Popov, Tabakaev, Zheleznova and Galkina2022), and many studies have reported its occurrence in S. scrofa worldwide (Hälli et al., Reference Hälli, Ala-Kurikka, Peltoniemi and Heinonen2010; Popiolek et al., Reference Popiolek, Knecht, Szczesna-Staskiewick and Czerwinska-Rozalow2010; Silva and Muller, Reference Silva and Muller2013; Gassó et al., Reference Gassó, Feliu, Ferre, Mentaberre, Casas-Díaz, Velarde, Fernández-Aguilar, Colom-Cadena, Navarro-Gonzalez, López-Olvera, Santiago, Fernéndez-Llario, Segalés and Serrano2015; Dodangeh et al., Reference Dodangeh, Azami, Daryani, Gholami, Sharif, Mobedi, Sarvi, Soleymani, Rahimi, Pirestani, Gohardehi and Bastani2017). In humans, it can cause symptoms such as a cough, headache, diarrhoea and respiratory discomfort owing to the migration of larvae in the lungs (Silva et al., Reference Silva, Barbosa, Magalhães, Gazzinelli-Guimarães, Dos Santos, Nogueira, Resende, Amorim, Gazzinelli-Guimarães, Viana, Geiger, Bartholomeu, Fujiwara and Bueno2021).
In the present study, A. suum was found in 2 different hosts, which suggests its potential dispersion among both native and invasive species (Sus scrofa). The increased interactions between these species, humans and domestic animals pose a risk to human health, livestock health and economy, and wildlife ecology. The populations of wild boar increase every year; therefore, the hunting of S. scrofa for population control was allowed by law (January legislation; Brasil, 2024a). Such measures should reduce the contact of wild boars with humans, but the effect on parasite transmission must be assessed.
We also identified Strongyloides spp. belonging to the superfamily Rhabditoidea. Members of this genus are characteristically host-specific, infecting a diverse range of domestic animal species worldwide (Thamsborg et al., Reference Thamsborg, Ketzis, Horii and Matthews2016; Jones et al., Reference Jones, Lall and Garcia2019). However, some species can parasitize humans, non-human primates and wild canids (Thamsborg et al., Reference Thamsborg, Ketzis, Horii and Matthews2016). In addition, Strongyloides spp. affect wild and domestic pigs, as well as Tayassuidae (Nascimento, Reference Nascimento2004; Gomes et al., Reference Gomes, Bonutti, Almeida and Nascimento2005; Brandão et al., Reference Brandão, Chame, Cordeiro and Chaves2009; Sampaio et al., Reference Sampaio, Sianto, Chame, Saldanha and Brener2023). In domestic pigs, 5spp. cause a decrease in feed conversion, causing losses in pork production (Hale and Marti, Reference Hale and Marti1984). Clinical signs are more frequent in young animals because of their immature immune systems. Notably, parasitized female pigs act as a reservoir, disseminating the parasite to their offspring. Parasitism at the beginning of a piglet’s life predisposes them to other infections (Jacobson, Reference Jacobson2022). In domestic pigs, females tend to store the larvae of Strongyloides spp. in adipose tissue, eliminating them in colostrum or milk (Thamsborg et al., Reference Thamsborg, Ketzis, Horii and Matthews2016). Considering the parasite cycle, as known in domestic pigs, and the importance of the females for the dissemination of this parasite to offspring, we suggest that the same can happen in wild swine and Tayassuidae. Although to confirm this hypothesis, further studies must be conducted.
The genus Eucyathostomum, identified by Molin in 1861, comprises 3 main species: E. dentatum, E. longesubulalum and E. copulatum. The specimens of E. dentatum used to originally describe the species were coincidentally also isolated from a D. tajacu. During the original description of the species, only a small number of gastrointestinal tract parasites were found in the host, and this is similar to the findings of the present study, as only 5 parasites were found in the peccary. Moreover, many studies have reported such infection in Tayassuidae from Brazil and other countries in South America (Nascimento et al., Reference Nascimento, Hoppe and Mapeli2005; Pereira-Junior et al., Reference Pereira-Junior, Sousa, Oliveira, Valadares, Hoppe and Almeida2016; Quiñajo et al., Reference Quiñajo, Nallar-Gutierrez and Alandia-Robles2014; Jones et al., Reference Jones, Lall and Garcia2019). Our results reinforce the notion that D. tajacu is a highly adapted host to E. dentatum, as previous studies have also identified the same infection in D. tajacu in the Amazon and Pantanal regions of Brazil (Nascimento et al., Reference Nascimento, Hoppe and Mapeli2005; Pereira-Junior et al., Reference Pereira-Junior, Sousa, Oliveira, Valadares, Hoppe and Almeida2016).
