Molecular Evidence of Babesia Equi Transmission in Haemaphysalis Longicornis

Ikadai, Hiromi; Sasaki, Mizuki; Ishida, Hidekazu; Matsuu, Aya; Igarashi, Ikuo; Fujisaki, Kozo; Oyamada, Takashi

doi:10.4269/ajtmh.2007.76.694

Cited by 34 publications

(26 citation statements)

References 20 publications

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“…The lack of transmission, even when adult female R. microplus ticks were acquisition fed on horses with high levels of parasitemia and positive egg masses were selected for rearing larvae, indicates that this intergenerational mode of transmission is, at best, very inefficient and unlikely to be of epidemiologic significance. Whether this holds true for the other known or putative vector tick species shown to pass B. equi parasites transovarially is unknown and awaits definitive transmission data (1,9).…”

Section: Discussionmentioning

confidence: 99%

Persistently Infected Horses Are Reservoirs for Intrastadial Tick-Borne Transmission of the Apicomplexan Parasite Babesia equi

et al. 2008

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Tick-borne pathogens may be transmitted intrastadially and transstadially within a single vector generation as well as vertically between generations. Understanding the mode and relative efficiency of this transmission is required for infection control. In this study, we established that adult male Rhipicephalus microplus ticks efficiently acquire the protozoal pathogen Babesia equi during acute and persistent infections and transmit it intrastadially to naïve horses. Although the level of parasitemia during acquisition feeding affected the efficiency of the initial tick infection, infected ticks developed levels of >10 4 organisms/pair of salivary glands independent of the level of parasitemia during acquisition feeding and successfully transmitted them, indicating that replication within the tick compensated for any initial differences in infectious dose and exceeded the threshold for transmission. During the development of B. equi parasites in the salivary gland granular acini, the parasites expressed levels of paralogous surface proteins significantly different from those expressed by intraerythrocytic parasites from the mammalian host. In contrast to the successful intrastadial transmission, adult female R. microplus ticks that fed on horses with high parasitemia passed the parasite vertically into the eggs with low efficiency, and the subsequent generation (larvae, nymphs, and adults) failed to transmit B. equi parasites to naïve horses. The data demonstrated that intrastadial but not transovarial transmission is an efficient mode for B. equi transmission and that persistently infected horses are an important reservoir for transmission. Consequently, R. microplus male ticks and persistently infected horses should be targeted for disease control.The maintenance of tick-borne infections in natural reservoir hosts is dependent upon the efficiency of acquisition and transmission events at the tick-host and tick-pathogen interfaces (7,20). Effective control of tick-borne infectious disease requires knowledge of the ability of specific vector stages to acquire, amplify, and transmit the pathogen. There are three nonmutually exclusive modes of tick-borne transmission (4). The first mode is transstadial transmission that occurs when a tick stage (e.g., larval or nymphal) acquires the pathogen from a mammalian reservoir host and a subsequent life cycle stage within the same tick generation transmits the pathogen to an uninfected host (11,18,20). In the second mode, ticks transmit the pathogen intrastadially; the pathogen is acquired by the tick, and following movement between individual animal hosts, the same tick stage transmits the pathogen to a naïve animal (18). In the third mode, transovarial passage is followed by pathogen transmission by one or more stages in the subsequent generation (3, 7). All three modes occur in the transmission of the apicomplexan parasites of the genus Babesia (4); however, the mode used by a given Babesia sp. cannot be inferred but, rather, requires testing and quantification of the ...

