Feral Raccoons Research Articles

Recent invasion and status of the raccoon (Procyon lotor) in Spain

In this study we present the results of a baseline study designed to assess the status of the raccoon (Procyon lotor) throughout Spain. The species was reported in 28 localities, mostly consisting of sporadic observations of single individuals. In central Spain an apparently thriving population of raccoons has been recently discovered. Our data confirmed the spread of feral raccoons throughout this region, where the species has already colonized about 100 km of streams and rivers. Predation on local fauna was also proved, and the first approximation for spatial movement and habitat use analyses in Spain is presented. Our results suggest that deliberate releases of raccoons by pet owners are an important cause for the existence of feral raccoons in Spain. Further research should focus on monitoring established individuals to collect detailed data on their population and reproductive parameters. Meanwhile, urgent actions should be taken to stop releases into the wild and to control and eradicate this unwelcome invasive species.

Difference in Age at First Conception between Early and Late Litters of Feral Raccoon (<i>Procyon lotor</i>) in Kanagawa Prefecture

Due to the long parturition period of raccoons, we assumed that age at first conception of late born females was later than that of early born females. From March 2005 to September 2008, 201 females estimated to be younger than 24 months were separated into early- and late-born groups on the basis of their estimated birth month (to the nearest 2 months), and parous status and body mass index (BMI) were examined. Age at first conception of late-born females (over 18 months old) was estimated to be later than that of early-born females (over 12 months old). The average BMI in early-born individuals at 12 months old might have affected their ability to conceive because of body fat deposition.

Indices Using External Measurements for Assessing Fat Deposition of Adult Feral Raccoons (Procyon lotor) in Kanagawa Prefecture, Japan

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.

Seroprevalence of Toxoplasma gondii Infection in Feral Raccoons (Procyon lotor) in Japan

Antibodies to Toxoplasma gondii were found in 92 (9.9%) of 929 feral raccoons ( Procyon lotor ) in Japan with the use of the latex agglutination test (LAT, 1∶64 or higher). Seropositivity varied by geographic location, season, and weight of raccoons trapped. Seroprevalences in the northern, central, and western areas of Japan were found to be 7.9% (39/492), 16.5% (47/285), and 3.9% (6/152), respectively. The seroprevalence by season varied from 8.5% (13/153) in spring to 18.9% (14/74) in winter, which was significantly higher than those in other seasons (P < 0.05). Seroprevalence of T. gondii was elevated in accordance with the increase in body weight of raccoons ( r(s) = 0.9), suggesting that the animals acquired the infection postnatally. The results suggest that the raccoon may serve as a useful indicator for the distribution of T. gondii in peridomestic environments in Japan.

Highly Pathogenic Avian Influenza Virus Infection in Feral Raccoons, Japan

Although raccoons (Procyon lotor) are susceptible to influenza viruses, highly pathogenic avian influenza virus (H5N1) infection in these animals has not been reported. We performed a serosurvey of apparently healthy feral raccoons in Japan and found specific antibodies to subtype H5N1 viruses. Feral raccoons may pose a risk to farms and public health.

Molecular Survey ofAnaplasmaandEhrlichiaInfections of Feral Raccoons (Procyon lotor) in Hokkaido, Japan

Infection by Anaplasma and Ehrlichia in feral raccoons (Procyon lotor) in Hokkaido, Japan, was examined by molecular methods. A polymerase chain reaction (PCR) screen for Anaplasmataceae, based on 16S rRNA, showed that 38 (5.4%) of 699 raccoons examined were positive. These 38 positive samples were examined for Anaplasma phagocytophilum, Anaplasma bovis, Ehrlichia chaffeensis, and Ehrlichia canis infection by species-specific nested PCR. Nested PCR results indicated that 36 of the 38 samples were positive for A. bovis. All 38 samples were PCR negative for A. phagocytophilum, E. chaffeensis, and E. canis. This is the first report of the detection of A. bovis in the peripheral blood of raccoons. A total of 124 raccoons were infested with ticks, including Ixodes ovatus, Ixodes persulcatus, and Haemaphysalis spp. The rate of A. bovis infection in raccoons infested with Haemaphysalis spp. (46.7%, 7/15) was significantly higher than that in raccoons without Haemaphysalis spp. infestation (3.7%, 4/109, p < 0.001). No significant differences were observed in A. bovis infection rates between raccoons infested with I. ovatus or I. persulcatus and those not so infested. A total of four ticks (two males and two nymphs) and one larval pools from four raccoons showed positive for A. bovis-specific nested PCR. This results support the correlation between the A. bovis infection of raccoons and Haemaphysalis infestation. In conclusion, raccoons could be possible reservoir animals for A. bovis, and A. bovis infection in raccoons may be related to infestation with Haemaphysalis spp.

