Epidemiological survey of infectious agents in free-ranging maned wolves (Chrysocyon brachyurus) in Northeastern Brazil

Abstract

Infectious diseases are one of the most concerning threats to maned wolves (Chrysocyon brachyurus) due to the potential impact on free-ranging populations. The species is currently classified as vulnerable according to the national list of threatened species and occurs mainly in open habitats, such as the Cerrado, a tropical savannah, which comprises its main distribution area in Brazil. In the northeastern region, it occurs in the Cerrado of Bahia, Piauí, Maranhão, and Tocantins states. Therefore, this study aimed to investigate the occurrence of infectious agents in Chrysocyon brachyurus through an epidemiological assessment of free-ranging individuals in western Bahia, specifically in the Barreiras microregion, a Cerrado area intensely fragmented and anthropized by agricultural activity. Eleven specimens were evaluated for serological titration, antigen research, and genetic material research for canine distemper virus (CDV), canine parvovirus (CPV), adenovirus-canine-type 1 (CAdV-1), canine coronavirus (CCoV), Leptospira interrogans and Toxoplasma gondii from 2020 to 2022. In addition to maned wolves, domestic dogs were also evaluated and tested. All maned wolves (100%) evaluated by the dot-ELISA technique exhibited immunoglobulin M (IgM) and seven (64%) exhibited immunoglobulin G (IgG) against CDV and CPV, while 100% exhibited IgG against CDV when using the immunochromatographic technique. Regarding CAdV-1, 90% were seropositive for IgG, while 64% exhibited IgG against T. gondii. Nine dogs from the region were also sampled, and all (100%) exhibited IgM and IgG against CDV and CPV. For IgG against T. gondii and against CAdV-1, 90% of the animals were seropositive. Molecular evaluation yielded negative results for all maned wolves and dogs assessed for CAdV-1, CDV, and T. gondii, as well as the CCoV antigen. These data indicate the occurrence of viral agents and Toxoplasma gondii in maned wolves and dogs, suggesting circulation in both populations.

Introduction

The maned wolf (Chrysocyon brachyurus Illiger, 1815) is the largest canid in South America. It is currently threatened, mainly by habitat loss and alteration due to deforestation and fragmentation of the Cerrado, an important biodiversity hotspot and its main home range in Brazil. Associated with this, increased contact with domestic animals provided by human activities in these modified habitats resulted in physiological and behavioral changes to maned wolves and, consequently, increased exposure to pathogens [1, 2]. The transmission of infectious agents due to close contact with domestic animals, especially dogs, has become one of the main threats to the species [3, 4].

The western region of the Bahia state has highly anthropized areas, which occur between important remnants of the Cerrado, a Brazilian savanna. These Cerrado remnants are home to a population of maned wolves that is still unknown regarding its demographic, genetic, ecological, and epidemiological data. This scarcity of information associated with known threats in the region, such as environmental destruction and continuous fragmentation of Cerrado areas, intense illegal hunting activity, and the presence of domestic animals, highlight the need for investigations and the establishment of risk factors for this population of maned wolves [5, 6].

This is the first study of sanitary evaluation with free-ranging C. brachyurus in agricultural areas of the Bahia state, and also the first comparative epidemiological assessment between wild and domestic canids in this region. The present work aimed to evaluate the occurrence of infectious agents in free-ranging maned wolves and compare them with those occurring in domestic dogs in western Bahia.

Methods

Study area

The study was conducted in farms located in the mesoregion of western Bahia, specifically in the microregion of Barreiras, in the rural zone of the municipalities of Barreiras and Luís Eduardo Magalhães. This microregion is located in the Rio Grande basin and has the Cerrado biome as its main vegetation type, with the predominant phytophysiognomy being the typical Cerrado, interspersed with palm swamps and “cerrado rupestre”. The predominant climate is hot and dry, characterized by two very distinct seasons: a rainy one in the austral summer and a dry one in the austral winter. It is a predominantly agricultural region, with landscapes dominated by agroecosystems focused on monoculture crops, mainly soybeans, corn, and sorghum, as well as cotton (Fig. 1).

