森田 達志

Although kinship (parent-offspring or siblings) contact has been suggested as a driving factor for sarcoptic mange epizootic in raccoon dogs (Nyctereutes procyonoides), no effect has been reported. In contrast, habitat fragmentation caused by urbanization may result in a high occurrence of sarcoptic mange, because habitat fragmentation may promote contact infection by increasing the population density of raccoon dogs. The habitat distribution of raccoon dogs may therefore influence epizootic sarcoptic mange. The genetic relationship between raccoon dogs was analyzed to examine Sarcoptes scabiei transmission between kin. The relationship between S. scabiei infection and the habitat of raccoon dogs was also investigated. Seventy-five raccoon dogs from Takasaki, Gunma prefecture, were examined from 2012 to 2018; 23 were infested with S. scabiei. The genotypes were determined using 17 microsatellite loci, and the relationships were categorized into four patterns by the ML-Relate software. There was no significant difference between infested pairs and other two pairs (Chi-squared test: χ2=0.034, df=1, P=0.85). Although it was difficult to predicate because the mortality rate was unclear in this study, kinship contact does not seem to be an important factor for sarcoptic mange epizootic. S. scabiei infection rates were significantly associated with the location of village sections (OR=1.55, 95%CI=1.11-2.17, P=0.011). It is suggested that direct/indirect contact between individuals living closely together is an important factor for the transmission of S. scabiei.

Bovine abortion, diarrhea, and respiratory disease complexes, caused by infectious agents, result in high and significant economic losses for the cattle industry. These pathogens are likely transmitted by various vectors and reservoirs including insects, birds, and rodents. However, experimental data supporting this possibility are scarce. We collected 117 samples and screened them for 44 bovine abortive, diarrheal, and respiratory disease complex pathogens by using Dembo polymerase chain reaction (PCR), which is based on TaqMan real-time PCR. Fifty-seven samples were positive for at least one pathogen, including bovine viral diarrhea virus, bovine enterovirus, Salmonella enterica ser. Dublin, Salmonella enterica ser. Typhimurium, and Neospora caninum; some samples were positive for multiple pathogens. Bovine viral diarrhea virus and bovine enterovirus were the most frequently detected pathogens, especially in flies, suggesting an important role of flies in the transmission of these viruses. Additionally, we detected the N. caninum genome from a cockroach sample for the first time. Our data suggest that insects (particularly flies), birds, and rodents are potential vectors and reservoirs of abortion, diarrhea, and respiratory infectious agents, and that they may transmit more than one pathogen at the same time.

A 12-year-old female Shih-Tzu with hyperadrenocorticism and hypothyroidism developed concurrent refractory generalized demodicosis that did not respond to doramectin treatment. Although amitraz treatment was effective, the dog developed severe diabetes, which resulted in the cessation of amitraz and trilostane. Attempts to control the diabetes were unsuccessful, and its hyperadrenocorticism was left untreated, leading to the recurrence of demodicosis. However, demodicosis went into complete remission with a single dose of fluralaner. Transient erythematous papules appeared on the trunk three days after the administration of fluralaner, but no other adverse reactions were noted. We demonstrated that fluralaner is a potent treatment for demodicosis, and skin eruptions are possible after the first dose of the drug.

<p>To examine outbreaks of mange in raccoon dogs (Nyctereutes procyonoides) with respect to population density, we analyzed camera trap videos, and isolated mites from raccoon dog carcasses. In a camera trapping survey, we categorized the skin condition of raccoon dogs, and used a number of independent videos to calculate the relative abundance index (RAI). The RAI of raccoon dogs with alopecia increased following an increase in the RAI of those without alopecia. Among 27 raccoon dog carcasses, 12 showed mange-compatible skin lesions. Sarcoptes scabiei was isolated from 11 of these raccoon dogs, indicating that sarcoptic mange was endemic in our study area. Therefore, a high relative population density may be a factor underlying epizootics of sarcoptic mange in raccoon dogs.</p>

Pulmonary metastrongylosis, a zoonotic disease found primarily in pigs, is caused by eight different species of the cosmopolitan nematode Metastrongylus genus. To date, only four human cases have been reported, all from Europe. Herein, a severe case of pulmonary infection caused by Metastrongylus salmi in an Ecuadorian man, with successful treatment with ivermectin, is described.

