Umemiya-Shirafuji Rika, Hatta Takeshi, Okubo Kazuhiro, Sato Moeko, Maeda Hiroki, Kume Aiko, Yokoyama Naoaki, Igarashi Ikuo, Tsuji Naotoshi, Fujisaki Kozo, Inoue Noboru, Suzuki Hiroshi
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Acta Parasitol. 2017 Dec 20;62(4):836-841. doi: 10.1515/ap-2017-0100.
Bovine piroplasmosis, a tick-borne protozoan disease, is a major concern for the cattle industry worldwide due to its negative effects on livestock productivity. Toward the development of novel therapeutic and vaccine approaches, tick-parasite experimental models have been established to clarify the development of parasites in the ticks and the transmission of the parasites by ticks. A novel tick-Babesia experimental infection model recently revealed the time course of Babesia ovata migration in its vector Haemaphysalis longicornis, which is a dominant tick species in Japan. However, there has been no research on the transovarial persistence of B. ovata DNA using this experimental infection model. Here we assessed the presence of B. ovata DNA in eggs derived from parthenogenetic H. longicornis female ticks that had engorged after semi-artificial mouse skin membrane feeding of B. ovata-infected bovine red blood cells. The oviposition period of the engorged female ticks was 21-24 days in the semi-artificial feeding. Total egg weight measured daily reached a peak by day 3 in all female ticks. Nested PCR revealed that 3 of 10 female ticks laid B. ovata DNA-positive eggs after the semi-artificial feeding. In addition, B. ovata DNA was detected at the peak of egg weight during oviposition, indicating that B. ovata exist in the eggs laid a few days after the onset of oviposition in the tick. These findings will contribute to the establishment of B. ovata-infected H. longicornis colonies under laboratory conditions.
牛梨形虫病是一种由蜱传播的原生动物疾病，由于其对牲畜生产力的负面影响，已成为全球养牛业主要关注的问题。为了开发新的治疗方法和疫苗，人们建立了蜱-寄生虫实验模型，以阐明寄生虫在蜱体内的发育情况以及蜱对寄生虫的传播。最近，一种新型的蜱-巴贝斯虫实验感染模型揭示了卵形巴贝斯虫在其传播媒介长角血蜱（日本的优势蜱种）体内的迁移时间进程。然而，尚未使用该实验感染模型对卵形巴贝斯虫DNA的经卵传递持久性进行研究。在此，我们评估了在以感染卵形巴贝斯虫的牛红细胞进行半人工小鼠皮肤膜喂养后饱血的孤雌生殖长角血蜱雌蜱所产的卵中卵形巴贝斯虫DNA的存在情况。在半人工喂养中，饱血雌蜱的产卵期为21至24天。所有雌蜱每日测量的总卵重均在第3天达到峰值。巢式PCR显示，10只雌蜱中有3只在半人工喂养后产下了卵形巴贝斯虫DNA阳性的卵。此外，在产卵期间卵重达到峰值时检测到了卵形巴贝斯虫DNA，这表明卵形巴贝斯虫存在于蜱产卵开始后几天所产的卵中。这些发现将有助于在实验室条件下建立感染卵形巴贝斯虫的长角血蜱种群。
