Severe hydrocephalus in a raccoon dog (Nyctereutes procyonoides)

Hydrocephalus is one of the most common central nervous system malformations in domestic dogs, yet they are poorly documented and studied in wild carnivoran mammals. A pup of raccoon dog (Nyctereutes procyonoides) was rescued and brought to Wildlife Center. The pup showed generalized ataxia, a domed skull, and an open bregmatic fontanelle. Ultrasound and MRI showed severe enlargement of the lateral ventricle with the loss of septum pellucidum resulting in a single large ventricle and cervical syringohydromyelia. Although treatment was attempted, the animal was euthanized due to poor prognosis. At necropsy, macroscopic findings were identical to the diagnostic imaging, where marked enlargement of the calvarium, and attenuated gyri and sulci were observed. Finally, hydrocephalus was confirmed. Here, we describe a case of hydrocephalus in a raccoon dog (Nyctereutes procyonoides).     

Clinical features of experimental trichinellosis in the raccoon dog (Nyctereutes procyonoides)

Three groups of six raccoon dogs (Nyctereutes procyonoides) were provided for the experiment: the first group was infected with pig-origin Trichinella spiralis, the second with raccoon dog-origin Trichinella nativa, and the third served as controls. Infection dose for both parasite species was 1000 larvae/kg of body weight, which led to intense final infection. Clinical signs, haematology and serum biochemistry with repeated blood samples were monitored up to 12 weeks post-infection. The most significant findings were a short-term eosinophilia in peripheral blood from the end of the first week post-infection until the end of the third week, loss of weight, and mild anaemia. In the early phase of the infection, the animals had gastrointestinal signs, loss of appetite and diarrhoea. No specific differences in clinical findings could be noticed between the groups infected with T. nativa and T. spiralis. In contrast to the symptoms reported in human outbreaks, fever was not observed in any of the infected animals and serum levels of muscle-specific enzymes did not change. No acute-phase response was observed in the enteral or parental phase of the infection. These findings indicate that because Trichinella spp. are very well adapted to the raccoon dog, it thus, could serve as the most crucial reservoir animal for sylvatic trichinellosis in Finland.     

Listeriosis in a raccoon dog (Nyctereutes procyonoides) associated with canine distemper

A wild raccoon dog (Nyctereutes procyonoides) that manifested severe illness and died was examined. Necropsy revealed severe emaciation, systemic icterus and petechial hemorrhages on the mucous membranes. Histopathologically, necroses were seen in the liver and brain stem associated with meningitis. Eosinophilic intranuclear inclusion bodies were observed in the spleen and intestinal mucosa, and eosinophilic intracytoplasmic inclusion bodies were seen in transitional epithelium in the bladder. Listeria monocytogenes 4b was isolated from the liver, spleen, kidneys and lungs, and the pathogen was also detected in the liver and brain stem immunohistopathologically. The disease was diagnosed as listeriosis associated with canine distemper virus infection in a raccoon dog.     

First record of Cryptosporidium infection in a raccoon dog (Nyctereutes procyonoides viverrinus)

Cryptosporidium species have been found in more than 150 species of mammals, but there has been no report in raccoon dogs. Here we found the Cryptosporidium organism in a raccoon dog, Nyctereutes procyonoides viverrinus, and identified this isolate using PCR-based diagnostic methods. Cryptosporidium diagnostic fragments of the 18S ribosomal RNA, Cryptosporidium oocyst wall protein and 70-kDa heat shock protein genes were amplified from the isolate and sequenced to reveal the phylogenetic relationships between it and other Cryptosporidium species or genotypes reported previously. The results showed that the raccoon dog isolate represented the C. parvum cattle genotype which could be a causative agent in human cryptosporidiosis.     

Influence of dietary protein level and the amino acids methionine and lysine on leather properties of blue fox (Alopex lagopus) pelts.

