The histology and growth rate of Nile crocodile (Crocodylus niloticus) claws.

The histology and growth of reptilian and crocodilian claws (ungues) have been extensively studied; however, Nile crocodile (Crocodylus niloticus) claws have not received adequate attention. Furthermore, age estimations for reptilian claws remain unexplored, despite Nile crocodile claws being used in long-term dietary reconstruction studies, assuming certain age-related patterns. In this study, we investigate the histology and growth patterns of Nile crocodile claws, aiming to infer axes for sampling cornified material for radiocarbon dating and establish age estimations for crocodilian claws. Our findings reveal that Nile crocodile claws exhibit growth patterns similar to other reptilians, presenting as modified scutes/scales with an age profile along the sagittal plane. This profile starts at the basal germ matrix and progressively expands in thickness and age dorsoventrally towards the apex or "tip." Consequently, the oldest corneous material is concentrated at the most dorsal point of the claw's apex. To validate previous dietary reconstruction assumptions, we conducted radiocarbon dating on this region of the claw, which supported the idea that retained corneous material in the claws is typically relatively young (5-10 years old) due to abrasion. Our study contributes insights into the histology and growth dynamics of Nile crocodile claws, shedding light on their use in dietary reconstruction studies and emphasizing the significance of considering age-related assumptions in such investigations.

Cross-species oncogenomics offers insight into human muscle-invasive bladder cancer.

BACKGROUND: In humans, muscle-invasive bladder cancer (MIBC) is highly aggressive and associated with a poor prognosis. With a high mutation load and large number of altered genes, strategies to delineate key driver events are necessary. Dogs and cats develop urothelial carcinoma (UC) with histological and clinical similarities to human MIBC. Cattle that graze on bracken fern also develop UC, associated with exposure to the carcinogen ptaquiloside. These species may represent relevant animal models of spontaneous and carcinogen-induced UC that can provide insight into human MIBC. RESULTS: Whole-exome sequencing of domestic canine (n = 87) and feline (n = 23) UC, and comparative analysis with human MIBC reveals a lower mutation rate in animal cases and the absence of APOBEC mutational signatures. A convergence of driver genes (ARID1A, KDM6A, TP53, FAT1, and NRAS) is discovered, along with common focally amplified and deleted genes involved in regulation of the cell cycle and chromatin remodelling. We identify mismatch repair deficiency in a subset of canine and feline UCs with biallelic inactivation of MSH2. Bovine UC (n = 8) is distinctly different; we identify novel mutational signatures which are recapitulated in vitro in human urinary bladder UC cells treated with bracken fern extracts or purified ptaquiloside. CONCLUSION: Canine and feline urinary bladder UC represent relevant models of MIBC in humans, and cross-species analysis can identify evolutionarily conserved driver genes. We characterize mutational signatures in bovine UC associated with bracken fern and ptaquiloside exposure, a human-linked cancer exposure. Our work demonstrates the relevance of cross-species comparative analysis in understanding both human and animal UC.

COOLING BY DOUSING WITH COLD WATER DOES NOT ALTER THE PATHOPHYSIOLOGICAL BIOCHEMICAL CHANGES INDUCED BY CAPTURE IN BLESBOK (DAMALISCUS PYGARGUS PHILLIPSI).

Wild animals are commonly captured for conservation, research, and wildlife management purposes. However, capture is associated with a high risk of morbidity or mortality. Capture-induced hyperthermia is a commonly encountered complication believed to contribute significantly to morbidity and mortality. Active cooling of hyperthermic animals by dousing with water is believed to treat capture-induced pathophysiological effects, but remains untested. This study aimed to determine the pathophysiological effects of capture, and whether cooling by dousing with cold water effectively reduces these effects in blesbok (Damaliscus pygargus phillipsi). Thirty-eight blesbok were randomly allocated into three groups: a control group that was not chased (Ct, n=12), chased not cooled (CNC, n=14), and chased plus cooled group (C+C, n=12). The CNC and C+C groups were chased for 15 min prior to chemical immobilization on day 0. Animals in the C+C group were cooled with 10 L of cold water (4 C) for 10 min during immobilization. All animals were immobilized on days 0, 3, 16, and 30. During each immobilization, rectal and muscle temperatures were recorded, and arterial and venous blood samples collected. Blesbok in the CNC and C+C groups presented with capture-induced pathophysiological changes characterized by hyperthermia, hyperlactatemia, increased markers of liver, skeletal, and cardiac muscle damage, hypoxemia, and hypocapnia. Cooling effectively returned body temperatures to normothermic levels, but neither the magnitude nor the duration of the pathophysiological changes differed between the CNC and C+C groups. Therefore, at least in blesbok, capture-induced hyperthermia appears not to be the primary cause of the pathophysiological changes, but is more likely a clinical sign of the hypermetabolism resulting from capture-induced physical and psychological stress. Although cooling is still recommended to prevent the compounding cytotoxic effects of persistent hyperthermia, it is unlikely to prevent stress- and hypoxia-induced damage caused by the capture procedure.