Lagochilascaris minor is an ascarid that belongs to the genus Lagochilascaris, which includes 7 distinct species. Rodents act as intermediary hosts by the development of the parasite in their musculature. This specimen deserves attention because of its host range, which includes humans and carnivores that consume the intermediary hosts (Campos et al., Reference Campos, Barbosa, Oliveira, Tavares, Cravo and Ostermayer2017; Trindade et al., Reference Trindade, Macedo, Drehmer and Muller2019; Cupertino et al., Reference Cupertino, Resende, Mayer, Carvalho and Siueira-Batista2020). To the best of our knowledge, this is the first report of L. minor in T. pecari, as it is typically found in felids and canids. Brazil has the highest number of previously described cases of L. minor in humans worldwide (Campos et al., Reference Campos, Barbosa, Oliveira, Tavares, Cravo and Ostermayer2017). Human lagochilascariasis is an emerging zoonotic disease caused by the consumption of infected game meat with transmission risk supported by the strengthening relationships between wild and domestic animals and humans, owing to habitat sharing (Barrera-Pérez et al., Reference Barrera-Pérez, Manrique-Saide, Reyes-Novelo, Escobedo-Ortegón, Sánchez-Moreno and Sánchez2012; Falcón-Ordaz et al., Reference Falcón-Ordaz, Iturbe-Morgado, Rojas-Martínez and Garcia-Prieto2016; Trindade et al., Reference Trindade, Macedo, Drehmer and Muller2019; Cardoso et al., Reference Cardoso, Neves and Amarante2020). Clinical signs of this disease in humans are related to the parasite location. For example, these parasites cause skin lesions that can be confused with abscess. However, erratic migration can lead to their presence in the host nervous system, lungs, sacral region, eyes and oral cavity (Campos et al., Reference Campos, Barbosa, Oliveira, Tavares, Cravo and Ostermayer2017).
Contamination by L. minor can occur through the consumption of raw or undercooked meat from contaminated animals, such as ungulates, rodents and Tayassuidae, which possibly act as intermediate hosts for this parasite. However, L. minor life cycle has not been completely elucidated (Barrera-Pérez et al., Reference Barrera-Pérez, Manrique-Saide, Reyes-Novelo, Escobedo-Ortegón, Sánchez-Moreno and Sánchez2012).
The increase in cases of L. minor infection in different animal species may be related to the migration of prey and predators across different ecosystems, as this allows for the translocation of the parasite, leading to soil contamination in different regions (Campos et al., Reference Campos, Barbosa, Oliveira, Tavares, Cravo and Ostermayer2017). Therefore, the T. pecari infected in the present study may play a new role as a definite host for this species, a role originally predominating to carnivores (Reis et al., Reference Reis, Mangoni, Mattos and Marques2011; Falcón-Ordaz et al., Reference Falcón-Ordaz, Iturbe-Morgado, Rojas-Martínez and Garcia-Prieto2016; Trindade et al., Reference Trindade, Macedo, Drehmer and Muller2019).
The genus Monodontus, first identified in wild boars in 1861 by Molin in Brazil (Travassos, Reference Travassos1937), includes several species, including M. semicircularis, M. aguiari, M. nefastus and M. rarus, with peccaries, agoutis, tapirs and rodents as their main hosts, respectively. Monodontus semicircularis was previously identified in peccaries and D. tajacu (Pereira-Junior et al., Reference Pereira-Junior, Sousa, Oliveira, Valadares, Hoppe and Almeida2016). This is consistent with the present study, as the original sample used to describe M. semicircularis was from a T. pecari specimen. Monodontus rarus was described in the rodent Euryzygomatomys guiara, and this is the first report of M. rarus in S. scrofa. The literature about this helminth is scarce; therefore, little is known regarding its epidemiology.
