Vertical transmission of Theileria lestoquardi in sheep

Zakian, Amir; Barati, Farid; Kahroba, Hooman; Jolodar, Abbas; Rashidi, Fardokht

doi:10.1016/j.vetpar.2014.04.007

Cited by 12 publications

(9 citation statements)

References 5 publications

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“…Indeed, transplacental transmission has been detected for a number of other Theileria spp. including T. equi [22] T. lestoquardi [24] and T. annulata [25] using molecular methods.…”

Section: Discussionmentioning

confidence: 99%

“…Prior studies indicate that transplacental transmission of other Theileria spp. can occur in their respective hosts including T. equi in horses [22, 23], T. lestoquardi in sheep [24] and rarely, T. annulata in cattle [25]. Transplacental transmission of T. orientalis was implicated in the infection and abortion of 100% of calves where the pregnant dams had been experimentally infected via ticks [26], while microscopic studies conducted in Japan suggested that transplacental transmission was occurring in field-affected cattle, but only at a low rate [27].…”

Section: Introductionmentioning

confidence: 99%

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Transplacental transmission of Theileria orientalis occurs at a low rate in field-affected cattle: infection in utero does not appear to be a major cause of abortion

Swilks

Fell

Hammer³

et al. 2017

Parasites Vectors

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BackgroundBovine theileriosis, caused by the haemoprotozoan Theileria orientalis, is an emerging disease in East Asia and Australasia. Previous studies have demonstrated transplacental transmission of various Theileria spp. but molecular confirmation of transplacental transmission of T. orientalis has never been confirmed in the field. In this study, cow-calf (< 48 h old) pairs were sampled across 3 herds; opportunistic samples from aborted foetuses or stillborn calves were also examined. Molecular (multiplex qPCR) and serological (ELISA) methods were used to determine infection prevalence and the presence of anti-Theileria antibodies in each herd. In addition, pregnant heifers and foetal calves were sampled at abattoir and tested for the presence of T. orientalis by qPCR.ResultsThe qPCR results indicated that, even though there was a high prevalence of T. orientalis infection in cows, the rate of transplacental transmission to their calves was low, with only one newborn calf from one herd and one foetus from the abattoir testing positive for T. orientalis DNA. Five aborted foetuses and stillborn calves, 3 of which were derived from a herd experiencing a high number of clinical theileriosis cases at the time of sampling, all tested negative for T. orientalis by qPCR. This suggests that in utero infection of calves with T. orientalis may not be a major driver of abortions during theileriosis outbreaks. Temporal monitoring of 20 calves born to T. orientalis-positive mothers indicated that T. orientalis was detectable in most calves between 10 and 27 days post-partum, consistent with prior field studies on adult cattle introduced to Theileria-affected herds. There was a positive correlation between the ELISA ratio of newborn calves and their mothers within 48 h of calving; however, maternal antibodies were only detectable in some calves and only for 4–4.5 weeks post-partum. All calves displayed high parasite loads peaking at 4–8 weeks post-partum, with only some calves subsequently mounting a detectable adaptive antibody response.ConclusionsThese findings indicate transplacental transmission of T. orientalis appears to play only a minor role in persistence of T. orientalis infection in the field; however calves are highly susceptible to developing high level T. orientalis infections at 4–8 weeks of age regardless of whether maternal antibodies are present post-partum.Electronic supplementary materialThe online version of this article (doi:10.1186/s13071-017-2166-9) contains supplementary material, which is available to authorized users.

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“…Indeed, transplacental transmission has been detected for a number of other Theileria spp. including T. equi [22] T. lestoquardi [24] and T. annulata [25] using molecular methods.…”

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Transplacental transmission of Theileria orientalis occurs at a low rate in field-affected cattle: infection in utero does not appear to be a major cause of abortion

Swilks

Fell

Hammer³

et al. 2017

Parasites Vectors

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“…Clinical signs include loss of condition, coughing, lethargy, enlargement of lymph nodes, and fever [1]. Mortality levels of up to 73% have been reported for malignant ovine theileriosis [2] and the disease can lead to reduced productivity and spontaneous abortions in survivors [3]. T .…”

Section: Introductionmentioning

confidence: 99%

Identification of Theileria lestoquardi Antigens Recognized by CD8+ T Cells

et al. 2016

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As part of an international effort to develop vaccines for Theileria lestoquardi, we undertook a limited screen to test T. lestoquardi orthologues of antigens recognised by CD8+ T lymphocyte responses against T. annulata and T. parva in cattle. Five MHC defined sheep were immunized by live T. lestoquardi infection and their CD8+ T lymphocyte responses determined. Thirteen T. lestoquardi orthologues of T. parva and T. annulata genes, previously shown to be targets of CD8+ T lymphocyte responses of immune cattle, were expressed in autologous fibroblasts and screened for T cell recognition using an IFNγ assay. Genes encoding T. lestoquardi antigens Tl8 (putative cysteine proteinase, 349 aa) or Tl9 (hypothetical secreted protein, 293 aa) were recognise by T cells from one animal that displayed a unique MHC class I genotype. Antigenic 9-mer peptide epitopes of Tl8 and Tl9 were identified through peptide scans using CD8+ T cells from the responding animal. These experiments identify the first T. lestoquardi antigens recognised by CD8+ T cell responses linked to specific MHC class I alleles.

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“…Transplacental parasite transfer from pregnant cattle to offspring through the placenta has been confirmed through molecular and serological methods for a range of Theileria spp. This mode of transmission has been demonstrated in species such as T. annulata [119] T. equi [120,121], and T. lestoquardi [122]. Transplacental transmission also occurs in T. orientalis infection [71,123,124].…”

Section: Lifecycle and Transmissionmentioning

confidence: 99%

Oriental Theileriosis

Yam¹,

Bogema²,

Jenkins³

2019

Ticks and Tick-Borne Pathogens

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Theileria orientalis, the causative agent of oriental theileriosis, is an apicomplexan haemoparasite and is one of several tick-borne Theileria spp. infecting cattle. Unlike the highly pathogenic transforming Theileria species (T. annulata and T. parva) which induce uncontrolled lymphocytic proliferation, T. orientalis is a non-transforming strain exerting its major pathogenic effects via erythrocyte destruction. Clinical symptoms associated with oriental theileriosis are largely consequences of the underlying anaemia. Because of its non-transforming nature, T. orientalis was previously considered a benign parasite, however, in the recent years, clinical outbreaks of T. orientalis have been increasingly observed throughout Asia and Australasia. Recent rapid spread of clinical theileriosis has been linked to a pathogenic genotype of the parasite, genotype Ikeda (Type 2). The geographic distribution of clinical outbreaks correlates to the range of the major vector tick, Haemaphysalis longicornis, although other vectors and modes of transmission are possible. This review includes discussion of T. orientalis epidemiology, transmission, pathogenesis, treatment and control and provides an update on the taxonomy of this organism which is still under debate.

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Vertical transmission of Theileria lestoquardi in sheep

Cited by 12 publications

References 5 publications

Transplacental transmission of Theileria orientalis occurs at a low rate in field-affected cattle: infection in utero does not appear to be a major cause of abortion

Transplacental transmission of Theileria orientalis occurs at a low rate in field-affected cattle: infection in utero does not appear to be a major cause of abortion

Identification of Theileria lestoquardi Antigens Recognized by CD8+ T Cells

Oriental Theileriosis

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