Publications by authors named "Johan Steyl"

Rhabdomyolyses is a clinical sign of capture myopathy in wild animals and may be linked to glycogen metabolism. To study potential mechanisms, 26 wild blesbok were chased for 15 min and immobilised, whereafter 12 of these blesbok were doused with ice-water (n = 14 chased only group; n = 12 chased + cooled group). An additional 12 blesbok served as resting (not chased) uncooled controls.

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Various zoonotic microorganisms cause reproductive problems such as abortions and stillbirths, leading to economic losses on farms, particularly within livestock. In South Africa, bovine brucellosis is endemic in cattle, and from 2013-2018, outbreaks of Brucella melitensis occurred in sable. Coxiella burnetii, the agent responsible for the zoonotic disease known as Q-fever and/or coxiellosis, also causes reproductive problems and infects multiple domestic animal species worldwide, including humans.

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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.

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Article Synopsis
  • Muscle-invasive bladder cancer (MIBC) is a serious disease in humans, and researchers are looking at dogs, cats, and cattle to learn more about it because these animals can also get a similar type of cancer.
  • Scientists found that while dogs and cats have some shared genetic changes with humans, their cancer has fewer mutations than human MIBC.
  • Cattle, on the other hand, have different mutations caused by eating bracken fern, which helps researchers understand how certain chemicals can lead to cancer in both animals and humans.
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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.

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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.

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Cases of -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 () with fatal natural theileriosis.

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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.

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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.

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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.

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In this study, infection in sable antelope () 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 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.

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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.

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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.

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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.

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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 , as well as nontheilerial hemoprotozoa and rickettsia-like bacteria, and coinfections with pathogenic and nonpathogenic species are often recorded.

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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.

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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.

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Article Synopsis
  • African horse sickness (AHS) is a deadly viral disease affecting horses, caused by the African horse sickness virus and marked by severe circulatory and respiratory failures.
  • Dogs can also get AHS, with 33 clinical cases reported over 12 years, even in the absence of a history of consuming infected horse meat.
  • Diagnosis of these dog cases involved observing symptoms like acute respiratory distress and using specific tests to confirm the presence of AHSV.
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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.

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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.

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Although nasal masses are uncommon in sheep and may have several causes, including neoplasia and bacterial, fungal and viral infections, these lesions may lead to economic losses resulting from weight loss and even death. It is therefore important to differentiate between various categories of upper respiratory tract obstructions and lower respiratory tract infections. The correct aetiological diagnosis of obstructive masses is essential for appropriate treatment and management to be given or action to be taken.

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A privately owned, 2-yr-old, 600-kg, intact male white rhinoceros presented with a progressive lameness of the left front limb of 8-mo duration with a focal swelling situated over the dorsoproximal aspect of third metacarpophalangeal joint. Radiographs of the affected limb showed a 28 mm × 26 mm exostosis at the dorsodistal third metacarpal bone. Surgical removal of the exostosis was performed and histopathologic examination confirmed a solitary osteochondroma.

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An outbreak of feline panleukopaenia virus (FPLV) infection was diagnosed by pathology, electron microscopy and polymerase chain reaction (PCR) in vaccinated captive-bred subadult cheetahs in South Africa. Subsequent to this disease outbreak, 12 cases of FPLV diagnosed on histology were confirmed by PCR in captive African black-footed cat, caracal, cheetah, lion, ocelot and serval. Phylogenetic analyses of the viral capsid protein gene on PCR-positive samples, vaccine and National Center for Biotechnology Information (NCBI) reference strains identified a previously unknown strain of FPLV, present since at least 2006, that differs from both the inactivated and the modified live vaccine strains.

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