Whip-like heterophil projections in consecutive blood films from an injured gopher tortoise (Gopherus polyphemus) with systemic inflammation

Diagnostic Clinical Pathology of Tortoises

Clinicopathologic evaluation of terrestrial tortoises is useful for health assessment and monitoring. There are specific considerations when evaluating data from these species, including sex, age, time of year/season, reproductive status, diet, captive versus wild, geographic location, methodology, and anticoagulant. The authors describe sample collection, hematology, biochemistry, and urinalysis features of terrestrial tortoises and discuss clinical relevance.

Clinical Pathology of Box Turtles (Terrapene spp.)

Box turtles are commonly presented for veterinary care and clinicopathologic testing is a vital component of case management. This article summarizes recent literature about box turtle clinical pathology and identifies directions for future research.

Island of misfit tortoises: waif gopher tortoise health assessment following translocation

Translocation, the intentional movement of animals from one location to another, is a common management practice for the gopher tortoise (Gopherus polyphemus). Although the inadvertent spread of pathogens is a concern with any translocation effort, waif tortoises-individuals that have been collected illegally, injured and rehabilitated or have unknown origins-are generally excluded from translocation efforts due to heightened concerns of introducing pathogens and subsequent disease to naïve populations. However, repurposing these long-lived animals for species recovery is desirable when feasible, and introducing waif tortoises may bolster small populations facing extirpation. The objective of this study was to assess the health of waif tortoises experimentally released at an isolated preserve in Aiken County, SC, USA. Our assessments included visual examination, screening for 14 pathogens using conventional or quantitative polymerase chain reaction (qPCR) and haematological evaluation. Of the 143 individuals assessed in 2017 and 2018, most individuals (76%; n = 109 of 143) had no overt clinical evidence of disease and, when observed, clinical findings were mild. In both years, we detected two known tortoise pathogens, Mycoplasma agassizii and Mycoplasma testudineum, at a prevalence of 10.2-13.9% and 0.0-0.8%, respectively. Additionally, we found emydid Mycoplasma, a bacterium commonly found in box turtles (Terrapene spp.), in a single tortoise that showed no clinical evidence of infection. The presence of nasal discharge was an important, but imperfect, predictor of Mycoplasma spp. infection in translocated tortoises. Hemogram data were comparable with wild populations. Our study is the first comprehensive effort to assess pathogen prevalence and hemogram data of waif gopher tortoises following translocation. Although caution is warranted and pathogen screening necessary, waif tortoises may be an important resource for establishing or augmenting isolated populations when potential health risks can be managed.

Left shift and toxic change in heterophils and neutrophils of non-mammalian vertebrates: A comparative review, image atlas, and practical considerations

Heterophils and neutrophils are important first cellular responders to inflammatory conditions. In addition to quantitative shifts in the numbers of these cells in blood, inflammatory disease states often have accompanying increases in immature precursor stages (left shift) and/or evidence of toxic change on blood film evaluation. Recognition of left shift and toxic change morphologies is a salient diagnostic finding with clinical relevance across species. The objectives of this report are to (a) review heterophil and neutrophil function and structure across the vertebrate animal kingdom, (b) compare morphologic features of left shift and toxic change in heterophils and neutrophils of non-mammalian vertebrates (NMV) to mammals, (c) provide an image guide demonstrating the breadth of morphologic diversity of heterophil and neutrophil lineages in health and disease across taxa, and (d) discuss practical considerations for clinical pathologists and other professionals involved in the recognition and interpretation of observations in the inflammatory leukogram of NMV.

Presumptive heterophil extracellular traps recognized cytologically in nine reptile patients with inflammatory conditions

Background

Neutrophil extracellular traps (NETs) represent a novel cellular mechanism of antimicrobial defense activity. Intravascular neutrophils produce extracellular web-like structures composed of chromatin, histones, and cytoplasmic granule proteins to attack and kill microbes. They may impact both pathogen and host; NETs correlate strongly with disseminated intravascular coagulation and mortality in critically ill humans. The mechanism was first discovered in human neutrophils in 2004. Presumptive heterophil extracellular traps (HETs) in a non-avian reptile species were first described in blood films of a gopher tortoise with systemic inflammation.

