Spirocerca vulpis sp. nov. (Spiruridae: Spirocercidae): description of a new nematode species of the red fox, Vulpes vulpes (Carnivora: Canidae)

Detection of Spirocerca lupi and an unknown Trichinella-like nematode in raccoon (Procyon lotor)

The raccoon Procyon lotor (Carnivora: Procyonidae) is an invasive species of growing importance for the introduction of alien pathogens or as additional hosts for autochthonous pathogens in Europe, including zoonotic parasites. As the population is steadily increasing and outcompeting the red fox (Vulpes vulpes) in Germany, the consumption of raccoon meat raises concerns about pathogens they may transmit. Therefore the presence of Trichinella larvae was here investigated in muscle samples (n = 904) of raccoons from northern Germany. No Trichinella larvae were found, thus confirming the general low occurrence of this parasite in Germany. However, Spirocerca lupi (n = 12) and an unidentified Trichinella-like nematode (n = 1) were accidently detected in the examined samples. The first is not a zoonotic parasite but has a high veterinary relevance as it can cause severe diseases in dogs. It is the first documented autochthonous infection of this nematode in Germany. The larvae of an unidentified Trichinella-like nematode were found in high abundance in all examined muscles of one raccoon, though they could not be identified to species level. Histological investigation revealed intramuscular cystic structures. This is the largest study investigating muscular parasites of raccoons in Europe so far, which suggests that this invasive animal species is infected by S. lupi and by a yet unknown Trichinella -like parasite.

Neglected zoonotic helminthiases in wild canids: new insights from South America

The global threat of neglected tropical diseases (NTDs) constitutes a public health issue in underdeveloped countries. Zoonotic helminthiases are the most common human NTD agents in developing countries in sub-Saharan Africa, Asia, and the Americas, causing a global burden of disease that exceeds that of more recognized infectious diseases such as malaria and tuberculosis. Wild canids are well-known mammals that act as natural reservoirs of zoonotic-relevant helminthiasis worldwide, thus playing a pivotal role in their epidemiology and transmission to humans. Here we evaluate the occurrence of zoonotic gastrointestinal helminths in two Neotropical wild canid species from the Amazonian and Andean regions of Colombia, i.e., the bush dog (Speothos venaticus) and the crab-eating fox (Cerdocyon thous). We recovered tapeworm proglottids from bush dog fecal samples and identified them molecularly as the canine-specific lineage of Dipylidium caninum by using cytochrome c oxidase subunit I (cox1) gene sequences. Moreover, examination of a crab-eating fox during necropsy revealed the presence of non-embryonated eggs of the neglected nematode Lagochilascaris cf. minor, in addition to eggs and gravid proglottids of the cestode Spirometra mansoni. These findings represent the first report of zoonotic-relevant cestodes, i.e., D. caninum ("canine genotype"), S. mansoni, and the nematode L. cf. minor, in bush dogs and crab-eating foxes as final hosts. The occurrence of these zoonotic helminthiases in wild canid species calls for regular monitoring programs to better understand the epidemiology and transmission routes of neglected dipylidiasis, lagochilascariosis, and sparganosis in South America.

Spirocerca lupi in the stomach of two Andean foxes (Lycalopex culpaeus) from Chile

The genus Spirocerca includes nematodes that parasitize the stomach and the oesophagus of carnivores, chiefly canids. Herein, we provide new data about the morphological, histopathological, and molecular characterization of Spirocerca sp. in Andean foxes (Lycalopex culpaeus) in Chile. Intact immature worms, identified as Spirocerca sp., were recovered in the lumen of the stomach from two foxes. Histologically, worms morphologically consistent with spirurid nematodes were present within the wall of the stomach and surrounded by nodular areas of inflammation with central necrotic debris. Molecular analysis of the cox1 gene yielded 19 sequences and 5 nucleotide sequence types with 99.95 to 99.98% similarity, being shared between both foxes. Nucleotide similarity ranged from 93.1 (with genotype 2 of S. lupi and S. vulpis) to 95.8% (with genotype 1 of S. lupi), a higher similarity than noted from sequences of S. lupi from an Andean fox from Peru (91.0 to 93.3%). However, the Poisson Tree Processes for species delineation did not support the existence of a new species Spirocerca. Phylogenetic and nucleotide analyses suggest that these specimens belong to a new variant or genotype of S. lupi or to a cryptic species. Whether the presence of the worms in the stomach has to do with genotypic differences in parasites or host or some combination is uncertain. Spirocerca lupi has never been found in Chilean dogs and must be investigated.

