| Autor: |
Giglioti, R., Oliveira, H.N., Santana, C.H., Ibelli, A.M.G., Néo, T.A., Bilhassi, T.B., Rabelo, M.D., Machado, R.Z., Brito, L.G., Oliveira, M.C.S. |
| Zdroj: |
Ticks and Tick-borne Diseases; July 2016, Vol. 7 Issue: 5 p657-662, 6p |
| Abstrakt: |
The levels of infection by Babesia bovisand Babesia bigeminawere estimated by absolute quantification through the quantitative PCR technique (qPCR). Fifty-one contemporaneous Angus cattle were evaluated on two occasions. The number of standard female Rhipicephalus microplusticks present on the left side of the body was counted and blood samples were drawn from the tail vein into tubes containing the anticoagulant EDTA. The blood samples were submitted to DNA extraction and used to quantify the number of copies (NC) of DNA from B. bovisand B. bigeminaby qPCR. The data on tick count and number of DNA copies were transformed for normalization and analyzed by a mixed model method. A multivariate model with repeated measures of the same animal, including the effects of collection, parasite species and their interaction, was used. The repeatability values were obtained from the matrix of (co)variances and were expressed for each species. The correlations between the counts of different species on the same animal, in the same collection or different collections, were also estimated. The results showed the qPCR could distinguish the two between infection by the two Babesiaspecies. Infection levels by B. bovisand B. bigeminawere detected in 100% and 98% of the animals, respectively. Significant differences were found (P<0.05) between the NC of the two Babesiaspecies, B. bovis1.49±0.07 vs. B. bigemina0.82±0.06. Low repeatabilities were found for the counts of R. microplusand NC of B. bovisand B. bigemina: 0.05, 0.10 and 0.02, respectively. The correlations between R. micropluscount and NC of B. bovisand B. bigeminawere both very near zero. However, an association was observed between the NC of the two species, with a correlation coefficient of 0.30 for measures from the same collection. The absence of associations between the quantity of DNA from B. bovisand B. bigeminaand the tick counts suggests that the variation of parasitemia by the hemoparasites did not depend on the tick infestation levels at the moment of each collection. The repeatability values estimated indicate that under the study conditions, the variations in the tick infestation levels and of parasitemia by B. bovisand B. bigeminadepend more on factors related to each collection than on intrinsic factors of the animal. |
| Databáze: |
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