In vitro excystation of Sarcocystis capracanis, Sarcocystis cruzi and Sarcocystis tenella (Apicomplexa)

Improved rates of in vitro excystation of sporozoites from sporocysts of Sarcocystis capracanis, Sarcocystis cruzi, and Sarcocystis tenella were obtained by pretreating sporocysts with an aqueous sodium hypochlorite (NaOCl) solution followed by incubation in excysting fluid (EF). After pretreatment with NaOCl, sporocysts were washed 4 times in Hanks' balanced salt solution and then incubated in various EF (pH 7.4) at 38.5 C in 5% CO2-95% air. Maximum rates of excystation (free sporozoites/(sporozoites in sporocysts + free sporozoites) X 100) for all 3 species of Sarcocystis occurred at 4 hr after incubation in EF. These rates were 17% for S. capracanis after incubation in EF containing 2% trypsin + 10% caprine bile; 90% for S. cruzi in 2% trypsin + 10% bovine bile; and 20% for S. tenella in 2% trypsin + 10% caprine bile. Only a 40% excystation rate occurred in sporocysts of S. cruzi that had been stored previously for 14 days in aqueous potassium dichromate. Excysted sporozoites of S. capracanis, S. cruzi, and S. tenella penetrated and developed to mature meronts in bovine pulmonary artery endothelial cells or bovine monocytes.     

Chemical immobilization of red foxes (Vulpes vulpes)

Red foxes (Vulpes vulpes) were immobilized with one of the following drug combinations: ketamine/xylazine (n = 22), ketamine/promazine (n = 35), ketamine/midazolam (n = 13), or tiletamine/zolazepam (n = 22). Foxes given ketamine/xylazine had the shortest induction and longest recovery times relative to other drug combinations, whereas foxes given ketamine/midazolam had the longest induction times. Recommended doses for the various combinations are given. Foxes given ketamine/xylazine were given either 0.1, 0.2, 0.4 mg/kg yohimbine, or saline 40 min after anesthetic induction. Administration of yohimbine significantly shortened arousal and recovery times relative to control values (P less than 0.001).     

Physiological responses of red foxes (Vulpes vulpes) to surgery

Radio transmitters were surgically implanted into the abdomens of red foxes (Vulpes vulpes). Blood samples were taken before, immediately after, and 8 hr after surgery and analyzed for hormonal, biochemical, electrolyte and hematologic changes. Samples were taken at the same times from control foxes. Adrenocorticotropin increased after surgery (P less than 0.05), but returned to pre-surgery values after 8 hr. Cortisol increased and remained elevated in the surgery group relative to pre-surgery values or to control values (P less than 0.05); Triiodothyronine and thyroxine both decreased from post-surgery values 8 hr later (P less than 0.05). Creatine kinase, total bilirubin and aspartate aminotransferase increased after 8 hr in both surgery and control groups (P less than 0.05). Carbon dioxide increased under anesthesia in both groups, but returned to initial values after 8 hr (P less than 0.05). The white blood cell count increased after 8 hr only in the surgery group (P less than 0.05). There were no differences between the groups for any value obtained from the initial blood sample. These data indicate that abdominal surgery results in prolonged adrenocortical activity and decreased thyroid hormone levels, but otherwise has minimal systemic effects in red foxes.     

Activity patterns and interactions of red foxes (Vulpes vulpes) in Oxford city

The activity patterns of red foxes ( Vulpes vulpes L.) living and breeding in urban areas of Oxford, and the interactions between individuals, were analysed from detailed radio-tracking data on 17 adults. Foxes were nocturnal and active during the night for a mean of 6h 52min min, irrespective of the time of year. The number of active/resting periods increased in autumn and winter, and in winter and spring the night was characteristically divided into several short cycles of activity of 2–2 1/2 h each, interspersed with similar periods of rest. The foxes occupied mutually exclusive group ranges and group members remained within 50m of each other for up to one-third of the time spent active at night. The implications of fox spatial relationships for rabies transmission are discussed.     

Presence of Leishmania infantum in red foxes (Vulpes vulpes) in southern Italy

Skin, lymph node (popliteal), and bone marrow samples were collected from 50 red foxes (Vulpes vulpes) from May 2004 to May 2005 in southern Italy. Samples were tested for Leishmania infantum by polymerase chain reaction (PCR). The parasite was detected by PCR from 20 of 50 (40%) fox carcasses. All 20 positive cases were PCR-positive from lymph node and bone marrow samples, whereas 17 of 20 positive cases were PCR-positive from skin samples. Infection status was not related to age or sex. This is the first report of leishmaniasis in red foxes in Italy based on PCR results, and these results reinforce the assumption that this wild canid can serve as a reservoir for Leishmania.     

