Experimental lead toxicosis of raccoons (Procyon lotor)

Four pairs of raccoons were treated orally with the following doses of lead acetate (mg/kg; 5 days/week, for 8 weeks): 0 (control), 1, 2 and 4. In the six experimental animals, this treatment produced dose-dependent increases in blood lead, without clinical signs or changes in haematological parameters. After 8 weeks, the liver and kidney of all lead-treated animals and the calvarium and radius of those receiving doses of 2 and 4 mg/kg contained elevated concentrations of lead. Acid-fast inclusions were observed by light and electron microscopy in the kidneys of all raccoons receiving the two highest doses and in one animal receiving the lowest dose. Hepatic acid-fast inclusions were seen in only one animal (dose 4 mg/kg). No inclusions were seen in osteoclasts of the radius. It is suggested that the findings, which support earlier observations that raccoons are fairly resistant to lead, may be of value in studying interactions between lead exposure and oral vaccination of wildlife against rabies.     

Architecture of the masticatory apparatus in eastern raccoons (Procyon lotor lotor)

The structure and function of the masticatory apparatus of raccoons resemble those found in carnivores. In this study, the architecture of the skull, dentition, and masticatory apparatus is described, and a model is proposed that suggests a mechanism used by raccoons to reduce different foods. The model suggests that (1) jaw movements are similar to those of cats, (2) the posterior regions of the superficial and deep parts of the temporalis and the anterior region of the medial pterygoid generate horizontal jaw movements, and (3) the anterior portions of the superficial and deep temporalis as well as portions of the masseteric complex generate vertical closing movement. The distributions of slow, fast fatigable, and fast fatigue-resistant fibers for the temporalis and masseteric complex are related to the possible actions of these muscles during mastication, as are the regional cross-sectional areas of the masticatory muscles.     

Alaria alata mesocercariae in raccoons (Procyon lotor) in Germany

Alaria alata is a trematode of carnivores from Europe. The mesocercarial stage was recently identified in wild boar meat from Europe. Previous histopathologic studies showed the presence of unidentified parasitic cysts within the tongues of raccoons from northern Germany. For identification of the parasite species, tissue samples of 105 raccoons originating from a National Park in northern Germany and from Berlin metropolitan area were collected. Histological examination of cryotome sections of frozen as well as paraffin-embedded tongues were used to identify parasite cysts. These were located in the connective and adipose tissue and in close proximity to small arterioles, suggesting a hematogenous spread of the parasite. Often, cysts were surrounded with mild infiltration by inflammatory cells. Additionally, mesocercariae were isolated from defrosted tongue samples of 11 raccoons. Molecular-biology assays confirmed the parasite species as A. alata. Except for one positive raccoon from Berlin City, all other positive raccoons originated from the sylvan Müritz National park, indicating an abundance of intermediate hosts in this area. Our results show that raccoons can act as paratenic hosts for A. alata and extend the broad host range of this parasite to a species introduced into Germany.     

First surveillance and molecular identification of the Cryptosporidium skunk genotype and Cryptosporidium parvum in wild raccoons (Procyon lotor) in Osaka,Japan

Parasitology Research - Recent research suggests that raccoons (Procyon lotor) can transmit several important pathogens affecting humans, including protozoans. In Japan, the number of wild raccoons...     

First detection of Baylisascaris procyonis in wild raccoons (Procyon lotor) from Leipzig,Saxony, Eastern Germany

Parasitology Research - Baylisascaris procyonis is a zoonotic nematode mainly harbored by the North American raccoon. It can cause severe neurological problems in paratenic hosts and humans. In...     

