北美浣熊的饲养管理和繁殖

动物园饲养的浣熊科动物经常出现异常的繁殖行为:食仔和弃仔现象,而随后的人工哺育需要耗费大量时间和精力.2011年上海动物园新引进3对亚成体浣熊,在参考国内外文献资料中浣熊的野外繁殖习性的基础上,在圈养条件下探索降低异常繁殖行为的方法,于2012年首次使3对浣熊成功繁殖和育幼.本文就北美浣熊的野外习性、饲养管理、繁殖特性等,结合观察到的-窝幼仔的发育情况和行为表现做初步小结,以期为今后的繁殖工作打下基础,减少动物的异常繁殖行为.     

Prevalence of Salmonella, Yersinia and Campylobacter spp. in feral raccoons (Procyon lotor) and masked palm civets (Paguma larvata) in Japan

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.     

Leptospirosis and tularaemia in raccoons (Procyon lotor) of Larimer County, [corrected] Colorado

Raccoons (Procyon lotor) are commonly implicated as carriers of many zoonotic pathogens. The purpose of this cross-sectional study was to look for Leptospira interrogans and Francisella tularensis in opportunistically sampled, free-ranging raccoons of Larimer Country, Colorado, USA. Sixty-five animals were included in the study and testing consisted of gross post-mortem examination, histopathology, and both immunohistochemistry and PCR for L. interrogans and F. tularensis. No significant gross lesions were identified and the most common histological lesions were lymphoplasmacytic interstitial nephritis and pulmonary silicosis; rare periportal hepatitis, splenic lymphoid hyperplasia and small pulmonary granulomas were also identified. Of 65 animals, 20 (30%) were positive for Leptospira on IHC but only one by PCR. Animals with inflammation in their kidneys were seven times more likely to be positive for Leptospira than animals without inflammation. The severity of inflammation was variable but often mild with minimal associated renal pathology. One animal was positive for Francisella on both IHC and PCR; IHC staining was localized to histiocytic cells within a pulmonary granuloma. In Colorado the significance and epidemiology of Leptospira is poorly understood. The high prevalence of infection in raccoons in this study population suggests that this species may be important in the regional epidemiology or could be used to estimate risk to domestic animals and humans. Identification of a single Francisella positive animal is significant as this is an uncommon disease in terrestrial animals within the state; the apparently higher prevalence in this peridomestic species implies that raccoons may be good indicators of the pathogen in the region. The results of this study suggest that raccoons may serve as effective sentinels for both Leptospira and Francisella in the state of Colorado. Further studies are needed to better characterize the prevalence and epidemiology of both organisms within the region.     

Motor Neuron Organization and Corticospinal Fibers in the Cervical Intumescence of the Raccoon (Procyon lotor) Spinal Cord

Experiments were performed on 19 raccoons to determine the organization of the spinal alpha motoneurons innervating the muscles of the thoracic limb. Chromatolysis of motoneurons was provoked by resecting major nerves or removing individual muscles or muscle groups. Proximal intrinsic limb muscle motoneurons were located cranially in the cervical spinal intumescence and distal muscle motoneurons more caudally. Flexor motoneurons were generally dorsal and more laterally located within the lateral motoneuronal cell group than were the cell bodies innervating their extensor antagonists. The distribution of motor cortex projections to motoneurons was studied in five raccoons by selective silver impregnation of degenerating fibers after unilateral motor cortex ablation. Degenerating cortical projections within the motoneuronal cell group (Rexed's lamina IX) were seen only in the more dorsal and the lateral portions in the seventh and eighth cervical and the first thoracic spinal cord segments. Motor cortex preterminal and terminal fibers were in close apposition to the proximal dendrites and the somata of alpha motoneurons innervating primarily the more distal limb musculature and particularly the intrinsic muscles of the manus.     