Ollulanus tricuspis is a small nematode parasite of the stomach, and its infection has been reported worldwide in cats but only one report in dogs as post-mortem diagnosis. Two dogs, kept in the Tokyo area, were presented for chronic vomiting. Chronic gastritis was diagnosed histologically, and many nematodes were detected in endoscopically-biopsied gastric samples and in the mucus of vomitus in both dogs. The parasites were small (&lt;1 mm), and their morphological characteristics were consistent with those previously reported for O. tricuspis. The symptoms in one dog completely disappeared after anthelmintic therapy. To our knowledge, this is the first report describing ante-mortem diagnosis of spontaneous gastric O. tricuspis infection in dogs in which infectivity and pathogenicity of the nematode are suggested.

A lethargic household dog was referred to a private hospital in Japan. Diagnosis was carried out by the polymerase chain reaction (PCR) method developed for human Orientia tsutsugamushi infection using the dog's anticoagulated peripheral blood. Karp, Kato and Kuroki-type genomes were detected and the dog was diagnosed with O. tsutsugamushi infection. These findings demonstrate that dogs can act as a host for O. tsutsugamushi and the PCR method developed for human beings can be used for the diagnosis of canine O. tsutsugamushi infection. A concurrent epidemiological study examined 10 asymptomatic dogs that were fed in the same area as the sick dog. Kuroki-type genome in all dogs, Gilliam-type genome in 6 dogs and Kawasaki-type genome in 3 dogs were detected. These results provide further evidence that dogs can be naturally infected with O. tsutsugamushi outdoors and that dogs play a role as a host in the lifecycle of O. tsutsugamushi.

The hearts, diaphragms, hind legs, and back muscles of 64 Japanese sika deer (Cervus nippon centralis) caught in a mountainous area of Hyogo Prefecture, Japan, were examined for Sarcocystis infection by detecting sarcocysts. Sarcocysts were detected in the muscles of 52 (81.3%) individuals, and their prevalence did not differ among 1-5-year-old individuals, although no sarcocysts were detected in deer younger than 1 year old. Sarcocyst prevalence was significantly lower in the back muscles than in the other tissues. The intensity of sarcocyst infection was also significantly higher in the heart than in any other organ examined. This high prevalence of Sarcocystis infection in Japanese sika deer may be attributable to their frequent contact with the feces of the final hosts, including the hunting dogs that accompany hunters culling deer, and stray dogs, wild foxes, and raccoon dogs. The detected sarcocysts were oval to rod-like in shape and the internal section was divided by septa into many compartments. Many crescent-shaped bradyzoites were present in each compartment. The average size of 177 sarcocysts was 698.5×170.2μm. However, the measurements ranged widely, with lengths of 243.0-1,067.4μm and widths of 58.7-351.1μm. The variation of the sizes of the sarcocysts did not correlate with their shape or location of parasitization in the host.

The purpose of this study was to assess the role of fleas for transmission of Bartonella species among wild rodents in Japan. Flea samples were collected from wild rodents and examined genetically for Bartonella infection. Bartonella DNA was detected from 16 of 40 (40.0%) Ilea samples. Sequence analysis demonstrated that 3 of 16 (18.8%) of the Bartonella-positive animals were infested with fleas from which the closely related Bartonella DNA sequence was detected, indicating that the fleas acquired Bartonella from the infested rodents. The DNA was detected in hemolymph, the midgut and the ovary (only in female), indicating that Bartonella might be colonized through the midgut and distributed into the body.

In June 2009, 27 guinea pigs kept at an animal petting facility at a zoo in Kanagawa Prefecture, Japan, were observed to scratch intensely, weaken, and develop lesions. Three sarcoptiform mites were found in skin scrapings taken from affected areas of 2 guinea pigs, and they were identified as Trixacarus caviae by morphological examination. This result confirmed the presence of T. caviae in Japan. For treatment, doses of 13.6-18.75 mg/head of selamectin were administered in a topical preparation applied to a single spot on the skin on the back of the neck, and no side effects were observed. In April 2010, a second outbreak of mange occurred at the zoo, and, following investigation, 2 mite eggs were observed. It was, therefore, thought probable that the mites had survived during the winter within nonclinical carriers. Accordingly, doses of 5.0-7.5 mg/head of selamectin were applied on days 0 and 28, after which clinical symptoms disappeared and general condition improved. This dose of selamectin was thus shown to be a suitable and economical treatment for guinea pigs infested with the mites. Because the mite is not always easily observed in infested guinea pigs and the potential for human infestation exists, clinicians should not hesitate to treat when the clinical presentation suggests infestation, particularly in a setting such as an animal petting facility, where large numbers of children and adults have direct contact with the animals.

