Speothos Venaticus Research Articles

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

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

Character displacement under influence of Bergmann's rule in Cerdocyon thous (Mammalia: Canidae)

In South America, the crab-eating fox Cerdocyon thous occurs in sympatry to the ecologically similar, and phylogenetically close Lycalopex vetulus to the North, and Lycalopex gymnocercus to the South of its range. We studied character displacement in Cerdocyon under the effect of Bergmann's rule and the presence (or absence either) of Lycalopex within the crab-eating fox range. We performed skull shape analysis on 191 C. thous specimens and divided them in three distinct groups, depending on whether Cerdocyon occurs in sympatry or in allopatry to Lycalopex species. We tested for differences in size and shape between Cerdocyon groups and regressed both skull size and sexual size dimorphism against latitude and temperature, while controlling for spatial autocorrelation in the phenotypes. Southern Cerdocyon specimens present enlarged temporalis muscle and slender carnassial, both suggestive of a shift towards increased carnivory. Such a niche shift is interpreted as a mean to reduce competition to the larger Lycalopex species, which is still smaller than Cerdocyon . Consistently with the above, the degree of sexual shape and size dimorphism in Cerdocyon increases southward. We found a complex but coherent pattern of size and shape differentiation in Cerdocyon groups, which is consistent with the effects of both competition and Bergmann's rule. Cerdocyon reduces competition to Lycalopex by growing larger in the North. To the South, Cerdocyon is still larger, in keeping with Bergmann's rule, but strongly differs in skull shape from both its Lycalopex competitor and from any other Cerdocyon . Since the Southern Lycalopex species is much more similar in size to Cerdocyon than its Northern congeneric, this suggests that shape differences serve the goal of reducing competition between Cerdocyon and Lycalopex to the South, as size differences do to the North. The absence of the hypercarnivorous canid Speothos venaticus from the southern range of Cerdocyon may have allowed such a pattern to take place.

A review of bush dog Speothos venaticus (Lund, 1842) (Carnivora, Canidae) occurrences in Paraná state, subtropical Brazil.

We report six new occurrence records of the bush dog Speothos venaticus, a widely distributed South American carnivore that is threatened with extinction. These records are accompanied by notes on the places where the records were made, such as vegetation type, date and information about the protection of areas. The records, obtained over the last 17 years in Paraná state, southern Brazil, offer an improved understanding of the species geographic range and the threats it faces and can enable better assessments of the conservation status of the species in southern Brazil.

New-record of the bush dog speothos venaticus in a human-altered landscape in west Minas Gerais, Brazil

The bush dog ( Speothos venaticus ) is a Neotropical canid with a wide geographic distribution. Although globally listed as Near Threatened, this species was listed as Vulnerable in a recent assessment by the Brazilian government. Few records of this mammal have been reported in the Brazilian Cerrado, and it is considered extinct in several localities as a result of human landscape fragmentation. The record presented here is the first evidence of bush dog presence in West Minas Gerais, Brazil, which augments the species distribution with expected occurrence for this region. The study site was a transitional area between the Cerrado and Atlantic Forest biomes, in the Triângulo Mineiro region, which is a highly fragmented landscape, dominated by cattle ranches with exotic pasture species and scattered natural patches. We only recorded a single bush dog individual in our survey (4,036 camera trap/night), but our sampling success was expected compared with that of other previous mammal surveys using the camera trapping method, in part, because of the species’ elusive behavior and low natural densities. This record enhances knowledge of the S. venaticus distribution. Potentially, we confirm the presence of the bug dog in a region that was regarded being environmentally suitable for this species occurrence, but where it has never been reported. Moreover, our result elucidates the potential of the natural remnants to harbor threatened species in highly human-influenced and non-protected landscapes, which is the dominant scenario found in West Minas Gerais, Brasil. .

Ecogeographical Variation in Skull Shape of South-American Canids: Abiotic or Biotic Processes?