Prevalence and distribution of Baylisascaris procyonis in urban raccoons (Procyon lotor) in Winnipeg,Manitoba

The prevalence of Baylisascaris procyonis was estimated in the urban raccoon population of Winnipeg through the fecal flotation of raccoon feces collected at active latrines and through gross postmortem and fecal flotation of samples collected from nuisance raccoons. Fecal flotation of latrine-collected feces was positive in 33 of 89 samples and, of 52 latrines identified, 26 were positive on 1 or more occasions. Trapped individual raccoons subjected to postmortem examination were positive in 57 of 114 animals captured. Comparing a single fecal flotation to the gold standard of finding adult worms in the small intestine had a sensitivity of 78.9% and specificity of 92.9%. This study suggests that carriage of Baylisascaris procyonis is widespread in raccoons in the Winnipeg urban ecosystem. Raccoon latrines in Winnipeg should be treated as infectious sites and efforts should be made to limit access of pets and people at risk to those sites.     

Electrocardiographic evaluation of the healthy raccoon (Procyon lotor)

Leads I, aVF, V3, and V10 ECG were obtained from 12 healthy raccoons anesthetized with xylazine and ketamine. Intervals and amplitudes of component deflections were remarkably uniform among the individuals. Vector orientation of QRS mimicked that for the dog; but the relatively low voltages to QRS mimicked those of cats. The QT interval varied inversely with heart rate, whereas the PQ interval varied directly with body weight. Relationship between heart rate and body weight was not significant (P greater than 0.05).     

Naturally occurring spirochetes in the colonic mucosa of raccoons (Procyon lotor)

The large intestines of 21 raccoons (Procyon lotor; 11 wild caught, 10 laboratory confined) were examined for the presence of intestinal spirochetes. Light microscopy of sections stained with hematoxylin and eosin and Warthin-Starry stain showed the presence of spiral shaped organisms deep within the lumina of intestinal glands at the ileocolonic junction of 16 raccoons (76% prevalence). All laboratory-confined, group-housed raccoons harbored the organisms, but only 6/11 (55% prevalence) live-trapped raccoons were positive for these spirochetes. The organisms were free in the glandular lumina, and there were no microscopic lesions. Two types of spirochetes were identified in the colonic glands: a slender spirochete 10-13 microm in length, 0.3 microm in diameter, and possessing long, thin tapered ends and a larger, regularly waved spiral organism (0.5 microm in diameter). The slender spirochete did not resemble any of the known spirochete genera and failed to grow on medium used to propagate oral treponemes and members of the genus Brachyspira.     

Methods of evaluating the spermatogenic ability of male raccoons (Procyon lotor)

Feral raccoons (Procyon lotor) have been growing in number in Japan, and they are becoming a problematic invasive species. Consequently, they are commonly captured and killed in pest control programs. For effective population control of feral raccoons, it is necessary to understand their reproductive physiology and ecology. Although the reproductive traits of female raccoons are well known, those of the males are not well understood because specialized knowledge and facilities are required to study them. In this study, we first used a simple evaluation method to assess spermatogenesis and presence of spermatozoa in the tail of the epididymis of feral male raccoons by histologically examining the testis and epididymis. We then evaluated the possibility of using 7 variables—body weight, body length, body mass index, testicular weight, epididymal weight, testicular size and gonadosomatic index (GSI)—to estimate spermatogenesis and presence of spermatozoa in the tail of the epididymis. GSI and body weight were chosen as criteria for spermatogenesis, and GSI was chosen as the criterion for presence of spermatozoa in the tail of the epididymis. Because GSI is calculated from body weight and testicular weight, this model should be able to be used to estimate the reproductive state of male raccoons regardless of season and age when just these two parameters are known. In this study, GSI was demonstrated to be an index of reproductive state in male raccoons. To our knowledge, this is the first report of such a use for GSI in a member of the Carnivora.     

Changes in the Immunolocalization of Steroidogenic Enzymes and the Androgen Receptor in Raccoon (Procyon lotor) Testes in Association with the Seasons and Spermatogenesis

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.     