Seroprevalence and risk factors of Toxoplasma gondii infection in invasive raccoons (Procyon lotor) in Central Europe

Toxoplasma gondii is an obligate intracellular protozoan that causes toxoplasmosis in warm-blooded animals. Most mammals, including humans, can become intermediate host, resulting in subclinical infection or even death. Generally, there is limited information on the epidemiology of T. gondii of game species in Germany. As omnivores, raccoons, which are particularly widespread and abundant in Germany, are particularly exposed to infection the parasite. Here, we report the seroprevalence of T. gondii antibodies from 15 study sites located in Luxembourg and Germany. Using the indirect modified agglutination test (MAT), 170 (37.4%; 95% CI: 33.0–41.9) out of 454 raccoons were surveyed to be T. gondii seropositive. While values ranged from 19.0% to 53.3%, there was no significant difference in seroprevalence between study areas. Animal weight had a strong influence on the presence of T. gondii antibodies in raccoon sera, with heavier animals more likely to be seropositive. Our results show that T. gondii infection is widespread in central European raccoons, suggesting a high degree of ecosystem circulation of the parasite.

     

Baylisascaris procyonis in raccoons (Procyon lotor) from North Carolina and current status of the parasite in the USA

Baylisascaris procyonis is an intestinal nematode of raccoons (Procyon lotor) that can cause fatal larva migrans in numerous species of birds and mammals, including humans. Historically, this parasite has been rare in the southeastern USA but recently has been reported in eastern Tennessee and isolated parts of Georgia and Florida. The objective of the current study was to investigate the distribution and prevalence of B. procyonis in raccoons from North Carolina. In western North Carolina, in counties bordering Tennessee, B. procyonis was detected in nine of 74 (12 %) raccoons sampled in 2010–2011. In general, worm burdens (average 20 worms) were low, but one raccoon had 122 adult worms. No difference was noted in prevalence by year or age, but significantly more males were infected compared with females. Sequences of the internal transcribed spacer 2 region from three samples were identical to B. procyonis. In central North Carolina (Guilford County), all 34 raccoons and 49 fecal samples tested were negative. Collation of data from previous studies conducted in the Southeast indicates that B. procyonis has been reported from numerous counties, but surveillance has been patchy and many negative results are >30 years old. These results indicate that B. procyonis is established in North Carolina and given the zoonotic and wildlife health implications of this parasite, additional surveillance in North Carolina and other southeastern states is warranted.     

Salmonella infections in the common raccoon (Procyon lotor) in western Pennsylvania

Ten Salmonella enterica serotypes were isolated from fecal samples collected from anesthetized raccoons (n = 738) trapped in six Pennsylvania counties from 2003 to 2005. Comparison of raccoon pulsed-field gel electrophoresis (PFGE) pulse type data with the Pennsylvania Department of Health PFGE database revealed that the patterns of seven Salmonella serotypes matched those isolated from humans with salmonellosis.     

Pancreatic endocrine carcinoma with multiple hormone production in a raccoon (Procyon lotor)

A pancreatic endocrine carcinoma with lung metastases was found in a 15-year-old male raccoon. This tumour was characterized by great variation in cell size and production of multiple polypeptide hormones. Endocrine markers expressed by the neoplastic cells were, in descending order of frequency, chromogranin A, pancreatic polypeptide (PP), glucagon, somatostatin and insulin. Co-expression of PP and glucagon, somatostatin or insulin was demonstrated immunohistochemically with consecutive sections, and cells with both glucagon and insulin were also observed. The pattern of co-expression was similar to that in the earliest stages of murine pancreatic development. Amyloid deposits in the islets of Langerhans, which reacted with antibody to islet amyloid polypeptide, were thought to be associated with age.     

Localization of epidermal hyaluronan in the foot pads of the North American raccoon (Procyon lotor)

The localization of the epidermal hyaluronan in the digital foot pads of the North American raccoon (Procyon lotor) was examined by light and electron microscopic histochemical methods. The thick epidermis contained five epidermal layers composed of typical keratinocytes. In the stratum basale and stratum spinosum, hyaluronic acid was clearly detectable at cytoplasmic processes, in close vicinity to the surface coat of the plasma membrane, and/or in the intercellular space between the basal and spinous cells. The results suggest that epidermal hyaluronan that fills the intercellular space may particularly control water maintenance in the epidermis of the raccoon digital pads to guarantee the optimal mechanoreceptive function of the very specific and sensitive sensoric subepidermal equipment in this mammalian species.     

