首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 31 毫秒
1.
The raccoon (Procyon lotor), indigenous to North America, has naturalized in Japan as an invasive alien species, having been introduced into the country in the 1970s. In Hokkaido, the northernmost island of Japan, feral raccoons have been increasing in number and spreading throughout the island. The age at the onset of puberty for raccoons is important for estimating individual lifetime reproductive success and population growth. The present study investigated the timing of and potential factors affecting the onset of puberty in male raccoons in Hokkaido. External characteristics and histology of testes were studied in 151 male feral raccoons and in 1 captive juvenile. For the majority of feral yearling raccoons, prepubertal development began in May, and spermatozoa production began in October prior to their second mating season. However, some larger juveniles attained puberty during the juvenile period. The captive juvenile, which was fed throughout the winter, attained puberty only 11 months after birth. These results suggest that if male raccoons can achieve enough body growth before the first mating season, puberty can be attained early. In both juveniles and yearlings, spermatozoa production was only observed after autumn. This timing coincided with the recrudescence of seasonally active spermatogenesis in adult males. Therefore, attaining puberty in male raccoons appears to require both adequate body nutrient development and several environmental factors that control seasonal testicular changes.  相似文献   

2.
The growth pattern and seasonal weight fluctuations of feral raccoons in Hokkaido were evaluated between 1999 and 2001. The growth rates inbody length and body weight were described for juveniles (young of the year) and yearlings (animals born in the previous season) using the Gompertz growth model. The asymptotic body sizes for males were greater than those for females. Young raccoons born during spring in the study area could potentially grow up to their asymptotic size at the beginning of their first winter, but they would not reach their full adult sizes until at least their second fall. Adult raccoons (animals > or = 2 -year-old) had seasonal weight fluctuations with annual weight loss of 25% to 28% of mean maximum weights in west-central Hokkaido, but these result would be an underestimate of the degree of annual weight fluctuations. Juvenile raccoons can be distinguished from the older animals by measuring body length or body weight during fall in Hokkaido.  相似文献   

3.
Feral raccoons (Procyon lotor) have been increasing in number since 1979 and are currently subject to pest control in Hokkaido. One of the reasons for the increase in numbers is thought to be the high reproductive potential of raccoons, but little is known about their reproduction. The main aim of this study was to clarify seasonal changes in spermatogenesis and peripheral testosterone concentration of raccoons in Hokkaido. In the present study, external characteristics and histology of the testis and epididymis and the plasma testosterone concentration were investigated in 68 feral, male raccoons culled for pest control and once a month in one live, captive male. The feral males exhibited seasonal changes in spermatogenesis, showing active spermatogenesis in autumn, winter and spring (October-June) with noted spermatogenesis and inactive spermatogenesis in summer (July-September) with lower mean levels of spermatozoa in the cauda epididymis. Even in the inactive period, spermatozoa were observed in about half of the individuals (14/26); therefore, individuals producing spermatozoa existed every month throughout the year. Testosterone concentrations were significantly high in the winter mating season. In the captive male, the testosterone concentrations were low from June to August, and spermatozoa could not be observed from July to September. These results suggest that raccoons exhibit seasonality of reproduction, but the time and duration of spermatogenetic decline varies widely among individuals. This individual variation in the inactive period is a feature of male raccoon reproduction and is unique among seasonally breeding mammals.  相似文献   

4.
Numbers of feral raccoon; the possible reservoir animal of Ehrlichia and Anaplasma, are increasing in Japan. Thus serological methods were utilized to examine Ehrlichia and Anaplasma infection in raccoons from Kanagawa Prefecture, Japan. By using an indirect immunofluorescence assay, among 187 feral raccoons examined, 1 (0.5%) serologically reacted with Ehrlichia canis, 3 (1.6%) with Ehrlichia chaffeensis and 1 (0.5%) with Anaplasma phagocytophilum with the titers of 1:40 or more. Although screening PCR for Ehrlichia and Anaplasma species failed to detect the presence of ehrlichial DNA in serum samples, results of the serological tests suggested that the feral raccoons might be infected with some species of Ehrlichia and Anaplasma.  相似文献   

