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1.
The direct and interactive effects of climate change on host species and infectious disease dynamics are likely to initially manifest\ at latitudinal extremes. As such, Alaska represents a region in the United States for introspection on climate change and disease. Rabies is enzootic among arctic foxes ( Vulpes lagopus) throughout the northern polar region. In Alaska, arctic and red foxes (Vulpes vulpes) are reservoirs for rabies, with most domestic animal and wildlife cases reported from northern and western coastal Alaska. Based on passive surveillance, a pronounced seasonal trend in rabid foxes occurs in Alaska, with a peak in winter and spring. This study describes climatic factors that may be associated with reported cyclic rabies occurrence. Based upon probabilistic modelling, a stronger seasonal effect in reported fox rabies cases appears at higher latitudes in Alaska, and rabies in arctic foxes appear disproportionately affected by climatic factors in comparison with red foxes. As temperatures continue a warming trend, a decrease in reported rabid arctic foxes may be expected. The overall epidemiology of rabies in Alaska is likely to shift to increased viral transmission among red foxes as the primary reservoir in the region. Information on fox and lemming demographics, in addition to enhanced rabies surveillance among foxes at finer geographic scales, will be critical to develop more comprehensive models for rabies virus transmission in the region. 相似文献
2.
The ERA strain of rabies virus was propagated in a baby hamster kidney cell line (BHK-21/C13). The viral titer was 10(1.8) tissue culture infective doses (TCID) higher than that of commercial ERA vaccine. The ERA/BHK-21 vaccine in baits retained titers of 10(6.3) to 10(6.4), TCID when subjected to daily temperature fluctuations from 9 degrees C to 24 degrees C for 21 days. This titer, according to a dose response in laboratory foxes, was still capable of immunizing up to 100% of foxes consuming a bait. The ERA/BHK-21 vaccine, when presented in baits, produced antibodies in 80 to 100% of dogs consuming more than one bait. Duration of immunity in foxes, from feeding the ERA strain rabies virus in baits, as determined by resistance to challenge with virulent virus, was at least 48 months. The vaccine strain retained some pathogenicity for nontarget species. In tests carried out on foxes, raccoons, dogs, cats and cattle, the vaccine did not cause vaccine-induced rabies. One of 14 skunks which consumed four baits developed vaccine-induced rabies, but virus could not be isolated from the salivary glands of this animal. The vaccine, when presented in baits, caused vaccine-induced rabies in 37% of laboratory mice, 3.4% of Microtus and 2.6% of Peromyscus species. Rabies virus could not be isolated from the salivary glands of rodents with vaccine-induced rabies. It was concluded that ERA virus propagated in BHK-21/C13 cells and incorporated in an acceptable bait produced a high titer, stable, immunogenic and safe vaccine for foxes. 相似文献
3.
A concentrate of wild rabies antibody was prepared from hyperimmune serums of three dogs refractory to wild rabies. The animals resisted repeated intramuscular injections of large doses of wild rabies virus in emulsions of whole brain, in emulsions of submaxillary salivary glands, and in emulsified mixtures of brain and submaxillary glands taken from naturally rabid dogs. The antibody was conjugated with fluorochrome and then absorbed by a procedure that gave “cell-free” working solutions of fluorescent antibody. The procedure entailed parallel absorption steps with minced pathological canine submaxillary glands from (1) naturally rabid dogs (these glands contained specific, undegraded, natural antigens of live wild rabies virus plus nonspecific substances and antigens) and (2) nonrabid dogs from a rabies endemic region (these glands contained nonspecific substances and antigens). Extracts from submaxillary glands of the three naturally rabid dogs and one nonrabid dog were stained with a cell-free solution of the fluorescent antibody. The glands of the rabid dogs contained fluorescent aggregates of intense green spherical and filamentous particles. When nonfluorescent canine hyperimmune serum was incubated with rabies-containing submaxillary extract, the rabies antigens were quenched. When nonfluorescent equine fixed virus antiserum was incubated with such extracts, the aggregates still retained bright fluorescence. 相似文献
4.
Quantitative distribution of rabies virus and the character of immunofluorescence in various parts of the central nervous system [CNS] and salivary glands were investigated in 21 naturally infected foxes. A mean death period was recorded in mice infected with the virus obtained from various parts of the CNS and salivary glands of the investigated foxes. The highest average titer of the virus was found out in the salivary glands - 4.46 log MLD50 per 0.03 ml i. c. The average titer was 2.30 log in the cornu ammonis, 1.99 log in the lobus olifactorius, 1.80 log in the spinal cord of the sacro-lumbar region, 1.73 log in the cortex, 1.71 log in the medulla oblongata, and 1.64 log in the cerebellum. The highest intensity of specific fluorscence was recorded in the thalamus, lobus piriformis, and cornu ammonis. In these regions, numerous round fluorescent inclusion bodies similar to Babes-Negri bodies occurred. Babes-Negri bodies in the cornu ammonis of foxes were proved in 81% of cases. Mice infected with the virus obtained from the salivary glands showed the shortest mean death period - 12.2 days and from the cornu ammonis it was 14.6 days. In virus infection from the other parts of the CNS the mean death period ranged from 16.0 to 17.4 days. 相似文献
5.
