Wild Boars In Japan Research Articles

Effects of childhood experience with nature on tolerance of urban residents toward hornets and wild boars in Japan.

Urban biodiversity conservation often aims to promote the quality of life for urban residents by providing ecosystem services as well as habitats for diverse wildlife. However, biodiversity inevitably brings some disadvantages, including problems and nuisances caused by wildlife. Although some studies have reported that enhancement of nature interaction among urban children promotes their affective attitude toward of favorable animals, its effect on tolerance toward problem-causing wildlife is unknown. In this study, we assessed the tolerance of 1,030 urban residents in Japan toward hornets and wild boar, and analyzed the effects of childhood experience with nature on tolerance using a structural equation model. The model used sociodemographic factors and childhood nature experience as explanatory variables, affective attitude toward these animals as a mediator, and tolerance as a response variable. The public tolerance toward hornets and boars was low; over 60% of the respondents would request the removal of hornets and wild boar from nearby green spaces by government services, even when the animals had not caused any damage. Tolerance was lower in females and elderly respondents. Childhood experience with nature had a greater influence on tolerance than did sociodemographic factors in the scenario where animals have not caused any problems; however, its effect was only indirect via promoting positive affective attitude toward wildlife when the animals have caused problems. Our results suggest that increasing people’s direct experience with nature is important to raise public tolerance, but its effect is limited to cases where wildlife does not cause any problems. To obtain wider support for conservation in urban areas, conservationists, working together with municipal officials, educators and the media, should provide relevant information on the ecological functions performed by problem-causing wildlife and strategies for avoiding the problems that wildlife can cause.

Generation of hepatitis E virus-like particles of two new genotypes G5 and G6 and comparison of antigenic properties with those of known genotypes

In addition to the four major genotypes (G1 through G4) known for human hepatitis E virus (HEV), two new genotypes (G5 and G6) were suggested, based on unique viral nucleotide sequences derived from wild boars in Japan. It has been unknown whether the virus of these new genotypes can cause hepatitis in humans; neither G5 nor G6 HEV has been found in patients to date. To study the antigenic properties of G5 and G6 HEV, we expressed N-terminus-truncated HEV ORF2 protein by a recombinant baculovirus system, and we obtained virus-like particles (VLPs) for both G5 and G6. The VLPs showed antigenic cross-reactivity against G1, G3 and G4 HEV more strongly than against ferret or rat HEV. Moreover, both anti-G5 and anti-G6 VLPs antibodies could neutralize G3 HEV's ability to infect PLC/PRF/5 cells, suggesting that G5 and G6 HEV have the same serotype as human HEV.

Molecular characterization of a novel hepatitis E virus (HEV) strain obtained from a wild boar in Japan that is highly divergent from the previously recognized HEV strains

Although a consensus classification system for hepatitis E virus (HEV) genotypes is currently unavailable, HEV variants (JBOAR135-Shiz09 and wbJOY_06) from wild boars (Sus scrofa leucomystax) have provisionally been classified into two novel genotypes (5 and 6). While performing a survey of HEV infections among 566 wild boars that were captured in Japan between January 2010 and August 2013, we found 24 boars (4.2%) with ongoing HEV infections: 13 had genotype 3 HEV, 10 had genotype 4 HEV and the remaining boar possessed a novel HEV variant (designated wbJNN_13). The entire wbJNN_13 genome comprised 7247 nucleotides excluding the poly(A) tail, and was highly divergent from known genotype 1 to 4 HEV isolates derived from humans, swine, wild boars, deer, mongoose and rabbits by 22.4–28.2%, JBOAR135-Shiz09 and wbJOY_06 by 19.6−21.9% and rat, ferret, bat and avian HEV isolates by 40.9–46.1% over the entire genome. Phylogenetic trees confirmed that wbJNN_13 is distantly related to all known HEV isolates. A Simplot analysis revealed no significant recombination among the existing HEV strains. These results indicate the presence of at least three genetic lineages of presumably boar-indigenous HEV strains. Further studies to fully understand the extent of the genomic heterogeneity of HEV variants infecting wild boars are warranted.

Evidence of natural transmission of group A rotavirus between domestic pigs and wild boars (Sus scrofa) in Japan

Group A rotaviruses (RVAs) are a major cause of acute dehydrating diarrhea in infants and young animals worldwide. RVAs have also been detected in several wild and zoo animals, indicating wide susceptibility of wild animals. However, the role of wild animals in the infection cycle of RVAs is unclear. Wild boars are indigenous in many countries in the world. Japanese wild boars (Sus scrofa leucomystax) have been migrating close to human habitats in Japan, indicating the possibility of natural transmission between domestic animals or humans and wild boars. We investigated infection of RVAs in wild boars in Japan to identify types of RVAs infecting wild animals. We obtained stool samples from 90 wild boars and detected a VP4 gene of RVAs by RT-semi-nested PCR. RVAs were detected in samples from four of the 90 wild boars. Nucleotide analyses of VP7 and VP4 genes revealed that the four strains belong to G9P[23], G4P[23], G9P[13] and G4P[6], suggesting a relation to porcine and human RVAs. We therefore characterized RVAs circulating among domestic pigs living in the same area as the wild boars. We collected stool samples from 82 domestic pigs. RVAs were detected in samples from 49 of the 82 domestic pigs. Phylogenetic and similarity analyses provided evidence for natural transmission between domestic pigs and wild boars. The results also suggested that natural reassortment events occurred before or after transmission between domestic pigs and wild boars. Our findings indicate the possibility that RVAs circulate among wild animals, humans and domestic animals in nature.

