| Project/Area Number |
06454130
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Applied veterinary science
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| Research Institution | Faculty of Agriculture, Tottori University |
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Principal Investigator |
UMEMURA Takashi Tottori University Faculty of Agriculture, Professor, 農学部, 教授 (00151936)
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| Co-Investigator(Kenkyū-buntansha) |
YAGIHASHI Takeshi Nippon Institute for Biomedical Sciences, Research Director, 第3部, 部長 (20072465)
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| Project Period (FY) |
1994 – 1995
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| Project Status |
Completed (Fiscal Year 1995)
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| Budget Amount *help |
¥7,200,000 (Direct Cost: ¥7,200,000)
Fiscal Year 1995: ¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1994: ¥5,000,000 (Direct Cost: ¥5,000,000)
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| Keywords | Pigs / Otitis media / Mycoplasmosis / Mycoplasma hyorhinis / Pathogenesis / Experimental pathology / Mycoplasma hyorhinis / 耳管炎 / マイコプラズマ ハイオリニス |
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| Research Abstract |
The ear of 479 pigs from 8 commercial farms, ranging age from 1 day to 1 year old were pathologically and microbiologically examined. 364(76.0%) of 479 pigs were affected wit otitis. Eustachitis was the most common and preceded an inflammation of other sites of the ear, and an acute eustachitis occurred from as early as 1 week of life. Common bacterial habitants of the upper respiratory tracts such as Pasteurella multocida and Actinomyces pyogenes were the most frequent isolates from the exudate in the tympanic cavity or in the tympanic bulla. Immunohistochemical examination of frozen cryostat sections revealed Mycoplasma hyorhinis (Mhr) antigens on the luminal surface of the eustachian epithelia in 14 (50.0%) of 28 piglets examined. Mhr was isolated from the auditory tubes and tympanic cavities of 19 (67.9%) and 16 (57.1%) of 28 piglets, respectively. All the pigs positive for Mhr had an acute eustachitis. Experimental reproduction of otitis was performed using seventeen, 17- to 22-day-old, SPF piglets. Mhr inoculated in the middle ear multiplied and induced transient, purulent-catarrhal inflammation of the ear. From these results, it was concluded that porcine otitis media might be caused primarily by Mhr infection and be a novel mycoplasmal disease.
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