The influence of dietary protein, methionine, and lysine on leather quality in blue fox pelts was studied. The pelt material originated from animals in two consecutive feeding trials (Exp. 1 and Exp. 2) with three protein levels: conventional, slightly lowered, and very low. The two lowest protein diets were fed as such or as supplemented with methionine or with lysine (lysine only in Exp. 2). The following physical leather properties were measured: breaking load (BRL), tensile strength (TEN), relative elongation at break (PEB), straining of skins at pelting, and shrinkage at dressing. A decline in the dietary protein content reduced BRL and, hence, leather firmness, and increased straining and the corresponding shrinking in Exp. 1. The supplemented methionine tended to improve leather strength and elasticity by increasing TEN and PEB in Exp. 1, whereas lysine elicited no response. Methionine supplementation at the slightly lowered protein level increased BRL in both experiments by almost 10% as compared with the respective non-supplemented diet. We conclude that with high protein quality diets, a level of 200 g/kg DM (as digestible protein) appears to be adequate for producing pelts with firm, elastic leather, provided that an adequate amount of methionine is included in the diet.     

Periovulatory endocrinology and oocyte maturation in unmated mature blue fox vixens (Alopex lagopus)

Nine of 10 mature blue fox vixens (Alopex lagopus) in spontaneous oestrus ovulated approximately 2 days after the preovulatory increase in luteinizing hormone (LH). Plasma concentrations of follicle-stimulating hormone and progesterone increased simultaneously with the LH peak, whereas oestradiol-17 beta peaked 1 day previously. In the tenth vixen, an LH peak was not observed, and neither visible follicles nor corpora lutea were found in the ovaries 6 days after peak vaginal electrical resistance. Eggs were ovulated as primary oocytes, but oocyte maturation was initiated within the day of ovulation (2 days after the LH peak). Within the next 2 days (3-4 days after the LH peak) the first polar body was extruded, and the cumulus mass was completely dissociated from the zona pellucida. The interval between the preovulatory LH peak and initiation of the final oocyte maturation is thus considerably longer in the blue fox than for example in the cow (48-72 h compared with 9-12 h). This suggests that the relationship between these two events is somewhat different in the blue fox.     

育成期舍饲蓝狐结肠菌群多样性分析

旨在分析蓝狐结肠菌群的组成及其多样性,为蓝狐肠道菌群体外培养提供基础数据。随机选取6只健康育成期(3～4月龄)雌性舍饲蓝狐,采集结肠食糜后采用高通量测序技术对蓝狐结肠菌群结构进行分析。结果表明:6个样品共获得377 798条有效序列,平均为62 966条有效序列;共获得2 064个OTU,平均为307个OTU,归类于12菌门、180个菌属。在门分类水平上,以厚壁菌门(Fir-micutes,70.25%)、拟杆菌门(Bacteroidetes,22.36%)、变形菌门(Proteobacteria,5.69%)、放线菌门(Acti-nobacteria,1.13%)为主,4个菌门占所有细菌总数的99.43%。在属分类水平上,以乳杆菌属(Lactoba-cillus,28.50%)、巨单胞菌属(Megamonas,7.48%)、拟普雷沃菌属(Alloprevotella,7.41%)、Peptoclostridi-um(6.33%)、乳球菌属(Lactococcus,5.38%)、Dialiste (4.39%)、巨型球菌属(Megasphaera,3.53%)、De-sulfovibrio(2.97%)、拟杆菌属(Bacteroides,2.48%)、unidentified_Lachnospiraceae(2.38%)为主。结果表明,在饲养条件下,蓝狐结肠中具有相对复杂的菌群结构,且个体间存在较大差异,研究为课题组进一步揭示蓝狐结肠菌群功能以及探索蓝狐结肠菌群体外培养研究提供了基础数据。     

Reproduction of the raccoon dog (Nyctereutes procyonoides) after feeding or food deprivation in winter

The wild raccoon dog (Nyctereutes procyonoides, Canidae, Carnivora) goes through autumn fattening followed by winter sleep. Farmed raccoon dogs also exhibit autumn fattening but not winter sleep, as a result of daily feeding and lack of nests. We studied the effects of food deprivation and winter sleep or active winter feeding on the physiology and reproduction of farm-born raccoon dogs. Eighty-six animals were put on a 2-month fast in November-December. The fast caused no deleterious effects on the health of the raccoon dogs. In the spring the food-deprived animals had slightly more cubs per mated female than the fed animals. There was a significant negative correlation between the number of cubs obtained and the mean body mass of the females at the beginning of the mating season. The highest mean number of cubs was obtained by the females that weighed 5-7 kg. The results indicate that the raccoon dog is finely adapted to a long period of food deprivation in the winter. Furthermore, winter sleep and food deprivation could be introduced to farm conditions by providing the raccoon dogs with nestboxes and withholding food for a period of 6-8 weeks in mid-winter.     