5.
Larva migrans caused by the common raccoon ascarid, Baylisascaris procyonis, is a zoonotic disease of critical importance in North America. Recently we encountered the first proven outbreak of this disease in Japan in domestic rabbits (Oryctolagus cuniculus) in a small wildlife park. In this park, raccoons (Procyon lotor) had been kept for 9 years, and one raccoon was donated to the park by a pet owner 8 weeks prior to the occurrence of an outbreak in rabbits. Of 12 total raccoons, three raccoons including the donated one shed B. procyonis eggs in the feces, and two of these positive raccoons were kept in metal mesh cages on wooden pedestals, 2 m distant from the rabbit enclosure. Circumstantial evidence indicates that the donated raccoon is the likely source of this outbreak. Treatment of the raccoons with an ascaricide and decontamination by extensive flaming of the cages and the contaminated dirt floor of the park achieved a transient disappearance of ascarids from all 12 enclosed raccoons. Three months after the control measures began, recurrent ascarid infection was detected in three young raccoons of less than 1.5 years of age. The potential risk of serious zoonosis by B. procyonis as well as the difficulty in a clearance of contaminated areas should be considered by pet owners and public health workers in Japan.  相似文献   

6.
We examined the use of external measurements and relative fat deposition of adult feral raccoons (Procyon lotor) to develop relative indices of body fat deposition in post-growth feral raccoons. From March 2006 to March 2010, 288 adult raccoon carcasses (110 males, 178 females) collected in Kanagawa Prefecture, Japan, which were determined to be 24 months old, were subjected to external measurements of body weight (BW), girth measurement (GM), and body mass index (BMI). To assess relative body fat deposition, we visually classified abdominal subcutaneous fat into three grades (Visible Fat Index [VFI]: I-III). Significant differences in the means of BW (both sexes:P<0.01), GM (females: P<0.05, males: P<0.01), and BMI (both sexes: P<0.01) were detected between seasons. Notably, the means of BW, GM, and BMI (all, both sexes: P<0.01) differed significantly between VFI grades. However, by discriminant analysis with BW, GM, and BMI as independent variables, we obtained a significant discriminant function (both sexes: P<0.01) for distinguishing VFI I from higher VFI grades, but no significant equation was obtained for distinguishing between VFI II and VFI III. Based on the obtained structure matrix of discriminant analysis, BMI was the most valuable component for the discrimination of VFI grades. Thus, we conclude that BMI is a suitable complementary index for assessing relative body fat deposition of adult feral raccoons in Kanagawa Prefecture and may be generalizable to populations in other areas.  相似文献   

7.
The population and distribution of feral raccoons (Procyon lotor) are expanding in Japan after escape or release from animal-owners. Wakayama Prefecture is one of the most typically devastated areas by this exotic carnivore, particularly in the last five years after a latent distribution for more than ten years. Official control measures of feral raccoons commenced in the summer of 2002 by several municipalities, and 531 animals collected in 12 municipalities between May 2003 and April 2005 were submitted for parasitological examination of gastrointestinal helminths. Detected parasites included six nematodes (Physaloptera sp. [prevalence; 5.1%], Contracaecum spiculigerum [0.9%], Strongyloides procyonis [25.5%], Ancylostoma kusimaense [0.8%], Arthrostoma miyazakiense [0.4%], and Molineus legerae [1.1%]), seven trematodes (Isthmiophora hortensis [4.9%], echinostomatid sp. with 34-39 collar spines [1.7%], Metagonimus takahashii [12.4%], M. yokogawai [0.8%], Plagiorchis muris [0.2%], Macroorchis spinulosus [1.9%], and Consinium ten [0.2%]), one cestode (Mesocestoides sp. [0.2%]), and six acanthocephalan spp. (Centrorhynchus bazalenticus [0.2%], Centrorhynchus teres [5.5%], Sphaerirostris lanceoides [2.4%], Plagiorhynchus ogatai [0.6%], Porrorchis oti [1.5%], and Southwelina hispida [1.9%]). Most of the collected parasites are food-borne, indigenous helminth species. Physaloptera sp. has never been recorded in indigenous wild carnivores in Japan, and resembles closely P. rara, prevalent in raccoons of North America, in morphology. The position of a pair of phasmids in the posteroventral region of the adult male, however, could differentiate it from P. rara. Since Strongyloides procyonis is known to cause creeping eruption as well as intestinal infection in a healthy human volunteer, we should be concerned about the rapid increase in the population and distribution of feral raccoons in Japan from the viewpoint of public health as well.  相似文献   