Canine adenovirus type 1 (CAdV-1) is the aetiological agent of infectious canine hepatitis (ICH) in domestic dogs (Canis familiaris). In spite of the widespread use of vaccination, CAdV-1 continues to circulate in the dog population. Although a high number of serological screenings have indicated that CAdV-1 is widespread in fox species, little is known about the potential role of foxes as reservoirs of CAdV-1. Furthermore, very little data exist on the molecular features of this virus in foxes. To add to existing knowledge on CAdV-1 circulating in wild carnivores, tissue samples from CAdV-seropositive red foxes (Vulpes vulpes, n?=?10) from the northern mainland of Norway and arctic foxes (Vulpes lagopus, n?=?10) from the Svalbard archipelago, Norway, were investigated using a molecular approach to detect CAdV-1 DNA and important structural and non-structural genes of the detected viruses were sequenced and analysed. Amplicons characteristic for CAdV-1 were amplified from 14 out of 20 foxes (7 red foxes and 7 arctic foxes) and spleen and lymph node tissues resulted optimal targets for the viral DNA detection. The nucleotide sequences showed unique features that distinguished the viruses detected in this study from the CAdV-1 to date identified in wild carnivores and dogs. Greater attention should be given to genetically different CAdV-1 circulating in wild carnivores that may be transferred to dogs, potentially causing disease and reducing the effectiveness of available vaccines. 相似文献
7.
The trials reported here show that the fox is highly susceptible to rabies virus. Vaccination with ERA rabies vaccine was capable of protecting foxes against challenge with naturally occurring strains of sylvatic rabies. Oral immunization against rabies using ERA rabies vaccine was possible. 相似文献
8.
OBJECTIVE: To describe the lesions and distribution of viral antigens in bats infected by Australian bat lyssavirus. DESIGN: A retrospective histopathological and immunohistochemical study of bats naturally infected with the virus. PROCEDURE: Tissues from 37 infected bats were examined. Nineteen flying foxes (fruit bats) and two insectivorous bats were examined in detail. Brains of another 16 flying foxes were poorly fixed and were examined less fully. RESULT: Lesions varied considerably between individuals and, where present, were mostly those of nonsuppurative meningoencephalomyelitis and ganglioneuritis similar to lesions seen in rabies and rabies-like diseases. The number of cells with intracytoplasmic inclusion bodies (Negri bodies) was variable; none were seen in some bats. Intracytoplasmic vacuolation of neurons was a common finding. Lesions occurred throughout the central nervous system but were most frequent and severe in the hippocampus, thalamus and midbrain, and medulla oblongata and pons. Indirect immunoperoxidase tests for lyssavirus antigen reactions varied in intensity and distribution, but also occurred mostly in the hippocampus, thalamus and midbrain, and medulla oblongata and pons. In peripheral tissues, reactions were seen in autonomic ganglia, in nerve plexuses of the gastrointestinal tract, in nervous tissues within muscles and immediately adjacent to individual muscle fibres, in an adrenal medulla, and in epithelial tissues in one of eight salivary glands examined. CONCLUSION: The main lesion in Australian bat lyssavirus infection is nonsuppurative inflammation similar to that seen in rabies and other rabies-like diseases, except that the number of Negri bodies is more variable. Reactions to immunoperoxidase tests for lyssavirus vary in intensity and distribution and may occur in both central and peripheral nervous systems. These reactions do not always occur in the salivary glands, even if brain infection is present. 相似文献
9.
Rabies first became evident in Canada during the late 18th and early 19th centuries. However, only a few sporadic outbreaks, mainly in domestic animals, were noted before 1945. Rabies in foxes spread into the Canadian provinces from the Arctic regions during the late 1940s. The disease gradually died out in most areas except Ontario. A second major outbreak, involving skunks, progressed from North Dakota into the Prairie provinces during the late 1950s and 1960s. Today, the major problem areas in Canada with respect to rabies are southern Ontario, which accounts for 85% of the Canadian diagnoses, and the Prairie provinces where rabies is enzootic in skunks. Rabies is rare in humans in Canada; however more than 40,000 cases have been reported in wild and domestic animals since 1958. Control of rabies is currently being undertaken through vaccination of domestic animals and wildlife, population reduction of wildlife vectors, and human preexposure rabies vaccination. 相似文献
10.
