Feral Raccoons Research Articles

Differences in Tick Infestation Intensity by Season, Sex, Age Class, and Body Region of Feral Raccoons (Procyon lotor) in the Miura Peninsula, Japan

Differences in Tick Infestation Intensity by Season, Sex, Age Class, and Body Region of Feral Raccoons (Procyon lotor) in the Miura Peninsula, Japan

Direct detection and quantification of Toxoplasma gondii in meat samples from feral raccoons (Procyon lotor) in Germany by magnetic-capture real-time PCR

Because the number of wild raccoons in Germany is increasing constantly, it appears to be economic reasonable to use their meat as food. For this purpose, it is essential to generate data regarding the pathogen load of the meat to be consumed and handled. It is known that raccoons, particularly in Germany, show a high seroprevalence of Toxoplasma gondii. Because serological data only indicates contact of a host to a parasite additional direct detection is needed to prove presence of parasitic stages in particular tissues. Therefore, a total of 150 samples from raccoons with known serostatus were tested and quantified using magnetic-capture real-time PCR for Toxoplasma gondii. As it represents potentially consumption-relevant parts of raccoons, meat from forelimb and hindlimb was examined. Samples were stratified into three groups based on the animals’ serostatus (each 50 negative, low positive, and high positive). All samples from seronegative animals were found negative by MC-PCR as well. In a total of 56 meat samples from 100 seropositive animals, T. gondii DNA was detected. Statistically significant more samples were positive by MC-PCR in the high positive than in the low positive serostatus group (38/50 vs. 18/50, p < 0.0001). Furthermore, samples from the former group were also found to have statistically significant higher DNA equivalent values compared to samples from the low positive serostatus group (p < 0.0001). These results suggest that meat from seropositive raccoons may contain considerable numbers of T. gondii presenting a potential public health risk for humans whilst handling and consumption.

The Genetic Diversity and Structure of the Feral Raccoon (Procyon lotor) Population in Shikoku Island, Japan

We explored the genetic diversity and population genetic structure of an invasive alien species, the raccoon Procyon lotor, which was introduced into the Shikoku Island of Japan, using sequences of the mitochondrial control region and 10 polymorphic microsatellite loci. In 80 individuals examined, we detected two genetically divergent haplotypes, indicating that two maternal lineages had been introduced into Shikoku Island. Population clustering analysis suggested the nonexistence of genetic structure in the area. The relatedness network showed that the raccoon population in Shikoku Island consisted of closely related individuals. The genetic diversity of the Shikoku raccoon population was lower than that in the native range. These results and a prior report indicate that the Shikoku raccoon population is likely to have expanded from small numbers of founders originating from an initial invasive population. Raccoon captures outside Kagawa are decreasing, although past expansions into Tokushima and Ehime suggest that there are no geographical barriers among these areas. Therefore, action should be taken to prevent any re-expansion of the raccoon population in Kagawa. Intensive monitoring and the elimination of dispersers from Kagawa, as well as effort to eradicate potential source populations for expansion in Kagawa, are needed.

Population genetic structure of raccoons as a consequence of multiple introductions and range expansion in the Boso Peninsula, Japan

The raccoon (Procyon lotor) is an invasive carnivore that invaded various areas of the world. Although controlling feral raccoon populations is important to reduce serious threats to local ecosystems, raccoons are not under rigid population control in Europe and Japan. We examined the D-loop and nuclear microsatellite regions to identify spatially explicit and feasible management units for effective population control and further range expansion retardation. Through the identification of five mitochondrial DNA haplotypes and three nuclear genetic groups, we identified at least three independent introductions, range expansion, and subsequent genetic admixture in the Boso Peninsula. The management unit considered that two were appropriate because two populations have already genetic exchange. Furthermore, when taking management, we think that it is important to monitor DNA at the same time as capture measures for feasible management. This makes it possible to determine whether there is a invasion that has a significant impact on population growth from out of the unit, and enables adaptive management.

Changes in Population Structure of the Freshwater Turtle Mauremys japonica Following the Invasion of Feral Raccoon Procyon lotor in the Southern Tip of the Boso Peninsula, Japan

The raccoon (Procyon lotor) was introduced to Japan from North America, and has been implicated in the population declines or local extinctions of native freshwater turtles. We conducted a capture–recapture study of the Japanese pond turtle (Mauremys japonica) at two sites in the Boso Peninsula, Japan, to investigate the effects of P. lotor predation on the demography of native turtle populations, during the period from 2014 to 2017, shortly after an invasion of P. lotor. The study revealed a steady decline in turtle population size, along with changes in age structure, characterized by a skew toward older age classes. We also found a number of living individuals with amputated limbs, which we suspect to be evidence of P. lotor predation. Such injuries highlight the importance of the early detection of population declines and identification of related warning signals or demographic characteristics, which in turn will enable the timely implementation of appropriate conservation measures to prevent local extinctions of freshwater turtles.