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Section: Discussionmentioning

confidence: 99%

Persistently Infected Horses Are Reservoirs for Intrastadial Tick-Borne Transmission of the Apicomplexan Parasite Babesia equi

et al. 2008

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“…T. equi is generally transmitted through transstadial and intrastadial transmission . Transovarial transmission of T. equi occurs, but the precise role in epidemiology has not been detailed …”

Section: Epidemiology/ecologymentioning

confidence: 99%

“…20 Transovarial transmission of T. equi occurs, but the precise role in epidemiology has not been detailed. 42,43 Discovery of the vector D. reticulatus in the Netherlands in 2010 combined with recognition of a subclinically B. caballi-infected horse led to a surveillance of that area that resulted in identification of several of T. equi-and B. caballi-infected horses. 6 Before 2009, only 2 tick species known to transmit T. equi naturally had been identified within the southernmost parts of the United States: D. nitens and R. microplus.…”

Section: Epidemiology/ecologymentioning

confidence: 99%

Review of Equine Piroplasmosis

Wise

Kappmeyer

Mealey

et al. 2013

Veterinary Internal Medicne

204

243

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Equine piroplasmosis is caused by one of 2 erythrocytic parasites Babesia caballi or Theileria equi. Although the genus of the latter remains controversial, the most recent designation, Theileria, is utilized in this review. Shared pathogenesis includes tick-borne transmission and erythrolysis leading to anemia as the primary clinical outcome. Although both parasites are able to persist indefinitely in their equid hosts, thus far, only B. caballi transmits across tick generations. Pathogenesis further diverges after transmission to equids in that B. caballi immediately infects erythrocytes, whereas T. equi infects peripheral blood mononuclear cells. The recent re-emergence of T. equi in the United States has increased awareness of these tick-borne pathogens, especially in terms of diagnosis and control. This review focuses in part on factors leading to the re-emergence of infection and disease of these globally important pathogens.

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“…It parasitizes a variety of hosts including domestic and wild animals and human beings under natural conditions (Teng and Jiang 1991;Tenquisf and Charleston 2001;Inokuma et al 2002;Kim et al 2003;Shimada et al 2003) and transmits zoonotic pathogens including Theileria sergenti (Teng and Jiang 1991), Babesia ovata (Cho et al 2002), B. equi (Ikadai et al 2007), rickettsia and Coxiella burneti (Q fever) (Hoogstraal et al 1968), which can cause severe diseases in human and animals. Therefore, it is one of the most detrimental ticks to the health of human and animals.…”

Section: Introductionmentioning

confidence: 98%

Development and biological characteristics of Haemaphysalis longicornis (Acari: Ixodidae) under field conditions

Zheng

Chen

et al. 2010

Exp Appl Acarol

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The development and biological characteristics of Haemaphysalis longicornis were investigated under field conditions in Xiaowutai National Natural Reserve Area, North China. Unfed larvae, nymphs and adults were fed on rabbits and exposed to daylight. Three free-living stages were allowed to develop in field plot selected in a tick natural habitat. The host seeking behavior and seasonal occurrence were observed. Haemaphysalis longicornis were active from mid March to mid October. The premoult period of nymphs and preoviposition of females were regulating phases of their life cycle. The developmental durations of eggs, larvae and adults were constant under field conditions regardless when the development started. The oviposition periods in May and June were statistically shorter than those in July and August. The daily oviposition patterns of females engorged in May and June demonstrated unobvious peak, which differed from those engorged in July and August. The daily oviposition peak of the latter occurred on the 4th day of oviposition. Moreover, a positive correlation was found between the mass of the laid egg and the body weight of engorged females (r = 0.62, P < 0.001). The female reproductive efficiency indices were 2.9, 6.1, 10.5 and 9.0 in May, June, July and August, respectively. The mean weight (3.33 mg) of engorged nymphs molting to females was significantly higher than that (2.35 mg) of those molting to males (P < 0.001), but the body weights of both sexes were overlapping.

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Molecular Evidence of Babesia Equi Transmission in Haemaphysalis Longicornis

Cited by 34 publications

References 20 publications

Persistently Infected Horses Are Reservoirs for Intrastadial Tick-Borne Transmission of the Apicomplexan Parasite Babesia equi

Persistently Infected Horses Are Reservoirs for Intrastadial Tick-Borne Transmission of the Apicomplexan Parasite Babesia equi

Review of Equine Piroplasmosis

Development and biological characteristics of Haemaphysalis longicornis (Acari: Ixodidae) under field conditions

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