Submaxillary salivary glands from 129 rabies suspected animals were studied by the following methods: a) microscopic examination of frozen sections stained by the Fluorescent antibody technique (FAT), and b) mouse infectivity test (MIT). Flourescent antibody staining of frozen sections from the salivary glands of rabid animals proved to be a satisfactory method for demonstrating rabies antigen, when compared with the mouse infectivity test. 相似文献
11.
Rabies virus in submaxillary salivary glands from naturally infected dogs was investigated by a paper electrophoresis technique, and the virus activity was quantitated by intracerebral titration in mice. Extracts from these salivary glands were found to contain (a) 10 4 to 10 6 mouse ICLD 50 units of wild rabies seed and (b) a protein complex that migrated electrophoretically in the albumin band and more conspicuously in the beta and gamma bands of normal horse serum. The protein complex was interpreted to comprise aggregates of neutralizing antirabies antibody. 相似文献
12.
Abstract The preferences of juvenile farmed silver foxes ( n = 14) and blue foxes ( n = 12) for an empty cage (105L × 115W × 70H cm) and a cage of equal size with a wooden nest box were assessed in an 11-day preference test. The silver foxes spent a higher percentage of their time (86 ± 8%) in the nest box cage than the blue foxes (66 ± 21%). The silver foxes, but not the blue foxes, had a strong preference for the nest box roof as a resting site (44% of total daily time). Assuming that greater use indicates a greater need, silver foxes may benefit more from the nest boxes than blue foxes. 相似文献
13.
Kapel, Chr. M., Sv. Aa. Henriksen, H. H. Dietz, P. Henriksen, P. Nansen: A study on the predilection sites of Trichinella spiralis muscle larvae in experimentally infected foxes (Alopex lagopus, Vulpes vulpes). Acta vet. scand. 1994, 35, 125-132.–Studies were carried out on the predilection sites of Trichinella spiralis muscle larvae in experimentally infected arctic foxes ( Alopex lagopus) and silver foxes ( Vulpes vulpes) reared in cages. The highest number of larvae per gramme tissue was found in the muscles of the legs, eyes, diaphragm, and tongue. The 2 fox species showed no significant differences with regard to predilection sites. 相似文献
14.
Groups of striped skunks ( Mephitis mephitis) were inoculated intramuscularly with graded doses of street rabies virus. At various intervals after inoculation, saliva and sera were tested for rabies virus and neutralizing antibodies, respectively. Skunks that developed rabies were killed in terminal stages of the disease and the following examinations were made: titers of virus and antibody in submandibular salivary glands and brain, extent of immunofluorescence in submandibular salivary glands, and histologic examination of various tissues. Skunks that received inocula containing 4 × 104 to 4 × 105 mouse intracerebral lethal dose50 (MICLD50) had detectable serum neutralizing antibodies by 7–12 days postinoculation; however, most of the skunks that received lower doses (40 to 4 × 103 MICLD50) did not have detectable serum neutralizing antibodies until clinical signs began. In the salivary glands, slight and extensive immunofluorescence corresponded to high and low titers of tissue neutralizing antibody. Also low viral titers were associated with high tissue neutralizing antibody titers. There was a close correlation between viral titers in right and left submandibular salivary glands. The results suggest that the immune response can impede the process of infection of the salivary glands resulting in lack of antigen or low amounts of antigen in this tissue. This could occur through interference with centrifugal neural transport of virus and/or neutralization of virus during transfer from neural elements to epithelial cells. Lack of infectious virus or low viral titers in salivary glands containing antigen and high levels of tissue neutralizing antibodies can be caused partly by postmortem virus neutralization (during viral titration). 相似文献
15.
Rabies seems to persist throughout most arctic regions, and the northern parts of Norway, Sweden and Finland, is the only part of the Arctic where rabies has not been diagnosed in recent time. The arctic fox is the main host, and the same arctic virus variant seems to infect the arctic fox throughout the range of this species. The epidemiology of rabies seems to have certain common characteristics in arctic regions, but main questions such as the maintenance and spread of the disease remains largely unknown. The virus has spread and initiated new epidemics also in other species such as the red fox and the racoon dog. Large land areas and cold climate complicate the control of the disease, but experimental oral vaccination of arctic foxes has been successful. This article summarises the current knowledge and the typical characteristics of arctic rabies including its distribution and epidemiology. 相似文献
16.
The epidemiological situation of rabies was investigated in Lithuania. Over the last decade, 2277 cases of rabies were registered among wild and domestic animals (mean number of cases per districts was 44). The highest distribution of rabies was found in the districts of Lazdijai and Utena (116 and 81 cases, respectively), and the lowest in the Svencioniai and Zarasai districts (one and eight cases, respectively). It was found that rabies among wildlife comprised 54% with the majority of cases being registered in foxes (626 cases, 27%) followed by raccoon dogs (470 cases, 21%). Within the last 3 years, cases of rabies among foxes and raccoon dogs increased significantly (three and six times, respectively), compared with the period from 1990 to 1997. Among domestic animals, 46% cases of rabies were registered, with cattle comprising 27%, and the cases among cats and dogs at 9 and 8%, respectively. During the period from 1993 to 1997 in Lithuania, 11,385 of humans were attacked by domestic and wild animals, and 21,173 humans were vaccinated against rabies for prophylactic reasons. Our survey has shown that, during the period from 1997 to 2000, the number of people attacked has increased drastically-31,348 (60%), but only 8021 (18%) of them were vaccinated. 相似文献
17.