Prevalence of Salmonella, Yersinia and Campylobacter spp. in Feral Raccoons (Procyon lotor) and Masked Palm Civets (Paguma larvata) in Japan

SummaryTo 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.

Morphological and molecular characterization of sylvatic isolates of Trichinella T9 obtained from feral raccoons (Procyon lotor)

Morphological and molecular characterization of sylvatic isolates of Trichinella T9 obtained from feral raccoons (Procyon lotor)

Molecular Survey of Rickettsial Agents in Feral Raccoons (&lt;i&gt;Procyon lotor&lt;/i&gt;) in Hokkaido, Japan

Rickettsial infection in feral raccoons (Procyon lotor) in Hokkaido, Japan was analyzed by molecular methods. Genus-specific nested polymerase chain reaction (PCR) analysis based on the Rickettsia citrate synthase (gltA) gene showed that 13 of 699 raccoons (1.9%) examined were positive for Rickettsia. Twelve of the 13 partial gltA sequence amplicons were successfully analyzed. The nucleotide sequence of one amplicon was identical to both Rickettsia heilongjiangensis and R. japonica, one was identical to R. felis, and the rest to R. helvetica. This is the first report on the detection of rickettsial agents in peripheral blood of raccoons.

Detection of Babesia DNA in small mammals and ixodid ticks in the North Urals, Western Siberia, and Far East of Russia

A total 932 small mammals and 458 questing adult Ixodes persulcatus from Sverdlovsk, Novosibirsk regions and Khabarovsk Territory as well as 128 Haemaphysalis japonica, 34 H. concinna and 29 Dermacentor silvarum from Khabarovsk Territory was examined on the Babesia presence by nested PCR based on the 18S rRNA gene. Babesia microti DNA were found in samples from small mammals in all studied regions — in 36.2% of samples from Sverdlovsk region, in 5.3% of samples from Novosibirsk region and in 6.7% of samples from Khabarovsk territory. The determined B. microti 18S rRNA gene sequences from Novosibirsk region (6 sequences) and from Khabarovsk Territory (10 sequences) were identical to each other and to the sequences of pathogenic for human B. microti US-type, while the determined B. microti 18S rRNA gene sequences from Sverdlovsk region (12 sequences) were identical to the sequence of B. microti strain Munich. B. microti were found most frequently in samples from Myodes spp., they were found also in Microtus spp., Apodemus spp., Sorex spp. and Sicista betulina. One from 347 analyzed I. persulcatus from Novosibirsk region and one from 77 I. persulcatus from Khabarovsk Territory were shown to contain B. microti US-type DNA. One I. persulcatus from Novosibirsk region have contained B. divergens DNA. This is the first determination of B. divergens in I. persulcatus and the first determination of B. microti in I. persulcatus in Asian part of Russia. Three novel genetic variants of Babesia sensu stricto were revealed in three H. japonica from Khabarovsk Territory. One novel Babesia genetic variant was closely related to Babesia sp. revealed in a feral raccoon in Japan (99.9% similarity on the basis of 18S rRNA gene sequences). Two others Babesia genetic variants were most similar to Babesia crassa (97.1–97.6% similarity); they clustered together with ruminant pathogens B. crassa and Babesia major.

Serological Survey of Five Zoonoses, Scrub Typhus, Japanese Spotted Fever, Tularemia, Lyme Disease, and Q Fever, in Feral Raccoons (Procyon lotor) in Japan

We investigated the seroprevalence of five tick- or mite-borne zoonoses, scrub typhus (Orientia tsutsugamushi), Japanese spotted fever (Rickettsia japonica), tularemia (Francisella tularensis), Lyme disease (Borrelia afzelii and Borrelia garinii), and Q fever (Coxiella burnetii), in feral raccoons (Procyon lotor) captured in Hokkaido and Kanagawa Prefectures in Japan. Of the 559 raccoons captured in Hokkaido, 8 (1.4%), 3 (0.5%), 1 (0.2%), and 1 (0.2%) carried antibodies against O. tsutsugamushi (Gilliam type), F. tularensis, B. afzelii, and B. garinii, respectively. Of the 193 animals investigated in Kanagawa, 31 (16.1%) and 14 (7.3%) carried antibodies against O. tsutsugamushi and R. japonica, respectively, and the major serotype (27/31) of O. tsutsugamushi was Kuroki. No antibodies against C. burnetii were detected in either area examined. Therefore, feral raccoons could be an indicator of the prevalence of these four tick- or mite-borne zoonoses in the peridomestic environment in Japan.