Fiber type and metabolic characteristics of skeletal muscle in 16 breeds of domestic dogs.

The domestic dog (Canis lupus familiaris) species comprises hundreds of breeds, each differing in physical characteristics, behavior, strength, and running capability. Very little is known about the skeletal muscle composition and metabolism between the different breeds, which may explain disease susceptibility. Muscle samples from the triceps brachii (TB) and vastus lateralis (VL) were collected post mortem from 35 adult dogs, encompassing 16 breeds of varying ages and sex. Samples were analyzed for fiber type composition, fiber size, oxidative, and glycolytic metabolic capacity (citrate synthase [CS], 3-hydroxyacetyl-coA dehydrogenase [3HAD], creatine kinase [CK], and lactate dehydrogenase [LDH] enzyme activities). There was no significant difference between the TB and VL in any of the measurements. However, there were large intra species variation, with some variables confirming the physical attributes of a specific breed. Collectively, type IIA was the predominant fiber type followed by type I and type IIX. The cross-sectional areas (CSA) of the fibers were all smaller when compared to humans and similar to other wild animals. There was no difference in the CSA between the fiber types and muscle groups. Metabolically, the muscle of the dog displayed high oxidative capacity with high activities for CS and 3HAD. Lower CK and higher LDH activities than humans indicate a lower and higher flux through the high energy phosphate and glycolytic pathways, respectively. The high variability found across the different breeds may be attributed to genetics, function or lifestyle which have largely been driven through human intervention. This data may provide a foundation for future research into the role of these parameters in disease susceptibility, such as insulin resistance and diabetes, across breeds.

Theileriosis in naturally infected roan antelope (Hippotragus equinus).

Cases of Theileria-associated mortality are rarely reported in African wild artiodactyls. Descriptions of lesions are limited, particularly in endangered hippotraginids. Here, we analyzed retrospectively the gross and histologic findings in 55 roan antelope (Hippotragus equinus) with fatal natural theileriosis. The most frequently recorded gross findings in 40 cases were widespread petechiae and ecchymoses (72.5%), probable anemia (67.5%), icterus (60%), splenomegaly (60%), hepatomegaly (52.5%), and pulmonary edema (50%). Histologic lesions in 34 cases were characterized by multi-organ infiltrates of parasitized and nonparasitized mononuclear leukocytes (MLs), and fewer multinucleate giant cells (MNGCs). Liver, lung, kidney, adrenal gland, and heart were most consistently infiltrated, followed by spleen and lymph nodes. Leukocytes were phenotyped in lung, liver, kidney, and heart specimens from 16 cases, using immunohistochemistry to detect CD20, CD3, myeloid/histiocyte antigen (MAC387), IBA-1, and CD204 surface receptors. A roan polyclonal anti-Theileria sp. (sable) antibody was applied to the same tissues to identify intraleukocytic parasite antigens. Similar proportions of intravascular and extravascular IBA-1-, CD204-, and MAC387-reactive putative monocyte-macrophages and fewer CD3-positive putative T-lymphocytes were identified in all organs, especially the lungs in infected roan. CD20-positive putative B-lymphocytes were significantly scarcer than in uninfected controls. Intraleukocytic Theileria parasites labeled consistently in affected tissues. Some parasitized and nonparasitized MLs and the MNGCs failed to label with selected leukocyte markers. Fatal theileriosis in roans may largely be the result of multi-organ monocyte-macrophage activation with associated tissue injury and overwhelming systemic inflammation. The identity of the parasitized leukocytes and characteristics of the lymphohistiocytic response require further clarification in roans.