Reproductive characteristics of the feral raccoon (Procyon lotor) in Hokkaido,Japan

Reproduction of feral raccoons (Procyon lotor) in Hokkaido, Japan, was examined during a 2-year period by analysis of placental scars or fetuses in the uterus. Of 242 collected females, 69 (29%) were juveniles, 71 (29%) yearlings, and 102 (42%) adults. The pregnancy rate averaged 66% in yearlings and was significantly lower than the 96% average observed in adults (p<0.01). Litter size ranged from 1 to 7 offspring per female, and averaged 3.6 in yearlings and 3.9 in adults. There was no significant difference in mean litter size between yearlings and adults. In Hokkaido, the raccoon mating season peaked in February and the majority of litters were born between March and May, similar to patterns described in North America, but some females mated in summer. The reproductive potential of feral raccoons in Hokkaido was similar to that reported in North America. The recent increase in raccoon numbers can be explained by their high productivity. Harvest data suggest that hunting pressure on juveniles is lower than that for older age classes when using box traps in summer. In order to reduce the feral raccoon population, alternative hunting methods that increase juvenile mortality rates are needed.     

Prevalence of psammoma bodies in meninges and choroid plexuses of raccoons (Procyon lotor) from Parramore Island, Virginia.

Microscopic evidence of multifocal mineralizations (psammoma bodies) were seen in brains of 33/53 (62%) raccoons (Procyon lotor) necropsied on Parramore Island, Virginia. Most mineralized foci had concentric laminations and were present in small capillaries of meninges of the brain (15/33), in choroid plexus (3/33), or at both these sites (13/33). In 2 raccoons, the lesions were confined to the meninges of the proximal cervical spinal cord. In most cases, the affected vessels appeared to have been completely occluded. However, no evidence of ischemic changes in the brain parenchyma was seen, and none of the raccoons had abnormal neurologic signs prior to euthanasia. The condition appears to be a common incidental histopathologic finding in raccoons from the eastern United States. Although the exact cause of this condition is not known, a primary vascular insult with resultant dystrophic mineralization of the affected vessels is suspected.     

Canine Distemper in Wild Raccoons (Procyon lotor) at the Metropolitan Toronto Zoo

An outbreak of canine distemper, involving at least 23 wild raccoons, occurred at the Metropolitan Toronto Zoo between May and August 1981. Wild red foxes were not found with distemper and the disease did not occur in the captive collection. The main clinical signs were lethargy, bilateral purulent ocular discharge, dehydration and emaciation. The main pathological findings were generalized lymphadenopathy, splenomegaly, and interstitial pneumonia. Heavy infestations with intestinal nematodes (Baylisascaris procyonis), and unidentified cestodes were found. Cryptosporidia were found on the epithelium of the duodenum in 42% of the animals examined. Eosinophilic intracytoplasmic and intranuclear inclusions were numerous in the epithelium of the urinary bladder, renal pelvis, stomach and lung. This local outbreak was part of a major eruption of the disease in raccoons in southern Ontario which began in early 1981 and persisted until the submission of this paper in mid 1983.     

Myocarditis and encephalitis associated with Sarcocystis neurona infection in raccoons (Procyon lotor)

Sarcocystis neurona associated granulomatous encephalitis was found in 2 of 84 adult raccoons. Both raccoons also had an extensive nonsuppurative myocarditis and one had S. neurona schizonts and merozoites in the myocardium. Only the asexual stages (schizonts and merozoites) of S. neurona are found in tissues of naturally infected animals (horse, mink, raccoons, cats, skunk, pony, seals, sea otters) and since these have not been reported outside the central nervous system, the presence of concurrent myocarditis in raccoons with the presence of S. neurona in the current study is of interest. Pathologists should consider the possible association of S. neurona with myocardial inflammation in other S. neurona susceptible animals.     

Notoedric mange in two free-ranging North American racoons (Procyon lotor) in Japan

Mange was diagnosed in two North American racoons (Procyon lotor) at Kamakura City in Kanagawa Prefecture, Japan. The mites were identified morphologically as Notoedres cati. Mite infestation affected the skin over the extremities and tail, and was characterized by moderate alopecia and erythematous dermatosis. Histopathologically, the affected skin showed marked epidermal hyperplasia and mites located within the parakeratotic stratum corneum. A slight dermal inflammatory response consisting principally of mononuclear cells was observed. N. cati mites were demonstrated in their tunnels using scanning electron microscopy (SEM). This is the first report of notoedric mange in racoons.     

Gastrointestinal helminths of feral raccoons (Procyon lotor) in Wakayama Prefecture, Japan

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.