Detection of <i>Anaplasma phagocytophilum</i> from Wild Boars and Deer in Japan

This study was conducted to determine the prevalence and geographic distribution of Anaplasma phagocytophilum, the causative agent of human granulocytic anaplasmosis, in wild deer and boars in Japan. We analyzed the blood samples of the study animals using PCR-targeting the 16S rDNA followed by DNA sequencing. Wild deer infected with Anaplasma spp., including Anaplasma bovis and Anaplasma centrale were detected in the region from Hokkaido to Kyushu. The infection rates of A. phagocytophilum, A. bovis, and A. centrale in deer were 15.6, 21.9, and 37.5%, respectively, and the corresponding infection rates in wild boar were 3.6, 17.9, and 3.6%, respectively. However, p44/msp2 genes specific to A. phagocytophilum were not detected among the 16S rDNA-positive samples on PCR analysis. In addition, the 16S rDNA sequences of A. phagocytophilum were 100% similar to those detected previously in the deer in Japan and 98.6% similar to those of A. phagocytophilum detected in the United States and Europe, and from the tick, Ixodes ovatus and Ixodes persulcatus in Japan. These findings suggested that the A. phagocytophilum-related sequences detected from deer and wild boars in Japan were different from those of typical A. phagocytophilum strains.

A nationwide survey of hepatitis E virus (HEV) infection in wild boars in Japan: identification of boar HEV strains of genotypes 3 and 4 and unrecognized genotypes

To investigate the nationwide prevalence of hepatitis E virus (HEV) infection and to characterize HEV genomes among Japanese wild boars (Sus scrofa leucomystax), 578 boars captured in 25 prefectures from 2003 to 2010 were studied. Anti-HEV IgG was detected in 8.1%, and HEV RNA in 3.3% of boars. Among the 19 boar HEV isolates obtained from infected boars, 14 isolates (74%) were classified as genotype 3, 4 isolates (21%) as genotype 4, and the remaining isolate (wbJOY_06) was distantly related to all known HEV isolates of genotypes 1-4, differing by 18.4-25.0% and 18.0-24.3% within the 412-nucleotide sequence of ORF1 and ORF2, respectively. A genotype 4 boar HEV isolate (wbJGF_08-1) obtained herein shared 98.6% identity over the entire genome with a human HEV isolate obtained from a patient who developed acute hepatitis after consuming undercooked wild boar meat, suggesting that wild boars are also reservoirs for genotype 4 HEV in humans.

Analysis of the full-length genome of a hepatitis E virus isolate obtained from a wild boar in Japan that is classifiable into a novel genotype

While performing a nationwide survey of hepatitis E virus (HEV) infection among 450 wild boars (Sus scrofa leucomystax) that had been captured in Japan between November 2005 and March 2010, we found 16 boars (3.6%) with ongoing HEV infection: 11 had genotype 3 HEV, four had genotype 4 HEV and the remaining boar was infected with HEV of an unrecognized genotype (designated wbJOY_06). The entire wbJOY_06 genome was sequenced and was found to comprise 7246 nt excluding the poly(A) tail. The wbJOY_06 isolate was highly divergent from known genotype 1-4 HEV isolates derived from humans, swine, wild boars, deer, mongoose and rabbits (n=145) by 22.6-27.7%, rat HEV isolates (n=2) by 46.0-46.2%, and avian HEV isolates (n=5) by 52.5-53.1% over the entire genome. A Simplot analysis revealed no significant recombination between the existing HEV strains of genotypes 1-4. Therefore, we propose that the wbJOY_06 isolate is the first member of a previously unidentified genotype.

Pseudorabies Virus Infection in Wild Boars in Japan

In Japan, most pig populations are now free from pseudorabies virus (PRV) due to the recent success of an extensive eradication program. However, PRV infection persists in Japanese wild boars (Sus scrofa leucomystax), representing another potential reservoir for the virus in Japan. In this study, the seroprevalence of PRV in wild boars captured in three different prefectures was ascertained. A virus neutralization (VN) test showed that 6 of 173 serum samples (3%) were positive for VN antibody; glycoprotein E-ELISA revealed infection with the wild-type, but not the available vaccine strain, PRV. These results indicate that PRV has continued to spread among wild boars in Japan.

