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At least 19 recordsLinked to original sources
PubMed1999

Toxoplasma gondii antibodies in naturally exposed wild coyotes, red foxes, and gray foxes and serologic diagnosis of Toxoplasmosis in red foxes fed T. gondii oocysts and tissue cysts.

Antibodies to Toxoplasma gondii were determined in sera from 222 coyotes (Canis latrans), 283 red foxes (Vulpes vulpes), and 97 gray foxes (Urocyon cinereoargenteus) from Indiana, Kentucky, Michigan, and Ohio during 1990-1993. Sera were examined in 1:25, 1:100, and 1:500 dilutions by the modified direct agglutination test (MAT) with formalinized whole tachyzoites plus mercaptoethanol. Antibodies were found in 131 (59.0%) of 222 coyotes, 243 (85.9%) of 283 red foxes, and 73 (75.3%) of 97 gray foxes. Antibodies were also measured by different serologic tests in 4 littermate T. gondii-free red foxes fed T. gondii tissue cysts or oocysts; the fifth littermate fox was not fed T. gondii. Antibodies were measured in fox sera obtained 0, 14, and 36-55 days after infection with T. gondii. All 4 foxes fed T. gondii developed MAT and dye test antibody titers of 1:200 or more 14 days later. The latex agglutination test (LAT) and indirect hemagglutination test (IHAT) were less sensitive than MAT for the diagnosis of T. gondii infection in foxes. Antibodies were not detected by LAT (titer 1:64) in the 2 foxes fed tissue cysts nor by IHAT in 1 of the foxes fed tissue cysts. Toxoplasma gondii was isolated by bioassay in mice from tissues of all 4 foxes fed T. gondii. The control fox had no T. gondii antibodies detectable by any of the serologic tests.

Agglutination Tests↗
PubMed1992

Metabolic rate and evaporative water loss at different ambient temperatures in two species of fox: the red fox (Vulpes vulpes) and the Arctic fox (Alopex lagopus).

1. Resting metabolic rate (RMR) and evaporative water loss (EWL) of adult red and arctic foxes were determined over ambient temperature (Ta) ranges of -13-37 degrees C and -5-30 degrees C as oxygen consumption and amount of water in expired air using an open flow system. 2. The average RMR was 2.60 +/- 0.14 W/kg for the winter red fox, 2.59 +/- 0.14 W/kg for the summer red fox, and 2.35 +/- 0.11 W/kg for the winter arctic fox. 3. The rate of increase of RMR was significant (P less than 0.05) only for Ta range above 27 degrees C. The slopes for this Ta range were 0.152 for the winter red fox, and 0.283 for the winter arctic fox. 4. The upper critical temperature (Tuc) of the red fox is probably between 30 and 32 degrees C. The Tuc of the arctic fox is probably between 26 and 28 degrees C. The lower critical temperatures (Tlc) were not reached. 5. A strong linear relationship between the EWL and Ta was found for Ta range above 27 degrees C. The slopes for this Ta range were 0.523 for the winter red fox, and 1.025 for the winter arctic fox. 6. Probably, there are neither significant intraspecific seasonal nor interspecific differences in the RMR and EWL. The two species seem to differ only in their critical temperatures.

Animals↗
PubMed1992

Diseases and parasites of red foxes, gray foxes, and coyotes from commercial sources selling to fox-chasing enclosures.

Fifty-six red foxes (Vulpes vulpes), 18 gray foxes (Urocyon cinereoargenteus), and 13 coyotes (Canis latrans) obtained by the South Carolina Wildlife and Marine Resources Department during an investigation of suspected illegal wildlife translocation were examined for diseases and parasites. Red foxes and coyotes were confiscated from an animal dealer based in Ohio (USA), and gray foxes were purchased from an animal dealer in Indiana (USA). Emphasis was placed on detection of pathogens representing potential health risks to native wildlife, domestic animals, or humans. All animals were negative for rabies; however, 15 gray foxes were incubating canine distemper at necropsy. Serologic tests disclosed antibodies to canine parvovirus, canine distemper virus, canine adenovirus, canine coronavirus, canine herpesvirus, and canine parainfluenza virus in one or more host species. Twenty-three species of parasites (two protozoans, three trematodes, four cestodes, eleven nematodes, and three arthropods) were found, including species with substantial pathogenic capabilities. Echinococcus multilocularis, a recognized human pathogen not enzootic in the southeastern United States, was found in red foxes. Based on this information, we conclude that the increasingly common practice of wild canid translocation for stocking fox-chasing enclosures poses potential health risks to indigenous wildlife, domestic animals, and humans and, therefore, is biologically hazardous.