8.
In order to clarify the breeding capability of male raccoons in Japan, the testes of raccoons, a nuisance animal, collected in Kanagawa Prefecture and Hokkaido were histologically inspected. Furthermore, testosterone concentrations in their blood were measured. The testosterone concentrations increased in winter and the diameter of seminiferous tubules and the spermatogenetic score decreased in summer for the animals captured in Kanagawa Prefecture. For the animals captured in Hokkaido, the diameter of seminiferous tubules did not change and the decrease of the spermatogenetic score in summer was slight. As the above results show, there is a breeding season in male raccoons in Japan, and the reduction of testicular function in summer was greater in animals captured in Kanagawa Prefecture than in animals captured in Hokkaido.  相似文献   

9.
Ninety-four raccoons (Procyon lotor) from 6 southeastern states were examined for hematotropic parasites, to evaluate the carrier potential of these animals as they relate to translocation and release for hunting purposes. Four species of hematotropic parasites were identified, viz, Babesia procyonis, Haemobartonella procyoni, Hepatozoon procyonis, and Trypanosoma cruzi. Lesions in infected raccoons were associated only with H procyonis. Babesia procyonis was enzootic in populations of raccoons used as sources for exportation and in raccoons resident in typical release areas. Haemobartonella procyoni, H procyonis, and T cruzi were prevalent only in locales of raccoon origin. Due to the potential pathogenicity of H procyonis and T cruzi in raccoons or other hosts, the practice of translocating raccoons from enzootic to nonenzootic areas was considered biologically hazardous.  相似文献   

10.
AIM: To compare liver copper, selenium and vitamin B12 concentrations in red deer of farmed and feral origin. METHODS: Liver samples were collected from red deer at a South Island deer slaughter premise and a game packing house in November 2000. The site of origin and age of each animal were recorded. A subsample of 107 livers was selected (n=5-10 per site of origin and age category) from farmed deer from central Canterbury, Nelson and Westland, and from feral deer from north, central and south Westland. Samples were analysed for copper, selenium and vitamin B12 concentrations and reported on a wet-matter basis. RESULTS: Mean liver copper concentrations for farmed and feral yearlings were 267 and 889 micromol/kg, respectively, and for farmed and feral adults were 206 and 677 micromol/kg, respectively. Liver copper concentrations were lower for farmed than for feral deer (p<0.001) and for feral adults than for feral yearlings (p=0.002). Mean liver selenium concentrations in farmed and feral yearlings were 2050 and 1539 nmol/kg, respectively, and in farmed and feral adults were 1938 and 1625 nmol/kg, respectively. Liver selenium concentrations varied significantly between regions and overall, farmed deer had higher liver selenium concentrations than feral deer (p=0.04). Mean liver vitamin B12 concentrations in farmed and feral yearlings were 456 and 742 nmol/kg, and for farmed and feral adults were 428 and 869 nmol/kg, respectively. Liver vitamin B12 concentrations were lower for farmed than for feral deer (p<0.001). CONCLUSION: Feral deer had higher liver copper and vitamin B12 concentrations and lower liver selenium concentrations than farmed deer in the regions studied.  相似文献   

11.
Acanthocephalan everted cystacanths were detected in the intestines of 61 out of 555 feral raccoons (Procyon lotor) trapped between May 2003 and April 2005 in the western region of mainland Japan (Honshu). All collected specimens were identified as the species of birds including 3 Centrorhynchus species (C. bazaleticus, C. elongatus, and C. teres), Sphaerirostris lanceoides, Plagiorhynchus ogatai, Porrorchis oti, and Southwelina hispida. Three species, C. bazaleticus, C. teres, and S. lanceoides, were new to distribution records in Japan and the Far East. Recovery rates of these acanthocephalans were higher from the raccoons trapped in spring and early summer (range 8.3-36.8%, average 21.5%) than during the remainder of the year (range 0-20.0%, average 6.3%). The reason for this seasonal change is unknown. There is little information on the acanthocephalan fauna of wild birds in Japan, however, recovery of the cystacanths from the feral raccoons captured through the year might provide useful information on the fauna and geographical distribution of avian acanthocephalans.  相似文献   