Fine structure of the oocyst wall and excystation ofEimeria procyonis from the American raccoon (Procyon lotor)

Oocysts ofEimeria procyonis, from the American raccoon (Procyon lotor), were broken, added to a cell suspension, fixed in Karnovsky's fluid, and studied with the electron microscope. The oocyst wall has three layers: a thin electron-dense inner layer (8–15 nm), an electron-lucent middle layer (25–35 nm), and a thick outer layer (120–140 nm). The outer layer has an electron-dense inner portion and an electron-lucent outer portion that contains membrane-bound vesicles. When exposed to a trypsin-sodium taurocholate fluid, sporozoites excysted from most sporocysts which were 35–43 months old, but not from sporocysts that looked normal and were 106 months old. Excysted sporozoites measured 13–16×3–4 (mean 14.3×3.2) m, usually had two refractile bodies, and had a nucleus with a prominent nucleolus.     

Trichinella spiralis,T. britovi,and T. nativa : infectivity,larval distribution in muscle,and antibody response after experimental infection of pigs

The infectivity of Trichinella spiralis, T. nativa, and T. britovi was experimentally compared in pigs. Blood sampling was performed weekly, and muscle juices were obtained at slaughter 10 weeks after inoculation. Muscle larvae were found in all of four pigs inoculated with T. spiralis [mean 190 larvae per gram (lpg)] and in three of four pigs inoculated with T. britovi (mean 7 lpg). No larvae were found in pigs inoculated with T. nativa. For T. spiralis and T. britovi, the neck muscle (m. splenius) appears to be a predilection site in addition to the tongue, the diaphragm, and the jaw. High antibody responses were found in all experimental groups, independent of the antigen used, and even in pigs in which no muscle larvae were recovered. The strong and consistent antibody response found with meat juice indicates the usefulness of this material where a blood sample is not obtainable, e.g. meat samples from wild animals. Immunoblotting (Western blots) on slaughter sera revealed no species specificity when comparing homologous versus heterologous staining. Received: 30 July 1997 / Accepted: 25 September 1997     

Histochemical analysis of glycoconjugates in the ceruminous glands of the North American raccoon (Procyon lotor).

The distribution and selectivities of glycoconjugates in the ceruminous glands of the North American raccoon (Procyon lotor) were studied by light and electron microscopic histochemical methods, particularly lectin histochemistry. In the modified apocrine glands present, the apocrine secretion mode was combined with exocytosis, whereby the secretory epithelium and the luminal secretion of the ceruminous glands exhibited considerable amounts of complex carbohydrates with various terminal sugars (alpha-D-mannose, beta-D-galactose, alpha-L-fucose, alpha-N-acetyl-galactosamine, beta-N-acetyl-D-glucosamine, N-acetyl-neuraminic acid). Alpha-L-fucose and N-acetyl-neuraminic acid were distinctly prominent in secretory granules or within the free surface coat of the plasma membrane of the glandular cells, as well as in the luminal secretion. Several free sugars (alpha-D-mannose, alpha-L-fucose, beta-D-galactose, beta-N-acetyl-D-glucosamine) were also detectable in the secretion of associated sebaceous glands. The ceruminous gland secretion may control viscoelasticity and/or bacterial degradation of the glandular secretion mixture to improve the protection of the external auditory canal against physical damage or microbial contamination.     