Zinc (Zn) is an essential trace element for DNA synthesis and for cell growth and differentiation. The deficiency induces a wide range of disorders including immunodeficiency. In this study, the influence of Zn deficiency to the mice infected with Babesia microti was examined, and was compared with the influence in the rats infected with B. rodhaini previously reported. Experiments of B. microti infection were conducted using Zn-deficient (ZD; allowed to eat ad libitum on the ZD diet), Zn-adequate (ZA; allowed to eat ad libitum on the ZA diet), and diet-restricted (DR; supplied 2 g/day on the ZA diet) mice. It was suggested that the Zn deficiency exacerbated the infection dynamics of the mice with B. microti by the growth retardation, the reduction of immunity and the decrease in PCV. The results in the mice supported the consequences in the rats previously reported.

A 10-year-old castrated male Shih Tzu presented with severe generalized pruritus. Skin scrapings revealed the presence of Sarcoptes scabiei var. canis. A Yorkshire terrier in the same household simultaneously developed pruritus due to scabies. Both dogs were treated with 300 mu g/kg ivermectin, at first orally and then subcutaneously at 14 day intervals. However, live mites were still found on day 35, and the skin condition deteriorated in both dogs. These findings suggested that the S. scabiei in these dogs was clinically refractory to ivermectin. The pruritus in both dogs rapidly and completely disappeared following topical fipronil administration. This appears to be the first report of canine scabies refractory to ivermectin treatment.

2005年2月、北海道北広島市にて腰部から尾部にかけ著しい脱毛と痂皮を形成したアライグマProcyon lotor雄幼獣一個体が捕獲され、当該病変部から多数の小型ダニ類が検出された。形態および2nd internal transcribed spacer(ITS-2)の塩基配列から、これらのダニ類はSarcoptes scabieiと同定された。本症例は日本産アライグマのS.scabieiによる疥癬の初報告となった。(著者抄録)

Zinc deficiency induces a wide range of disorders including immunodeficiency. It is known that microbial infections occur with a high frequency in the zinc-deficient hosts, but the study on the correlation between parasitic infection and zinc status ill hosts is scarcely performed. We observed that the influence of zinc deficiency to the rats infected with Babesia rodhaini. Experiments of B. rodhaini infection were conducted using zinc-deficient (ZD; eat ad libitum or 10 g/day on the ZD diet), zinc-adequate (ZA; eat ad libitum on the ZA diet), and diet-restricted (DR; eat 7 g/day on the ZA diet) rats. The Findings in this study suggested that the zinc deficiency had deleterious effects on the hemodynamics and mortality of the rats infected with A rodhaini.

Prevalence of lung worms belonging to the genus Metastrongylus was surveyed on 42 Japanese wild boars (Sus scrofa leucomystax) captured officially for wildlife damage control in the western parts of Tokyo, Japan from April 2000 to April 2001. The number of parasites was the highest in the caudal lung lobes. Four species, M. elongatus (ME), M. salmi (MS), M. asymmetricus (MA) and M. pudendotectus (MP), were identified. All the boars were infected with 2 or more species, and 64.3% of the boars had all 4 species. The composition of species, ME:MS:MA:MP=1.3:3.4:1.0:1.4, was drastically different from the previous reports. The peak of the average number of the parasites was observed in the period of January to March 2001 because of the increase of MS.

Life cycle of Eimeria krijgsmanni-like coccidium isolated from the feces of naturally infected mice purchased from commercial sources was examined. The parasite was purified by single oocyst isolation and maintained by passage in the mice before experiments. The sporulated oocysts; were ovoid or ellipsoid, measuring 19.3 x 14.8 mu m on average. One or two small polar granules were present. Micropyle and oocyst residuum were absent. Sporocysts were ellipsoid, measuring 11.6 x 7.2 mu m on average with a small Stieda body and sporocyst residuum. Six groups of respective 5 mice (4-week-old) were inoculated with doses varying from 2.0 x 10(1) to 10(6) oocysts. All the mice examined began to shed oocysts from 7 day postinoculation (PI) and their maximum number of oocysts per grain of feces were 10(6) on day 8 PI. Patency was 6 or 7 days. This parasite had severe virulence to the mice that is, the mice given 10(6) oocysts showed anorexia, diarrhoea and rough hair from I day and all of them died on day 3 PI. The mice given 10(3) or more oocysts showed the clinical signs described above from day 5 and 4 of them received 10(5) died on day 9 or 10 PI. The parasites occurred within the epithelial cells of cecum, colon and rectum of infected mice. Sporozoites, 13.9 x 3.0 mu m, with two large refractil bodies on side of the nucleus located subcentrally were observed on day 1 and 2 PI. Merozoites were first observed at 24 hr PI, and sexual stages were found from 4 day PI. No parasites were detected in the small intestine and mecenteric lymph nodes.