Gray Wolf (Canis lupus italicus) and Red Fox (Vulpes vulpes) Parasite Survey in Anthropized and Natural Areas of Central Italy

Gastrointestinal nematodes and protozoa and other parasite occurrences were evaluated in free-ranging wolf (Canis lupus italicus) and red fox (Vulpes vulpes) populations from natural and anthropized areas of Central Italy. Analyzed fecal samples were collected from 60 foxes and 40 wolves in the anthropized areas, and 41 foxes and 39 wolves in the natural areas. In foxes, hookworm infections (p < 0.0001) were more frequently recorded in the anthropized environment, while coccidia (p < 0.05) and Cryptosporidium spp. (p < 0.0001) were more frequent in the natural area. In wolves, a higher frequency of hookworms (p < 0.0001) was observed in natural areas, while coccidia were more common in the anthropized area (p < 0.05). Moreover, in the natural environment, trichuroid nematodes (p < 0.0001) were significantly more frequent in wolves than in foxes, while Cryptosporidium (p < 0.001) and Giardia duodenalis (p < 0.001) were more common in foxes. In the anthropic area, the occurrence of hookworms was found to be significantly higher in foxes (p < 0.0001), while trichuroid nematodes were more common in wolves (p < 0.0001). The obtained data are indicative of a different diffusion of specific parasite taxa in wolves and foxes living in the natural and/or anthropized environments examined herein.

MORPHOLOGICAL AND GENETIC CHARACTERIZATION OF DIDELPHONEMA LONGISPICULATA (NEMATODA: SPIRUROIDEA) IN THE BLACK-EARED OPOSSUM DIDELPHIS MARSUPIALIS

Didelphonema longispiculata (Hill, 1939), a gastric nematode parasite of the black-eared opossum, Didelphis marsupialis Linnaeus, 1758, collected from 2 municipalities of Mato Grosso state, Brazil, in the ecotone region of the Amazon and Cerrado biomes was analyzed with integrative taxonomy using light and scanning electron microscopy (SEM) for morphological studies and sequencing of the 18S small subunit ribosomal RNA for phylogenetic inference through maximum likelihood and Bayesian phylogenetic inference. Here details of the helminth surface, oral aperture with octagonal border, pseudo- and inter-labia, amphids, external cephalic papillae, 2 dorsal and ventral internal plates distally indented, and stoma with strongly chitinized wall are presented. Caudal male papillae, spicules, female vulva, anus, and caudal tip were detailed using SEM. Morphological characteristics and phylogenetic data corroborated the taxonomic placement of the genus Didelphonema within the subfamily Ascaropsinae.

CHARACTERIZATION OF LESIONS INDUCED BY SPIROCERCA VULPIS (SPIRURIDAE: SPIROCERCIDAE) IN RED FOXES (VULPES VULPES)

Spirocerca lupi infection in dogs (Canis domesticus) is associated with esophageal lesions that may evolve to a neoplastic stage in the form of esophageal sarcoma. In the red fox (Vulpes vulpes) infected with the closely related Spirocerca vulpis, similar lesions may occur in the stomach, but neoplastic forms have not been reported. We characterize Spirocerca vulpis-induced lesions in the fox, using pathology and immunohistochemical (IHC) techniques. Seventy-one out of 163 Spirocerca vulpis-positive red foxes were selected and subjected to histopathological study. Lesions were classified as patchy or diffuse. Ten patchy and 10 diffuse lesion samples were studied using three IHC markers (CD68, CD3, and CD79α for macrophages, T lymphocytes, and B lymphocytes, respectively) and H&E stain for neutrophils and eosinophils. Intensity of necrosis, hemorrhages, and the presence of collagen was also analyzed. Of the S. vulpis-positive red foxes, 96.9% had S. vulpis nodules localized in the gastric area (wall and/or omentum), and 3.1% had nodules in the small intestine. All the samples had a moderate to severe lymphoplasmacytic infiltrate. Mild eosinophil infiltration was observed in both types of lesions, while neutrophil infiltration was significatively higher in the patchy than in the diffuse lesions. Fibrosis with mature collagen fibers was also predominant in the patchy lesions along with the presence of T lymphocytes and macrophages. Both the patchy and diffuse patterns had very few B lymphocytes. These findings suggest that the diffuse form is an earlier stage of the lesion, which eventually evolves into patchy forms. Neoplastic forms were not seen. Although more studies are necessary, this study describes the lesions, characterizes the inflammatory infiltrates, and establishes a possible evolution of the different pathological forms of S. vulpis infection in the red fox.