Helminthes in Feral Raccoon (Procyon lotor) as an Alien Species in Iran

The raccoon, Procyon lotor Linn. (Procyonidae) is native to North and Central America but has been introduced in several European and Asian countries including Japan, Germany and Iran. Objective of this study was to determine frequency of gastrointestinal and tissue helminthes from feral raccoons in Iran. During 2015-2017, 30 feral raccoons including 12 males and 18 females were collected from Guilan Province, northern Iran (the only region in Iran where raccoons are found). The gastrointestinal tracts and tissues such as lung, liver and muscles were examined for presence of helminthes. Twenty raccoons (66.7%) were found infected with five intestinal helminth species. The prevalence of infection with Strongyloides procyonis Little, 1966 (Nematoda) was 63.3%, Plagiorchis koreanus Ogata, 1938 (Trematoda) (13.3%), Centrorhynchus sp. Lühe, 1911 (Acanthocephala) (10.0%), Camerostrongylus didelphis Wolfgang, 1951 (Nematoda) (3.3%), and Spirocerca lupi Rudolphi, 1809 (Nematoda) (3.3%). No larvae or adult worms were found in other tissues of the examined raccoons. Most of the raccoons were infected with S. procyonis. The public health importance of zoonotic parasites transmittable through raccoons, the rapid control and decrease of raccoon populations and their distribution in Iran are also discussed.

16S rRNA Gene Amplicon Sequence Data from Feces of Five Species of Wild Animals in Japan.

We report 16S rRNA amplicon sequence data from feces from 58 wild boars, 60 feral raccoons, 9 wild Japanese badgers, 21 wild masked palm civets, and 8 wild raccoon dogs in Japan. The predominant bacterial taxa in the fecal microbiota were similar in part but varied among the animal species.

A novel Babesia sp. associated with clinical signs of babesiosis in domestic cats in South Africa

BackgroundFeline babesiosis, sporadically reported from various countries, is of major clinical significance in South Africa, particularly in certain coastal areas. Babesia felis, B. leo, B. lengau and B. microti have been reported from domestic cats in South Africa. Blood specimens from domestic cats (n = 18) showing clinical signs consistent with feline babesiosis and confirmed to harbour Babesia spp. piroplasms by microscopy of blood smears and/or reverse line blot (RLB) hybridization were further investigated. Twelve of the RLB-positive specimens had reacted with the Babesia genus-specific probe only, which would suggest the presence of a novel or previously undescribed Babesia species. The aim of this study was to characterise these organisms using 18S rRNA gene sequence analysis.ResultsThe parasite 18S rRNA gene was cloned and sequenced from genomic DNA from blood samples. Assembled sequences were used to construct similarity matrices and phylogenetic relationships with known Babesia spp. Fifty-five 18S rRNA gene sequences were obtained. Sequences from 6 cats were most closely related to published B. felis sequences (99–100% sequence identity), while sequences from 5 cats were most closely related to B. leo sequences (99–100% sequence identity). One of these was the first record of B. leo in Mozambique. One sequence had 100% sequence identity with the published B. microti Otsu strain. The most significant finding was that sequences from 7 cats constituted a novel Babesia group with 96% identity to Babesia spp. previously recorded from a maned wolf (Chrysocyon brachyurus), a raccoon (Procyon lotor) from the USA and feral raccoons from Japan, as well as from ticks collected from dogs in Japan.ConclusionsBabesia leo was unambiguously linked to babesiosis in cats. Our results indicate the presence of a novel potentially pathogenic Babesia sp. in felids in South Africa, which is not closely related to B. felis, B. lengau and B. leo, the species known to be pathogenic to cats in South Africa. Due to the lack of an appropriate type-specimen, we refrain from describing a new species but refer to the novel organism as Babesia sp. cat Western Cape.

Difference in the factors of effect on reproductive rate of feral raccoon (Procyon lotor) between high- (2008-2010) and low- (2015-2017) density terms in Kanagawa Prefecture, Japan

Difference in the factors of effect on reproductive rate of feral raccoon (Procyon lotor) between high- (2008-2010) and low- (2015-2017) density terms in Kanagawa Prefecture, Japan

The diet of feral raccoon dog (Nyctereutes procyonoides) and native badger (Meles meles) and red fox (Vulpes vulpes) in Denmark

