Tick-borne diseases in ruminants are common in tropical and subtropical regions and lead to meat and milk production losses. In this study, polymerase chain reaction (PCR) was used to assess the presence of Theileria ovis in Rhipicephalus bursa ticks. We have demonstrated that the PCR enabled detection of T. ovis in field isolates of R. bursa collected from naturally infested sheep and goats in eastern Turkey. The sampling was done in spring season (between May and June 2004). A total of 420 R. bursa were collected and randomly selected 192 number of them (97 female and 95 male) were dissected. Primers specific for 520 bp fragments small subunit ribosomal RNA (ssu rRNA) gene of T. ovis amplified products from 37 of the 192 (19.27%) samples. The parasite was detected in 17 (17.52%) female and in 20 (21.05%) male ticks. Two T. ovis amplicons from the tick samples were purified and sequenced. The resulting sequences were identical to the nucleotide sequence of the Turkish sheep strain of T. ovis. These results showed that R. bursa might play an important role in the field as a natural vector of T. ovis. 相似文献
Forsyth, L.M.G., Jackson, L.A., Wilkie, G., Sanderson, A., Brown, C.G.D. and Preston, P.M., 1997. Bovine cells infected in vivo with Theileria annulata express CD11b, the C3bi complement receptor. Veterinary Research Communications, 21 (4), 249-263Bovine cells from cattle infected with Theileria annulata were phenotyped with monoclonal antibodies recognizing bovine leukocyte antigens. Macroschizont-infected, transformed cell lines prepared from peripheral blood mononuclear cells of cattle, infected with sporozoites, were assessed by flow cytometry; parasitized cells in tissues from infected cattle were examined by immunocytochemical techniques. Co-expression of markers for different cell lineages by the cell lines precluded a definite conclusion as to their phenotypic origins. For, while the pattern of leukocyte antigens expressed by these in vivo-derived schizont-infected cells, which included CD11b, was indicative of a myeloid origin, the possibility that they were NK cells could not be excluded. The monoclonal antibody (MAb) IL-A15, which recognizes CD11b, reacted with a high proportion of parasitized cells in sections of tissues from infected cattle at all stages of acute disease. Mononuclear cells infected with parasites at all stages of differentiation, from macroschizont to microschizont, expressed CD11b. Such parasitized cells occurred throughout the lymphoid tissues, being found in the thymus, spleen and lymph nodes, particularly the prescapular node draining the site of infection, the hepatic, mesenteric and precrural nodes, as well as in the reticulo-endothelial tissue of the liver, kidney, lung, abomasum, adrenal and pituitary glands. These observations provided the first evidence for a myeloid origin for the parasitized T. annulata cells found in infected bovine tissues and blood and suggested a mechanism whereby schizonts could transfer from cell to cell during mechanical infection with schizont-infected cells. 相似文献
AIM: To describe the prevalence and spatial distribution of cattle herds infected with Ikeda and non-Ikeda types of Theileria orientalis in New Zealand between November 2012 and June 2013.
METHODS: Pooled serum samples collected historically between November 2012 and June 2013 were obtained from cattle herds throughout New Zealand. Each pooled sample consisted of approximately 20 individual cattle samples from that herd, and was provided with details of the spatial location of the herd (n=722). DNA from all samples was tested using two quantitative PCR assays for the detection of T. orientalis (all types) and the Ikeda type. The proportion of herds that were positive for T. orientalis and Ikeda type, or that were positive for T. orientalis but negative for Ikeda type (non-Ikeda positive) was determined for different regions of New Zealand.
RESULTS: The highest prevalence of herds infected with Ikeda type was detected in the Northland (33/35; 94%) and Auckland and the Waikato (63/191; 33%) regions. Only 2/204 (1%) herds were positive for the Ikeda type in the South Island. A high percentage of herds that were positive for non-Ikeda types was detected in the Gisborne and Hawkes Bay (23 (95%CI=13–37)%), Auckland and Waikato (22 (95%CI=16–29)%) and Bay of Plenty (24 (95%CI=10–44)%) regions.
CONCLUSIONS AND CLINICAL RELEVANCE: The high prevalence of Ikeda type detected in cattle herds in the Northland, Auckland and Waikato regions represents a risk to naive cattle being introduced into these regions. There is also the potential for resident cattle herds in the Gisborne and Hawkes Bay, Auckland, Waikato and Bay of Plenty regions to experience increased infection with the Ikeda type.
The overall impact experienced by regions will depend on other factors such as the number of herds present and the predominant type of farming, as well as the interplay between tick ecology, cattle immunity and movement patterns of cattle. 相似文献
AIMS: To use quantitative PCR assays to detect Theileria orientalis Ikeda type in cattle presumed infected with T. orientalis, to examine the relationship between theilerial piroplasm count and haematocrit (HCT), and the relationship with quantification cycle threshold (Cq) values.
