Experimental Encephalitozoonosis in the Blue Fox

Newborn and young pups up to the age of 15 days were exposed to E. cuniculi, either by keeping the pups in cages together with orally inoculated foster-mothers and their offspring, or by oral inoculation with E. cuniculi spores. A majority of pups appeared sero-positive to E. cuniculi with the india-ink immuno-reaction from 35 to 87 days post exposure; spores of E. cuniculi were detected in organs of some of the animals. The non-inoculated pups kept together with the orally inoculated pups became seropositive from 49 to 129 days after the oral inoculations. However, the exposure of newborn and young pups failed to induce clinical encephalitozoo-nosis, and when killed at the time of pelting the body weights and fur quality appeared to be within the normal range in all exposed foxes. No macroscopic lesions were detected in the various organs. Histologically focal interstitial nephritis occurred in the great majority of the seropositive animals. Meningoencephalitis was seen in some of the foxes, whereas slightly thickened walls of some arteries, mainly in the myocardium, were found in a few animals. The lesions of the brain and kidneys seem to be very similar to those seen in chronic cases of rabbit encephalitozoonosis. Polyarteritis nodosa and severe encephalitis and interstitial nephritis with extensive proliferations of plasma cells, which are almost constant findings in cases of clinically diseased foxes, were not detected in any of the subclinically infected animals. Various factors that might be of significance in the pathogenesis of the disease are discussed, and it is concluded that intrauterine infection of the pups via the transplacental route appears to be an essential supposition for the establishment of clinical fox encephalitozoonosis.     

Experimental Encephalitozoonosis in the Blue Fox

Spores of Encephalitozoon cuniculi were recovered from foetal and placental tissues from blue fox females orally inoculated with the parasite. The results provided evidence for transplacental transmission of the causative agent of fox encephalitozoonosis.     

Liquoid-Induced Disseminated Intravascular Coagulation in the Blue Fox

The present experiments were performed to study the effects of a single high intravenous dose of Liquoid (10 mg/kg body weight) upon platelets, coagulation activities and hematocrit in blue foxes, and their correlation with the survival time. Both “short-living” (< 9 h) and “long-living” (24 h or more) blue foxes showed a marked consumption of coagulation factors, initial fall in fibrinogen, positive ethanol gel test and a gradual decrease in platelet counts. In addition “short-living” animals developed a marked rise in hematocrit, reflecting a considerable increase in vascular permeability. We conclude that activation of plasma proteases has as one of its effects increased permeability in microvasculatory vessels and that this may play a central role for the course and outcome of Liquoid-induced disseminated intravascular coagulation.     

Encephalitozoonosis in arctic lemmings

Encephalitozoonosis was identified for the first time in arctic lemmings (Dicrostonyx stevensoni and crosses of D. stevensoni and Dicrostonyx rubricatus). The most common clinical findings were circling, torticollis, posterior paralysis, depression, blindness and death related to parasitic granulomas in many tissues. Granulomas were most frequent in the central nervous system, but were seen in many other tissues throughout the body. Granulomas were characterized by collections of macrophages and varying numbers of lymphocytes and neutrophils with or without necrosis of parenchymal tissue. Most granulomas contained protozoon cysts with ultrastructural characteristics of Encephalitozoon cuniculi. Protozoon cysts were seen in vascular endothelium in many tissues accompanied by minimal or no inflammatory reaction.     

Encephalitozoonosis in pharmacologically immunosuppressed mice

Encephalitozoon cuniculi is a parasite that has been identified as a cause of opportunistic infections in immunocompromised individuals. This study was performed to evaluate E. cuniculi infection in pharmacologically immunosuppressed mice. Mice were immunosuppressed with cyclophosphamide (100mg/kg twice a week, IP) or cyclosporin (10mg/kg daily, IP) and inoculated with 10(7)E. cuniculi spores IP. The E. cuniculi spores were cultivated in MDCK cells. E. cuniculi identification was performed by light microscopy studies using Gram-Chromotrope, Hematoxylin-Eosin and Toluidine blue-fuchsin staining techniques, as well as by PCR at 15, 30 and 45 days post-inoculation (DPI). Cyclophosphamide-immunosuppressed mice have greatly reduced amounts of CD8(+), CD4(+) and CD3(+) T cells and CD19(+) B cells. The cells from these mice were analyzed by FACS and showed acute disseminated and fatal encephalitozoonosis. Mice treated with ciclosporin, which is both antiparasitic and immunosuppressive, have a milder, chronic, non-lethal infection and showed a significant reduction only in CD3(+) and CD4(+) T cell numbers. Our results support the role of CD8(+) T cells in controlling infection by E. cuniculi and show that preventive measures are essential for preventing this zoonosis in individuals undergoing chemotherapy for cancer or other immunosuppressive therapies.     

