HEMOGRAM:

The CBC findings are not overly dramatic.

At first glance, and the relative proportion of lymphocytes to segmented neutrophils stands out as a finding to give some consideration to. In many species, inflammation can manifest as an inversion of the proportion of lymphocytes to neutrophils rather than a leukocytosis (or change in the total number of WBC).

Two separate publications have reported the opposite finding (predominance of segmented neutrophils) in sloth bears from India (Journal of Wildlife Diseases 44:509 and Vet Med Int 2014:341047) whereas a recent publication reported that brown-throated sloths in Brazil were lymphocyte rich (Vet World 2020 Sep 13:2033).

The information we received did not specify what breed of sloth Molasses is. Even if it did, we might not have much help in interpreting these data. We always have to consider the methods of animal capture and restraint when evaluating data in wildlife species. A physiological (epinephrine-mediated) lymphocytosis could easily make a species or a breed appear lymphocyte rich. We don't want to miss a neutropenia or a lymphotosis.

What can we do to help....we can look to morphology for some clues. If we look at her lymphocytes, they are small with condensed chromatin. One example is demarcated by the blue triangle. My default would be to think this is a normal finding. Her neutrophils (indicated by the black arrows) are segmented with no evidence of toxic change. Typically, a neutropenia that is indicative of inflammation will have morphological clues. The cell in the pink circle is an eosinophil.

Sloth WBCs_cropped_annotated-1.jpg

Lets look at few more lymphocytes:

Sloth WBCs 2 cropped.jpg

The cell inside the blue triangle is about the same size as the neutrophils in the image, and approximately 2 RBC could fit inside that nucleus. Thus, we can call it small in size. The cytoplasm is very lightly basophilic. This is a pretty protypical lymphocytes. The lymphocyte in the pink circle is also small in size, but the cytoplasm is deeply basophilic. This is a nice example of a reactive lymphocyte. This heterogeneity across the lymphoid population is another tick towards reactive. Of course, there are species who normally display moderate anisocytosis (variation in cell size) across their lymphoid population (cows, pigs, and goats).

SERUM BIOCHEMSITRY:

Her serum electrolytes seem low for a mammal, and alkaline phosphatase (ALP) activity also catches my eye.

When I go to the literature, most sources report that sloths have a higher ALP that our common domestic mammals. What gets interesting is the reported differences in urban versus rural sloth populations. Wait what? Why? Most sources attribute the difference to diet, but in an indirect manner. The diet of a sloth can markedly impact the digestion time (which is quite slow to begin with).

Take home point, if only ALP is high it is probably reasonable to interpret the finding as clinically insignificant in the sloth.

So what was wrong with Mollasses?

Nothing. She was just getting her annual physical exam. Her case is a good example of how to work through a data set from a very special species.