Looking for prognosticators in ovine anaplasmosis: discriminant analysis of clinical and haematological parameters in lambs belonging to differently susceptible breeds experimentally infected with Anaplasma ovis

Abstract

BackgroundA study was carried out to evaluate the response of different native sheep breeds to experimental infection with Anaplasma ovis, the most prevalent sheep tick-borne pathogen in Apulia (Southern Italy). Thirty-four lambs belonging to a Northern European breed (Suffolk) and two Southern Italian breeds (Comisana and Altamurana) were infected. Eleven clinical as well as haematological parameters were monitored at different temporal resolutions on the same subjects before and after the infection, resulting in a data set of 435 observations. The present work, aiming to further the research, presents the results of a multivariate analysis carried out to identify which parameters out of the eleven considered are the most reliable parameters to be considered as markers of the disease phenotype as well as prognosticators of practical clinical importance.ResultsData were analysed by discriminant analysis. Out of the eleven considered variables (red blood cells, packed cell volume, mean corpuscular volume, mean corpuscular haemoglobin, mean corpuscular haemoglobin content, haemoglobin concentration, white blood cells, neutrophils, leukocytes, platelets, rectal temperature), only seven were included in the step-wise model since significantly increasing the Mahlanobis distance between the two closest groups. Both discriminant functions resulted to be highly significant (P < 0.0001) and the percentage of variation accounted for by the first discriminant function was 63.6% of the variance in the grouping variable.ConclusionsTaken together, the observed results stress the marked differentiation among the three breeds in terms of physio-pathological phenotypes indicating packed cell volume and red blood cell count as the most informative parameters in the routine clinical practice for A. ovis infection in sheep.

Re-evaluation of the interrelationships among the behavioral tests in rats exposed to chronic unpredictable mild stress

“…To identify which indexes out of the nineteen considered (the body weight and sucrose preference in 6 weeks, total score of OFT, coat state score, proportion of time spent in the open arms in EPM, grooming latency of splash test, escape latency of MWM, proportion of immobility) are the most reliable as markers of the disease phenotype. In the stepwise approach adopted here, variables were entered sequentially[ 22 ].When all the variables in the model met the criterion to stay and none of the other variables met the criterion to enter, the stepwise selection process stopped [ 22 ]. The stability of the distinguishing function models was tested by cross validation.…”

Molecular Detection and Identification of Babesia spp., Theileria spp., and Anaplasma spp. in Sheep From Border Regions, Northwestern China

“…Two generally species of Babesia species (Babesia motasi and B. ovis) (2,3) and several species of Theileria (Theileria ovis, T. lestoquardi, T. sespecies, T. luwenshuni, and T. uilenbergi) of ovine babesiosis and theileriosis are distributed in Asia, Africa, Europe, and the Far East (4)(5)(6). Furthermore, ovine anaplasmosis is mainly caused by A. ovis and A. marginale (7,8). Clinical signs of babesiosis, theileriosis, and anaplasmosis in sheep and goats include anemia, fever, abortion, weight loss, reduce milk supply, jaundice, and even death, causing huge economic losses for sheep, and goat production (3,5,7).…”

Theileria sp. OT3 and other tick-borne pathogens in sheep and ticks in Italy: Molecular characterization and phylogeny

“…In this study, sheep dogs may have acted as reservoirs of this Ehrlichia species; however, this epidemiological aspect of E. ovina/canis and its pathogenic role in sheep needs to be investigated. The absence of clinical symptoms related to TBDs in sheep is not new (Savini et al, 1999;Giudice et al, 2011), and may be related to the resistance of autochthonous breeds, as recently demonstrated for A. ovis in Italy (Ciani et al, 2013).…”