Species morphological changes can be mutually influenced by environmental or biotic factors, such as competition. South American canids represent a quite recent radiation of taxa that evolved forms very disparate in phenotype, ecology and behaviour. Today, in the central part of South America there is one dominant large species (the maned wolf, Chrysocyon brachyurus) that directly influence sympatric smaller taxa via interspecific killing. Further south, three species of similar sized foxes (Lycalopex spp.) share the same habitats. Such unique combination of taxa and geographic distribution makes South American dogs an ideal group to test for the simultaneous impact of climate and competition on phenotypic variation. Using geometric morphometrics, we quantified skull size and shape of 431 specimens belonging to the eight extant South American canid species: Atelocynus microtis, Cerdocyon thous, Ch. brachyurus, Lycalopex culpaeus, L. griseus, L. gymnocercus, L. vetulus and Speothos venaticus. South American canids are significantly different in both skull size and shape. The hypercarnivorous bush dog is mostly distinct in shape from all the other taxa while a degree of overlap in shape—but not size—occurs between species of the genus Lycalopex. Both climate and competition impacts interspecific morphological variation. We identified climatic adaptations as the main driving force of diversification for the South American canids. Competition has a lower degree of impact on their skull morphology although it might have played a role in the past, when canid community was richer in morphotypes.Electronic supplementary materialThe online version of this article (doi:10.1007/s11692-015-9362-3) contains supplementary material, which is available to authorized users.

Records of the bush dog (Speothos venaticus) in Central Amazonia, Brazil

The bush dog (Speothos venaticus) is a small Neotropical canid. Although its distribution covers the entire Amazon basin, the occurrence of bush dogs in vast areas of the Amazon remains hypothetical. The records of bush dogs presented in this study reduce a large gap in the known distribution of the species in Central Amazonia and include the 1st documentation of the species from forest seasonally flooded by black water (Igapo). O cachorro-vinagre e um canideo Neotropical de pequeno porte. Apesar de sua distribuicao cobrir toda a Bacia Amazonica, existem apenas alguns registros da especie neste bioma. Portanto, a ocorrencia do cachorro-vinagre permanece hipotetica em vastas areas da Amazonia. Os registros de cachorro-vinagre apresentados neste trabalho reduzem uma enorme lacuna dentro da area de distribuicao conhecida para a especie na Amazonia Central, e incluem a primeira documentacao da especie em floresta sazonalmente alagada por aguas pretas (Igapo).

Morphometric analysis of the mandibular foramen of Bush Dog (Speothos venaticus, LUND 1842)

The objective of this work was to perform a morphometric evaluation of the mandibular foramen of Bush Dog in order to establish its more precise topography and to offer subsides for a more effective local anesthetic blockage of the mandibular alveolar nerve. Twenty hemimandibles of Bush Dog (Speothos Venaticus) were used. With the aid of a universal caliper rule, the 6 reference points were measured: LONG (from the most lateral margin of the condylar process up to the first inferior incisor tooth); TRANS (from the ventral margin up to the dorsal mandible margin between the second premolar tooth and the first inferior molar tooth); FVENTRAL (from the most rostral margin of the mandibular foramen up to the ventral mandibular margin); ANG (from the end of the most rostral margin of the mandibular foramen up to the mandible angular process), COND (from the end of the most rostral margin of the mandibular foramen up to the medial margin of the mandible condylar process) and COR (from the most rostral margin of the mandibular foramen up to the medial margin of the mandible cononoid process). Following, the data obtained were submitted to descriptive statistical analysis and to the student’s t-test with p = 0.05. It was observed that for a better local anesthetic blockage of the inferior alveolar nerve, the needle should be introduced 13,11 to 14,01 mm from the mandible ventral margin and 21,45 to 21,94 mm from the angular process.

Transmissibility of Leishmania infantum from maned wolves (Chrysocyon brachyurus) and bush dogs (Speothos venaticus) to Lutzomyia longipalpis

Leishmania (Leishmania) infantum is the cause of visceral leishmaniasis in the Americas. The disease is transmitted mostly through the bite of the invertebrate vector, the phlebotomine Lutzomyia longipalpis in the New World. Although the domestic dog is considered the most important reservoir of the disease, other mammalian, including wildlife, are susceptible to infection. The goal of this study was to perform xenodiagnosis to evaluate the capacity of naturally infected maned wolves (Chrysocyon brachyurus) and bush dogs (Speothos venaticus) to transmit Leishmania infantum to female sand flies (L. longipalpis). Xenodiagnoses were performed in February and August, 2013, when 77.7% (three maned wolves and four bush dogs) or 100% of the animals were positive, respectively. However, parasite loads in the engorged sand flies was low (<200 promastigotes and <150.2parasites/μg of DNA). No statistically significant differences were observed between the two species or the two time points (February and August). In conclusion, this study demonstrated that maned wolves (C. brachyurus) and bush dogs (S. venaticus) asymptomatically infected with L. infantum are capable of transmitting L. infantum to the invertebrate host L. longipalpis, although the parasite loads in engorged phlebotomines exposed to these animals were very low.