蓝狐发情期及妊娠期血清五种生殖激素含量变化

为探究发情期及妊娠期雌性蓝狐(Alopex lagopus)生殖激素的变化规律,选取11只繁殖期雌性蓝狐,采用放射免疫法(RIA)测定血清中雌二醇(E2)、促黄体生成素(LH)、促卵泡素(FSH)、孕酮(P)以及催乳素(PRL)的含量。结果表明,促卵泡素和促黄体生成素在发情期及妊娠期血清中浓度一直处于较稳定水平,并呈波动式分泌,最大值分别为(2.18±0.69)U/L和(8.82±1.83)U/L,同种激素不同检测日期数据两两比较差异不显著(P> 0.05);雌二醇在发情期和妊娠期血清中浓度亦处于较稳定水平,最大值出现在发情第1天,为(27.73±23.19)ng/L,数据两两比较差异亦不显著(P> 0.05);孕酮在发情期维持较高水平,最大值在发情第3天,为(2.41±1.35)μg/L,之后在妊娠期持续下降,分娩当天达到最低点,为(0.13±0.14)μg/L,数据两两比较差异显著(P <0.05);催乳素在发情期先下降,最低值为(0.15±0.04)U/L,第3天开始升高,并在妊娠期保持较高水平,到分娩时维持最高(0.21±0.05)U/L,数据两两比较差异不显...     

First Characterization in China of Encephalitozoon cuniculi in the Blue Fox (Alopex lagopus)

Encephalitozoon cuniculi is a microsporidian parasite that infects a wide range of vertebrates, including primates. It has recently emerged as an opportunistic parasite of patients infected with the human immunodeficiency virus. The blue fox (Alopex lagopus; also known as the arctic fox) is one of the most susceptible species for encephalitozoonosis. Here, we report an outbreak of encephalitozoonosis at a fox farm in China. The isolated parasites displayed the typical morphology of E. cuniculi as assessed by Masson's trichrome staining. Analysis of the internal transcribed spacer sequence indicated that the isolated parasite is a genotype III strain of E. cuniculi. Furthermore, phylogenetic analysis of the PTP1 gene verifies classification of this new strain (termed LN‐1) with other genotype III E. cuniculi strains, though the PTP3 and SWP1 sequences diverge from the reference strain. This is the first report of encephalitozoonosis in farmed blue foxes in China.     

A Variation of Secondary Sex Ratio in Blue Fox Alopex lagopus L.

The effects of several genotypic and paratypic factors on the secondary (at birth) sex ratio was analyzed in blue fox bred in captivity. In particular, variation of sex ratio was for the first time studied as dependent on sire's age (without considering dam's age), the ages of both sire and dam, and the lines of both parents. The initial data were obtained from the Pushkino breeding facility, Moscow oblast in 1985 through 1989. In total, 15 396 puppies were analyzed. The frequency of males ( ) in this population was 0.551 ± 0.004 (confidence interval 0.543 P 0.559). Parents' ages and litter size had no effect on the proportion of males in the progeny. In one of the two blue fox subpopulations under study, dam's line proved to be associated with a significant departure of sex ratio to a higher proportion of males, suggesting the effect of genotypic factors on the variation of secondary sex ratio in blue fox.     

Mesangioproliferative Glomerulonephritis in Mink with Encephalitozoonosis

Renal specimens from 6 mink with encephalitozoonosis were studied by light and electron microscopy and immunohistochemistry. The glomeruli of affected kidneys had a mesangioproliferative glomerulonephritis which was characterized by an increase in mesangial cells and matrix in most glomeruli. Some glomeruli were partially or completely sclerosed. There were protein or granular casts in the cortical and medullary tubules. Interstitial nephritis, vasculitis and tubular cysts were found. Electron microscopy demonstrated extensive matrix and increased cellularity in the mesangial areas. Glomeruli showed segmentally thickened or wrinkled capillary basement membranes. Electron dense deposits were found in the glomerular basement membranes and mesangium. Peroxidase-anti-peroxidase immunohistochemistry demonstrated that IgG and IgM positive material was present as granular deposits in the glomerular basement membrane and occasionally in the mesangium.     