Fig. 1.

Capture areas  for maned wolves (red pins) and domestic dogs (yellow pins) in the microregion of Barreiras, Bahia. Legend: (Map Biomas 2020)

To capture the maned wolves, three farms were initially selected: two located in the municipality of Barreiras (11°50′09''S, 46°17′27''W and 11°47′56.97"S, 46° 2′35.84"W) and one located in the municipality of Luís Eduardo Magalhães (12° 4′56.06"S, 46° 7′57.11"W). All selected farms were previously assessed for the occurrence of the species through questionnaires addressed to their employees and detection of the presence of individuals using camera traps.

Animal capture and sampling

The maned wolves were captured by live-box traps, made especially for the species, during three campaigns (totaling 37 days). The maned wolves were then chemically restrained with tiletamine and zolazepam (Telazol®, Zoetis, Campinas, SP, Brazil) at a dose of 3 to 5 mg/kg, intramuscularly (IM), for clinical evaluation and sampling. The procedures were performed at the capture site and the animals were released after full anesthetic recovery. The maned wolves were characterized in terms of sex and age, and the age was estimated by the technical team of the National Research Center for Carnivores Conservation (CENAP) / Chico Mendes Institute for the Conservation of Biodiversity. This estimate was based on the evaluation of the dentition, considering dental wear in canines, pre-molars and molars, presence/absence of incisors and gingival retraction.

In addition to the animals sampled in field captures, the analysis also used data from maned wolves rescued from private farms in the study region. Adult specimens were physically restrained using a catch pole and were subjected to the same chemical restraint and clinical evaluation protocols described above. For young maned wolves, restraint was carried out using only leather gloves.

Adult dogs were also sampled in three farms investigated. Individuals who had free access to protected areas were selected. This pre-selection was carried out through questionnaires applied to owners and employees who owned dogs on these farms, and by identifying some individuals in protected areas during the faunal survey previously carried out with camera traps.

For laboratory tests, 15 mL of blood were sampled from the lateral, jugular, or cephalic saphenous veins of adult maned wolves. For young maned wolves and domestic dogs, the maximum amount of 1% of the total body weight was respected, and thus the sampled volume varied according to body weight. The samples were then packed in a thermal box containing recyclable ice, with a temperature of approximately 8 ºC. They were processed for serum extraction. Serum and whole blood aliquots were packed in 0.5 mL Eppendorf tubes and frozen in a -20 °C freezer for subsequent serological and molecular analyses.

Diagnostic analyses

Rapid immunochromatographic tests, validated for dogs, were performed to detect the parvovirus and canine coronavirus antigens (Test Corona/Parvo Ag®, Alere S.A., Bionote, Belo Horizonte, MG, Brazil) in both maned wolves and domestic dogs, through a rectal swab sample. The test consists of an immunochromatographic assay for both a qualitative and a differential detection of parvovirus (CPV) and canine coronavirus (CCoV) antigens in fecal samples. It is presented in the format of a plastic cassette containing the letters “C” and “T”, as control and test lines respectively, on its surface. The “C” lines are used for procedural control, while “T” lines are visible in the result window whenever parvovirus or canine coronavirus antigens are present in the tested sample.

None of the tests used in the study were directly validated for anti-wolf antibodies. However, since C. brachyurus is a canid, it is believed that the response to the pathogens in these animals is similar to that of domestic dogs. Rapid tests for the detection of immunoglobulin G (IgG) antibodies against the canine distemper virus (CDV) (Alere S.A., Bionote, Belo Horizonte, MG, Brazil) were performed using serum from the animals. The interpretation was chromatographic, using a predetermined scale. When positive, titrations were classified as high (above > 128), medium (16 to 64), or low (< below 16). The application and interpretation of all rapid tests followed the instructions of the manufacturers.