12.
Serum samples from 427 raccoons (93 from Pennsylvania, 45 from New Jersey, 72 from South Carolina, 68 from Virginia, 30 from Iowa, and 119 from Ohio) were evaluated for Toxoplasma gondii antibodies in dilutions of 1:25, 1:50, and 1:500. The distribution of T gondii antibody titers was less than 1:25 for 212 raccoons (49.6%), 1:25 for 34 raccoons (7.9%), 1:50 for 117 raccoons (27.4%), and greater than or equal to 1:500 for 64 raccoons (14.9%). Tissue cysts were seen in the liver, and tachyzoites were in the brain of a raccoon with abnormal neurologic signs and concurrent infection with canine distemper virus. Organisms in the liver were stained with anti-T gondii serum, and the raccoon had a T gondii titer of 1:160 in the agglutination test.  相似文献   

13.
To estimate the public and animal health risk that alien species pose, the prevalence of Salmonella, Yersinia, and Campylobacter spp. in feral raccoons (Procyon lotor, n=459) and masked palm civets (Paguma larvata, n=153), which are abundant alien species in Japan, was investigated in urban and suburban areas of Japan. Salmonella enterica was detected from 29 samples [26 raccoons, 5.7%, 95% confidence interval (CI) 7.8-3.5%; three masked palm civets, 2.0%, 95% CI 4.2-0%]. Many of the isolates belonged to serovars that are commonly isolated from human gastroenteritis patients (e.g. S. Infantis, S. Typhimurium, and S. Thompson). The antimicrobial susceptibility test showed that 26.9 % of the isolates from raccoons were resistant to at least one antimicrobial agent, whereas none of the isolates from masked palm civets were resistant. Yersinia sp. was detected from 193 samples (177 raccoons, 38.6%, 95% CI 43.0-34.1%; 16 masked palm civets, 10.5%, 95% CI 15.3-5.6%). All virulent Yersinia strains belonged to Yersinia pseudotuberculosis, which was isolated from seven (1.5%, 95% CI 2.6-0.4%) raccoons and six (3.9%, 95% CI 7.0-0.8%) masked palm civets. According to the detection of virulence factors, all the Y. pseudotuberculosis isolates belonged to the Far Eastern systemic pathogenicity type. Campylobacter spp. was detected from 17 samples (six raccoons, 1.3%, 95% CI 2.3-0.3%; 11 masked palm civets, 7.2%, 95% CI 11.3-3.1%). Among these, three isolates from raccoons were identified as C. jejuni. These results showed that these pathogens can be transmitted by human activities, other wild animals, and the environment to feral raccoons and masked palm civets, and vice versa. As these animals have omnivorous behaviour and a wide range of habitats, they can play an important role in the transmission of the enteric pathogens.  相似文献   

14.
The raccoon is a seasonal breeder with a mating season in the winter. In a previous study, adult male raccoons exhibited active spermatogenesis with high plasma testosterone concentrations, in the winter mating season. Maintenance of spermatogenesis generally requires high testosterone, which is produced by steroidogenic enzymes. However, even in the summer non-mating season, some males produce spermatozoa actively despite low plasma testosterone concentrations. To identify the factors that regulate testosterone production and contribute to differences in spermatogenetic activity in the summer non-mating season, morphological, histological and endocrinological changes in the testes of wild male raccoons should be known. In this study, to assess changes in the biosynthesis, metabolism and reactivity of testosterone, the localization and immunohistochemical staining intensity of four steroidogenic enzymes (P450scc, P450c17, 3βHSD, P450arom) and the androgen receptor (AR) were investigated using immunohistochemical methods. P450scc and P450c17 were detected in testicular tissue throughout the year. Seasonal changes in testosterone concentration were correlated with 3βHSD expression, suggesting that 3βHSD may be important in regulating the seasonality of testosterone production in raccoon testes. Immunostaining of P450arom and AR was detected in testicular tissues that exhibited active spermatogenesis in the summer, while staining was scarce in aspermatogenic testes. This suggests that spermatogenesis in the raccoon testis might be maintained by some mechanism that regulates P450arom expression in synthesizing estradiol and AR expression in controlling reactivity to testosterone.  相似文献   