Genetic evidence for the presence of two species ofOnchocercafrom the wild boar in Japan

In order to clarify the genetic differences between Onchocerca dewittei japonica, the causative agent of zoonotic onchocerciasis in Japan and a related undescribed Onchocerca sp., both parasitizing wild boar (Sus scrofa) of which the infective larval stages are indistinguishable from each other, we compared the sequences of the mitochondrial cytochrome c oxidase subunit 1 (CO1) gene region from four infective larvae (recovered from experimentally infected black flies), one microfilaria, and one adult of O. dewittei japonica, and from one infective larva (recovered from an experimentally infected black fly), one microfilaria, and a pool of several microfilariae of O. sp. The length of the CO1 gene region was 649 bp for all samples but there was a difference of 8.8 to 9.4% in the sequences between the two species although there were intraspecific variations of 0 to 0.5%. The CO1 sequences of O. sp. did not correspond to any of those deposited in the databases. Our study provides evidence that O. dewittei japonica and O. sp. are genetically different from each other.

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.

Serological Survey of Arthropod-Borne Viruses among Wild Boars in Japan

A total of 90 blood samples were collected from wild boars in the Kyushu region of Japan, and a seroepidemiological survey for 7 arthropod-borne viruses was performed using hemagglutination inhibition tests. The individual seropositive rates for each virus were 52.2% for Japanese encephalitis virus (JEV), 47.8% for Getah virus (GETV), 13.3% for Akabane virus, 10.0% for Aino virus and less than 5% for Bluetongue virus, Chuzan virus and Ibaraki virus. The results indicated that among the 7 viruses, JEV and GETV infections were prevalent among the wild boars and that the animals were involved in the natural transmission cycle of JEV and GETV in Japan. It is necessary to consider the participation of wild animals for the control of arthropod-borne virus infections.

Analysis of the full-length genome of hepatitis E virus isolates obtained from wild boars in Japan

Two (2.3 %) of 87 wild-caught boars in Japan had detectable hepatitis E virus (HEV) RNA. The two boar HEV isolates (wbJTS1 and wbJYG1) obtained in the present study and a previously reported isolate (wbJSG1) whose partial sequence had been determined were sequenced over the entire genome. The wbJSG1, wbJTS1 and wbJYG1 isolates comprised 7225 or 7226 nt, excluding the poly(A) tail, and segregated into genotype 3. They differed by 8.5-11.2 % from each other and by 8.6-18.4 % from 17 reported genotype 3 HEV isolates, including one boar isolate, in the full-length sequence. When compared with 191 reported genotype 3 HEV isolates whose partial sequences were known, these three boar isolates were closer to Japanese isolates than to isolates of non-Japanese origin (89.2+/-2.6 vs 85.9+/-2.2 %; P<0.0001). A proportion of wild boars in Japan are infected with markedly heterogeneous HEV strains that are indigenous to Japan and may serve as reservoirs of HEV.

本邦に棲息する野生猪のHEV感染に関する実態予備調査

本邦に棲息する野生猪のHEV感染に関する実態予備調査

Occurrence of yersiniosis and listeriosis in wild boars in Japan.

From December 1994 to February 1995, 131 wild boars (Sus scrofa leucomysta) living in a mountainous area in Japan were examined for yersiniosis and listeriosis. Of 131 wild boars, 76 (58%) were males and 55 (42%) were females. Four Yersinia spp. including Y. pseudotuberculosis, Y. enterocolitica, Y. frederiksenii, and Y. aldovei, were isolated from 49 (37%) of 131 wild boars. Yersinia pseudotuberculosis was isolated from five (4%) of 131 wild boars. All Y. pseudotuberculosis isolates were serotype 4b and harbored virulence plasmids. Yersinia pseudotuberculosis was isolated only from boars under 2-yr-old. No human pathogenic Y. enterocolitica was isolated. Listeria monocytogenes was isolated from two (1%) of the wild boars and both isolates were serotype 4b. These findings indicated that wild boar could be a reservoir of Y. pseudotuberculosis and L. monocytogenes in Japan.

The trade in wild pig meat: Australia and Japan

SUMMARY Socioeconomic developments in Japan since World War Two have influenced the supply of wild pig meat (inoshishi niku) from Japanese domestic sources. Trends in the supply of meat from wild boar as well as the development of the farming of wild boar in Japan are discussed. The special nature of trading in wild pig meat in Japan is outlined. Australian exports of wild pig meat to Japan depend upon developments within Japan and the relevant links are identified. Some historical background is also provided on the Australian game industry supplying wild pig meat, the location and the structure of the industry are specified and the economic value of the industry is discussed, including its exports and prices paid for wild pig meat. Comparative aspects of the industry and of trade in wild pig meat in Japan and in Australia are highlighted. In conclusion, difficulties involved in identifying the Australian product in the Japanese market are noted.

Natural Infection of Muscle of Wild Boars in Japan by Immature Paragonimus westermani (Kerbert 1878)

Natural Infection of Muscle of Wild Boars in Japan by Immature Paragonimus westermani (Kerbert 1878)

Immature Lung Flukes First Found in the Muscle of the Wild Boar in Japan

Immature Lung Flukes First Found in the Muscle of the Wild Boar in Japan