At the same time, laboratory analyses using dot-ELISA (Enzyme-Linked Immunosorbent Assay), a semiquantitative technique, were performed to detect immunoglobulin M (IgM) antibodies against CDV and CPV. This was also done for IgG antibodies against CDV, CPV and canine adenovirus type-1 (CAdV-1). The analyses were performed at Tecsa® Tecnologia em Sanidade Animal, a private laboratory located in Belo Horizonte, Minas Gerais state. Interpretations of the serological titration results and their respective classifications are described in Table 1.

Table 1.

Classification of serological titrations for CDV, CPV and CAdV-1 using the dot-ELISA technique

Classification	dot-ELISA technique
	CDV	CPV	CDV	CPV	CAdV-1
Score	IgM1	IgM1	IgG2	IgG2	IgG2
S0	SN	SN	SN	SN	SN
S1	1:10	1:10	< 1:8	< 1:40	1:4
S2	1:50	1:50	1:16	1:40	1:8
S3	1:250	1:250	1:32	1:80	1:16
S4	1:1250	1:1250	1:64	1:160	1:32
S5	1:6250	1:6250	1:128	1:320	1:64
S6	> 1:6250	> 1:6250	1:256	≥ 1:640	1:128

CDV canine distemper virus, CPV canine parvovirus, CAdV-1 canine adenovirus type-1, ¹Immunoglobulin M for CDV and CPV: score 0: seronegative; scores 1 and 2: weak positive or inconclusive; score 3: medium positive; score 4 to 6: strong positive; ² Immunoglobulin G for CDV, CPV and CAdV-1: score 0: seronegative; scores 1 and 2: weak positive; scores 3 and 4: positive; score 5 and 6: strong positive

The indirect immunofluorescence (IFR) technique was used to detect IgM and IgG antibodies against Toxoplasma gondii in maned wolves and dogs. The animals were considered seropositive whenever they exhibited antibodies at a 1:32 dilution.

The detection of antibodies against Leptospira interrogans in maned wolves and domestic dogs was made using the microagglutination technique (MAT), searching for the following serovars: Autumnalis, Australis, Bataviae, Bratislava, Castellonis, Canicola, Grippotyphosa, Hardjo, Hedbomadis, Icterohaemorragiae, Javanica, Pomona, Pyronges, Tarassovi, Wolffi, Copenhageni, and Djasiman. Both canid species were considered seropositive when titrations were equal to or greater than 1:100.

Total blood samples of maned wolves and domestic dogs were evaluated for the presence of genetic material of CDV, CAdV-1, and T. gondii using the probe-based qPCR (real-time Polymerase Chain Reaction with TaqMan probe) technique.

Subsequently, the frequency of exposure to each investigated pathogen was calculated by the percentage of sampled animals that exhibited detectable IgM and/or IgG antibodies [7]. The BioEstat 5.3 software was used to evaluate the correlation of test results with the age of maned wolves, comparing pups and adults, as well as the results obtained in maned wolves and dogs, using Pearson’s correlation test [8]. Coefficients with absolute values below 0.30 were listed as corresponding to little-if-any (linear) correlation; between 0.30 and 0.50 as weakly correlated; between 0.50 and 0.70 as moderately correlated; between 0.70 and 0.90 as strongly correlated; and above 0.90 as very strongly correlated [9]. Lastly, the Kappa statistic test was used to compare the results obtained by rapid tests (immunochromatography) and laboratory analyses (dot-ELISA) for the detection of IgG antibodies against CDV for maned wolves.

Results

Sampling was conducted between October 2020 and September 2021. Three capture campaigns were carried out, lasting approximately 12 days and using 6 traps in each campaign. In total, there were 37 days of sampling, totaling a sampling effort of 212 traps/day. These traps were baited with boiled chicken, sardines, bacon, and seasonally available fruits. They were checked daily at 7 am, and re-baiting was carried out every 24 h or at each capture or disarming event.

Three healthy adult animals and eight rescued animals were sampled, being three adults and five pups (Table 2). Additionally, nine adult and healthy domestic dogs were sampled in the same farms where the wolves were sampled.