Helminths of red foxes (Vulpes vulpes) and raccoon dogs (Nyctereutes procyonoides) in Lithuania

Red foxes and raccoon dogs are hosts for a wide range of parasites including important zoonotic helminths. The raccoon dog has recently invaded into Europe from the east. The contribution of this exotic species to the epidemiology of parasitic diseases, particularly parasitic zoonoses is unknown. The helminth fauna and the abundance of helminth infections were determined in 310 carcasses of hunted red foxes and 99 of raccoon dogs from Lithuania. Both species were highly infected with Alaria alata (94·8% and 96·5% respectively) and Trichinella spp. (46·6% and 29·3%). High and significantly different prevalences in foxes and raccoon dogs were found for Eucoleus aerophilus (97·1% and 30·2% respectively), Crenosoma vulpis (53·8% and 15·1%), Capillaria plica (93·3% and 11·3%), C. putorii (29·4% and 51·5%), Toxocara canis (40·5% and 17·6%) and Uncinaria stenocephala (76·9% and 98·8%). The prevalences of the rodent-transmitted cestodes Echinococcus multilocularis, Taenia polyacantha, T. crassiceps and Mesocestoides spp. were significantly higher in foxes than in raccoon dogs. The abundances of E. multilocularis, Mesocestoides, Taenia, C. plica and E. aerophilus were higher in foxes than those in raccoon dogs. A. alata, U. stenocephala, C. putorii and Echinostomatidae had higher abundances in raccoon dogs. The difference in prevalence and abundance of helminths in both animals may reflect differences in host ecology and susceptibility. The data are consistent with red foxes playing a more important role than raccoon dogs in the transmission of E. multilocularis in Lithuania.     

Xylazine hydrochloride-ketamine hydrochloride immobilization of free-living red foxes (Vulpes vulpes) in Spain.

A combination of xylazine hydrochloride-ketamine hydrochloride was used to immobilize 83 wild red foxes (Vulpes vulpes) (15 pups and 68 adults) at Do?ana National Park (Spain). Mean ketamine hydrochloride doses were 17.1 mg/kg (SE = 1.53) and 12.3 mg/kg (SE = 0.4) for pups and adults, respectively, and mean xylazine hydrochloride doses for the same groups were 6.2 mg/kg (SE = 0.63) and 4.7 mg/kg (SE = 0.14), respectively. Mean induction times and first reaction times were 1.6 minutes and 22.5 minutes for pups and 3.8 minutes and 39.4 minutes for adults, respectively. Recommended doses for wild adult foxes of unknown weight are 75 mg of ketamine hydrochloride and 20 mg of xylazine hydrochloride.     

Levamisole can reduce bait monopolization in wild red foxes Vulpes vulpes

1. Baits are used worldwide to deliver vaccines, contraceptives and poison to wild animal species. In carnivores, multiple bait uptake and bait monopolization by dominant individuals may reduce baiting effectiveness. This study investigated whether a conditioned‐taste‐aversion agent, levamisole, can be used to decrease bait consumption by individual wild foxes Vulpes vulpes. 2. The results indicated that after consuming levamisole‐treated baits, foxes avoided eating treated baits but consumed untreated baits. We concluded that the reduction in bait consumption was achieved through learned aversion to levamisole rather than via conditioned‐taste‐aversion to baits. Adding levamisole to baits could potentially be used to reduce bait monopolization by individual wild foxes.     

High genetic diversity and low population structure in red foxes (Vulpes vulpes) from Croatia

The red fox (Vulpes vulpes) is a highly adaptable omnivorous mammal distributed across all continents on the northern hemisphere. Although the red fox is present throughout Europe, where it plays an important ecological and socio-economic role not only as a game species but also as a rabies reservoir, few studies have examined its population-level mitochondrial DNA variability. In this study, 27 mitochondrial DNA control region haplotypes were identified in 229 red fox samples taken from four regions in Croatia. Haplotype diversity of Croatian red foxes (0.901) was found to be among the highest of all European red fox populations studied to date. Genetic differentiation among regions was quite low, and statistically significant estimates of differentiation were obtained only when comparing the population from the peninsular region of Istria with the three continental populations. It seems that landscape barriers like rivers and small mountains do not restrict gene flow among foxes in the continental part of Croatia, while the combination of a narrow land bridge and altitudes exceeding 1000 m limit fox migration between Istria and the rest of the continent. Better understanding of small-scale population structure will require analysis of highly variable nuclear markers like microsatellites.     

Reproductive management of silver foxes (Vulpes vulpes) in captivity

Specific protocols need to be developed that take into consideration the requirements of silver foxes. This study was designed to investigate the reproduction of 26 pairs of silver foxes (Vulpes vulpes). Reproduction parameters (breeding season, age at puberty, fecundity and fertility) of the foxes were examined under experimental conditions, and new techniques to optimize fox breeding were assessed. Staining of the vaginal smears with the double Harris-Schorr stain allowed for the precise detection of estrus and proved to be more reliable than simply measuring vaginal resistance. Ultrasonography was demonstrated to be useful for pregnancy diagnosis and prediction of parturition. Results demonstrate that the methods reported in this paper are easily applicable to similar studies carried out on small groups of animals within the framework of fox animal experimentation.     

