Circovirus Spread Via Semen Studied( 環狀病毒的散佈與精液的研究)

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Circovirus Spread Via Semen StudiedDec 17, 2007 1:29 PM
Because porcine circovirus-associated disease (PCVAD) has spread rapidly across North America, boar semen has been implicated as a possible source for dissemination of the virus.
To address this issue, and determine if there are differences in semen shedding of porcine circovirus type 2 (PCV2) isolates, 15, 7-month-old PCV2-negative boars were randomly allotted to three different groups. The first group served as control, the second was inoculated with PCV2a (North American-like virus) and the third group was inoculated with PCV2b (European-like virus).
Semen and serum were collected during the 90-day trial at Iowa State University (ISU).
Research concluded that PCV2a and PCV2b were both shed in low levels in semen in the two groups, of experimentally infected boars. Semen was shed for up to 12 weeks.
Overall, the amount of shedding was low and variable among individual boars within groups, and peak shedding occurred approximately three weeks post-challenge.
Detection of PCV2 in semen corresponded well with detection of PCV2 DNA in serum samples and blood swabs.
This trial verified that mature boars shed low quantities of PCV2a and PCV2b in semen, and that semen is a potential route for PCV2 transmission amongst swine herds.
In a second trial, a swine bioassay model was used to determine if PCV2-positive semen was infectious. Twelve, 4-week-old, PCV2-negative pigs were divided into four groups. All of the 4-week-old naїve pigs that were inoculated intraperitoneally (abdominal area) with PCV2-positive semen became infected with either PCV2a or PCV2b.
But when the same semen samples were extended, and used to artificially inseminate PCV2-negative gilts in a third trial, those gilts did not develop PCV2 infection, nor did they show evidence of PCV2-associated reproductive failure. All gilts inseminated with PCV2-positive semen became pregnant and carried pregnancy to term. There was no evidence that fetuses became infected with PCV2.
Researchers concluded that experimental inoculation of boars with PCV2 produces infection; however, it has yet to be determined if PCV2-positive semen is a risk for transmission and dissemination of PCVAD.
Research was funded by the Pork Checkoff.
Researcher: Tanja Opriessnig, Iowa State University. Contact Opriessnig by phone (515) 294-1950, fax (515) 294-6961 or e-mail tanjaopr@iastate.edu.



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[ 本帖最後由 程嘉華(Jessie) 於 2008-1-31 10:09 編輯 ]

瑞泰牧場

Circovirus 傳播了通過精液Studied(?????????????)
Circovirus 傳播了通過精液StudiedDec 17, 2007 年1:29 PM
由於豬的circovirus 伴生的疾病(PCVAD) 迅速地傳播了橫跨北美洲, 公豬精液被牽連了作為一個可能的來源為病毒的傳播。
論及這個問題, 和確定如果有在豬的circovirus 類型2 (PCV2) 孤立精液流出上的區別, 15, 7 月的PCV2 消極公豬任意地被定量對三個不同小組。第一小組擔當控制, 秒鐘被接種了與PCV2.a (北部美國像病毒) 並且第三個小組被接種了與PCV2b (歐洲像病毒) 。
精液和清液被收集了在90 天試驗期間在衣阿華州立大學(ISU) 。
研究認為, PCV2.a 和PCV2b 是兩個棚子在低水平在精液在二個小組中, 實驗性地被傳染的公豬。精液是棚子12 個星期。
總之, 相當數量流出是降低和可變物在各自的公豬之中在小組心頭, 並且峰頂流出發生了大約三個星期崗位挑戰。
PCV2 的偵查在精液很好對應了以PCV2 DNA 的偵查在清液樣品和血液拖把裡。
這次試驗核實, 成熟公豬流洒PCV2.a 和PCV2b 的低數量在精液, 並且精液是一條潛在的路線為PCV2 傳輸在豬之中成群。
在第二次試驗, 豬生物鑒定模型被使用確定如果PCV2 正面精液是感染的。十二, 4 星期的, PCV2 消極豬被劃分了成四個小組。腹膜內被接種的所有4 星期的naїve 豬(胃腸區域) 與PCV2 正面精液成為了傳染與或PCV2.a 或PCV2b 。
但當同樣精液樣品是延長的, 並且過去常常人為地播種PCV2 消極鍍金面在第三次試驗, 那些鍍金面沒有開發PCV2 傳染, 亦不他們顯示證據PCV2 伴生的再生失敗。所有鍍金面播種與PCV2 正面精液成為懷孕和運載的懷孕命名。沒有證據, 胎兒成為了傳染與PCV2 。
研究員認為, 公豬的實驗性接種與PCV2 導致傳染; 但是, 它有被確定如果PCV2 正面精液是一種風險為PCVAD 的傳輸和傳播。
研究由豬肉自動扣除資助了。