Animals↗
PubMed1988

[Genome mapping of the silver fox. I. Determination of the chromosomal location of 8 fox genes and the search for homologous regions on fox and human chromosomes].

Twenty-three silver fox-Chinese hamster somatic cell hybrids were analysed for the expression of fox enzyme loci and the segregation of fox chromosomes. This analysis made it possible to assign the gene PGD to chromosome 2, MDH2 to chromosome 3. NP to chromosome 10. APRT, ENO1, PGM1 to chromosome 12, MDH1 and IDH1 to chromosome 16. Possible use of the above-mentioned clone panel for fox gene mapping is analysed. An attempt to reveal homologous regions on fox and human chromosomes was made by comparative analysis of prometaphase fox and human chromosomes containing the homologous genes. The means and perspectives of verification of the hypothesis proposed are discussed.

Animals↗
PubMed1984

The blood-testis barrier in sterile blue fox - silver fox hybrids compared with that in normal foxes of both species.

The integrity of the blood-testis barrier in the blue fox, the silver fox and hybrids of these 2 species was compared at the ultrastructural level during the breeding season by use of a lanthanum penetration technique. In the normal blue and silver fox, penetration of the tracer was blocked at the level of the inter-Sertoli cell junctions, whereas these junctions were permeable in the hybrids, permitting penetration of lanthanum into the adluminal compartment of the seminiferous epithelium. Spermatogenesis in the hybrids was found to be arrested at the early pachytene stage of meiotic prophase. The observed permeability of the inter-Sertoli cell contacts in the hybrids indicates a lack of occluding junctions, and this may be partly the cause of the sterility in these animals.

Animals↗
PubMed2005

A tale of two foxes--case reports: 1. Radial nerve paralysis treated with acupuncture in a wild fox. 2. Acupuncture in a fox with aggressive and obsessive behaviour.

Case 1. This is believed to be the first report of acupuncture treatment for traumatic radial nerve paralysis in a wild fox. From the first treatment, improvement in the range of mobility and sensation of the limb was evident. Additionally, the attitude of this wild animal changed from fear and aggression to complete cooperation: he lay peacefully during every treatment in a calm, drowsy state. Case 2. This reports the calming effects of acupuncture on a fox which had been showing aggressive behaviour and obsessive circling following toxoplasma infection.

Acupuncture Therapy↗
PubMed1977

Allelic expression in intergeneric fox hybrids (Alopex lagopus x Vulpes vulpes). II. Erythrocyte glucose-6-phosphate dehydrogenase in Artic and silver foxes: purification and properties.

The functional properties of purified glucose-6-phosphate dehydrogenase (G6PD) from the erythrocytes of Artic foxes (Alopex lagopus) and silver foxes (Vulpes vulpes) were investigated. It was found that pH optima for G6P D range from 8.15 to 8.25 in Arctic foxes and from 10.2 to 10.4 in silver foxes. For G6P, the estimated Km values were 74 X 10(-6) M (at pH 8.2) and 166 X 10(-6) M (at pH 10.2) in Artic foxes and 58 X 10(-6) M (at pH 10.2) and 40 X 10(-6) M (at pH 8.2) in silver foxes. The Km values for NADP were estimated as 62 X 10(-6) M (at pH 8.2) and 86 X 10(-6) M (at pH 10.2) in the Artic foxes and 15 X 10(-6) M (at pH 10.2) and 12 X 10(-6) M (at pH 8.2) in the silver foxes. It was found that Mg2+ ions exert a significant activating effect on G6P D in the Arctic fox and do not affect appreciably its activity in the silver fox. The experimental data indicate that slight differences in the electrophoretic mobility of G6P D are associated with considerable functional differences in this enzyme between the two fox species.

Animals↗
PubMed1981

Natural La Crosse virus infection in the red fox (Vulpes fulva), gray fox (urocyon cinereoargenteus), raccoon (Procyon lotor), and opossum (Didelphis virginiana).