Corrigendum: Hepatogenous photosensitisation in cows grazing turnips (Brassica rapa) in South Africa.

No abstract available.

Pathological findings in African buffaloes (Syncerus caffer) in South Africa.

The African buffalo (Syncerus caffer) is an iconic species of South African megafauna. As the farmed buffalo population expands, the potential impacts on population health and disease transmission warrant investigation. A retrospective study of skin biopsy and necropsy samples from 429 animals was performed to assess the spectrum of conditions seen in buffaloes in South Africa. Determination of the cause of death (or euthanasia) could not be made in 33.1% (136/411) of the necropsy cases submitted due to autolysis or the absence of significant lesions in the samples submitted. Infectious and parasitic diseases accounted for 53.5% (147/275) of adult fatal cases and non-infectious conditions accounted for 34.9% (96/275). Abortions and neonatal deaths made up 11.6% (32/275) of necropsy cases. Rift Valley fever, bovine viral diarrhoea, malignant catarrhal fever, tuberculosis, bacterial pneumonia, anaesthetic deaths, cachexia and hepatotoxic lesions were the most common causes of death. The range of infectious, parasitic and non-infectious diseases to which African buffaloes were susceptible was largely similar to diseases in domestic cattle which supports concerns regarding disease transmission between the two species. The similarity between diseases experienced in both species will assist wildlife veterinarians in the diagnosis and treatment of diseases in captive African buffaloes. The present study likely does not represent accurate disease prevalence data within the source population of buffaloes, and diseases such as anthrax, brucellosis and foot and mouth disease are under-represented in this study. Hepatic ductal plate abnormalities and haemorrhagic septicaemia have not, to our knowledge, been previously reported in African buffaloes.

Hepatogenous photosensitisation in cows grazing turnips (Brassica rapa) in South Africa.

Holstein cows on a farm in the Humansdorp district, Eastern Cape province, South Africa, developed reddened, painful teat skin 3 days after grazing a mixed forage crop dominated by bulb turnip (Brassica rapa, Barkant cultivar). The crop was grazed 45 days after planting and 10% of the herd developed symptoms. More characteristic non-pigmented skin lesions started manifesting 1-2 days after the appearance of the teat lesions. Affected cows had elevated serum activities of gamma-glutamyl transferase, glutamate dehydrogenase and aspartate aminotransferase. These blood chemistry findings confirmed a secondary (hepatogenous) photosensitivity. As a result of the severity of the teat and skin lesions, seven cows were slaughtered and tissue samples from five of them were collected for histopathological examination. Liver lesions in cows that were culled 3 or more weeks after the onset of the outbreak showed oedematous concentric fibrosis around medium-sized bile ducts and inflammatory infiltrates in portal tracts. Characteristic lesions associated with other known hepatobiliary toxicities were not found. No new cases were reported 5 days after the cattle were removed from the turnips. The sudden introduction of the cows, without any period of transitioning or adaptation to grazing turnips, as well as the short latent period, clinical signs of photosensitisation, blood chemistry and histopathology, confirmed a diagnosis of Brassica-associated liver disease, a condition seen in New Zealand but not previously described in South Africa. Brassica forage crops are potentially toxic under certain conditions and farmers must be aware of these risks.

Clinical and hematologic features of experimental theileriosis in roan calves (Hippotragus equinus).