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First paragraph: Ixodes boliviensis Neumann, 1904 was originally described from a male, female and nymph collected from a bush dog Speothus venaticus Lund, 1842 in Bolivia (Neumann 1904). Subsequently, this tick has been reported parasitizing several species of mammals, especially Carnivora, in locations ranging from Mexico to Bolivia (Guglielmone et al . 2004). Throughout Mexico and Central America this species is more common in mountainous areas, at altitudes varying from 800 to 2500 m (Alvarez et al. 2005, Bermudez & Miranda 2011, Troyo et al . 2014); though in Mexico has also been reported in lowlands (Guzman et al. 2007).

Diagnosis of Leishmania infantum infection by Polymerase Chain Reaction in wild mammals

Visceral leishmaniasis is a chronic infectious disease caused by Leishmania infantum (synonym: Leishmania chagasi) and transmitted by the sandfly Lutzomyia longipalpis in Brazil. It is an endemic zoonosis in several regions of the country, including Belo Horizonte (State of Minas Gerais). In urban areas, the domestic dog is susceptible and considered the most important animal reservoir. However, L. infantum has been previously diagnosed in other species, including captive primates and canids. This study aimed to evaluate the presence of the agent DNA in captive animals as well as some free ranging animals from the Zoo-Botanical Foundation of Belo Horizonte by Polymerase Chain Reaction. Eighty one blood samples from primates, carnivores, ruminants, edentates, marsupial, and a monogastric herbivore were analyzed. Three primates Alouatta guariba (brown howler monkey), and two canids Speothos venaticus (bush dog) were positive, demonstrating the importance of leishmaniasis control in endemic areas for preservation of wildlife species in captivity.

Behavioral responses to mammalian blood odor and a blood odor component in four species of large carnivores.

Only little is known about whether single volatile compounds are as efficient in eliciting behavioral responses in animals as the whole complex mixture of a behaviorally relevant odor. Recent studies analysing the composition of volatiles in mammalian blood, an important prey-associated odor stimulus for predators, found the odorant trans-4,5-epoxy-(E)-2-decenal to evoke a typical “metallic, blood-like” odor quality in humans. We therefore assessed the behavior of captive Asian wild dogs (Cuon alpinus), African wild dogs (Lycaon pictus), South American bush dogs (Speothos venaticus), and Siberian tigers (Panthera tigris altaica) when presented with wooden logs that were impregnated either with mammalian blood or with the blood odor component trans-4,5-epoxy-(E)-2-decenal, and compared it to their behavior towards a fruity odor (iso-pentyl acetate) and a near-odorless solvent (diethyl phthalate) as control. We found that all four species displayed significantly more interactions with the odorized wooden logs such as sniffing, licking, biting, pawing, and toying, when they were impregnated with the two prey-associated odors compared to the two non-prey-associated odors. Most importantly, no significant differences were found in the number of interactions with the wooden logs impregnated with mammalian blood and the blood odor component in any of the four species. Only one of the four species, the South American bush dogs, displayed a significant decrease in the number of interactions with the odorized logs across the five sessions performed per odor stimulus. Taken together, the results demonstrate that a single blood odor component can be as efficient in eliciting behavioral responses in large carnivores as the odor of real blood, suggesting that trans-4,5-epoxy-(E)-2-decenal may be perceived by predators as a “character impact compound” of mammalian blood odor. Further, the results suggest that odorized wooden logs are a suitable manner of environmental enrichment for captive carnivores.

The bush dogSpeothos venaticus: area requirement and habitat use in cultivated lands

AbstractWe radio-tracked a pack of bush dogsSpeothos venaticus(7–10 individuals) near Água Boa in Mato Grosso, Brazil, for 18 months to investigate their use of habitat in cultivated land. The pack's home range was 709 km2(fixed-kernel 95%), which exceeds estimates of home range for the largest Neotropical carnivore, the jaguarPanthera onca. Of the 245 locations where the dogs were recorded 95% were within native vegetation (savannah and forest), even though these habitats comprised only 34% of the pack's home range. This indicates a preference for native vegetation, and this was reinforced by composition analysis of habitat use, which showed that the pack used savannah and forest more than expected and cultivated areas less than expected. Analysis of activity showed that the bush dogs were moving quickly in more than half of the locations in cultivated areas, foraging in most savannah locations and resting in most forest locations. Our results indicate that bush dogs can live in areas with a high proportion of cultivated land (66%), possibly because of the structural connectivity of the landscape (80% of the native habitat is within a single patch). However, their home range appears to be inflated compared to that of other carnivores, which may have a negative effect on the species in the long term.