The raccoon dog (Nyctereutes procyonoides) is an East Asian Canid that has been introduced in Europe. Introduction of alien species is an increasing conservation issue. We examined the diet of a recently established raccoon dog population in Denmark by analysing stomach content in 249 carcasses collected in 2008–2016. Raccoon dog diet was compared to the diet of native badger (Meles meles) and red fox (Vulpes vulpes) in Denmark. The most common food for raccoon dogs were invertebrates (frequency of occurrence, FO 69%), small mammals (FO 68%), birds (FO 41%), fruits (FO 38%), amphibians (FO 36%) and carrions (FO 34%). The occurrence of invertebrates was highest during spring and summer, while fruits, cereals and carrions were eaten most often during autumn and winter. As expected, raccoon dog shared the major food categories with badger and red fox, but generally, it had a wider dietary niche. Overall, dietary overlap between raccoon dog and badger was 0.74 (Pianka index, Ojk). The dietary overlap with red fox was relatively high in all seasons, peaking in summer (Ojk 0.87) and dropping in winter (Ojk 0.79). Despite the dietary overlap between the alien racoon dog and native red fox and badger, the species may coexist due to partitioning of feeding habitats and/or because the red fox is limited by other factors, e.g. diseases and anthropogenic activities. The introduced raccoon dog seems to fit a dietary niche between badger and red foxes in human-dominated landscapes in north-western Europe.

Is the raccoon (Procyon lotor) out of control in Europe?

The northern raccoon (Procyon lotor) is an invasive species in Europe and poses a serious threat to indigenous biodiversity and human health. Raccoons can also cause important economic losses. Despite the risks, no comprehensive report on the raccoon status in Europe is available. In this article, I estimate the raccoon invaded range and population trends and evaluate the impacts on native ecosystems and wildlife to (1) determine the raccoon status and discuss the invasion process on a continental scale, (2) identify the threats, and (3) propose guidelines for designing management strategies for raccoon populations. Raccoons have been introduced in Europe since the late 1920s but raccoon population growth and range expansion rates have been increasing since 1970s after a lag period. In addition, recent introductions through the pet trade have resulted in the establishment of new feral raccoon populations. Therefore, the raccoon spatial distribution is a result of multiple introductions and range expansion from the primary raccoon populations in central and eastern Europe over the last 40 years. First individuals escaped from fur farms or were released for hunting. Nowadays, the pet trade is the major introduction pathway. Raccoons have adapted to different environments, even urban and residential areas. In central Europe, the raccoon population has increased by over 300% and grows at exponential rates since the 1990s. The raccoon is out of control in Europe because of increasing population trends, range expansion and no efficient management strategy. However, no impacts have still been reported through an evidence-based approach. There is a pressing need for a long-term management strategy of raccoon populations in Europe.

馬追・野幌丘陵における野生化アライグマの生息数(密度)の推定とその生息環境(III)

馬追・野幌丘陵における野生化アライグマの生息数(密度)の推定とその生息環境(III)

Detection and molecular characterization of Babesia, Theileria, and Hepatozoon species in hard ticks collected from Kagoshima, the southern region in Japan

To reveal the distribution of tick-borne parasites, we established a novel nested polymerase chain reaction (PCR) system to detect the most common agents of tick-borne parasitic diseases, namely Babesia, Theileria, and Hepatozoon parasites. We collected host-seeking or animal-feeding ticks in Kagoshima Prefecture, the southernmost region of Kyusyu Island in southwestern Japan. Twenty of the total of 776 tick samples displayed a specific band of the appropriate size (approximately 1.4–1.6kbp) for the 18S rRNA genes in the novel nested PCR (20/776: 2.58%). These PCR products have individual sequences of Babesia spp. (from 8 ticks), Theileria spp. (from 9 ticks: one tick sample including at least two Theileria spp. sequences), and Hepatozoon spp. (from 3 ticks). Phylogenetic analyses revealed that these sequences were close to those of undescribed Babesia spp. detected in feral raccoons in Japan (5 sequences; 3 sequences being identical), Babesia gibsoni-like parasites detected in pigs in China (3 sequences; all sequences being identical), Theileria spp. detected in sika deer in Japan and China (10 sequences; 2 sequences being identical), Hepatozoon canis (one sequence), and Hepatozoon spp. detected in Japanese martens in Japan (two sequences). In summary, we showed that various tick-borne parasites exist in Kagoshima, the southern region in Japan by using the novel nested PCR system. These including undescribed species such as Babesia gibsoni-like parasites previously detected in pigs in China. Importantly, our results revealed new combinations of ticks and protozoan parasites in southern Japan. The results of this study will aid in the recognition of potential parasitic animal diseases caused by tick-borne parasites.