Molecular evidence for the presence of new Babesia species in feral raccoons (Procyon lotor) in Hokkaido, Japan

We recently reported that feral raccoons (Procyon lotor) with splenomegaly native to Japan were carriers of a Babesia microti-like parasite identical to that found in the United States, which was likely introduced to Japan from North America via raccoons imported as pets. Thus, we attempted extensive molecular survey for piroplasma infections of feral raccoon with normal spleen in Hokkaido, Japan using nested PCR that target broadly to 18S ribosomal RNA gene (SSU-rDNA) of all the parasites in the genus Babesia, Theileria, Cytauxzoon and B. microti group. Of the 348 raccoon samples analyzed, 9 gave positive signals. Cloning and phylogenetic analysis on SSU-rDNA sequences revealed that six of nine positives were found to be infected with Babesia and the remaining three with previously unreported Sarcocystis. Babesia sequences were further separated into two distantly related groups, those that reside in a novel phylogenetic group were consisted solely of four parasites found in this study, while those which included one identical sequence found in the three of our specimens were assembled together with both Babesia parasites of tick's in Japan and of raccoon's in U.S. These results may indicate that not only a B. microti-like parasite but also at least two yet undescribed Babesia species are being established in their new life cycles in the feral raccoon populations in Japan.

Serological Evidence of Coronavirus Infection in Feral Raccoons in Hokkaido, Japan

Serological Evidence of Coronavirus Infection in Feral Raccoons in Hokkaido, Japan

Detection of Antibodies against Japanese Encephalitis Virus in Raccoons, Raccoon Dogs and Wild Boars in Japan

Japanese encephalitis virus (JEV) infects numerous animal species including humans, horses and pigs. In this study, antibodies against JEV in feral raccoons (Procyon lotor), wild boars (Sus scrofa) and raccoon dogs (Nyctereutes procyonoides) in Japan were examined. The results showed that 40.7% (22 out of 54), 64.5% (40 out of 62), 69.1% (47 out of 68) and 0% (0 out of 20) of raccoons in Hyogo, Osaka, Wakayama and Hokkaido, respectively, had virus-neutralizing antibodies against JEV. In addition, 83.3% (30 out of 36) of wild boars and 63.2% (12 out of 19) of raccoon dogs in Wakayama were seropositive for JEV. There were no significant differences in seroprevalence of JEV between males and females or between adults and juveniles in these wild animals. JEV seroprevalence was compared between 37 raccoons and 30 wild boars captured in a limited period (November 2007 to February 2008), and we found that wild boars (86.7%) were significantly more seropositive for JEV antibody than raccoons (59.5%). In conclusion, JEV was prevalent in wild mammals, indicating that the possibility of JEV infection in humans may still be high in Japan. In addition, these wild animals may be good sentinels to estimate JEV infection risk in residents, as they live near humans and are not vaccinated.

Detection of Antibody to Canine Distemper Virus in Wild Raccoons (Procyon lotor) in Japan

Canine distemper virus (CDV) causes a lethal disease among members of the Carnivora. To clarify the distribution of CDV in wild animals, we examined 106 raccoon sera collected from two prefectures in Japan, Hyogo and Osaka, from 2005 to 2007. Among them, 34 raccoons (32.1%) possessed a virus-neutralizing (VN) antibody to KDK-1 strain (genotype Asia-1). There was no significant difference in seroprevalence of CDV regardless of places, gender, and body weights. In Hyogo, a geometric mean of VN titers to KDK-1 was significantly higher than that to Onderstepoort (vaccine strain), indicating that KDK-1-like CDV different from vaccine strain might have spread among raccoon population in Hyogo. In conclusion, CDV is epidemic among feral raccoons in Japan, suggesting that CDV might have been spreading among Japanese wild animals.