Noninvasive techniques provide novel insights for the elusive bush dog (Speothos venaticus)

The bush dog (Speothos venaticus), a small and rarely seen canid from Central and South America, has proven extremely challenging to locate and study in the wild, making the development of species-specific and comprehensive carnivore conservation strategies difficult. From May to August 2011, a detection-dog–handler team located 34 scats from bush dogs in the northern (n = 26) and central (n = 8) zones of Misiones, Argentina. We identified 22 unique genotypes (14 northern and 8 central) and assigned sex to 100% of the genotyped scats. Only half of the scats were located inside 7 protected areas (4 northern and 3 central); the remaining half were located in 4 sites outside of protected areas (3 northern and 1 central). Results suggest low but significant differentiation between zones for bush dogs (FST = 0.049, P = 0.010). Bush dogs demonstrated high habitat-use flexibility and a close association with altered habitat; however, altered habitat may not be optimal for the species because of the potential for lower prey densities and risk of exposure to life threatening diseases by domestic dogs. The effectiveness of noninvasive techniques (detection dogs, genetic analyses of scat, Geographic Information System technology) in studying the ecology of bush dogs not only opens the door for additional studies of a species that has proven difficult to study with standard survey techniques, but also provides an alternative approach that conservationists can use independent of habitat type and presence of humans. © 2014 The Wildlife Society.

Regionally extinct species rediscovered: the bush dog Speothos venaticus in Minas Gerais, south-eastern Brazil

AbstractThe bush dog Speothos venaticus, a rare Near Threatened South American canid that lives in packs, was thought to be extinct in Minas Gerais state, south-eastern Brazil, until recently. Here, we report four recent records of the species in Minas Gerais, the first in the state since the description of the species in 1842. All records are from the Cerrado ecosystem in the north and north-west of the state; two are from animals found dead, one from footprints and another from a camera trap. Three of the records were inside or close (&lt; 10 km) to strict protected areas, in a region recognized as the Protected Areas Mosaic Sertão Veredas–Peruaçu, where we expect any new records of the bush dog to be found. We discuss the low probability of detecting the bush dog and the main regional threats to the species, and emphasize the need to protect large and interconnected natural areas and keep them free of domestic dogs to avoid the extinction of the bush dog in Minas Gerais.

Bartonella clarridgeiae and Bartonella vinsonii subsp. berkhoffii exposure in captive wild canids in Brazil.

SUMMARY Wild canids are potential hosts for numerous species of Bartonella, yet little research has been done to quantify their infection rates in South America. We sought to investigate Bartonella seroprevalence in captive wild canids from 19 zoos in São Paulo and Mato Grosso states, Brazil. Blood samples were collected from 97 wild canids belonging to four different native species and three European wolves (Canis lupus). Indirect immunofluorescent antibody testing was performed to detect the presence of B. henselae, B. vinsonii subsp. berkhoffii, B. clarridgeiae, and B. rochalimae. Overall, Bartonella antibodies were detected in 11 of the canids, including five (12·8%) of 39 crab-eating foxes (Cerdocyon thous), three (11·1%) of 27 bush dogs (Speothos venaticus), two (8·7%) of 23 maned wolves (Chrysocyon brachyurus) and one (12·5%) of eight hoary foxes (Lycalopex vetulus), with titres ranging from 1:64 to 1:512. Knowing that many species of canids make excellent reservoir hosts for Bartonella, and that there is zoonotic potential for all Bartonella spp. tested for, it will be important to conduct further research in non-captive wild canids to gain an accurate understanding of Bartonella infection in free-ranging wild canids in South America.

Morphology of the lingual papillae of the black-backed jackal (Canis mesomelas).

We examined the dorsal lingual surface of an adult black-backed jackal (Canis mesomelas) by using scanning electron microscopy. The filiform papilla on the lingual apex exhibited a crown-like shape with several pointed processes. The connective tissue core of the filiform papilla was U-shaped. The filiform papillae on the lingual body had several pointed processes. The connective tissue core of the filiform papillae consisted of one large and several small conical papillae. The fungiform papillae on the lingual apex and body had a smooth surface. The connective tissue core of the fungiform papillae was not hollow and did not have processes. The vallate papillae were surrounded by a groove and pad with many processes on the surface. The connective tissue core of the vallate papillae had many ditches. Thus, the tongue of the black-backed jackal more closely resembles that of the bush dog than those of the raccoon dog or fox.