METHODS: Blood samples in EDTA (n=1,024), derived from herds affected by anaemia associated with T. orientalis infection (TABA) between April and October 2013, were submitted for testing using quantitative PCR (qPCR) assays for T. orientalis and Ikeda type. Nucleotide sequencing of the major piroplasm surface protein (MPSP) gene was performed on 16 samples to identify T. orientalis types. Blood smear and/or HCT results were supplied with most samples. For data analysis, the number of theilerial piroplasm per 1,000 erythrocytes counted was categorised as negative (0), low (1–9), moderate (10–100) or high (>100). HCT was categorised as severely anaemic (<0.15 L/L), mildly anaemic (0.15–0.24 L/L) or not anaemic (>0.24 L/L). Differences between categories in proportion of samples positive for Ikeda type or mean Cq value were examined using χ2 tests or analysis of variance, respectively.
RESULTS: Of 1,022 samples containing amplifiable DNA, 916 (90%) were positive for T. orientalis and 789 (77%) were positive for Ikeda type. Nucleotide sequencing of MPSP amplicons also identified the presence of Chitose and Buffeli types in 11 samples without Ikeda. Ikeda was detected in a greater proportion of severely anaemic (288/302; 95%) than mildly anaemic (227/252; 90%) cattle (p=0.02). In non-anaemic cattle, 344/406 (85%) were positive for T. orientalis and 247/406 (60%) were positive for Ikeda type. In samples from cattle that were piroplasm-positive, a greater proportion of anaemic (483/505, 96%) than non-anaemic (211/307; 69%) cattle were positive for Ikeda type (p<0.001). In piroplasm-negative cattle, 20/37 (54%) anaemic and 25/78 (32%) non-anaemic cattle were Ikeda-positive (p<0.05). The distributions of Cq values differed between piroplasm count and HCT categories (p<0.001). Mean Cq differed between high and negative, and low piroplasm categories (p<0.001), but not between high and moderate categories (p=0.81), and differed between severely anaemic and mildly anaemic (p<0.001), and non-anaemic categories (p<0.001).
CONCLUSIONS: The Ikeda type was found in a high proportion of cattle during outbreaks of TABA in New Zealand. Analysis of Cq values suggested a relationship of Ikeda parasitaemia with severity of anaemia, but further investigation is required to better understand the role of parasitaemia in the pathogenesis of TABA. 相似文献
AIMS: To describe the epidemiology of the epidemic of bovine anaemia associated with Theileria orientalis infection (TABA) in New Zealand between 30 August 2012 and 4 March 2014.METHODS: Blood samples and associated data were obtained from cases of TABA. The case definition for TABA was met when piroplasms were present on blood smears and the haematocrit was ≤0.24?L/L. Samples were analysed using quantitative PCR (qPCR) assays for the detection of T. orientalis Ikeda type. Only cases that were positive in the qPCR assays were included in the analysis. A case herd was defined as a herd that had ≥1 animal positive for T. orientalis Ikeda.Movement records for farms were accessed through the national animal identification and tracing scheme. The OR for cattle movements onto a case farm compared to a non-case farm was estimated using a generalised estimating equation model and the geodesic distance for movements onto case and non-case farms compared using Student's t-test. The kernel-smoothed risk of disease at the farm level was calculated using an extraction map and the clustering of diseased farms in time and space was measured using the spatial temporal inhomogeneous pair correlation function.RESULTS: In the first 18 months there were 496 case herds; 392 (79%) were dairy and 104 (21%) beef herds. Of 882 individual cases, 820 (93.0%) were positive for T. orientalis Ikeda in the qPCR assays. Case herds were initially clustered in the Northland, then the Waikato regions. The OR for a case farm compared to a non-case farm having ≥1 inward cattle movements was 2.03 (95% CI=1.52–2.71) and the distance moved was 26 (95% CI=20.8–31.3) km greater for case farms. The risk of disease was highest in a north, north-eastern to south, south-western belt across the Waikato region. The spatial-temporal analysis showed significant clustering of infected herds within 20–30 days and up to 15?km distant from a case farm.CONCLUSIONS: Theileria orientalis Ikeda type is likely to have been introduced into regions populated with naïve cattle by the movement of parasitaemic cattle from affected areas. Local spread through dispersed ticks then probably became more important for disease transmission between herds once the disease established in a new area.CLINICAL RELEVANCE: Dairy and beef farming in the North Island of New Zealand will be significantly changed in the coming years by the incursion of this new disease. 相似文献