Toxic and Carcinogenic Effects of Dimethylnitrosamine (Dmna) in the Blue Fox (Alopex Lagopus)

Single doses of DMNA from 8 to 15 mg/kg body weight (B.W.) were given in the feed, by stomach tube or by subcutaneous application to 37 foxes. The course and intensity of the disease was not influenced by the application route, but was directly related to the amount of DMNA given per kg body weight, and caused hemorrhagic centrolobular liver necrosis and acute vessel changes especially in the hepatic vein system. The possibility of liver regeneration after a single DMNA exposure depends on the degree of damage in the hepatic vein system. Some animals can recover from the acute disease caused by DMNA. But if the hepatic vessel changes are enough pronounced, progressive changes occur in the hepatic vein system eading to liver cirrhosis. The observation period of the foxes after a single exposure was from 13 to 380 days. LD50 should not be determined after a surviving time of 3 days but rather after 4 weeks. In our material LD50 was 10 mg DMNA/kg B.W. In an experiment over a longer period of time 18 foxes divided into 3 groups were given 2 weekly doses of DMNA in food. They were treated with daily estimated doses of 1.0, 0.2 and 0.1 mg DMNA/kg B.W., respectively. The foxes in Groups 1 and 2 developed ascites, jaundice and liver failure after intake of 45–70 mg DMNA/kg B.W. The foxes in Group 1 treated with 1 mg DMNA/kg B.W. showed centrolobular hemorrhagic liver necrosis and productive vessel changes in the hepatic vein system. The second group given 0.2 mg DMNA/kg B.W. developed hemorrhagic centrolobular necrosis which healed with fibrosis leading to cirrhosis and chronic occlusion in many of the hepatic veins. In addition noduli of chondroid lamellae and foci of hematopoietic tissue and early stages of hemagiomatous liver tumors were found in the liver. The group exposed with 0.1 mg DMNA/kg B.W./day did not develop hemorrhagic centrolobular liver necrosis, but thickening in the walls of the hepatic veins. After more than 3½ years of exposure multiple hemangiosarcomae were growing out from the changed vessel walls. In an experiment over a shorter time period with daily exposure of DMNA doses in the feed below 0.15 mg/kg B.W., all the foxes were completely healthy and only some showed beginning changes in the hepatic vein walls. Hematomae were often seen in foxes dying after a single DMNA dose. One fox treated with 0.1 mg DMNA/kg B.W. died of brain bleeding after 220 days of treatment. Chronic vessel changes were found in the heart and kidneys of the DMNA treated foxes. These results emphasize the fact that DMNA gives vessel changes of a more general nature.     

Extraglomerular Lesions in Kidneys of Mink with Encephalitozoonosis

Extraglomerular renal lesions were studied by light and electron microscopy in 13 farmed mink which showed cataractous eyes associated with spontaneous encephalitozoonosis. The extraglomerular renal lesions consisted of multiple renal cysts, multifocal-to-coalescing interstitial nephritis and vasculitis. Tubular cysts of varying size were present in the corticomedullary junction and medulla. The inflammatory infiltrates were composed mostly of lymphocytes and plasma cells and usually accompanied an interstitial fibrosis. Vasculitis, perivasculitis and sclerotic arteries were frequently seen.     

Brain and Spinal Cord Lesions in Encephalitozoonosis in Mink

Central nervous system lesions were studied by light microscopy in 43 farmed mink, aged 5 months to 2 1/2 years, with spontaneous encephalitozoonosis and showing cataractous eye changes. Lesions were found in the brain and spinal cord of all animals examined but were generally mild and chronic. The lesions were consistent with those previously described in spontaneous encephalitozoonosis in other carnivores. Parasites in parasitophorous vacuoles and free or phagocytosed in necrotic and granulomatous lesions were demonstrated in animals aged 5 months to 1 year. The occurrence of arterial lesions of the polyarteritis nodosa type found in the youngest animals probably indicates fetal infection. In animals aged 1 1/2 and 2 1/2 years active lesions were usually lacking and the changes were characterized by arterial sclerosis, sometimes with aneurysmal formations, small perivascular lympho-plasmacytic cuffings and focal gliosis.     