Population viability analysis of feral raccoon dog (Nyctereutes procyonoides) in Denmark

To assess the effects of actions implemented by the Danish Action Plan (DAP) for eradication of the raccoon dog, the population dynamics of the raccoon dog in Denmark was simulated. A population viability analysis (PVA) was generated with the stochastic simulation program, VORTEX, based on population parameters of raccoon dog in other European countries (Poland, Finland and Germany), combined with statistics on dead raccoon dogs reported to the Dan- ish National Veterinary Institute between 2008 and 2012. Simulations showed that the present feral population of raccoon dogs would expand markedly and reach an assessed carrying capacity of 30 000 individuals with no intervention within 10 years. Simulations of the current culling strategy showed that the raccoon dog in Denmark would reach the carrying capacity with only a few years' delay compared to simulations with no intervention. This indicates that more efficient and intensive actions are needed to reach the goal of the DAP, aiming at eradicating the breeding population of raccoon dogs in Denmark within 2015. Simulations suggested that around 950 individuals should be culled a year from 2012 to 2015. Sensitivity analysis that was performed showed that the only parameter that had a strong influence on the population dynamic was the first year mortality.

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.

Molecular survey of Babesia gibsoni using Haemaphysalis longicornis collected from dogs and cats in Japan.

ABSTRACTA nationwide survey of Babesia gibsoni using Haemaphysalis longicornis collected from dogs and cats in Japan was conducted using molecular methods. A total of 1,341 H. longicornis, including 305 females, 14 males, 332 nymphs and 690 larvae (153 pools) from 44 prefectures, were examined by B. gibsoni-targeted PCR. Partial sequence analysis revealed that 12 of 13 positive samples sequenced, including samples from Tottori, Hiroshima, Yamaguchi, Tokushima, Ehime and Oita prefectures (all in western Japan), were identical to B. gibsoni, and 1 sample from Kyoto Prefecture was most closely related to a Babesia species recently detected from feral raccoons in Hokkaido. H. longicornis is a candidate for transmission vector tick of the new Babesia species.

Potential resource competition between an invasive mammal and native birds: overlap in tree cavity preferences of feral raccoons and Ural owls

Invasive mammals include good tree climbers that use tree cavities for resting and nesting. Tree cavities are important but limited resources in most forests; thus, some invasive mammals can be serious competitors for native cavity-using species, especially cavity-nesting birds. Despite the potential impact, such inter-class competition has rarely been considered. We examined the possibility of resource competition for tree cavities between the invasive raccoon Procyon lotor and the native Ural owl Strix uralensis. Both species are nocturnal and use tree cavities during daytime. We assessed an overlap in cavity use for both species as an indication of potential competition by monitoring 341 cavities during their breeding season in a natural park in Hokkaido, Japan. Of 341 potentially available cavities, raccoons and Ural owls used 37 and 32, respectively. The characteristics of 58 cavities used by raccoons or owls were compared to 49 random cavities to determine if they selected cavities with certain characteristics. As predicted from a large amount of tree cavities and a low raccoon density in this managed forest, we did not find direct evidence of competition, such as physical interaction, intrusion to cavities, or habitat segregation. Cavity types used by both species overlapped considerably in terms of height, entrance size, depth, and other characteristics: their habitats were widely overlapped. Further, in four cavities, one species was replaced by the other. Given the similar habitat requirements, the invasive raccoon could be a potential competitor for Ural owl when raccoon density increases and/or cavity availability decreases, which is the case for many forests in Japan. This study suggests that potential threats of resource competition among not only closely but also distantly related taxa should be taken into consideration when studying the impacts of invasive species.

Molecular Detection of Spotted Fever Group Rickettsia in Feral Raccoons (&lt;i&gt;Procyon lotor&lt;/i&gt;) in the Western Part of Japan

Rickettsial infection in feral raccoons (Procyon lotor) in the western part of Japan (Shimane, Fukuoka, Saga and Nagasaki Prefectures) was surveyed by a nested polymerase chain reaction (PCR) assay detecting the rickettsial citrate synthase (gltA) gene. Four of one hundred and ninety-four feral raccoon spleens (2.1%) were positive for Rickettsia spp. One gltA gene sequence was identical to R. helvetica, whereas the other 3 sequences were identical and had the highest similarity (98.4%) to R. amblyommii. Simultaneously, we determined a partial sequence of the rickettsial 17-kilodalton (17K) genus-common antigen gene in the later 3 raccoon samples. Their sequences were identical and had the highest similarity (98.5%) to Rickettsia sp. Hj126. Based on the sequences of gltA and 17K antigen genes, these raccoons might be infected with spotted fever group (SFG) rickettsia most closely related to R. amblyommii and/or Rickettsia sp. Hj126. Feral raccoons may be a susceptible reservoir for SFG rickettsiae in Japan.

Timing of Puberty and Its Relationship with Body Growth and Season in Male Raccoons (&lt;i&gt;Procyon lotor&lt;/i&gt;) in Hokkaido

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.

Seasonal Changes in Spermatogenesis and Peripheral Testosterone Concentration in Raccoons (&lt;i&gt;Procyon lotor&lt;/i&gt;) in Hokkaido

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.