Theileria sp. (sable) infection commonly causes significant calf mortality in endangered roan antelopes (Hippotragus equinus). Schizont-induced leukocyte transformation and systemic immune dysregulation with associated cytopenias characterizes theileriosis in livestock. Data on related hematologic alterations are scarce in roan antelopes. The objective of this study was to investigate temporal changes in selected clinical parameters and hematologic measurands in experimentally infected (EI) roan calves. Six of eight calves developed theileriosis after inoculation with a Theileria sp. (sable)-infected tick stabilate. Consecutive measures of rectal temperature, lymph node size, white blood cell count (WBC), packed cell volume (PCV), hemoglobin concentration, differential leukocyte counts, leukocyte and erythrocyte morphology and percentage parasitemia were recorded. Data were compared with 15 age-matched PCR-negative control calves and nine older immune animals that had recovered from natural infection. Two non-pyrexic EI calves recovered uneventfully. Six pyrexic calves were treated, four of which died. Time to pyrexia and/or observation of schizonts and piroplasms was approximately two weeks. Total WBCs were unchanged post-infection (PI); neutrophils and typical monocytes decreased whereas typical lymphocytes (Ls) and atypical mononuclear leukocytes (AMLs), which were grouped together, increased. Parasitized and non-parasitized lymphocyte and AML (L/AML) size increased significantly PI. Piroplasms occurred intermittently at low frequencies («1 % of erythrocytes) after infection. Fatally infected calves were dehydrated, anemic, and icteric with hemorrhages and multi-organ infiltration by AMLs. The PCV and hemoglobin concentration increased PI, and platelet clumps were consistently observed. Experimental acute theileriosis in roan antelopes follows a similar pattern of disease progression to that in domestic livestock. Parasitized and non-parasitized AMLs are pivotal to the pathogenesis and require phenotypic characterization if we are to further our understanding of disease progression and severity in roan antelopes.

Investigation of Brucella melitensis in Sable Antelope (Hippotragus niger) in South Africa.

In this study, Brucella melitensis infection in sable antelope (Hippotragus niger) was investigated on two wildlife ranches in South Africa over a 12-year period in order to determine the origin of the outbreaks and the role of livestock in maintaining the disease. Retrospective data were obtained from farm records and interviews as well as samples tested from different disease scenarios and clinical settings. On one ranch, 10 of 74 sable tested seropositive for B. melitensis in 2004 but were certified clear of infection after no further brucellosis cases were detected following repeated serological tests and culling over a five-year period. Recrudescence occurred in 2013 (7 of 187 brucellosis positives) and in 2014 (one positive), with persistent, latent infection being the most reasonable explanation. In a second case study, linked to the first one through a common vendor, 15 of 80 sable tested positive in 2016, some five years after the acquisition of the animals from a putative source. Brucella melitensis biovar 1 and/or 3 were isolated from each outbreak on both ranches. Both outbreaks resulted in substantial losses for the owners, arising from testing and culling and significant resource expenditure by the state. The study identified the diagnostic challenges for identifying and resolving disease outbreaks in wildlife, the persistence of B. melitensis in sable, the risks associated with animal movements, and the need for a wildlife-sensitive disease control scheme. Although the actual source of infection could not be identified, the investigation points away from local livestock as a source of ongoing infection while the persistent infection is consistent with the disease circulating within small, ranched populations and being spread through the keeping and trading of high-value animals. The implications of the study findings to disease control in wildlife are discussed.

A review of pathological findings in impalas (Aepyceros melampus) in South Africa.

Impalas (Aepyceros melampus) are common African antelope. A retrospective study was conducted of 251 impala cases from game farms, national parks and zoos submitted by veterinarians and pathologists in South Africa (2003-2016). Histopathology slides as well as records of macroscopic lesions and additional diagnostic tests performed were examined. Non-infectious conditions, such as acute pulmonary congestion and oedema, cachexia, traumatic injury and anaesthetic-related mortality were the most common causes of morbidity and mortality. Bacterial sepsis was the most common infectious disease, whilst skeletal muscle and myocardial sarcocystosis and verminous cholangitis and pneumonia were the most common parasitic diseases. Although the retrospective nature of this study limits the significance of the relative prevalence of lesions in the three locations, management decisions and diagnostic plans may be informed by the results. Impala from game farms had significantly more cachexia cases than those from other locations. Impala from zoos had significantly more lymphoid depletion than those from other locations. These findings suggest that nutrition and pasture management, enclosure design, management of intra- and interspecies aggression and improved anaesthetic protocols could improve animal welfare and survival of impala on game farms and in zoos. This report presents a detailed survey of diseases and conditions found in impala that provides baseline data for veterinary pathologists.

Shuni Virus in Wildlife and Nonequine Domestic Animals, South Africa.