APPLYING CLINICALLY PROVEN HUMAN TECHNIQUES FOR CONTRACEPTION AND FERTILITY TO ENDANGERED SPECIES AND ZOO ANIMALS: A REVIEW

Reversible contraception that does not alter natural behavior is a critical need for managing zoo populations. In addition to reversible contraception, other fertility techniques perfected in humans may be useful, such as in vitro fertilization (IVF) or oocyte and embryo banking for endangered species like amphibians and Mexican wolves (Canis lupus baileyi). Furthermore, the genetics of human fertility can give a better understanding of fertility in more exotic species. Collaborations were established to apply human fertility techniques to the captive population. Reversible vasectomy might be one solution for reversible contraception that does not alter behavior. Reversible approaches to vasectomy, avoiding secondary epididymal disruption, were attempted in South American bush dogs (Speothos venaticus), chimpanzees (Pan troglodytes), gorillas (Gorilla gorilla), Przewalski's horse (Equus przewalski poliakov), and Sika deer (Cervus nippon) in a variety of zoos around the world. These techniques were first perfected in > 4,000 humans before attempting them in zoo animals. In vitro fertilization with gestational surrogacy was used to attempt to break the vicious cycle of hand rearing of purebred orangutans, and egg and ovary vitrification in humans have led to successful gamete banking for Mexican wolves and disappearing amphibians. The study of the human Y chromosome has even explained a mechanism of extinction related to global climate change. The best results with vasectomy reversal (normal sperm counts, pregnancy, and live offspring) were obtained when the original vasectomy was performed "open-ended," so as to avoid pressure-induced epididymal disruption. The attempt at gestational surrogacy for orangutans failed because of severe male infertility and the lack of success with human ovarian hyperstimulation protocols. Vitrification of oocytes is already being employed for the Amphibian Ark Project and for Mexican wolves. Vasectomy can be a reversible contraception option in zoo animals, even in endangered species. Ongoing use of gamete and embryo freezing may salvage vanishing species.

Neotropical echinococcosis: Second report of Echinococcus vogeli natural infection in its main definitive host, the bush dog (Speothos venaticus)

The bush dog (Speothos venaticus) acts as the natural definitive host in the life cycle of Echinococcus vogeli, the causative agent of polycystic hydatid disease, a zoonotic neglected disease in the South America. We report a case of natural infection by Echinococcus vogeli in a bush dog from the Brazilian Amazon, confirmed by the morphological and morphometric examination of adult parasites and their hooks obtained from the small intestine of the canid. Additionally, mitochondrial DNA sequence analysis corroborated these findings. This is the second report of natural infection by E. vogeli in a bush dog.

Primera identificación de Echinococcus vogeli en una paca en la provincia de Misiones, Argentina

We report the first finding of Echinococcus vogeli in a paca, Cuniculus paca, in the tropical forest of Misiones, in the north of Argentina. The presence of the bush dog, Speothos venaticus, E. vogeli's only natural definitive host, was also reported. The polycystic hydatids, 2 to 3cm in diameter, were only found in the liver of an adult paca. The size range of the hooks and the relative proportion blade/handle did not show significant differences with respect to the ones reported for E. vogeli. The size of E. granulosus hooks, measured for comparison purposes, was significantly smaller (p<0.0001). These results confirmed the presence of E. vogeli in Argentina. The probability of finding neotropical echinococcosis in humans reinforces the need to expand the search for E. vogeli in Argentina. Echinococcosis due to E. vogeli is very aggressive and may cause death in about a third of the human population affected.

Variable inbreeding effects across life‐history stages in a captive carnivorous mammal population

AbstractStudies evaluating inbreeding depression and purging in captive populations often focus on a single life‐history stage, commonly juvenile survival, using it as a binomial response variable to model inbreeding effects. Through the use of a statistical procedure known as survival analysis, and focusing on four life stages, we examined the effects of inbreeding and other demographic and life‐history variables on the survival of the bush dog Speothos venaticus captive population. Through generalized linear mixed models, we assessed the impact of these variables upon litter sizes and proportional viability of pups within a litter. We found a negligible effect of inbreeding on survival in two viability periods up to weaning age. On the other two life stages, up to the age of sexual maturity, inbreeding assumed a negative effect on survival. Individual inbreeding led to decreased litter size, whereas maternal age negatively affected litter sizes and the proportional viability of pups within the litter. Partial purging could have removed some genetic load in this captive population; however, our results indicate that even in populations maintained in benign conditions of captivity, deleterious effects of inbreeding are differentially expressed across life‐history stages. Our results also underscore that investigating a single life‐history stage could lead to erroneous conclusions about inbreeding and purging effects, misguiding management of captive populations.