Ascarops strongylina, belonging to Ascaropsinae, uses the dung beetle as an intermediate host. Reported in D. tajacu in Brazil by Nascimento et al. (Reference Nascimento, Hoppe and Mapeli2005), this species was also found infecting S. scrofa (De-La-Muela et al., Reference De-La-Muela, Hernández-de-Luján and Ferre2001; Perin et al., Reference Perin, Lapera, Arias-Pacheco, Mendonça, Oliveira, Souza Pollo, Santos Silva, Tebaldi, Silva and Lux-Hoppe2023), pigs (Sharma et al., Reference Sharma, Shingh, Shingh and Rath2020), bats (Shimalov, Reference Shimalov2021) and rodents (Ganzoring et al., Reference Ganzoring, Batsaikhan, Ganzoring, Batsaikhan, Oku and Kamiya2003). Physocephalus sexalatus is another parasite belonging to the same family, which has already been found in dung beetles, collared peccaries, pigs and wild boars (Samuel and Low, Reference Samuel and Low1970; De-La-Muela et al., Reference De-La-Muela, Hernández-de-Luján and Ferre2001; Arriola et al., Reference Arriola, Gonzalez, Gomez-Puerta, Lopez-Urbina, Garcia and Gilman2014; Corn et al., Reference Corn, Pence and Warren2024). Although most studies have reported A. strongylina in S. scrofa, none were found in the present study, though we did find the species in D. tajacu.
A study in Peru investigated the relationship between these parasites and the occurrence of cysticercosis. Arriola et al. (Reference Arriola, Gonzalez, Gomez-Puerta, Lopez-Urbina, Garcia and Gilman2014) found that there is a relationship between A. strongylina and cysticercosis exposure, likely associated with the consumption of meat, which raises the concern of impact on public health. Only 2 peccaries (8%) presented with co-infection, which is common in wild animals (Karvonen et al., Reference Karvonen, Jokela and Laine2019). The presence of the first parasite may predispose the animal to other concomitant infections (Jacobson, Reference Jacobson2022), and although we did not find cysticerci, the risk mentioned in the literature should serve as a warning to human populations who may consume the meat of these animals.
We identified O. major in 2 peccaries using the description of Brazilian D. tajacu described by Machado-Filho (Reference Machado-Filho1963). Our study corroborates Gomez-Puerta’s (Reference Gomez-Puerta2011) finding related to the same species of peccaries in Peru.
Destruction of the host’s wild habitat for livestock and crop farming, coupled with population growth, leads to random contact between animal and human populations (Gałęcki et al., Reference Gałęcki, Sokół and Koziatek2015), promoting competition for physical and food resources between the Tayassuidae and Suidae. The expansion of the anthropogenic barrier affects parasitic fauna by reducing the number of available hosts. In addition, the reduction in native areas enables more direct contact between species owing to competition for shelter and food, enabling the introduction of new parasites into different species (Weinstein and Lafferty, Reference Weinstein and Lafferty2015).
Based on these findings, it is possible to observe that the same parasites did not make up the parasitic fauna of peccaries, possibly because of the adaptation of the parasites due to a reduction in the population of their preferred host. Another hypothesis is related to the reduction in the physical space available for wild animals due to deforestation (Morais et al., Reference Morais, Domingues, Oliveira, Paula, Listoni and Ribeiro2017), which decreases their geographic range and increases their contact with feces and local waste. Furthermore, it is important to highlight that in some regions of Brazil consumption of meat from wild animals, such as wild boars, peccaries and collared peccaries, is common (Pereira-Junior et al., Reference Pereira-Junior, Sousa, Oliveira, Valadares, Hoppe and Almeida2016; Morais et al., Reference Morais, Domingues, Oliveira, Paula, Listoni and Ribeiro2017), which increases the interaction between parasites from wild animals and humans due to carcass handling and meat consumption, increasing the possibility of being infected with a zoonotic parasite.
Considering the ecological niches, the co-occurrence of taiassuids and suids within the same geographic area provides opportunities for interaction among them. It can be observed that the interaction between taiassuids and suidae occurs due to the occupation of the same geographic area and has a similar diet, as both feed on fruits and vegetables, which can promote the parasitic interaction of helminth communities in both groups (Dodangeh et al., Reference Dodangeh, Azami, Daryani, Gholami, Sharif, Mobedi, Sarvi, Soleymani, Rahimi, Pirestani, Gohardehi and Bastani2017; Lima et al., Reference Lima, Butti, Miotto, Silva and Berlinck2022). Brandão et al. (Reference Brandão, Chame, Cordeiro and Chaves2009) highlighted that the diet range, together with its opportunistic dietary nature, increased the chances of interaction and contact with different parasites. This may be the reason for the diversity of the helminthological fauna in these animals. Therefore, studies on the parasitic fauna of wild animals, as well as the interactions among the environment, parasites and hosts, must be conducted.