MOLECULAR INVESTIGATION OF VECTOR-BORNE PATHOGENS IN RED FOXES (VULPES VULPES) FROM SOUTHERN FRANCE

Because of their free-ranging nature, the probability of wild animals being exposed to vector-borne pathogens is likely higher than that of humans and pets. Recently, the red fox (Vulpes vulpes) has been suspected as being a reservoir or host of several pathogens of veterinary and public health importance. We conducted a molecular survey on 93 red foxes hunted in 2008-18, in the departments of Bouches-du-Rhône and Var, in southeastern France, for pathogens including Leishmania infantum, Piroplasmida, Hepatozoon spp., nematodes, Coxiella burnetii, Borrelia spp., Rickettsia spp., and Anaplasmataceae. Spleen samples were screened for the presence of vector-borne pathogens by PCR followed by sequencing. Pathogens were detected in 94% (87/93) of red foxes, and coinfections were identified in 24% (22/93) of foxes. We identified DNA from Hepatozoon canis, L. infantum, and Babesia vogeli in 92% (86/93), 15% (14/93), and 3% (3/93) of red foxes, respectively. We also found DNA of nematodes in 3% (3/93) of foxes; Spirocerca vulpis was identified in one fox and Dirofilaria immitis in the two others. Interestingly, C. burnetii genotype 3, previously described in humans from the same region, was identified in 3% (3/93) of foxes and Anaplasma platys in 2% (2/93) of foxes. We did not detect DNA of Borrelia spp., Bartonella spp., or Rickettsia spp. In our study, the prevalence of pathogens did not vary by fox origin, sex, or tick carriage. Molecular evidence of B. vogeli, H. canis, S. vulpis, D. immitis, C. burnetii, and A. platys in red foxes has not previously, to our knowledge, been reported from southern France. We propose that red foxes are potential reservoirs for several pathogens, including major zoonotic agents such as L. infantum. They could be incidental hosts for pathogens, such C. burnetii. The high prevalence for H. canis suggests an important role of foxes in domestic dog (Canis lupus familiaris) infection. These animals may pose a threat to human and animal health.

Morphological and molecular characterization of Spirocerca lupi (Nematoda: Spirocercidae) from domestic dogs in Vietnam with reference to Spirocerca vulpis

Spirocerca lupi is a common parasitic nematode associated with esophageal cancer of canids. Recent surveys have revealed an increasing number of canids infected with Spirocerca spp. in Africa, the Americas, Europe and Western Asia, and described a new species, Spirocerca vulpis, from red foxes (Vulpes vulpes). However, in Southeast Asia, research on Spirocerca spp. is scarce. Therefore, the aim of this study is to explore Spirocerca infection in domestic dogs in Vietnam and to identify the Spirocerca species by analyzing their morphometric and molecular data. We found Spirocerca spp. specimens in 51 (17.7%) out of 287 dogs examined with the intensity of infection ranging from one to 29 nematodes per dog. These nematodes were morphologically and molecularly identified as S. lupi. For morphology, the presence/absence of teeth, the ratio of glandular to muscular esophagus lengths, and the position of the vulva opening of S. lupi and S. vulpis varied between reports, suggesting caution in identification of Spirocerca species based exclusively on morphological characteristics. The molecular analysis based on a partial cox1 sequence revealed that S. lupi from Vietnam is genetically close to those from India and China, but far different from those of Israel, South Africa, Peru and Hungary. Given high genetic and morphological variations, more extensive surveys on Spirocerca spp. from various mammalian hosts at a greater scale are necessary to elucidate the divergence of this nematode.