We screened nonequine animals with unexplained neurologic signs or death in South Africa during 2010-2018 for Shuni virus (SHUV). SHUV was detected in 3.3% of wildlife, 1.1% of domestic, and 2.0% of avian species. Seropositivity was also demonstrated in wildlife. These results suggest a range of possible SHUV hosts in Africa.

Zoonotic Alphaviruses in Fatal and Neurologic Infections in Wildlife and Nonequine Domestic Animals, South Africa.

Alphaviruses from Africa, such as Middelburg virus (MIDV), and Sindbis virus (SINV), were detected in horses with neurologic disease in South Africa, but their host ranges remain unknown. We investigated the contribution of alphaviruses to neurologic infections and death in wildlife and domestic animals in this country. During 2010-2018, a total of 608 clinical samples from wildlife and nonequine domestic animals that had febrile, neurologic signs or unexplained deaths were tested for alphaviruses. We identified 32 (5.5%) of 608 alphavirus infections (9 SINV and 23 MIDV), mostly in neurotissue of wildlife, domestic animals, and birds. Phylogenetic analysis of the RNA-dependent RNA polymerase gene confirmed either SINV or MIDV. This study implicates MIDV and SINV as potential causes of neurologic disease in wildlife and nonequine domestic species in Africa and suggests a wide host range and pathogenic potential.

The Pathology of Pathogenic Theileriosis in African Wild Artiodactyls.

The published literature on schizont-"transforming," or pathogenic theileriosis, in African wild artiodactyls is dated and based on limited information. Here the authors review the taxonomy, diagnosis, epidemiology, hematology, pathology, and aspects of control in various species. Molecular studies based on 18S and 16S rRNA gene sequences have shown that African wild artiodactyls are commonly infected with diverse Theileria spp., as well as nontheilerial hemoprotozoa and rickettsia-like bacteria, and coinfections with pathogenic and nonpathogenic Theileria species are often recorded. Although theileriosis is still confusingly referred to as cytauxzoonosis in many species, the validity of a separate Cytauxzoon genus in artiodactyls is debated. The epidemiology of theileriosis is complex; the likelihood of fatal disease depends on the interplay of parasite, vertebrate host, tick vector, and environmental factors. Roan calves (Hippotragus equinus) and stressed animals of all host species are more susceptible to fatal theileriosis. Even though regenerative anemia is common, peripheral blood piroplasm parasitemia does not correlate with disease severity. Other than anemia, common macroscopic lesions include icterus, hemorrhages (mucosal, serosal, and tissue), fluid effusions into body cavities, lung edema, and variably sized raised cream-colored foci of leukocyte infiltration in multiple organs. Histopathologic findings include vasocentric hyperproliferation and lysis of atypical leukocytes with associated intracellular schizonts, parenchymal necrosis, hemorrhage, thromboembolism, and edema. Immunophenotyping is required to establish the identity of the schizont-transformed leukocytes in wild ungulates. Throughout the review, we propose avenues for future research by comparing existing knowledge on selected aspects of theileriosis in domestic livestock with that in African wild artiodactyls.

West Nile Virus in Wildlife and Nonequine Domestic Animals, South Africa, 2010-2018.

West Nile virus (WNV) lineage 2 is associated with neurologic disease in horses and humans in South Africa. Surveillance in wildlife and nonequine domestic species during 2010-2018 identified WNV in 11 (1.8%) of 608 animals with severe neurologic and fatal infections, highlighting susceptible hosts and risk for WNV epizootics in Africa.

Conserving wildlife in a changing world: Understanding capture myopathy-a malignant outcome of stress during capture and translocation.