Objective

While prior reports are limited to blood film review and in vitro studies, this descriptive case series highlights the cytological identification of presumptive HETs in nine reptile patients.

Methods

Subjects included six gopher tortoises, one blood python (Python curtus), one Burmese python (P. bivittatus), and one desert king snake (Lampropeltis getula splendida). All six gopher tortoises (Gopherus polyphemus) had upper respiratory disease with bacterial etiology (including Helicobacter sp. and/or Mycoplasma sp.), and snakes had upper respiratory tract infection confirmed with serpentovirus (n = 2) or bacterial dermatitis (n = 1).

Results

Cytology samples with identified HETs included tissue imprints (n = 4), nasal discharge (n = 3), an oral swab (n = 1), and a fine needle aspirate of a skin lesion (n = 1). The identification of specific bacterial (n = 6) and/or viral pathogens (n = 2) was notable.

Clinical relevance

To the authors’ knowledge, this is the first report of presumptive HETs recognized in reptile cytology specimens, suggesting an active cellular process in vivo in response to systemic inflammation in non-avian reptiles, and contributing to further understanding of extracellular traps in these species.

Comprehensive health assessment and blood analyte reference intervals of gopher tortoises (Gopherus polyphemus) in southeastern FL, USA

The gopher tortoise (Gopherus polyphemus), a keystone species, is declining throughout its geographic range. Lack of knowledge with respect to the potential infectious diseases present within wild populations creates a dilemma for wildlife biologists, conservationists and public policy makers. The objective of this study was to conduct a health assessment of two previously unstudied gopher tortoise aggregations located at two sites in southeastern FL. Samples were collected from 91 tortoises (48 adults, 35 juveniles, 8 hatchlings) captured at Florida Atlantic University's Harbor Branch Oceanographic Institute, in Fort Pierce, FL, USA in 2019, and Loggerhead Park in Juno Beach, FL, USA, during 2018-2019. Samples of blood, nasal swabs and oral/cloacal swabs were analyzed for hematology, plasma protein electrophoretic profiles and infectious disease testing including Mycoplasma spp. serology and polymerase chain reaction (PCR) assays for Ranavirus, Herpesvirus and Anaplasma spp. Hematological and plasma protein electrophoresis reference intervals are presented for adult and juvenile tortoises from both sites combined. Clinical signs consistent with upper respiratory tract disease (URTD) were observed in 18/91 (20%) tortoises, and antibodies to Mycoplasma agassizii were detected in 33/77 (42.9%) tortoises. Adult tortoises were significantly more likely than juveniles to have URTD clinical signs, and statistically significant, positive relationships were observed between the presence of antibodies to Mycoplasma spp. and carapace length, packed cell volume and plasma globulin concentrations. Anaplasma spp. inclusions were observed in 8/82 (10%) tortoises, but PCR detected Anaplasma sp. in 21/83 (25%) tortoises. Herpesvirus and Ranavirus were not detected in any blood or swab samples. This work contributes important baseline information on the health of gopher tortoises toward the southern end of the species' range.

What Is the Evolutionary Fingerprint in Neutrophil Granulocytes?

Over the years of evolution, thousands of different animal species have evolved. All these species require an immune system to defend themselves against invading pathogens. Nevertheless, the immune systems of different species are obviously counteracting against the same pathogen with different efficiency. Therefore, the question arises if the process that was leading to the clades of vertebrates in the animal kingdom-namely mammals, birds, amphibians, reptiles, and fish-was also leading to different functions of immune cells. One cell type of the innate immune system that is transmigrating as first line of defense in infected tissue and counteracts against pathogens is the neutrophil granulocyte. During the host-pathogen interaction they can undergo phagocytosis, apoptosis, degranulation, and form neutrophil extracellular traps (NETs). In this review, we summarize a wide spectrum of information about neutrophils in humans and animals, with a focus on vertebrates. Special attention is kept on the development, morphology, composition, and functions of these cells, but also on dysfunctions and options for cell culture or storage.