Occurrence of Helicobacter Infection in the gastric mucosa of free-living red foxes (Vulpes vulpes)

We studied gastric Helicobacter spp. in five red foxes (Vulpes vulpes). Samples of stomach from the cardia, corpus, pyloric antrum, and duodenum were subjected to histopathologic, immunohistochemical, and transmission electron microscopy (TEM) examination for the presence of Helicobacter and gastritis. All foxes had gastric Helicobacter-like organisms (GHLOs) on examination by light microscopy and TEM. Gastric Helicobacter-like organisms were present in all areas of the stomachs. Chronic mild or moderate gastric inflammation was associated with infection by GHLOs in one or more regions of the stomach, but there was no correlation between inflammation and infection. It is not clear whether the organisms were causing the minimal histologic lesions observed, but the gastric mucosa of free-living foxes appears to be commonly colonized with GHLOs. The frequent colonization of free-living foxes with distinct GHLOs possibly reflects their special characteristic in feeding and/or social behavior or the potential commensal nature of the bacteria in free-ranging foxes.     

Molecular and morphological circumscription of Mesocestoides tapeworms from red foxes (Vulpes vulpes) in central Europe

Here we examine 3157 foxes from 6 districts of the Slovak Republic in order to determine for the first time the distribution, prevalence and identity of Mesocestodes spp. endemic to this part of central Europe. During the period 2001-2006, an average of 41.9% of foxes were found to harbour Mesocestoides infections. Among the samples we confirmed the widespread and common occurrence of M. litteratus (Batsch, 1786), and report the presence, for the first time, of M. lineatus (Goeze, 1782) in the Slovak Republic, where it has a more restricted geographical range and low prevalence (7%). Using a combination of 12S rDNA, CO1 and ND1 mitochondrial gene sequences together with analysis of 13 morphometric characters, we show that the two species are genetically distinct and can be differentiated by discrete breaks in the ranges of the male and female reproductive characters, but not by the more commonly examined characters of the scolex and strobila. Estimates of interspecific divergence within Mesocestoides ranged from 9 to 18%, whereas intraspecific variation was less than 2%, and phylogenetic analyses of the data showed that despite overlapping geographical ranges, the two commonly reported European species are not closely related, with M. litteratus more closely allied to North American isolates of Mesocestoides than to M. lineatus. We confirm that morphological analysis of reproductive organs can be used to reliably discriminate between these often sympatric species obtained from red foxes.     

Predictive factors for flea occurrence in red foxes (Vulpes vulpes) from semi-arid Mediterranean environments

The role of red fox as host for a wide range of parasites, particularly fleas and other arthropods causing vector-borne diseases, in combination with its capability to adapt to anthropized environments, makes this wild canid an epidemiologically remarkable species at the wildlife–domestic–human interface, especially in the present time of rise of emerging and re-emerging diseases. This study evaluated the prevalence and parasite intensity of fleas in 88 foxes from Murcia Region (Southeastern Spain) and determined the geographic distribution of areas with the highest potential risk of flea presence. Pulex irritans, Ctenocephalides felis, Spilopsyllus cuniculi and Nosopsyllus fasciatus were identified. The overall prevalence was 76.13%. This is the first time that N. fasciatus has been reported in foxes from Murcia Region. The predictive model established a certain pattern to determine the areas with the highest risk of acquiring fleas. Positive correlation of daily potential evapotranspiration (ET₀) in winter and the opposite effect occurring for ET₀ in summer were obtained, as well as positive correlations for mean daily temperature (T_mean) in summer and mean precipitation (P_mean) in winter and summer. The model was also found positively correlated in the forest habitat ecotone areas and the anthropized areas.     

Changes in the numbers of foxes (Vulpes vulpes) in Scotland

More foxes were killed in Scotland from 1971 to 1978 than in the previous decade, but in some parts the rate of increase was not being maintained. Fluctuations in the numbers of foxes killed were associated with big changes in the numbers of Field voles.     

Molecular survey of Anaplasma phagocytophilum and Ehrlichia canis in red foxes (Vulpes vulpes) from central Italy

During the 2007-2008 hunting season, 150 spleen samples were collected from free-ranging red foxes (Vulpes vulpes) in central Italy. The specimens were tested by two nested PCR assays to detect DNA of Anaplasma phagocytophilum, etiologic agent of granulocytic ehrlichiosis of animals and humans, and DNA of Ehrlichia canis, which causes the monocytic ehrlichiosis in canids. None of the foxes were PCR-positive for E. canis; 25 (16.6%) were positive for A. phagocytophilum. No specific gross alterations were detected at necropsy, and no histopathologic lesions found on PCR-positive spleen samples.