非洲软蜱Ornithodoros moubata对HIV机械传播的评估。

PubMed ID
发表日期 1993年Mar月

原始出处 艾滋病(英国伦敦)
AIDS (London, England)
作者 Humphery-Smith  I  Donker  G  Turzo  A  Chastel  C  Schmidt-Mayerova  H 

文献标题 非洲软蜱Ornithodoros moubata对HIV机械传播的评估。
Evaluation of mechanical transmission of HIV by the African soft tick, Ornithodoros moubata.

文献摘要 OBJECTIVES

评估非洲小屋坦帕鸟Ornithodoros moubata在28和35摄氏度时机械传播HIV-1的能力,并重新评估HIV-1在节肢动物细胞系中的传染性。

DESIGN

为了评估O.moubata对HIV-1的传播,根据HIV-1存活率、“血粉”大小和喂食间隔时间,允许不同发育阶段的蜱在体外饲养室中以含有HIV-1BRU的严重感染的淋巴母细胞血粉为食。

METHODS

用51Cr标记的人红细胞评估血粉反流,用台盼蓝评估人在蜱体内的成淋巴细胞存活率。用与CEM淋巴细胞共培养的蜱匀浆逆转录酶活性评价HIV-1在蜱体内的存活率。采用聚合酶链反应和Southern印迹分析方法,对体外培养的节肢动物细胞中HIV-1前病毒进行检测。

RESULTS

HIV-1BRU在成年O.moubata中存活长达10天。这是有记录以来HIV在节肢动物中存活时间最长的记录。与其他研究一致。O、 毛茛把以前的血粉部分反流到进食区。人CEM成淋巴细胞在28℃和35℃的消化道内部分存活7天。成年雌蜱的血餐高达240微升(约为蚊子的70倍),而最有可能的潜在机械媒介(第四和第五阶段若虫)平均摄入39微升(最多73微升),有些蜱在没有蜕皮的情况下,最早在喂食后14天就重新进食。与实验方案相关的缺点表明,艾滋病毒在O.moubata体内的存活率可能在自然感染后达到14天,或者蜱虫可能更早地重新进食。虽然HIV-1BRU和HIV-1NDK在28℃和35℃下不能在CD4-白纹伊蚊C6/36蚊细胞中复制,但HIV-1NDK以其前体形式被检测到。

CONCLUSIONS

我们的调查显示,通过O.moubata的机械传播HIV-1不太可能在实验室中发生。在野外条件下可能不是这样。

在一个体外饲养室里,非洲小坦帕蜱(Ornithodoros moubata)以富含CEM淋巴母细胞的人类血液为食,血液中含有大量的HIV-1bru,这样就可以在非洲某些地区的环境温度28摄氏度和35摄氏度的环境温度下检测蜱类传播HIV-1的能力。作者还使用白纹伊蚊蚊细胞和HIV-1bru和HIV-1ndk在28和35摄氏度下重新检测了HIV-1在节肢动物细胞系中的传染性。一些成年雌性蜱虫的血液摄取量高达240微升,约为蚊子摄取量的70倍(平均106.3微升)。另一方面,第四期和第五期若虫是最有可能的HIV机械载体,平均消耗39 mcl(最大73 mcl)。对尚未蜕皮的若虫,最短间隔时间为14天。但其他研究表明,蜱虫通常在14天内重新进食。这些蜱虫在喂食一只哺乳鼠时,会将先前血粉的一部分反流到进食区。成年蜱携带有活力的HIV-1bru长达10天,这是记录在案的节肢动物中存活时间最长的HIV-1bru。然而,其他证据表明,在自然条件下,O.moubata的HIV存活时间实际上可能是14天。4.5%和1.3%的人CEM淋巴母细胞在蜱虫消化道的28℃和35℃下存活7天。HIV-1bru和HIV-1ndk都不能在CD4-A.albopictus C6/36蚊子细胞中复制,但是作者确实发现了一些证据表明HIV-1的逆转录在体外是不可能的,但它可能在一定程度上促进了HIV-1在中非地区的传播,那里HIV流行率很高。


OBJECTIVES

To assess the ability of the African Hut Tampan, Ornithodoros moubata, to mechanically transmit HIV-1 and to re-appraise HIV-1 infectivity in an arthropod cell line at 28 and 35 degrees C.