Light Microscopic and Ultrastructural Characteristics of Heterophil Toxicity and Left-shifting in Green Sea Turtles (Chelonia mydas) from Taiwan

Heterophil toxic change (TC) and left-shifting (LS) are widely used as indicators of accelerated granulopoiesis. However, the ultrastructure of heterophil TC and LS in sea turtles remain poorly understood. This study aimed to describe the ultrastructural characteristics of sea turtle TC and LS heterophils, compare the staining quality of accessible staining methods, and provide a better understanding of the clinical applications and limitations of heterophil TC and LS examinations. Blood samples were collected from 21 rescued sea turtles from January 2017 to September 2018. Morphologic (n = 22) and ultrastructural (n = 15) examination of TC and LS heterophils were performed, and the qualities of three staining methods (Wright-Giemsa stain, Diff-Quik stain and Liu's stain) were analyzed to diagnose TC and LS heterophils. In addition, the diagnostic values of TC and LS heterophils were examined. Diff-Quik stain was significantly inferior in the assessment of heterophil TC and/or LS comparing to the Wright-Giemsa stain and Liu's stain (Mann-Whitney test, P < 0.001). Microscopic examinations of heterophil TC and/or LS were comparable to transmission electron microscopy examinations (Cohen's kappa coefficient, κ = 1). The correlation between the presence of heterophil TC and/or LS and clinical inflammatory state was weak (Spearman's rank correlation coefficient, rs = 0.171, p = 0.445). In conclusion, this is the first study to describe the ultrastructural characteristics of reptile TC and LS heterophils. Wright-Giemsa stain and Liu's stain were suitable staining methods for the microscopic observations of TC and LS heterophil in sea turtles. Given the poor correlation between TC and/or LS and clinical findings, TC and LS are not a suitable diagnostic indicator of green sea turtles' inflammation status.

Clinical Manifestation and Molecular Characterization of a Novel Member of the Nannizziopsiaceae in a Pulmonary Granuloma From a Galapagos Tortoise (Chelonoidis nigra)

Nannizziopsiaceae is a family of fungal organisms within the order Onygenales containing two genera of important reptile pathogens, Nannizziopsis and Paranannizziopsis. A captive Galapagos tortoise (Chelonoidis nigra) from Boca Raton, Florida, United States, was presented for a clinical history of chronic progressive lethargy and inappetence. At initial presentation, the tortoise had a moderate non-regenerative anemia, leukocytosis, whip-like heterophil projections, erythrocyte fragmentation, and fibrin strands, with the latter two raising concern for disseminated intravascular coagulation. A single large encapsulated pulmonary granuloma was identified through imaging, including plain film radiography and bronchoscopy. Direct intralesional samples were obtained from transcarapacial celioscopy for fungal culture, cytology, histopathology, and polymerase chain reaction. Amplification and sequencing of the ITS2 region of the rRNA genes with Bayesian and maximum likelihood analyses placed the fungus in the family Nannizziopsiaceae within the order Onygenales, representing a novel fungal species.

Extracellular Traps: An Ancient Weapon of Multiple Kingdoms

The discovery, in 2004, of extracellular traps released by neutrophils has extended our understanding of the mode of action of various innate immune cells. This fascinating discovery demonstrated the extracellular trapping and killing of various pathogens by neutrophils. During the last decade, evidence has accumulated showing that extracellular traps play a crucial role in the defence mechanisms of various cell types present in vertebrates, invertebrates, and plants. The aim of this review is to summarise the relevant literature on the evolutionary history of extracellular traps used as a weapon in various kingdoms of life.