On pseudorabies in carnivores in Denmark. II. The blue fox (Alopex lagopus)

In the autumn of 1968 Pseudorabies was demonstrated in blue foxes (Alopex lagopus) on two fur farms in Jutland. The foxes had been fed with dead piglets from herds of swine belonging to the two farmers.At the same time the disease was diagnosed in piglets from these herds. At the two fur farms there were, respectively, 34 and eight foxes in all; respectively 26 and two died with signs of pruritus. Only few of the surviving foxes had had the opportunity to eat piglets. Eight weeks after the period of disease no antibodies against psedorabies virus could be demonstrated in serum of three surviving foxes.The virus content in various organs of six foxes submitted to the Laboratory was determined by titration in tissue cultures (Table 1).The results indicate that the spreading of virus from the port of entry of the virus to the brain must have occurred by nervous routes.The presence of virus in the tonsils of five of the six foxes and in the nasal mucosa of the sixth one, together with similar results from examination of dogs at this institute would seem to suggest that a transmission of the disease from these carnivores to other animals is possible.Based upon the high virus titers in the medulla oblongata and pons, and with reference to similar results of examination of dogs and to a previous publication on Pseudorabies in Danish red foxes, it is concluded that these tissues must be the material of choice for demonstration of Pseudorabies virus in these carnivores.     

Neuropathology and host-parasite relationship of acute experimental toxoplasmosis of the blue fox (Alopex lagopus)

The neuropathology and host-parasite relationship of experimental infection with the RH-strain of Toxoplasma gondii were studied in 27 blue foxes (Alopex lagopus) aged 0 to 23 days, using light microscopy, including immunohistochemical staining, and transmission and scanning electron microscopy. All cases displayed multifocal necrotic lesions with numerous parasitic tachyzoites in the brain and spinal cord. The gray matter and the meninges were most seriously affected. Although a wide variety of cell types were parasitized, neurons and astrocytes seemed to be the main target cells. Individual parasitophorous vacuoles usually contained only a few tachyzoites, with rosette formations as a prominent feature. The present ultrastructural study supports the theory that the parasites actively invade the host cells by mechanisms that are different from those of phagocytosis. This is apparently the first report indicating that the formation of the network of tubular structures within the parasitophorous vacuole of T. gondii is associated with a transient, sack-like formation in the posterior end of the tachyzoites.     

Comparison between microscopic and automated differential leukocyte counts in the silver fox (Vulpes vulpes) and the blue fox (Alopex lagopus)

Differential leukocyte (WBC) counts in blood from clinically healthy silver foxes (n=32) and blue foxes (n=37) obtained from an automated hematology analyzer (Technicon H*1 Hematology System) with canine software were compared with microscopic differential WBC counts (M-diff). There was good agreement between the automated differential cell count (A-diff) and the M-diff for neutrophil and lymphocyte percentages. The correlation was lower for monocyte percentages and variable for eosinophil percentages. There was no significant difference between the A-diff and M-diff in either fox species. The A-diff counts were very precise, and may be a good alternative to the traditional M-diff for screening populations of clinically healthy foxes or for studies on stress and animal welfare. Intercept values, however, indicated a constant bias that must be taken into account before interpreting results based on different methods of analysis     

Trichinella nativa and T. spiralis induce distinguishable histopathologic and humoral responses in the raccoon dog (Nyctereutes procyonoides)