Natural infection of sentinel red foxes (Vulpes fulva) and free-ranging red foxes, gray foxes (Urocyon cinereoargenteus) and raccoons (Procyon lotor) with La Crosse (LAC) virus was demonstrated. One isolate of LAC virus was obtained from a sentinel red fox in an enzootic area. The viremia titer of the LAC virus-infected red fox was above the threshold of infection for Aedes triseriatus mosquitoes. Antibody responses were measured by the microneutralization test employing four California group viruses: LAC, snowshoe hare, trivittatus, and Jamestown Canyon. Four of six sentinel red foxes developed LAC virus neutralizing antibody. Antibody titers peaked between days 7 and 34 and were still detectable by dat 345 post-infection. Homologous LAC virus antibody titers were consistently 4-fold or greater than heterologous titers. Serological evidence for natural LAC virus infection was demonstrated in 33 of 57 (58%) free-ranging red foxes, 18 of 32 (57%) gray foxes, and 4 of 16 (25%) raccoons. Antibody titers were comparable in free-ranging foxes infected naturally and those infected experimentally by mosquito bite. The prevalence of infection was significantly different (P less than 0.001) for foxes trapped on three distinct areas within the enzootic region. Rates of infection in foxes by area coincided with LAC virus antibody prevalence observed in free-ranging chipmunks and with reported cases of human LAC encephalitis in Wisconsin.

Animals↗
PubMed1981

Prevalence of selected pathogenic microbial agents in the red fox (Vulpes fulva) and gray fox (Urocyon cinereoargenteus) of southwestern Wisconsin.

Free-ranging red foxes (Vulpes fulva) and gray foxes (Urocyon cinereoargenteus) were trapped in southwestern Wisconsin. Fox sera were tested to determine the prevalence of antibody for five different Leptospira interrogans serovars, canine distemper virus (CDV), infectious canine hepatitis virus (ICHV), and Franciscella tularensis infections. Grippotyphosa was the most prevalent leptospiral serovar antibody observed. Twenty-five of 53 (47%) red foxes and 11 of 36 (31%) gray foxes had specific antibodies to grippotyphosa. Juvenile foxes had geometric mean antibody titers to grippotyphosa significantly higher (P less than 0.05) than those of the adults of both species. CDV antibody was detected in sera of red foxes only. Six of 57 (11%) red foxes had CDV antibody. ICHV antibody was detected in 2 of 57 (3%) red foxes and 3 of 32 (9%) gray foxes. Antibody to F. tularensis was not detected in any fox sera.

Adenoviruses, Canine↗
PubMed2000

Milk intake in blue fox (Alopex lagopus) and silver fox (Vulpes vulpes) cubs in the early suckling period.

Milk intake of fox cubs (2-16 days of age; body weight, 96-649 g) in ten blue fox litters and ten silver fox litters were measured by the water isotope dilution (WID) technique following a single intraperitoneal injection of tritiated water (3HHO). Litter size varied from four to 14 in blue foxes and from three to eight in silver foxes. Silver fox cubs had higher birth weights than blue foxes. Inter-species body weights and growth rates were apparently dependent on litter size and the dam's constitution. In both species growth rate increased with age and body weight (7-35 g per day). In the cubs, the biological half-life of body water turnover (BWT) rose from 1.5 days at 2-3 days of age to 2.5 days at 13-16 days of age, although a considerable scatter was seen. The mean daily milk intake of the cubs varied with body weight, from 31 to 193 g per day, whereas daily milk intake per unit of body mass remained stable at 30-35 g per 100 g body weight. The ratio of milk intake to body weight gain varied considerably among cubs, averaging 4.5 g/g during the 3-week experimental period. In suckling fox cubs, the calculated daily intake of metabolically energy (ME) corresponded fairly with the estimated energy requirements for growth and maintenance of the young. Finally, the applicability and the accuracy of the WID technique was evaluated in ten 3-week-old fox cubs, by tube-feeding with a milk replacer for 48 h, which documented that the daily rates of milk intake and water turnover can be accurately measured in suckling fox cubs by the WID technique following a single injection of 3HHO.

Animals↗
PubMed2003

Comparative nutrient digestibility of arctic foxes (Alopex lagopus) on Svalbard and farm-raised blue foxes (Alopex lagopus).