One dose of inactivated, adjuvanted rabies vaccine of cell culture origin (Rabisin) induced good but short-duration immunity in close to 100% of the 50 semi-domesticated reindeer (Rangifer tarandus tarandus L.) vaccinated. Most of the animals (44) had rabies virus antibody titre ≥1.5 IU/ml at 38 days after vaccination. Five animals had titre 0.5 IU. Antibody titres were not, however, present 1 year after primary vaccination in most animals. About 1 year (360-413 days) after primary vaccination, 22 of the 39 reindeer that could be sampled had rabies virus antibody titre <0.5 IU/ml. 相似文献
18.
Coat colour variation is determined by many genes, one of which is the melanocortin receptor type 1 ( MC1R) gene. In this study, we examined the whole coding sequence of this gene in four species belonging to the Canidae family (dog, red fox, arctic fox and Chinese raccoon dog). Although the comparative analysis of the obtained nucleotide sequences revealed a high conservation, which varied between 97.9 and 99.1%, we altogether identified 22 SNPs (10 in dogs, six in farmed red foxes, two in wild red foxes, three in arctic foxes and one in Chinese raccoon dog). Among them, seven appeared to be novel: one silent in the dog, three missense and one silent in the red fox, one in the 3′‐flanking region in the arctic fox and one silent in the Chinese raccoon dog. In dogs and red foxes, the SNPs segregated as 10 and four haplotypes, respectively. Taking into consideration the published reports and results of this study, the highest number of missense polymorphisms was until now found in the dog (9) and red fox (7). 相似文献
19.
Histopathologic (hematoxylin and eosin [HE]) and immunoperoxidase (streptavidin-biotin complex) methods were used for examination of formalin-fixed tissues of rabid raccoons from an enzootic area of Pennsylvania. Extensive morphologic lesions of rabies encephalitis were present in the cerebrum and the brain stem regions. Negri bodies were detected by both methods and were present in the brain (cerebral cortex, hippocampus, brain stem, cerebellum, and cervical spinal cord) and in the ganglia of the trigeminal nerves. The viral inclusions were also seen in ganglion cells in the tongue, parotid salivary glands, pancreas, intestines, and adrenal glands. These sites were not associated with any inflammatory cellular infiltrate. The immunoperoxidase method was superior to HE for the detection of Negri bodies. Because lesions of rabies encephalitis were consistently observed in the cerebrum, brain stem, and cervical spinal cord regions, these areas of the brain should be included when raccoons are examined by the fluorescent antibody test for rabies. 相似文献
20.
This experiment was conducted to study the effects of Lactobacillus probiotics on growth performance,nutrient digestibility and serum biochemical indexes in arctic foxes during the winter fur-growing period. Forty 135-day-old female arctic foxes with a similar body weight were randomly divided into 4 groups with 10 replicates per group and 1 fox per replicate. The foxes in control group were fed basal diets,while that of groups Ⅱ,Ⅲ and Ⅳ were fed basal diet+0.02% colistin sulfate, basal diet+1 mL Lactobacillus probiotics (active Lactobacillus was 3×10 9 CFU/mL) and basal diet+10 mL Lactobacillus probiotics,respectively. The results showed that:Compared to the control group,the addition of Lactobacillus probiotics significantly increased the average daily gain (P<0.05) and significantly decreased the F/G of arctic foxes during the winter fur-growing period (P<0.05).The apparent digestibility of EE and GE were significantly increased when arctic foxes fed diet supplemented with Lactobacillus probiotics (P<0.05).Supplementation of high level Lactobacillus probiotics could significantly decrease serum total cholesterol (P<0.05). Additionally,serum alanine aminotransferase concentration of group Ⅱ was extremely significantly higher than that of the other three treatments (P<0.01). Moreover,the serum aspartate aminotransferase concentration was significantly higher than the control group (P<0.05). In conclusion,the addition of Lactobacillus probiotics had beneficial effects on growth performance and apparent digestibility of EE and GE when arctic foxes got 3×10 9 CFU/mL active Lactobacillus from the probiotics per day. The total cholesterol in serum was significantly decreased when arctic foxes get 3×10 10 CFU/mL active Lactobacillus from the probiotics per day. It might cause the liver damage when arctic fox got colistin sulfate for a long time. 相似文献
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