Table 2.

Date, location, gender, age, and history of sampled maned wolves (Chrysocyon brachyurus) (MW1-MW11)

Maned wolves	Date	Latitude	Longitude	Sex	Age	History
MW1	03/10/20	11°52′19.2''S	46°19′50.0''W	F	4 Y	Field capture
MW2	26/10/20	11°50′09''S	46°17′27''W	M	4 Y	Agonistic interaction
MW3	28/06/21	12°25′24.76"S	46°15′2.33"W	M	6 Y	Agonistic interaction
MW4	19/06/21	11°50′32.37"S	46°24′16.12"W	F	30 D	Healthy pup
MW5	19/06/21	11°50′32.37"S	46°24′16.12"W	M	30 D	Healthy pup
MW6	19/06/21	11°50′32.37"S	46°24′16.12"W	M	30 D	Healthy pup
MW7	13/07/21	11°33′23.4"S	46°04′33.0"W	M	7 Y	Run over
MW8	21/07/21	11°49′36.13"S	45°59′48.15"W	M	4 Y	Field capture
MW9	27/07/21	11°53′27.1''S	46°20′33.7"W	F	2 Y	Field capture
MW10	20/08/21	11°53′59.0''S	46°12′35.0''W	M	50 D	Forest fire
MW11	13/09/21	12°12′44''S	45°57′33''W	M	90 D	Sick pup

D days, F Female, M Male, Y years

Concerning the rapid tests, all maned wolves and dogs evaluated reported negative for the presence of the CCoV and CPV antigens. Additionally, the presence of genetic material from CDV, CAdV-1 and as T. gondii was not detected in any maned wolf or domestic dog, according to the probe-based qPCR method.

For antibody titration, the results of the rapid and laboratory tests for maned wolves and dogs are available in Tables 3 and 4, respectively. The titles referring to each agent researched are detailed below for each individual sampled. The interpretation and classification of titers on a semiquantitative scale, using the dot-ELISA method (S0-S6) with their respective cutoff points, follows what is presented in Table 1.

Table 3.

Antibody titers and frequency of exposure for canine distemper virus (CDV), canine parvovirus (CPV), canine adenovirus type 1 (CAdV-1), Toxoplasma gondii and Leptospira interrogans of sampled maned wolves

Maned wolves	CDV			CPV		CAdV-1	Toxoplasma gondii		Leptospira interrogans
	IgM1	IgG-RT	IgG1	IgM1	IgG1	IgG1	IgM2	IgG2	IgM/IgG3
MW1	250	128	< 8	50	< 40	16	SN	SP	SN
MW2	250	< 16	SN	250	SN	16	SN	SP	SN
MW3	250	< 16	16	50	40	16	SN	SP	SN
MW4	50	< 16	< 8	50	< 40	4	SN	SN	SN
MW5	250	< 16	SN	10	SN	SN	SN	SN	SN
MW6	50	< 16	SN	50	SN	4	SN	SN	SN
MW7	250	< 16	< 8	10	< 40	16	SN	SP	SN
MW8	1250	< 16	< 8	10	< 40	32	SN	SP	SN
MW9	250	< 16	< 8	50	< 40	32	SN	SP	SN
MW10	250	< 16	SN	10	SN	16	SN	SN	SN
MW11	250	128	< 8	50	< 40	32	SN	SN	SN
FE	11/11 (100%)	11/11 (100%)	7/11 (64%)	11/11 (100%)	7/11 (64%)	10/11 (91%)	0/11 (0)	6/11 (54%)	0/11 (0)

¹: dot-ELISA technique; ²: Indirect immunofluorescence reaction (IFR); ³: Microagglutination technique (MAT); IgG: Immunoglobulin G; IgM: Immunoglobulin M; SN: seronegative; SP: seropositive; FE: frequency of exposure; RT: rapid test

Table 4.