Arctic foxes from Svalbard (n=4) and farmed blue foxes (n=4) was used in a digestibility experiment with a high-carbohydrate feed to add more information to the nutritional physiology of the arctic fox, and to compare its digestive capacity with that of the farmed blue fox. The arctic fox has a diet containing mainly protein and fat from mammals and birds, while farmed blue foxes have been exposed to an omnivorous dietary regime for more than 80 generations. The experiment showed in general no difference in digestive capacity for protein and fat between the foxes (P>0.05), but for carbohydrates, including starch and glucose, the blue fox revealed higher digestibility values. The superior digestive capacity for carbohydrates in blue fox might be a result of a long-term selection of animals digesting dietary carbohydrates more efficiently, or that an early age exposition to dietary carbohydrates has given permanent improvement of the carbohydrate digestion in the gut.

Amino Acids↗
PubMed2002

[Morphology of hair pigmentation in wild red foxes, silver foxes, and their hybrids].

The effects of dominant allele Ar of locus Agouti on the morphology of hair pigmentation were described in foxes. The Ar allele was shown to determine the type of melanin and its content in hair with no effect on the morphology of pigment granules and their distribution throughout a hair. Using the method of electron spin resonance (ESR), the types of melanin (eumelanin and pheomelanin) and their content in the hair of red (ArArEE) and silver (aaEE) foxes and their hybrids (AraEE) were determined. In silver foxes, only one type of melanin (eumelanin) was found. In red foxes and their hybrids (which are phenotypically similar but darker than red foxes), both types of melanin (eu- and pheomelanin) were found. The highest melanin content was detected in the coat of silver foxes. In the hybrids, the total melanin content was lower than in silver foxes, but significantly higher than in red foxes. In red foxes, the contribution of pheomelanin to the total hair melanin content was twice as large as in the hybrids.

Animals↗
PubMed2001

Assessment of the epidemiological status of Echinococcus multilocularis in foxes in France using ELISA coprotests on fox faeces collected in the field.

The aim of this study was to estimate the relevance of Echinococcus multilocularis coproantigen detection in fox faeces collected in the field to identify different levels of endemicity for Echinococcus multilocularis on a large scale (n x 10 km(2)). Six study sites were selected in a high endemicity area and two study sites in a low endemicity area in eastern France on the basis of landscape composition. Sampling was undertaken in the winters of 1996-97, 1997-98 and 1998-99. At each site, (i) necropsy and intestine examination was undertaken on a sample of shot foxes (total number of foxes, 222), and (ii) fox faeces were collected in the field along road verges, and scored for degradation status (total number of faeces, 625). Fox faeces were also sampled in a control area (n=30) in western France in the summer of 1998. Intestines were examined according to the sedimentation method. Echinococcus multilocularis coproantigens were detected by using two ELISA tests: EM-ELISA and EmA9-ELISA. The necropsy prevalence in high and low endemicity areas was 63.3% and 19.4%, respectively, and the distribution of adult worms in the fox population was highly overdispersed (75.5% of the total biomass was harboured by 11.6% of foxes). Using the two ELISA tests, there was no difference in the detection of E. multilocularis coproantigens in field faeces, regardless of the degradation status. The medians of EM- and EmA9-ELISA OD values of field faeces in high endemicity area were significantly higher than in low endemicity area (P<0.001 for both ELISA). The distribution of EM-ELISA OD values in low endemicity area was significantly higher (P=0.002) than in the control area. Moreover, for the two ELISA, the observed ELISA OD value distributions in high endemicity area, low endemicity area and control area seemed representative of the distribution of adult worms in fox populations. These results indicate that E. multilocularis coproantigen detection in field faeces could serve for large-scale surveillance, as an alternative to necropsy.

Animals↗
PubMed1987

Ultrastructure and stereology of leukocytes and platelets of normal foxes and a fox with a Chediak-Higashi-like syndrome.

Peripheral blood leukocytes and platelets from five normal foxes (Vulpes vulpes) and a fox with phenotypical characteristics of Chediak-Higashi syndrome (CHS) were examined by electron microscopy. Lymphocytes, monocytes, neutrophils, eosinophils, and platelets from the affected fox contained giant membrane-bound granules that resembled lysosomes. In eosinophils and neutrophils from the affected fox and a normal fox, relative cell volume occupied by granules and number of granules per unit area were calculated. Relative cell volume occupied by granules was the same in both foxes, but there were significantly fewer granules per unit area in the affected fox. This result is consistent with the idea that the giant granules arose from fusion of pre-existing, normal-sized granules, as occurs in CHS. In platelets from the affected fox, no osmiophilic granules were seen. Our findings agree with those from studies of CHS-affected blood cells in other species.