In this study, we observed that some species and genera occurred in all 3 host species, strengthening the hypothesis that the parasitic communities in these groups are shared, and when they occur in the same biome with a high level of anthropization, such as the Brazilian Cerrado, they represent a potential risk for humans and domestic animals, serving as spill-backs. Our conclusions are limited by the number of animals assessed; however, it is important to note that such constraints are inherent to working with wild animals. We only work with occasional samples due to ethical principles, where the animal being studied is more valuable alive than dead for research use, especially T. pecari, which is considered a species vulnerable to extinction, and D. tajacu, which is already extinct in some areas of its natural occurrence (IUCN, Internation Union for Conservation of Nature and Natural Resources, 2025). Our network analysis showed greater diversity in T. pecari, which is expected due to the more expansive nature of this host, coexisting well in anthropized environments and invading crops (IBAMA, Instituto Brasileiro do Meio Ambiente e dos Recursos Naturais Renováveis, 2025), behaviour similar to S. scrofa in wild environments, also justifying the presence of a shared species (A. suum), as they share habitats and behaviours. This demonstrates that it has characteristics that allow greater ecological flexibility, such as resistance to immunological barriers or the ability to transmit through different routes. Although a single sample of D. tajacu, A. strongylina, was not reported in other hosts, even those susceptible to parasitism, demonstrating that this parasite may be more associated with less anthropized locations, since D. tajacu avoids locations with a lot of human alteration (IBAMA, Instituto Brasileiro do Meio Ambiente e dos Recursos Naturais Renováveis, 2025).
In conclusion, wild boars and peccaries can be reservoirs and disseminators for different zoonotic parasite species. Notably, this is the first study to report L. minor in T. pecari and M. rarus in S. scrofa. Shared ecological niches and dietary similarities allow Tayassuidae and Suidae to share parasitic fauna. Furthermore, the consumption of meat from these animals, together with the aforementioned factors, increases the zoonotic potential of parasites. It is important to constantly monitor and study these animals to evaluate their relationship with the environment and parasites.
Data availability statement
All data generated are included in this manuscript.
Acknowledgements
The authors thank the Goiás State Research Support Foundation, the Coordination for the Improvement of Higher Education Personnel and the National Council for Scientific and Technological Development for the financial support.
Author contributions
L.F.-S., R.C.P., A.M.-J. and D.G.S.R. performed the conceptualization; L.F.-S., G.O.M., B.S.A.-R., Z.M.A.-S., G.E.S.C., J.V.O.A.A., V.L.B.S., E.A.Z. and I.S.M. carried out the investigation and collection of helminths; H.T.F., M.A.O.V., I.A.B. and D.G.S.R. were responsible for acquiring the sampled individuals and research supplies; I.A.B., K.C.S., R.C.P., E.M.C. and D.G.S.R. were responsible for acquiring financial resources for the research and data validation; T.S.C. was responsible for the formal and statistical analysis of the data; L.F.S., G.O.M., B.S.A.-R., Z.M.A.-S., G.E.S.C., J.V.O.A.A., V.L.B.S., E.A.Z. and I.S.M. wrote the original draft; H.T.F., M.A.O.V., I.A.B., K.C.S., R.C.P., E.M.C., T.S.C. and A.M.-J. revised the final version and R.C.P., A.M.-J and D.G.S.R. supervised and managed the project.
Financial support
The funding was provided by the Goiás State Research Support Foundation (nos 202310267001408 and AUX2024361000033); the Coordination for the Improvement of Higher Education Personnel for the scholarships to L.F.S., B.S.A.-R., Z.M.A.-S., V.L.B.S., I.S.M. and T.S.C; and the National Council for Scientific and Technological Development for the research scholarships to R.C.P., A.M.-J. and D.G.S.R.
Competing interests
The authors declare there are no conflicts of interest.
Ethical standards
Sus scrofa was slaughtered by hunters under the population control measures of the Brazilian Defense Ministry (concession no. 7479935). The carcasses of 5 T. pecari and 1 D. tajacu, which were killed in fires or by being run over on highways in the Midwest, were collected and assessed for parasites, with permission from SISBIO (approval no. 84201-3).
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