Molecular phylogenetic study in Spirocercidae (Nematoda) with description of a new species Spirobakerus sagittalis sp. nov. in wild canid Cerdocyon thous from Brazil

The nematode family Spirocercidae Chitwood and Wehr, 1932, comprises three subfamilies, Spirocercinae Chitwood and Wehr, 1932; Ascaropsinae Alicata and McIntosh, 1933; and Mastophorinae Quentin, 1970, which occur worldwide. Spirocercids infect canids and can cause severe illness. The crab-eating fox, Cerdocyon thous (Linnaeus, 1766), is a canid that inhabits most of South America, including Brazil and is a host for several parasitic worms, in particular, nematodes. However, few reports or genetic data are available on the spirocercids found in this host. In the present study, we describe a new species of Spirobakerus Chabaud and Bain 1981, from the intestine of two crab-eating foxes from two different biomes in Brazil. Spirobakerus sagittalis sp. nov. presents a) unequal spicules, with a long, thin left spicule with a lanceolated shape at the tip; b) a pair of sessile papillae and a median unpaired papillae located anteriorly of the cloaca, and c) a tuft without spines at the tip of the tail in females. The molecular phylogenetic analysis indicated that S. sagittalis sp. nov. is basal to the other species of the subfamily Ascaropsinae, which was not recovered as monophyletic. Our phylogenies also indicated that Spirocercidae is paraphyletic, given that Mastophorinae did not group with Ascaropsinae and Spirocercinae. We provide the first molecular data on the genus Spirobakerus and expand the molecular database of the spirocercids. However, further studies, including the sequences of other spirocercid taxa, are still needed to infer the relationships within this family more accurately.

Parasitic helminth infections of dogs, wolves, foxes, and golden jackals in Mazandaran Province, North of Iran

Background and Aim:

There is a large amount of information on intestinal parasites in stray dogs and golden jackals (Canis aureus) in Mazandaran Province, Iran. However, there is little information about foxes and wolves, which have a potential role in the spread of dangerous parasitic diseases, such as echinococcosis and toxocariasis. The aim of the present study was to identify the genus or species of parasitic worms in stool samples obtained from carnivores in Mazandaran Province, Iran, from August 2017 to April 2018.

Materials and Methods:

A total of 274 fecal samples were collected from carnivores, including dog, fox, wolf, and C. aureus in three areas of Mazandaran Province, Iran. All specimens were examined by centrifugal fecal flotation using a solution of Sheather’s sugar to detect helminths eggs. Then, all samples were assessed using a light microscope. Data analysis was performed by SPSS version 18 (Chicago, IL, USA).

Results:

In this study, seven genera of helminths were observed, including Ancylostoma, Uncinaria, Toxocara, Dipylidium, Toxascaris, Taenia, and Spirocerca. The prevalence of helminth infections was 97.7% (127 out of 130), 56.7% (51 out of 90), 51.4% (18 out of 35), and 52.6% (10 out of 19), among dogs, C. aureus, foxes, and wolves, respectively. The highest prevalence of Ancylostoma and Toxocara infections occurred in the eastern and central areas of the province (42.1% and 35.7%, respectively).

Conclusion:

Based on the results of this study, the infection with intestinal zoonotic helminths in carnivores was an important public health factor in Mazandaran. Therefore, these infections can be potentially harmful to humans and other animals.

Endoparasitic fauna of two South American foxes in Chile: Lycalopex culpaeus and Lycalopex griseus

Native foxes face serious threats related to anthropic activities and the uncontrolled pets. However, the transmission of several pathogens such as parasites by domestic dogs is an important conservation issue with limited attention in Chile. The lack of a proper identification of the helminths of wild canids in the country, based mostly in coprological studies, limited our knowledge in potential interspecific transmission. Thus, the aim of the present survey was to identify the parasitic fauna of two native canids, the Andean fox (Lycalopex culpaeus) (n=49) and Chilla (Lycalopex griseus) (n=17), from several localities in Chile through a complete parasitological survey. Sixteen different species were identified, 9 of which are new host records for Andean fox and two for Chilla fox in South America, and three are recorded for first time in Chile. Also, five of them are of zoonotic concern and six are known to use domestic dogs as their principal hosts. These findings have implications for public health and the conservation of canids whose interspecific transmission of parasites with domestic dogs is confirmed through these findings. The need for an exhaustive surveillance of wild carnivores is emphasized considering these hosts as important sources of micro- and macroparasites.