Light and scanning electron microscopic study on the tongue and lingual papillae of the common raccoon, Procyon lotor

We observed the external surface and connective tissue cores (CTCs), after exfoliation of the epithelium of the lingual papillae (filiform, fungiform, foliate and vallate papillae) of the common raccoon (Procyon lotor) using scanning electron microscopy and light microscopy. The tongue was elongated and their two-third width was almost fixed. Numerous filiform papillae were distributed along the anterior two-thirds of the tongue and fungiform papillae were distributed between the filiform papillae. Eight vallate papillae that had a weak circumferential ridge were distributed in a V-shape in the posterior part of the tongue and numerous taste buds were observable in the circumferential furrows of vallate papillae. Weak fold-like foliate papillae were observable at the lateral edge in the posterior part of the tongue and a few salivary duct orifices were observable beneath the foliate papillae. An islet-like structure with numerous taste buds, was observable on the deep part of the salivary duct of foliate papillae. Large conical papillae were distributed at the posterior part and root of the tongue. After removal of epithelium, filiform papillae of CTCs were appeared to be a thumb or cone-like main core and associating several finger-like short accessory cores. These cores were surrounded an oval concavity. The main core was situated behind the concavity and associated with accessory cores. CTCs of fungiform papillae were cylinder-like with numerous vertically running ridges and with a few concavities seen at the top of the cores. CTCs of vallate papillae and their surrounded circumferential ridge were covered with numerous pimple-like protrusions. The lingual papillae of Common raccoon's tongue had morphological feature of carnivore species.     

The distribution of excretory/secretory antigens during the muscle phase of Trichinella spiralis and T. pseudospiralis infections

The in situ distribution of excretory/secretory (ES) antigens of the infective-stage larvae of Trichinella spiralis and T. pseudospiralis was compared at various periods of development by immunofluorescent laser confocal microscopy and the immunoperoxidase method. In the former infection, epitopes of the ES antigens were always confined exclusively within the nurse cell, i.e., in the cytoplasmic region, hypertrophic nuclei, stichocytes, and cuticular surface of worms. In the latter infection, as early as at day 15 postinfection, ES epitopes were located along the infected myofibers, in the adjacent muscles, hypertrophic nuclei, stichocytes, and cuticular surface of worms. By day 30 postinfection there was a marked increase in both the distribution and the intensity of ES antigens in infected as opposed to uninfected myofibers. A new method was also developed to reveal the number of hypertrophic nuclei, small cells, and larvae in intact nurse cells. As many as four worms could be accommodated within a single complex. The number of hypertrophic nuclei within each complex varied from 15 to 81. Received: 10 May 1999 / Accepted: 28 May 1999     

Inflammatory response during the muscle phase of Trichinella spiralis and T. pseudospiralis infections

An attempt was undertaken to determine whether a concurrent infection of Trichinella spiralis and T. pseudospiralis can reduce cellular infiltrations against the former species during the muscle phase of worm development. BALB/c, nude and CBA/N mice were orally infected with either species or a mixture of both. New-born larvae (NBL) of either or both species were also injected subcutaneously into the right/left leg of BALB/c mice. In T. spiralis oral infection, myositis was strongest in BALB/c, intermediate in CBA/N and weakest in nude mice. In T. pseudospiralis oral infection, slight cellular infiltrations were observed around the worms in BALB/c but not in nude or CBA/N mice. However, in mixed oral infections of two species, infiltrations around the sites of T. spiralis were not reduced. In mice injected with T. pseudospiralis NBL, infiltrations around the infective-stage larvae were mostly absent. However, in mice injected with T. spiralis NBL, prominent granulomatous reactions were observed near the sites of worms. The tissue reaction was substantially stronger than that in oral infections. In mice injected with NBL of both species (into different legs), a heavy infiltration was also observed at the site of T. spiralis. A marked increase in levels of IL-4 and IL-6 was detected in the popliteal lymphocytes of BALB/c mice injected with either live or dead NBL of T. spiralis at days 15 and 20 post-injection. This indicated that the worms mainly elicited a TH2 response during the muscle phase of development. An indirect fluorescent antibody test and laser confocal microscopic studies demonstrated the presence of CD4 and CD8 cells in the cytoplasmic region of the nurse cell complex of T. spiralis.