Animals↗
PubMed2002

Potential remedy against Echinococcus multilocularis in wild red foxes using baits with anthelmintic distributed around fox breeding dens in Hokkaido, Japan.

The effect of bait-delivered anthelmintic to reduce the prevalence of Echinococcus multilocularis in wild red foxes was evaluated in Koshimizu, in the eastern part of Hokkaido, Japan. The study area (200 km2) was divided into baited and non-baited sections. The anthelmintic baits were distributed around fox den sites in the baited section every month for 13 months. After 1 year of the anthelmintic bait distribution, the prevalence of E. multilocularis in foxes, evaluated either by the parasite egg examination (from 27.1 to 5.6%) or coproantigen ELISA (from 59.6 to 29.7%), decreased in the baited section contrasting to that in the non-baited section (parasite egg: from 18.8 to 24.2%; ELISA: from 41.9 to 45.8%). The prevalence of E. multilocularis in grey red-backed vole Clethrionomys rufocanus, caught around fox dens, born after bait distribution also decreased and was significantly lower than that in non-baited section. However, within the study periods, the coproantigen-positive rate in fox faeces sporadically increased, while egg-positive rate constantly decreased. Since coproantigen ELISA can detect pre-patent infection, this observation indicates that reinfection pressure in the baited section was still high even after the 13 months of anthelmintic bait distribution. Therefore, the bait distribution longer than our study period is required for the efficient control of E. multilocularis in wild red fox population.

Animals↗
PubMed2000

A comparative chromosome map of the Arctic fox, red fox and dog defined by chromosome painting and high resolution G-banding.

A complete set of paint probes, with each probe specific for a single type of dog chromosome, was generated by DOP-PCR amplification of flow-sorted chromosomes. These probes have been assigned to high-resolution G-banded chromosomes of the dog and Arctic fox by fluorescence in-situ hybridization. On the basis of these results we propose improved nomenclature for the G-banded karyotypes of the dog and Artic fox. A comparative map between the Arctic fox, red fox and dog has been established based on results from chromosome painting and high-resolution G-banding. This map demonstrates that the euchromatic complements of these three canid species consists of 42 conserved segments. Thirty-four of these 42 segments are each represented by a single dog chromosome with dog chromosomes 1, 13, 18 and 19 each retaining two segments, respectively. The autosomes of the Arctic fox and red fox could be reconstructed from these 42 blocks in different combinations through chromosomal fusions. Our findings suggest that chromosome fusion has been the principal mechanism of karyotype evolution occuring during speciation in canids.

Animals↗
PubMedDate not supplied

[Crossing blue fox (Alopex lagopus) to red fox (Vulpes vulpes) using artificial insemination].

An experiment with breeding red fox to blue fox by artificial insemination is described. The conception rate obtained was low. Of five blue fox vixens three whelped, and average litter size was 6.5. None of the six red fox vixens whelped. Examination of semen from the hybrid males showed aspermia. The testosterone levels in the male hybrids were significantly lower than those in male blue fox, the difference was less outstanding between the hybrids and the red fox males. The histological investigation of testes of the hybrids indicated that the spermatogenesis was arrested in the later prophase of the first meiotic division.

Animals↗
PubMed2006

Cloning of fox (Vulpes vulpes) Il2, Il6, Il10 and IFNgamma and analysis of their expression by quantitative RT-PCR in fox PBMC after in vitro stimulation by Concanavalin A.

The immune response in the fox (Vulpes vulpes), despite the success of the oral rabies vaccine is not well characterised, and specific immunological tools are needed. A quantitative RT-PCR using SyBR Green to investigate fox cytokine expression after antigen PBMC in vitro re-stimulation is presented here. First, we cloned by homology with dog cytokine sequences the fox IL2, IL6, IL10, IFNgamma and a partial 18S sequence. Fox specific primers were then defined and used to set up a species-specific quantitative RT-PCR assay using SyBR Green and 18S housekeeping gene as internal standard. The technique was validated using total RNA from fox PBMC stimulated with a polyclonal activator, Concanavaline A.

Amino Acid Sequence↗