Reproductive Characteristics of Feral Raccoons (Procyon lotor) Captured by the Pest Control in Kamakura, Japan

In order to examine reproductive characteristics of feral raccoons in Kamakura, 335 raccoons were collected from March 2005 to March 2007. Raccoons were classified into five age classes: Class I, less than 5 months old; Class II, 5-11 months; Class III, 12-17 months; Class IV, 18-23 months; and Class V, over 23 months old. Females were examined for their age specific pregnancy rate and litter size. To determine when raccoon births occur in the region, birth months of fetuses were estimated by the fetal growth rate, and birth months of Class I individuals were examined by tooth eruption. From fetuses of 18 pregnant females and 47 Class I individuals, it was found that the raccoon births occur from February to October. Of 163 females examined, all of Class I-II females were nulliparous. Pregnancy rate was 47.6% in Class III females, which was significantly lower than 75.0% in Class IV and 78.1% in Class V. The litter size of fetuses ranged from 2 to 5, and 3.9 on average; and that of placental scars ranged from 1 to 7, 3.8 on average. Our findings suggest that parturition of raccoons is a bimodal distribution and age at first parturition may occur between 12 and 17 months old. In order to reduce the raccoon population successfully, females of all ages should be captured throughout the year.

Range expansion of feral raccoons from the northwestern part of Kanagawa prefecture to Yamanashi prefecture, Japan

Range expansion of feral raccoons from the northwestern part of Kanagawa prefecture to Yamanashi prefecture, Japan

Isolation and Establishment of the RaccoonEhrlichia-Like Agent in Tick Cell Culture

Feral animals are reservoirs of emerging human pathogens, as well as carriers of closely related wildlife diseases. The latter may interfere with epidemiologic studies by inducing cross-reactive antibodies, or by providing false positive signals in PCR based tests. We cultured a novel intracellular bacterium from the blood of two raccoons (Procyon lotor): RAC413 and RAC414. RAC413 had been experimentally inoculated with blood from a wild-caught raccoon, and provided the material for a blood passage into RAC414. The microbes grew in Ixodes scapularis (black-legged tick) cells, line ISE6, inoculated either with the leukocyte or erythrocyte fraction of anticoagulated blood. Giemsa-stained cells sampled two and three months after initial inoculation of the cultures revealed inclusions similar to those of Ehrlichia sp., except that individual bacteria commonly were elongated and clustered within endosomes. Electronmicroscopy confirmed the presence of irregularly shaped bacteria with evenly granular bacterioplasm bounded by a unit membrane. 16S rDNA sequencing identified the microbes as the raccoon Ehrlichia-like agent previously detected in feral raccoons from Georgia, United States. In conclusion, the availability of a culture isolate of this agent will facilitate future studies to determine its biology, epidemiologic significance, vector association, and host range. The Ehrlichia-like agent infecting raccoons joins a growing list of tick-borne agents cultivable in tick cells.

Epidemiology, histpathology, and muscle distribution of Trichinella T9 in feral raccoons (Procyon lotor) and wildlife of Japan

The prevalences of Trichinella T9 in trapped raccoons (Procyon lotor) and several other potential mammalian reservoirs in Hokkaido, Wakayama, and Nagasaki Prefectures were investigated. Muscle samples were collected from 2003 to 2006 from 1,080 raccoons, 113 raccoon dogs including 2 species (Nyctereutes procyonoides albus and N. p. viverrinus), 41 wild boars (Sus scrofa leucomystax), 14 martens (Martes melampus), 10 badgers (Meles meles), 5 Siberian weasels (Martes sibirica coreana), 7 mink (Mustela vison), and 1 red fox (Vulpes vulpes japonica). The samples were digested, and the prevalence and mean intensity of infection with the Trichinella muscle larvae were determined. The prevalence and intensity of the muscle larvae were 0.9% and 93.3 larvae/g (range 0.4-201.8) in raccoons, and 1.6% and 61.6 larvae/g in raccoon dogs, respectively. The infected animals were captured in different areas in Hokkaido Prefecture. These results confirmed that raccoons, which have been introduced from North America since the 1970s, are involved in the sylvatic cycle of Trichinella in Japan. In raccoons, the muscle density of Trichinella T9 larvae was highest in the tongue, and larvae were not found in the heart muscle or diaphragm. This is the first report of Trichinella T9 infection of feral raccoons in Japan.

北海道におけるアライグマ捕獲のための Egg^ Trap の有効性と混獲防止効果の検証

北海道におけるアライグマ捕獲のための Egg^ Trap の有効性と混獲防止効果の検証