Ovarian and Testicular Function in the Blue Fox (Alopex Lagopus) after Oral Administration of Fenchlorphos During the Breeding Season

The possible effect of fenchlorphos, 0-0-dimethy1-0-(2.4.5-trichlorophenyl) phosphorothioate, upon the reproductive endocrinology in blue foxes (Alopex lagopus) was investigated. Five females were administered fenchlorphos orally at a dose of 100 mg/kg daily from 10 days before oestrus and up to the 21st day of gestation. This dose represents the therapeutic dose for the treatment of sarcoptic mange. Blood samples were collected for the analyses of progesterone, oestradiol-17β and luteinizing hormone (LH) in plasma. The vixens were ovario-hysterectomized on day 23, except 1 animal in the control group which was operated on day 17. Additionally, sperm quality and mating performance in 3 male blue foxes, which were administered 100 mg/kg fenchlorphos daily during the first 3 weeks of the mating season, were examined. Pregnancy was recorded in 2 medicated and 4 control animals. No pathological changes were observed in the uterus and the ovaries. The plasma concentrations of the hormones were similar to those obtained from the control group. No evidence of any disturbances concerning spermatogenesis in the males was observed. However, their libido appeared to be reduced. None of the males achieved a mating during and after the period of medication.     

Clustered Fox genes in lophotrochozoans and the evolution of the bilaterian Fox gene cluster

FoxC, FoxF, FoxL1 and FoxQ1 genes have been shown to be clustered in some animal genomes, with mesendodermal expression hypothesised as a selective force maintaining cluster integrity. Hypotheses are, however, constrained by a lack of data from the Lophotrochozoa. Here we characterise members of the FoxC, FoxF, FoxL1 and FoxQ1 families from the annelid Capitella teleta and the molluscs Lottia gigantea and Patella vulgata. We cloned FoxC, FoxF, FoxL1 and FoxQ1 genes from C. teleta, and FoxC, FoxF and FoxL1 genes from P. vulgata, and established their expression during development. We also examined their genomic organisation in C. teleta and L. gigantea, and investigated local syntenic relationships. Our results show mesodermal and anterior gut expression is a common feature of these genes in lophotrochozoans. In L. gigantea FoxC, FoxF and FoxL1 are closely linked, while in C. teleta Ct-foxC and Ct-foxL1 are closely linked, with Ct-foxF and Ct-foxQ1 on different scaffolds. Adjacent to these genes there is limited evidence of local synteny. This demonstrates conservation of genomic organisation and expression of these genes can be traced in all three bilaterian Superphyla. These data are evaluated against competing theories for the long-term maintenance of gene clusters.     

The Indirect Fluorescent Antibody Test (IFAT) for the Detection of Nosema Cuniculi Antibodies in the Blue Fox (Alopex Lagopus)

During recent years nosematosis has been a major problem in the breeding of blue fox in the Scandinavian countries, causing heavy losses among growing pups (Nordstoga 1972, Nordstoga et al. 1974). The lack of reliable methods for diagnosing the infection in live foxes has so far made epizootiologic studies of the disease very difficult. However, reports on the IFAT in rabbits with nosematosis (Cox et al. 1972, Chalupsky et al. 1971, 1973, 1974), encouraged the search for a method of detecting Nosema antibodies in fox sera.     

Experimental trials to determine effective fence designs for feral Cat and Fox exclusion

Summary   Exclusion fencing is being increasingly used to protect areas of high conservation value or to create 'islands' of protected habitat for native fauna. The objective of this study was to test a range of fence designs to assess the optimum physical and/or electrical barrier required to exclude feral Cats ( Felis catus ) and Red Foxes ( Vulpes vulpes ). We tested against six fence designs by placing individual animals (18 Cats and 18 Foxes) in 20 × 20 m pens and recording their responses to various fence components. Fence design 1 was 1.8-m high with one electric wire at 1200 mm and another at 1500 mm offset by 80 mm and a curved overhang 600 mm in diameter. Fence design 2 and 3 had single electric wires placed at 400 mm and 1700 mm, respectively. Fence design 4 had a single electric wire at the end of the overhang. Fence design 5 had no electric wire and fence design 6 was 1.2-m high with an overhang and no electric wire. Neither feral Cats nor Foxes were able to scale the 1.8-m fence regardless of the position or absence of electric wires. One Fox and one feral Cat successfully breached the 1.2-m high fence by jumping onto the overhang and climbing over. Four Foxes excavated holes underneath the fence and one chewed through the mesh. Results from this work indicate that fences designed to exclude feral Cats and Foxes should be 1.8-m high, have an overhang that is at least 600 mm in circumference that is curved or shaped in such a way that prevents animals climbing over from underneath, and have an apron with a mesh hard enough to prevent Foxes chewing through. Exclusion fences do not require electric wires. The omission of electric wires will provide significant savings in building and maintenance costs for exclusion fencing.