First report of Spirocerca vulpis in red foxes (Vulpes vulpes) in Portugal

Recent studies have described Spirocerca lupi-like nematodes in the stomach of red foxes (Vulpes vulpes) in Europe. A phylogenetic analysis of those specimens using mitochondrial DNA and their morphological reexamination allowed their characterization as a different species, Spirocerca vulpis. Between the years of 2010 and 2017, roundworms were collected from seven red foxes of northeastern Portugal found at necropsy with nodular lesions on their stomach wall. Histopathological analysis of four foxes revealed granulomatous lesions of the gastric nodules. On morphological assessment, by light microscopy, nematodes revealed the presence of six triangular teeth-like buccal capsule structures, which are absent in S. lupi. Polymerase chain reaction was run to amplify a 551 bp partial fragment of the cytochrome c oxidase subunit 1 gene. Sequences were 99% similar to S. vulpis (85% coverage) of red foxes from Spain and Bosnia and Herzegovina, 99% similar (99% coverage) to sequences of Spirocerca sp. of red foxes from Denmark and 93% similar (99% coverage) to S. lupi from South Africa. This is the first report of S. vulpis in foxes or any other host from Portugal.

Unravelling Spirocerca vulpis from red foxes from Switzerland: a 20-year-old record

Spirocerca vulpis is a parasitic nematode of red foxes associated with gastric nodule formation. Since its description in 2018, this species has been reported in red foxes from Spain, Bosnia and Herzegovina, Italy, and Portugal. We present here the analysis of uncharacterized nematodes obtained from gastric nodules of a red fox from Switzerland in 1999. The specimens were identified as S. vulpis based on the observation of teeth-like structures in the buccal capsule and a 99.4% sequence identity to S. vulpis DNA from Spain. Phylogenetic analysis demonstrated the clustering of the Swiss sequences in a different group from specimens of other geographical locations. Altogether, this study constitutes the first report of S. vulpis in Switzerland and a report of the oldest specimen of this species in the world. Our findings highlight the widespread distribution of S. vulpis in Europe which may be facilitated by the free-roaming nature of red foxes.

Occurrence, prevalence, and explanatory environmental variables of Spirocerca vulpis infestation in the foxes of western Spain

The main aim of this study was to not only establish the prevalence of the recently described Spirocerca vulpis parasite in the wild-life cycle of carnivores in western Spain but to also elaborate a model to explain the risk of infestation based on 16 topo-climatic and habitat variables. During the period from June 2016 to November 2017, 1644 carcasses of red foxes (Vulpes vulpes) and another 105 wild mammals, legally hunted or killed in car accidents, were analyzed. Parasitic nodules of Spirocerca were found in 6% of the foxes, and the molecular analyses established a homology of our samples with the species S. vulpis. There were no differences in the occurrence of the infestation between sexes, but there were differences in terms of age, such that infestation was proportionally more frequent among young individuals. In terms of temporality, a higher percentage of positive cases was observed during the late-autumn and winter months, especially between December and February. This study provides new data on the factors that predispose S. vulpis infection in the red fox. Model results indicate that a spatial pattern exists in the occurrence and prevalence of this species in the studied area (higher probabilities to the west), and that this pattern seems to mainly be associated with topo-climatic variables.

Insights on Spirocerca lupi, the Carcinogenic Dog Nematode

Spirocerca lupi is a nematode transmitted by dung beetles that infects domestic and wild canids in tropical and subtropical regions and is associated with neoplasia. It produces a distinctive pathology with the formation of esophageal nodules classified as inflammatory, preneoplastic, or neoplastic with metastasis to distant organs. Aberrant central nervous system migration of this nematode is also responsible for severe neurological manifestations. Reports of spirocercosis have increased over the last two decades showing spread of this canine helminth in five continents. S. lupi from different geographical locations is genetically distinct with two genotypes, genotype I from Africa, Asia, and Australia, and genotype II from Europe, and recently separated from Spirocerca vulpis, a new species described in red foxes from Europe.