The number of species that merit conservation interventions is increasing daily with ongoing habitat destruction, increased fragmentation and loss of population connectivity. Desertification and climate change reduce suitable conservation areas. Physiological stress is an inevitable part of the capture and translocation process of wild animals. Globally, capture myopathy-a malignant outcome of stress during capture operations-accounts for the highest number of deaths associated with wildlife translocation. These deaths may not only have considerable impacts on conservation efforts but also have direct and indirect financial implications. Such deaths usually are indicative of how well animal welfare was considered and addressed during a translocation exercise. Importantly, devastating consequences on the continued existence of threatened and endangered species succumbing to this known risk during capture and movement may result. Since first recorded in 1964 in Kenya, many cases of capture myopathy have been described, but the exact causes, pathophysiological mechanisms and treatment for this condition remain to be adequately studied and fully elucidated. Capture myopathy is a condition with marked morbidity and mortality that occur predominantly in wild animals around the globe. It arises from inflicted stress and physical exertion that would typically occur with prolonged or short intense pursuit, capture, restraint or transportation of wild animals. The condition carries a grave prognosis, and despite intensive extended and largely non-specific supportive treatment, the success rate is poor. Although not as common as in wildlife, domestic animals and humans are also affected by conditions with similar pathophysiology. This review aims to highlight the current state of knowledge related to the clinical and pathophysiological presentation, potential treatments, preventative measures and, importantly, the hypothetical causes and proposed pathomechanisms by comparing conditions found in domestic animals and humans. Future comparative strategies and research directions are proposed to help better understand the pathophysiology of capture myopathy.

Clinical presentation and pathology of suspected vector transmitted African horse sickness in South African domestic dogs from 2006 to 2017.

African horse sickness (AHS) is a fatal vector transmitted viral disease of horses caused by the African horse sickness virus (AHSV). This disease is characterised by circulatory and respiratory failure, resulting from vascular endothelial injury affecting many organs. The susceptibility of dogs to AHS has been demonstrated in the past following experimental infection through consumption of infected horse meat. Thirty three clinical cases of AHS in dogs (cAHS) have been documented, without a history of ingesting infected horse meat, over a period of 12 years. The clinical cases included in this study presented with a history of acute respiratory distress syndrome or sudden death. The macroscopic and histological changes were mostly characterised by acute interstitial pneumonia, serofibrinous pleuritis and mediastinal oedema. Confirmation of cAHS was obtained by AHS specific NS4 antibody immunohistochemistry and/or AHSV specific duplex real time RT-quantitative PCR. Here, we document the clinical and postmortem diagnostic features of confirmed cAHS cases with no history of ingestion of AHS infected horse meat.

MELANOMA IN GOLDEN AND KING WILDEBEESTS ( CONNOCHAETES TAURINUS).

Pigmentation of the skin is a crucial component in the pathogenesis of melanocytic neoplasms and other skin-related tumors, as melanin is known to function in both the absorbance of ultraviolet radiation and as an antioxidant. Very limited information exists regarding the incidence and metastatic potential of neoplastic conditions of the skin in game animals, especially wildebeests, relative to domestic animals. Four cases of cutaneous melanoma in color-variant golden and king wildebeests ( Connochaetes taurinus) (from 2014 to 2015) in South Africa were investigated. Melanoma in these captive animals was characterized using histopathology, transmission electron microscopy, and an immunohistochemistry panel, which consisted of monoclonal antibodies against three melanocytic markers: Melan A, PNL2, and S100. Overall, 2/4 cases (50%) of the melanocytic neoplasms stained strongly positive for all the melanocytic markers, while 4/4 cases (100%) stained positively for at least one of the markers. Cutaneous melanocytic neoplasia has not been reported in wildebeests; the current study suggests that selection of wildebeests for coat color potentially predisposes to this condition.

Perineal urethrostomy to treat obstructive urolithiasis in a captive hand-raised steenbok (Raphicerus campestris).

The steenbok (Raphicerus campestris) is a small antelope of the family Bovidae native to the African continent. Urolithiasis, the formation of urinary calculi in the urinary tract, can be caused by a variety of factors such as diet, dehydration, infection and anatomical predisposition. Urolithiasis, with uroliths identified as magnesium calcium phosphate carbonate in composition, was diagnosed in a hand-reared 5-month-old steenbok. Perineal urethrostomy was performed as a component of the broad treatment regime that included fluid therapy, antibiotic and anti-inflammatory treatment. However, the animal died 4 days later as a result of systemic hypoxia and energy depletion because of stress and cachexia. The challenges of post-surgical treatment, the importance of positive energy balance in small ruminants under stressful circumstances, as well as the role of diet of hand-reared antelope in predisposition to urolith formation are highlighted.