Three experimental groups of six male raccoon dogs (Nyctereutes procyonoides) each were formed by placing one of three littermates from six litters into each group. One group was inoculated with pig-origin Trichinella spiralis, the second was inoculated with raccoon dog-origin T. nativa, and the third served as a control group. The infective dose was 1,000 larvae/kg of body weight. Every third week, biopsies from M. triceps brachii were taken, and serum samples were collected for up to 12 weeks postinfection. In the early phase of the infection, cysts of both parasites were elongated cylinders that later became more spherical. However, at the end of the experiment, the cysts of T. nativa were more rounded than those of T. spiralis (mean length/width = 2.5 versus 1.5 in T. spiralis versus T. nativa, respectively). Both species accumulated a collagen-rich capsule around the nurse cell, but the capsule was thicker in T. nativa. In both parasites, the total surface area of the sagittal section of the cyst was equal. Inflammation was more intense around T. nativa cysts. Specific antibodies were recognizable 2 weeks after infection by both enzyme-linked immunosorbent assay (ELISA) and western blot. In western blots, serum from both T. nativa- and T. spiralis-infected animals recognized the same components, but reaction with the homologous antigen was stronger. The same pattern was also seen in the ELISA. Immunoreactive epitopes were localized only in internal organs and cuticula of larvae in muscle.     

The raccoon dog (Nyctereutes procyonoides) as definitive host for Sarcocystis spp. of reindeer (Rangifer tarandus)

A raccoon dog (Nyctereutes procyonoides; Family: Canidae), was given cardiac muscle of reindeer infected with S. grueneri, and started shedding Sarcocystis sporocysts 10 days post feeding. The sporocysts measured 13.9 (12.4–15.7) × 10.1 (9.2–11.2) µm, and were excreted for at least 16 days. The raccoon dog is thus an additional definitive host for S. grueneri (Yakimoff & Sokoloff, 1934) Gjerde, 1984.Another raccoon dog was given skeletal muscle infected with 4 species of Sarcocystis, none of which was S. grueneri. The raccoon dog started shedding Sarcocystis sporocysts on day 10 post feeding, and excreted sporocysts for at least 16 days. The sporocysts measured 14.0 (12.3–15.6) × 10.1 (9.2–11.2) µm, and are considered to be sporocysts of S. tarandivulpes Gjerde, 1984.This is the first record of the raccoon dog as an experimental definitive host for Sarcocystis.     

The raccoon dog (Nyctereutes procyonoides) in Germany--an established Neozoon as host and vector for parasites and other pathogenes

Some invasive wildlife species have the potential to act as additional host and vector species for parasitic and other infectious diseases. We used the raccoon dog (Nyctereutes procyonides), a carnivore species that has its origin in Asia, as an example to demonstrate biological and ecological prerequisites which enables an invasive species to occupy a new habitat permanently. Studies conducted during the last ten years identified a total of 23 endoparasites, two ectoparasites, six bacterial or protozoan species and five viruses, found in the Nyctereutes procyonoides ussuriensis subspecies in its newly occupied range or in N. procyonoides koreensis in its original range. Results of studies in Finland and Germany furthermore showed that biological characteristics of the raccoon dog make this carnivore an appropriate host or vector for a variety of parasites and infectious diseases. This may result in a growing importance of this invasive carnivore for the epidemiology of transmissible diseases in Germany. Especially with regard to zoonotic disease outbreaks, the raccoon dog should therefore be paid more attention in disease prevention and eradication strategies.     

An outbreak of septic endometritis in the Arctic blue fox (Alopex lagopus) caused by Clostridium carnis

An outbreak of endometritis and septicaemia in farms that raise Arctic blue foxes is described. Eleven animals from eight different farms were examined, most of them pregnant or with newly delivered litters. Pathological examination indicated inflammation of the uterus, and focal necrotic changes in the liver. In some animals evidence of hemorrhaging was found in the anterior part of the small intestine. Bacteriological examination revealed abundant growth from different organs of the animals of a pure culture of a small, slender, Gram-variable, sporeforming rod, which was identified phenotypically as aerotolerant Clostridium carnis. This identification was confirmed by DNA hybridization. The organism caused death in mice 1–2 days after intraperitoneal inoculation, and killed an Arctic blue fox which was inoculated intracervically. Two foxes, pretreated with diethyl-stilboestrol, became seriously ill after intrauterine inoculation, but survived. The spontaneous outbreak of the disease was characterized by sudden onset of septicaemia with few or no clinical symptoms before the animals succumbed.     