First epidemiological data on Spirocerca vulpis in the red fox: A parasite of clustered geographical distribution

This is the first study describing the epidemiology of Spirocerca vulpis after its description as a new species in 2018. During the period 2006-2013, a total of 286 red foxes (Vulpes vulpes) from the Valencian Community (southeast Spain) were necropsied. Based on data collected, S. vulpis prevalence and intensity were calculated, as well as the spatial distribution of this nematode. Influence of host (sex and age) and environmental factors on S. vulpis occurrence was evaluated. MAXENT software was used to model and predict the parasite distribution. Continuous and discrete prediction maps were built using ArcMap 10.6. The prevalence of S. vulpis was 22% (63/286; 95% CI: 17.4-27.3), and the median intensity was 5 (IQR 11) nematode specimens. No significant difference in term of intensity was found between males and females; regarding the host age, S. vulpis was found only in adult foxes, with the exception of one juvenile individual. The distribution of S. vulpis in foxes was skewed to the left, highlighting that parasite infection affects few individuals within a population, with parasitized animals being responsible to maintain the infection at the population level. The majority of parasitized foxes had a parasite burden lower than eight parasites/individual. S. vulpis distribution in Valencian Community presents sharply defined areas in which there are optimal environmental conditions for maintaining the life cycle of this parasite. Climatic variables and altitude are the main factors influencing the parasite presence. Our results indicate that S. vulpis has epidemiological characteristics similar to those of S. lupi and, therefore, based on the phylogenetic proximity of both nematode species, it is likely that coprophagous beetle species might play a key epidemiological role in the maintenance of this newly described Spirocerca species. Moreover, it is currently unknown if S. vulpis can infect the dog and other wild canid species apart from the red fox and, if so, what are the pathogenic effects on these host species. Therefore, it is necessary to continue investigating the epidemiology of this parasite in order to know the range of appropriate host species. This information will enable to know if S. vulpis endemic areas should be considered as health risk points for dogs, especially for the most exposed, such as those living in rural areas, and hunting dogs.

Phylogenetic analysis of Spirocerca lupi and Spirocerca vulpis reveal high genetic diversity and intra-individual variation

Background

Spirocerca lupi is a parasitic nematode of canids that can lead to a severe and potentially fatal disease. Recently, a new species, Spirocerca vulpis, was described from red foxes in Europe, suggesting a high genetic diversity of the Spirocerca spp. infecting canids. The genetic variation and phylogenetic relationships of S. lupi collected from naturally-infected domestic dogs from Australia, Hungary, Israel, Italy, India and South Africa, and S. vulpis from red foxes from Bosnia and Herzegovina, Italy and Spain, was studied using mitochondrial and rDNA markers.

Results

A high intra-individual variation was found in the first internal transcribed spacer (ITS1) locus in all Spirocerca spp., ranging between 0.37–2.84%, with up to six haplotypes per specimen. In addition, a combination of phylogenetic and haplotype analyses revealed a large variability between S. lupi specimens collected from different geographical locations using the ITS1 (0.37–9.33%) and the cytochrome c oxidase subunit 1 (cox1) gene (1.42–6.74%). This genetic diversity led to the identification of two S. lupi genotypes circulating among dogs (PTP support > 0.829), including genotype 1 found in S. lupi from Australia, India, Israel and South Africa, and genotype 2 represented by specimens from Hungary and Italy. These genotypes presented pairwise nucleotide distances of 0.14%, 8.06% and 6.48 ± 0.28% in the small rDNA subunit (18S), ITS1 and cox1 loci, respectively. Additionally, Nei’s genetic distance in the ITS1 showed a further subdivision of genotype 1 worms into 1A (Israel and South Africa) and 1B (Australia and India). A morphological analysis of the anterior and posterior extremities of genotype 1 and genotype 2 worms using scanning electron microscopy did not show any differences between the specimens, contrary to the morphological differences between S. lupi and S. vulpis.

Conclusions

These findings demonstrate the high genetic variability among Spirocerca spp. from different geographical locations, thereby expanding our understanding of the epidemiology, evolution and phylogenetic variability within the genus.

Electronic supplementary material

The online version of this article (10.1186/s13071-018-3202-0) contains supplementary material, which is available to authorized users.