Date of Award
Master of Science
Comparative and Experimental Medicine
Deanna M. Schaefer
Bente Flatland, John J. Schaefer, Ricardo Videla
Background: Accurate measurement of RBCs (red blood cells) by automated hematology analyzers such as the ADVIA 120/2120 requires isovolumetric cell sphering; however, camelid RBC membranes are resistant to shape change. There are no published reports of method validation for hematologic analysis of camelid blood. Mycoplasma haemolamae and gastrointestinal nematodes can cause anemia in camelids. Parasite control programs aim to suppress parasite loads without promoting resistance, but there are few evidence-based guidelines for acceptable parasite loads in camelids.Objectives: 1) Demonstrate whether camelid RBCs sphere in the ADVIA sphering reagent, and determine the optimal ADVIA setting for CBC (complete blood count) analysis, 2) Compare M. haemolamae PCR status with RBC values, and 3) Determine the fecal egg count (FEC) threshold above which RBC values are consistently below the median of the reference interval.Methods: Camelid and canine blood were each added to ADVIA sphering reagent or saline, and evaluated by light microscopy for erythrocyte sphering. Camelid blood was analyzed on an ADVIA 120 hematology analyzer using one of three species settings, and values compared to manual measurements, including packed cell volume (PCV), Z2 Coulter counter RBC count, and calculations of other RBC values. Mycoplasma haemolamae was detected by real-time PCR. The number of trichostrongyle eggs per gram (epg) of feces was determined using the Modified McMaster’s test.Results and Conclusions: Camelid erythrocytes do not sphere when mixed with ADVIA sphering reagent. The ADVIA 120 equine setting provides the closest approximations to Z2 counter RBC count estimates, but ADVIA results for most other RBC values appear inaccurate. PCV, hemoglobin, and RBC count are not significantly different between M. haemolamae positive and negative animals, but are significantly lower in animals with FEC> [greater than] 600epg. For all animals with FEC>600epg, RBC values are below the medians of the reference intervals. Positive M. haemolamae PCR is not associated with lower RBC values in healthy camelids, consistent with previous reports that most infections are subclinical. Maintaining FEC below 600 epg is recommended in camelids.
Viesselmann, Lisa C., "Validation Of Complete Blood Count Methodology, And Determination Of The Relationship Between Endoparasite Load And Erythrocyte Values In New World Camelids. " Master's Thesis, University of Tennessee, 2018.