Antibody titers and frequency of exposure for canine distemper virus (CDV), canine parvovirus (CPV), adenovirus-canine-type 1 (CAdV-1), Toxoplasma gondii and Leptospira interrogans of domestic dogs

Dogs	CDV		CPV		CAdV-1	Toxoplasma Gondii		Leptospira interrogans
	IgM1	IgG1	IgM1	IgG1	IgG1	IgM2	IgG2	IgM/IgG3
D1	250	32	10	80	16	SN	SP	SN
D2	250	128	10	80	32	SN	SP	SN
D3	250	64	10	160	32	SN	SP	SN
D4	250	32	10	160	32	SN	SP	SN
D5	250	128	10	160	32	SN	SP	SN
D6	250	32	50	160	4	SN	SP	SN
D7	250	< 8	50	160	8	SN	SP	SN
D8	250	16	10	160	SN	SN	SP	SN
D9	250	32	10	320	64	SN	SN	SN
FE	9/9 (100%)	9/9 (100%)	9/9 (100%)	9/9 (100%)	8/9 (89%)	0/9 (0)	8/9 (89%)	0/9 (0)

¹: dot-ELISA technique; ²: Indirect immunofluorescence reaction (IFR); ³: Microagglutination technique (MAT); IgG: Immunoglobulin G; IgM: Immunoglobulin M; SN: seronegative; SP: seropositive; FE: frequency of exposure

All maned wolves were seropositive for IgG against CDV using the immunochromatographic technique (rapid test). Using the dot-ELISA technique, only 64% (7/11) of the maned wolves were seropositive for IgG presence against CDV and CPV. Regarding the presence of IgM, 100% of the sampled maned wolves were seropositive for CDV and CPV. IgG titration against CAdV-1 resulted in 91% (10/11) seropositive maned wolves. The investigation of antibodies against T. gondii resulted in 54% (6/11) of maned wolves reporting seropositive to IgG presence. None of the maned wolves were reactive for antibodies against L. interrogans.

For domestic dogs, all sampled animals were seropositive for IgM and IgG against both CDV and CPV. Serological investigation for CAdV-1 and T. gondii resulted in 89% (8/9) of the dogs being seropositive for IgG. For the maned wolves, a negligible correlation was observed between age and the serology results of antibodies against CDV (IgM, p = 0.0777; IgG, p = 0.13), CPV (IgG, p = 0.13), and CAdV-1 (IgG, p = 0.1254). For IgM versus CPV, the correlation was moderate (p = 0.6345). On the other hand, the correlation for T. gondii was very strong (p = 1), indicating that all adults were seropositive for the presence of antibodies, while the pups yielded negative results.

The comparison of serological results (dot-ELISA) of maned wolves and domestic dogs showed a strong correlation (p = 0.7808) for the frequency of IgM and a weak correlation (p = 0.3296) for IgG against CDV; a moderate correlation for IgM and IgG against CPV (p = 0.5406 and p = 0.5292, respectively), and a strong correlation (p = 0.7863) for IgG against CAdV-1. For T. gondii, this correlation was moderate (p = 0.5165) for the results of the analysis of all maned wolves, when compared to dogs. However, by including only adult maned wolves, the correlation reported was strong (p = 1). There was a poor agreement (k = -0.1818) between the results obtained in the rapid tests for IgG detection against CDV, when compared to those of the dot-ELISA laboratory tests in maned wolves. There were 36.36% (4/11) of false-positive results in the rapid tests, all corresponding to low titration values (< 16).

Discussion

It is important to highlight that, although there is no validation of rapid immunochromatographic tests for wild carnivores like maned wolves, these are widely used in sanitary investigations for diagnosis and epidemiological surveys of these animals, because they provide immediate results at a lower cost when compared with laboratory analyses [10–12]. Therefore, the comparative analyses presented in this study are interesting because they help to evaluate the reliability of these resources [13]. For example, the rapid test using immunochromatography techniques for IgG against CDV resulted in 36% false-positive results for maned wolves in this study when compared with dot-ELISA.

