Procedure—Birds were anesthetized, and ventrodorsal
radiographic projections were obtained. Maximum
width of the cardiac silhouette, width of the thorax at
the level of the maximum width of the cardiac silhouette,
and width of the coracoid were measured on the
radiographs. Sternum length was directly measured
on individual birds. Results of physical examination,
electrocardiography, and echocardiography were normal
in all birds.
Results—Mean cardiac silhouette width-to-sternum
length ratio was 38%, mean cardiac silhouette widthto-
thorax width ratio was 55%, and mean cardiac silhouette
width-to-coracoid width ratio was 600%.
Width of the cardiac silhouette was strongly correlated
with length of the sternum, width of the coracoid,
and width of the thorax. No significant differences
between species were detected.
Conclusions and Clinical Relevance—Results suggest
that in healthy adult medium-sized psittacines,
the cardiac silhouette on a ventrodorsal radiographic
projection should be 35 to 41% of the length of the
sternum, 51 to 61% of the width of the thorax, and
545 to 672% of the width of the coracoid. (J Am Vet
Med Assoc 2002;221:76–79)
Objective—To evaluate the use of computed tomography (CT) for detection of pneumonia in snakes.
Animals—8 clinically normal Indian pythons (Python molurus) and 5 pythons with evidence of respiratory tract disease.
Procedures—Preliminary examinations (clinical examination, conventional radiography, and microbiologic examination of a transtracheal wash sample) were performed. The lungs of each snake were then examined by use of CT performed in accordance with a standardized protocol. Structures of the lungs were assessed, and thickness and attenuation of the parenchyma were determined.
Results—It was possible to assess lung parenchyma in all pythons. Mean ± SD attenuation in healthy pythons was −744.4 ± 47.1 Hounsfield units. Significant differences were not evident between the right and left lungs or among measurement areas within a lung. In all Indian pythons with clinical signs of dyspnea and microbiologic detection of pathogens, hyperattenuation of the alveolar tissue was evident.
Conclusions and Clinical Relevance—Analysis of the results revealed the benefit of CT for use in the diagnosis of pneumonia in snakes. A standardized protocol and reference values were established as a basis for CT assessment of the lungs of snakes.
OBJECTIVE To measure immunologic responses of snakes after experimentally induced infection with ferlaviruses.
ANIMALS 42 adult corn snakes (Pantherophis guttatus) of both sexes.
PROCEDURES Snakes were inoculated intratracheally with genogroup A (n = 12), B (12), or C (12) ferlavirus (infected groups) or cell-culture supernatant (6; control group) on day 0. Three snakes from each infected group were euthanized on days 4, 16, 28, and 49, and 3 snakes from the control group were euthanized on day 49. Blood samples were collected from live snakes on days −6 (baseline), 4, 16, 28, and 49. Hematologic tests were performed and humoral responses assessed via hemagglutination-inhibition assays and ELISAs. Following euthanasia, gross pathological and histologic evaluations and virus detection were performed.
RESULTS Severity of clinical signs of and immunologic responses to ferlavirus infection differed among snake groups. Hematologic values, particularly WBC and monocyte counts, increased between days 4 and 16 after infection. A humoral response was identified between days 16 and 28. Serum IgM concentrations increased from baseline earlier than IgY concentrations, but the IgY relative increase was higher at the end of the study. The hemagglutination-inhibition assay revealed that the strongest reactions in all infected groups were against the strain with which they had been infected. Snakes infected with genogroup A ferlavirus had the strongest immune response, whereas those infected with genogroup B had the weakest responses.
CONCLUSIONS AND CLINICAL RELEVANCE Results of this experimental study suggested that the ferlavirus strain with the highest virulence induced the weakest immune response in snakes.