15.
Anti-Toxoplasma antibody titres in 185 sera from clinically normal goats from 14 farms were assayed by both the latex agglutination and the indirect fluorescent antibody tests. The animals were of various breeds including Angora, New Zealand feral, Angora×feral, Saanen and Toggenburg. A high level of agreement between the two tests was obtained with 83.8% of titres corresponding to within one dilution and 96.8% to within two dilutions. In both tests, titres of 1:64 and above were considered positive. A total of 298 goat sera from clinically normal kids (n = 88), yearlings (n = 65) and adults (n = 145) from 17 farms were examined by the latex agglutination test. The prevalence of positive sera was 7% in kids, 23% in yearlings and 37% in adults. There was a significantly higher prevalence of positive sera in dairy than in fibre breeds.  相似文献   

16.
Objective-To evaluate the effectiveness of an oral rabies vaccination (ORV) project conducted from 1998 through 2007 in Anne Arundel County, Md, for the control of rabies in terrestrial animals. Design-Retrospective analysis of surveillance data (1997 through 2007). Animals-Free-ranging raccoons (Procyon lotor) and other terrestrial mammals. Procedures-Vaccinia-rabies glycoprotein recombinant virus oral rabies vaccine-bait units were distributed annually by aircraft and ground teams targeting free-ranging raccoons. Approximately 2 to 4 weeks following the vaccine-bait placement, raccoons were live trapped, sedated, processed, and then released. Serologic samples were tested for the presence of rabies virus-neutralizing antibodies (RVNAs). Bait acceptance was estimated by analysis of tetracycline biomarking of sampled teeth. Rabies incidence was determined by the passive identification of rabid terrestrial animals. Results-The incidence of rabies in terrestrial animals decreased 92% between 1997 (the year prior to the start of the ORV project) and 2007. The mean RVNA prevalence across all years was 33% among trapped raccoons in areas baited with a fish meal polymer bait type, whereas the mean bait acceptance was 30%. Adult raccoons had a seropositivity rate twice that of juvenile raccoons, whereas the bait acceptance rate between adults and juveniles did not differ significantly. For areas baited with a coated sachet bait, adults and juveniles had the same seroprevalence. Juveniles had better seroprevalence when the annual campaign started in September and October, compared with August. Conclusions and Clinical Relevance-The ORV project contributed to a significant decrease in annual incidence of terrestrial animal rabies in Anne Arundel County, Md, during the 10-year project period. For fish meal polymer baits, juvenile raccoons accessed bait at the same rate as adult raccoons but had a significantly lower prevalence of RVNAs. For coated sachet baits, seroprevalence was the same in both age groups. The time of year the bait distribution occurred and the bait type used may be partial explanations for the difference in RVNA seroprevalence between adults and juvenile raccoons.  相似文献   

17.
Sarcocystis infections in Georgia swine   总被引：1，自引：0，他引：1  
Tissues from 168 mature sows obtained at slaughter in northern and southern Georgia were examined for infection with Sarcocystis spp. Digestion techniques revealed zoites in 28 (16.5%) sows. Infected meat was fed to laboratory-reared dogs, cats, raccoons (Procyon lotor), and opossums (Didelphis marsupialis). Dogs and raccoons shed sporocysts (8.3 mum X 11.2 mum) 12 to 14 days after infection. Cats and opossums were refractory to infection. Sarcocystis-free pigs were infected with 50,000 sporocysts of swine-dog origin. Tissues from laboratory-infected swine were fed to dogs and raccoons. Both species shed sporocysts 14 days later. This is the 1st time in which a definitive host has been demonstrated for species of Sarcocystis occurring in North American swine. The raccoon constitutes a new definitive host for S suicanis Erber 1977. In contrast to previously reported low prevalences of Sarcocystis infections in swine, the relatively high prevalence reported here indicates that S suicanis may be of importance to swine producers in Georgia.  相似文献   