Regarding serological titration (dot-ELISA) for CDV and CPV, three (MW5, MW6, MW10) of the four individuals who presented isolated detection of IgM antibodies were pups of no more than eight weeks old. Since none of these pups exhibited symptoms compatible with viral infections, and the molecular diagnosis reported negative results, this suggests the possibility of the presence of maternal antibodies [14–17].

The other animals sampled (MW1, MW3, MW7, MW8, MW9, and MW11) were reported as seropositive in both titrations (IgM and IgG) for CDV and CPV. The joint detection of immunoglobulins may indicate different stages of the immunological response, such as recent contact with the viral agent, initiation of infection, subclinical manifestation, initial phase of convalescence, or past infection [18–23]. It is inferred that these findings indicate only a previous or recent exposure of these individuals, without an active response to infection at the time of sampling, since no clinical manifestations were observed, even in individuals who exhibited high titers (MW8). Furthermore, no genetic material of any of the tested pathogens was detected in their samples. Lastly, 82% (9/11) of the sampled individuals were monitored and/or followed up after the capture or rescue event, and none of them exhibited any clinical signs compatible with these diseases.

Until recently, few reports of infection with clinical manifestations and/or death by CDV and CPV have been described for C. brachyurus, and most of the reported cases concern individuals kept under human care [24–28]. However, both diseases are identified as important causes of neonatal mortality in captivity [25], which is worrisome for free-ranging populations, mainly because this is an endangered species [26, 29].

In general, the presence of antibodies against CDV and CPV comprises indirect evidence of exposure to these pathogens and the active circulation of these viral agents in the free-living population, with the probable participation of domestic dogs as a source of infection. This inference is reinforced by the high frequency of these pathogens found in non-vaccinated domestic dogs in this study. Furthermore, the presence of domestic dogs in the areas where the maned wolf occurs, previously recorded by photographic traps, reinforces their role as a probable source of infection for the maned wolf population. However, despite the high frequency found and high titers, it was not possible to identify the genetic material from any pathogen investigated. This makes it impossible to determine the genotype of the strains involved in the infection, which would allow for the identification of the probable source of infection and its respective reservoir.

The exposure of free-ranging maned wolves to CDV and CPV, associating domestic dogs as a reservoir, was already described in the Southeast and Midwest regions of Brazil [4, 30–32], and also for other South American countries, such as Bolivia [10, 29] and Argentina [3]. For Brazil, specifically, all surveys for CDV and CPV with maned wolves were conducted within conservation units and reported either a low prevalence or even the absence of CDV [4, 30, 31], probably due to a low frequency of direct contacts of these animals with domestic dogs. Conversely, the sampling for this study was carried out in heavily anthropized areas with relevant circulation of domestic dogs, previously demonstrated by faunal surveys [33]. This scenario represents an increase in the direct contact between species, resulting in higher detection rates, as found by [3] in maned wolves and domestic canids sampled in rural areas of Argentina [34–37].

The only maned wolf (MW5) seronegative for CAdV-1 was one of the cubs that belonged to the same litter of two other animals with low detectable titles (MW4 and MW6). The low levels of immunoglobulins detected, when associated with the age of these animals at the time of sampling, the absence of clinical signs and the negative results in molecular diagnosis, suggest the possibility of passive immunity.

The high frequency of IgG antibodies against CAdV-1 denotes a circulation of the pathogen among maned wolves in the region, since 80% of the seropositive individuals exhibited high titers (> 16). In the Brazilian state of Minas Gerais and in Argentina, seroprevalences of 93% and 100% were found for maned wolves, and 36% and 59% for domestic dogs, respectively [3, 32]. Similarly, in Bolivia, a prevalence of 100% was detected in free-ranging maned wolf populations [10, 29]. As in the present study, the investigations pointed to the domestic dog as a probable source of infection to wild canids, and CAdV-1 was considered endemic to the species in populations from Argentina and Bolivia [3, 38]. Domestic dogs can act as a source of infection of CDV, CPV, and CAdV (canine adenovirus) for wild canid populations, with significant impacts on free-ranging fauna [7, 32, 39–45]. In Brazil, in addition to serological surveys, molecular and phylogenetic evidence demonstrated transmission of these pathogens from domestic dogs to the maned wolf [28] and other wild canids [45–48].