Altered expression of melanocortin-1 receptor (MC1R) in a yellow-coloured wild raccoon dog (Nyctereutes procyonoides)

Background – The melanocortin 1 receptor (MC1R) gene plays a key role in determining coat colour in mammals by controlling the proportion of eumelanin and pheomelanin granules. Wild raccoon dogs have a mixed coat colour, with black to brown and grey hairs. Hypothesis/Objectives – The study was performed to identify the cause of the variant yellow coat colour in a wild raccoon dog. Animals – A wild raccoon dog that showed coat colour change to yellow and four wild‐type raccoon dogs that showed normal coat colour were included. Methods – To identify the cause of the variant yellow coat colour, we examined the sequence of the MC1R gene and its expression at the mRNA and protein levels. Results – The coding region of the MC1R gene of this raccoon dog comprised 954 bp, the same as for wild‐type raccoon dogs and domestic dogs. By comparing the gene with that in the wild‐type raccoon dog, a 2 bp deletion was detected in the 5′‐untranslated region, positioned 152 bp upstream of the start codon. However, there was no significant difference in the mRNA expression level. The yellow raccoon dog revealed a significantly decreased MC1R protein level compared with the wild‐type raccoon dogs, indicating an increase in pheomelanin synthesis. Conclusions and clinical importance – These results suggest that the variant coat colour in the yellow raccoon dog was associated with decreased MC1R function.     

Radiographic evaluation of congenital vertebral anomalies in Korean raccoon dogs (Nyctereutes procyonoides koreensis)

BackgroundThe normal vertebral anatomy of Korean raccoon dogs and their variants require research attention as a prerequisite for identifying pathologies and anomalies.ObjectivesThis retrospective study aimed at describing the vertebral formula and congenital vertebral anomalies in Korean raccoon dogs (Nyctereutes procyonoides koreensis).MethodsRadiographs of 82 raccoon dogs (42 males, 40 females) acquired from May 2013 to June 2020 in the Gangwon Wildlife Medical Rescue Center were reviewed to evaluate the cervical, thoracic, and lumbar vertebrae of the spine.ResultsNormal morphology of all vertebrae was observed in 50 of the 82 raccoon dogs, and the vertebral formula was cervical 7, thoracic 13, and lumbar 7. Congenital vertebral anomalies were found in 32 raccoon dogs: transitional vertebrae (TV) in 31 and block vertebrae in 2. Two raccoon dogs had 2 types of vertebral anomalies: one had TV and block vertebra, and the other had 2 types of TV. Twenty-nine raccoon dogs had thoracolumbar TV (TTV) and 3 had lumbosacral TV. TTV was morphologically classified into 4 different types: unilateral extra-rib in 5 raccoon dogs, bilateral extra-ribs in 14, bilateral elongated transverse processes in 4, and an asymmetric mixed formation of extra-rib with elongated transverse process in 6.ConclusionsThis study showed that TTV is common in Korean raccoon dogs, and that the vertebral formula is relatively diverse. The bilateral extra-ribs type TTV is the most common variant, which is almost similar to normal rib to be confused the radiographic evaluation.     

A case of granulosa cell tumour with cystic endometrial hyperplasia in a blue fox vixen (Alopex lagopus)

The clinical features of a case of granulosa cell tumour in the blue fox (Alopex lagopus) are described. The associated hormonal changes are discussed in relation to present knowledge of the regulation of the oestrous and furring cycles in this species.     

Health evaluation of arctic fox (Alopex lagopus) cubs in Sweden.

Hematologic, serum biochemistry, and serum cortisol reference ranges were established and tonsil/rectal bacterial and fecal parasite examinations were performed on 21 wild arctic fox (Alopex lagopus) cubs during July 1996. Several of the hematologic and serum biochemistry values fell within normal ranges for other wild canids or domestic dogs of the same age class. Serum alanine transaminase and creatine phosphokinase values were significantly higher in the youngest cubs. Proteus vulgaris and Escherichia coli were isolated from both tonsilar and rectal swabs of several cubs in all dens. The most common gastrointestinal parasite ova were Toxascaris leonina (59%), Isospora spp. (52%), Uncinaria stenocephala (33%), and Capillaria spp. (26%). Prevalence of T. leonina differed significantly between dens and between age groups. Hematologic and serum biochemistry values and degree of parasitism may be indicators of health, stress, and nutritional status of arctic foxes.