18.
To determine the transmissibility of transmissible mink encephalopathy (TME) agent to raccoons and to provide information about clinical course, lesions, and suitability of currently used diagnostic procedures for detection of transmissible spongiform encephalopathies (TSEs) in raccoons, 4 raccoon kits were inoculated intracerebrally with a brain suspension from mink experimentally infected with TME. One uninoculated raccoon kit served as a control. All 4 animals in the TME-inoculated group showed clinical signs of neurologic disorder and were euthanized between 21 and 23 weeks postinoculation (PI). Necropsy examinations revealed no gross lesions. Spongiform encephalopathy was observed by light microscopy, and the presence of protease-resistant prion protein (PrPres) was detected by immunohistochemistry and Western blot techniques. Scrapie-associated fibrils were observed by negative-stain electron microscopy in the brains of 3 of the 4 inoculated raccoons. These findings confirm that TME is experimentally transmissible to raccoons and that diagnostic techniques currently used for TSE in livestock detect prion protein in raccoon tissue. According to previously published data, the incubation period of sheep scrapie in raccoons is 2 years, whereas chronic wasting disease (CWD) had not shown transmission after 3 years of observation. Because incubation periods for the 3 US TSEs (scrapie, TME, and CWD) in raccoons appear to be markedly different, it may be possible to use raccoons for differentiating unknown TSE agents. Retrospective genotyping of raccoons using frozen spleens showed that the raccoon PrP gene is identical to the mink gene at codons 179 and 224. Further studies, such as the incubation periods of bovine spongiform encephalopathy and other isolates of scrapie, CWD, and TME in raccoons, are needed before the model can be further characterized for differentiation of TSE agents.  相似文献   

19.
In order to evaluate the present epidemiological situation of Trichinella infection in wild animals in Hokkaido, Japan, red foxes (Vulpes vulpes), raccoon dogs (Nyctereutes procyonoides) , brown bears (Ursus arctos) , martens (Martes melampus), rodents and insectivores captured in Hokkaido were examined for muscle larvae by the artificial digestion method from 2000 to 2006. Foxes (44/319, 13.8%), raccoon dogs (6/77, 7.8%) and brown bears (4/126, 3.2%) were found to be infected with Trichinella larvae and all other animal species evaluated were negative. Multiplex PCR and DNA sequencing revealed that larvae from a fox captured in Otofuke, in south-eastern Hokkaido, were T. nativa, and larvae from 27 animals including 21 foxes, 2 raccoon dogs and 4 brown bears captured in western Hokkaido were Trichinella T9.  相似文献   

20.
Fine-scale spatiotemporal studies can better identify relationships between individual survival and habitat fragmentation so that mechanistic interpretations can be made at the population level. Recent advances in Global Positioning System (GPS) technology and statistical models capable of deconstructing high-frequency location data have facilitated interpretation of animal movement within a behaviorally mechanistic framework. Habitat fragmentation due to singleleaf pinyon (Pinus monophylla; hereafter pinyon) and Utah juniper (Juniperus osteosperma; hereafter juniper) encroachment into sagebrush (Artemisia spp.) communities is a commonly implicated perturbation that can adversely influence greater sage-grouse (Centrocercus urophasianus; hereafter sage-grouse) demographic rates. Using an extensive GPS data set (233 birds and 282,954 locations) across 12 study sites within the Great Basin, we conducted a behavioral change point analysis and constructed Brownian bridge movement models from each behaviorally homogenous section. We found the probability of encountering pinyon-juniper among adults was two and three times greater than that of yearlings and juveniles, respectively. However, the movement rate in response to the probability of encountering pinyon-juniper trees was 1.5 times greater for juveniles. Parameter estimates indicated a 6.1% increase in the probability of encountering pinyon-juniper coupled with a 6.2 km/hour increase in movement speed resulted in a 56%, 42% and 16% increase in risk of daily mortality, for juveniles, yearlings, and adults, respectively. The effect of pinyon-juniper encounters on survival was dependent on movement rate and differed among age class. Under fast speed movements (i.e., flight), mortality risk increased as encountering pinyon-juniper increased across all age classes. In contrast, slower speeds (i.e., average) yielded similar adverse effects for juveniles and yearlings but not for adults. This analytical framework supports a behavioral mechanism that explains reduced survival related to pinyon-juniper within sagebrush environments, whereby encountering pinyon-juniper stimulates riskier movements that likely increase vulnerability to visually acute predators.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号