Regarding T. gondii, a strong correlation (p = 1) was found between age and frequency of IgG in maned wolves. In individuals under human care, a significant seroprevalence (91.7%) was also observed in adult animals [49]. This finding can be explained by the fact that infection by this protozoan is associated with the consumption of infected hosts, mainly small mammals, an item that is often present in the diet of adult maned wolves [10, 50]. The results for dogs exhibit a moderate correlation with those for maned wolves, and dogs are also considered accidental hosts. Therefore, these findings should be related to the sharing of the same environmental conditions, which predispose both dogs and maned wolves to exposure to the agent [10].

Seroepidemiological surveys also demonstrated a high prevalence of antibodies against T. gondii for wild maned wolves in Brazil, in regions of the Federal District (100%) [51], São Paulo state (88.2%) [52], and Minas Gerais state (> 75%) [31, 32], as well as in Bolivia (73%) [29]. The authors warn of the presence of the domestic cat (the definitive host of the parasite) in natural areas, sharing territories with other susceptible species, including the maned wolf. In this study, the presence of domestic cats was observed only in one farm. Therefore, it was not possible to infer any relationship of domestic cats with the frequence found for all maned wolves sampled in the region.

In general, canids are considered accidental hosts and can be used as indicators for environmental contamination by T. gondii, and no significant mortality from infection is observed [53]. However, co-infections with immunosuppressive agents, such as CDV, may induce the clinical manifestation of toxoplasmosis and even death, as was previously reported for red foxes (Vulpes vulpes), island foxes (Urocyon littoralis) [41, 54, 55], and the maned wolf [28]. All seropositive maned wolves in this study were seropositive for antibodies against CDV. Nonetheless, none of the animals, even those rescued, showed any characteristic symptoms of the disease. To date, there are no reports of deaths resulting exclusively from toxoplasmosis in maned wolves [55], but further studies are needed to infer a possible resistance of this species to infection.

The findings of this study demonstrate the exposure of the maned wolf to different pathogens that commonly occur in domestic animals. This indicates a potential risk to the conservation and viability of the maned wolf population in the western Bahia region. This was the first epidemiological survey conducted with the species in the state of Bahia. Therefore, more research is needed to identify and accurately map reservoirs, as well as to understand the structure and epidemiological dynamics of the agents identified in the populations of both domestic and wild canids.

Conclusion

The free-ranging maned wolf individuals in this research exhibited high frequency of exposure for CDV, CPV, CAdV-1 and the protozoan T. gondii, indicating active circulation of these agents in free-living populations and a potential risk for the local maned wolf population. The sampled domestic dogs exhibited similar results and may be the source of infection of most of these agents for wild canid species in western Bahia.

Author contributions

All authors contributed to the study conception and design. Paula Damasceno Gomes: conceptualization, funding acquisition, investigation, methodology, data curation, writing—original draft and writing—review and editing. Líria Queiroz Luz Hirano: formal analysis, methodology, funding acquisition, project administration, supervision, validation and writing – review & editing. Rogério Cunha de Paula: visualization, supervision, validation and writing—review and editing. All authors have read and approved the final manuscript.

Funding

This study received financial support from the Brazilian Fund for Biodiversity (Fundo Brasileiro para a Biodiversidade—FUNBIO), the Humanize Institute and Conservation International (CI).

Data availability

All data generated or analyzed during this study are included in this published article.

Declarations

Non-financial interests

The authors have no financial or proprietary interests in any material discussed in this article.

Legal and ethical statement

All applicable institutional and/or national guidelines for the care and use of animals were followed. The project was authorized by the Biodiversity Authorization and Information System (SISBIO-ICMBio; 74332–1). It was also approved by the Ethics Committee on Animal Use of the University of Brasília (CEUA-UnB;030/2020).

Competing interests

The authors declare no competing interests.