During a survey of the ciliate protozoal composition of the stomach contents of nine dromedary camels of Egypt, fourteen morphotypes of Entodinium ovumrajae, which has been considered as a species peculiar to camels, were found in six camels. Except for five morphotypes including one originally described as an independent species and its forms, these were newly detected. These morphotypes, divided into three groups, can be identified mainly by the morphology of their ectoplasmic processes. Each camel had on average, about five morphotypes of this species.

Rumen ciliate species and composition were surveyed on the reindeer kept in Inner Mongolia, China. As a result of survey, all the reindeer had the same 18 species of 8 genera of the ciliates in their rumen. Appearance of Entodinium parvum is the first record in this host species. Of the species detected, 15 species including Entodinium anteronucleatum, E. bicornutum, Enoploplastron confluens and Epidinium gigas which have been detected only from reindeer were common with those in the reindeer kept in the other areas, such as Alaska, Russia and Finland, indicating that every rumen ciliate faunae in reindeer has high similarity to each other, and suggesting that these hosts have been isolated from the other ruminants for long time and established characteristic ciliate fauna. The ciliate density was estimated as 1.1-2.5 x 10(6)/ml, which value was fairly higher than those in domestic ruminants. Surface structures of characteristic species were observed by SEM.

Djungarian (Phodopus sungorus) and Chinese (Cricetulus griseus) hamster IFN-gamma genes were cloned and sequenced. The Djungarian and Chinese hamster genes were both 525bp nucleotides, resulting in 174 amino acids in full length with a predicted molecular weight (MW) of 19,560 dal and 19,775 dal, respectively. The first 23 amino terminal amino acids consisted of a hydrophobic signal sequence when cleavaged, which would result in a mature 151 amino acid polypeptide with a predicted MW of 17,115 dal in the Djunaarian hamster IFN-gamma and 17,255 dal in the Chinese hamster one.

Parasitologic and histopathologic examinations were performed on a wild Japanese serow (Capricornis crispus) with severe dermatitis from Tochigi, Japan in February 1999. The serow was infested with a large number Chorioptes bovis. Marked parakeratotic hyperkeratosis was characteristic of the lesions induced by these mites. Japanese serow is a new host of C. bovis.

両後肢不全麻痺を呈する猫が来院後, 時間経過とともに後弓反張を呈し, 昏睡状態に陥った.血液検査, ウイルス検査, X線検査, CT検査などの各種検査および対症療法を実施したが, 原因不明のまま死亡した.剖検において, 脳底部に長さ13cmの虫体1隻, ならびに三尖弁の腱索に絡み付いた長さ9.5cmの虫体1隻が認められた.また, 病理組織検査において左側脳室から側頭葉を経て髄膜下にいたる虫道が確認された.検出された2隻の虫体は, ともに雄の犬糸状虫&lt;I&gt;Dirofilam immitis&lt;/I&gt;であり, 総排泄腔より交接刺が突出していることから未成熟虫から成虫のステージの虫体であると同定された.以上ヒの所見より, 後弓反張を呈した神経症状は犬糸状虫の脳内迷入が原因であると考えられた.

We have already reported that anti-erythrocyte antibody induced by Babesia gibsoni infection (aEAb) showed higher reactivity against aged and/or oxidized erythrocytes than intact ones in vitro (Morita et al., 1995). To clarify the meaning of such a binding character of aEAb in vivo, changes in erythrocyte oxidation were observed in artificially infected dogs. The ratio of methemoglobin concentration against total hemoglobin concentration (metHb%) as the indicator of erythrocyte oxidation was increased by the artificial infection in the intact dogs, suggesting that aEAb played a more important role in erythrocyte destruction in infected dogs. Though parasitemia approximately three times higher was observed in splenectomized dogs than that in intact dogs, metHb% did not increase in the splenectomized dogs. This suggests that the spleen plays a very important role in erythrocyte oxidation in dogs infected with B. gibsoni.

Effects of ageing treatment of erythrocytes to binding activity of the anti-erythrocyte antibody (s) in the serum of dogs infected artificially with Babesia gibsoni were examined by enzyme-linked immunosorbent assay (ELISA) using fixed cell antigen. When erythrocytes made senescent by two artificial ageing treatments, one of which was storing erythrocytes at 37°C in medium for some days and the other was oxidation of erythrocytes with phenylhydrazine, reactivity of anti-erythrocyte antibody (s) in the infected serum to both types of treated erythrocytes was increased. These results suggest that such antibody (s) could play a role as one of the causes of anemia in canine babesiosis. © 1995.