DESIGN

To evaluate HIV-1 transmission by O. moubata, as determined by HIV-1 survival, 'blood-meal' size and interval between feeds, various tick developmental stages were allowed to feed on a heavily infected lymphoblast-rich blood-meal containing HIV-1BRU in an in vitro feeding chamber.

METHODS

Blood-meal regurgitation was evaluated using 51Cr-labelled human erythrocytes, and human lymphoblast survival in ticks using Trypan blue. HIV-1 survival in ticks was evaluated by reverse transcriptase activity in tick homogenates cocultured with CEM lymphoblasts. Polymerase chain reaction and Southern blot analysis were used to detect proviral HIV-1 in arthropod cells in vitro.

RESULTS

HIV-1BRU remained viable for up to 10 days with O. moubata adults. This is the longest recorded survival of HIV in an arthropod. In agreement with other studies. O. moubata regurgitated part of its previous blood-meal into the feeding lesion. Human CEM lymphoblasts partially survived for up to 7 days at 28 and 35 degrees C inside O. moubata's digestive tract. The blood-meal of adult female ticks was as high as 240 microliters (approximately 70 times more than a mosquito), while the most likely potential mechanical vectors (fourth- and fifth-stage nymphs) ingested an average of 39 microliters (maximum, 73 microliters), with some ticks re-feeding as early as 14 days postfeed in the absence of a moult. Shortcomings associated with the experimental protocol suggest that HIV survival within O. moubata may reach 14 days following natural infection, or that ticks might re-feed earlier. Although HIV-1BRU and HIV-1NDK were unable to replicate at 28 and 35 degrees C in CD4- Aedes albopictus C6/36 mosquito cells, HIV-1NDK was detected in its proviral form.

CONCLUSIONS

Our investigations showed that mechanical transmission of HIV-1 by O. moubata is unlikely to occur in the laboratory. This may not be the situation under field conditions.

In an in vitro feeding chamber, African Hut Tampan ticks (Ornithodoros moubata) fed on CEM lymphoblast-rich human blood containing a copious amount of HIV-1 BRU so that the ability of the tick to transmit HIV-1 at 28 and 35 degrees Celsius--ambient temperatures in some parts of Africa--could be examined. The authors also used Aedes albopictus mosquito cells and HIV-1 BRU and HIV-1 NDK to reexamine HIV-1 infectivity in an arthropod cell line at 28 and 35 degrees Celsius. Some adult female ticks ingested as much as 240 mcl of blood, about 70 times the amount ingested by mosquitoes (mean, 106.3 mcl). On the other hand, the fourth and fifth stage nymphs which are the most likely mechanical vectors of HIV consumed a mean of 39 mcl (maximum, 73 mcl). The shortest interval between feeds for nymphs which had not yet molted was 14 days. But other studies suggested that ticks often refeed sooner than 14 days. The ticks regurgitated part of their previous blood meal into the feeding lesion when they later fed on a suckling mouse. Adult ticks harbored viable HIV-1 BRU for as long as 10 days, the longest recorded survival of HIV in an arthropod. Yet, other evidence indicated that HIV survival in O. moubata under natural conditions could actually be 14 days. 4.5% and 1.3% of human CEM lymphoblasts remained viable up to 7 days in the ticks' digestive tract at 28 and 35 degrees Celsius, respectively. Neither HIV-1 BRU nor HIV-1 NDK could replicate in CD4-A. albopictus C6/36 mosquito cells, but the authors did find some evidence of retrotranscription of HIV-1 is probably not possible in vitro, but it could contribute somewhat to HIV-1 transmission in areas of Central Africa where HIV prevalence is high.


获取全文 10.1097/00002030-199303000-00006