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The equine sarcoid is the most common skin neoplasia of fibroblastic origin in horses, characterized by an excessive accumulation of extracellular matrix produced by sarcoid fibroblasts under hypoxic condition. Neoplastic cells can adapt to hypoxia by using alternative energy sources, particularly those that arise from fatty acid oxidation (FAO). The Carnitine Palmitoyl Transferase 1A (CPT1A) belongs to Carnitine System (CS) and promotes the entrance of fatty acids into the mitochondria for β-oxidation. In this study, CPT1A expression was comparatively addressed in 25 equine sarcoids and 5 normal skin samples using immunohistochemistry (IHC). Specificity of CPT1A antibody was validated by Western Blotting (WB). In normal skin samples IHC staining was weak and mainly confined to basal epidermis and few dermal fibroblasts. Sarcoid fibroblast exhibited a strong cytoplasmic and nuclear signal in 60% of the tumor samples. Cytoplasmic CPT1A expression in sarcoid fibroblasts indicates that the protein is actively involved in metabolic reprogramming processes. Nuclear CPT1A expression suggests that the protein may also be involved in the regulation of neoplastic proliferation., Competing Interests: Declaration of competing interest None of the authors has any financial or personal relationships that could inappropriately influence or bias the content of the paper, (Copyright © 2024. Published by Elsevier Inc.)

Despite the ubiquitous nature of sarcoids, robust data regarding the selection of treatment modalities are scarce, with many treatments having little or no published data to support their use. Treatment options are numerous and vary with the location and type of sarcoid, treatment accessibility, and the financial status of the owner. Many treatments are expensive and time-consuming, and some have health and safety implications. It is this author's belief that, based on the limited evidence base, appropriate treatment options vary with the location and type of the sarcoid, and no one treatment is universally appropriate., Competing Interests: Disclosure The author has no affiliations other than I work for the University of Cambridge., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Background: Equine sarcoids (ES) are the most common cutaneous tumors in equids. Systemic treatment options are sparse. Subcutaneous (SC) injections of Viscum album extract (VAE) demonstrate efficacy as a systemic treatment directed against ES., Objectives/aim: To critically assess the therapeutic efficacy of orally administered VAE., Animals: Forty-five ES-affected, privately owned, 3-12 year-old horses., Methods: A 3-armed randomized placebo-controlled, double-blinded study was conducted in a double-dummy design. Horses were subjected to oral administration and SC injections of either VAE or placebo (VAE oral/placebo SC, VAE SC/placebo oral, placebo oral/placebo SC) over a 7-month treatment period. Primary endpoint was the change of baseline of a composite index of ES number and ES area after 14 months. Second endpoint was the clinical response., Results: No statistically significant difference in the composite endpoint between the 3 study arms was found. The primary endpoint showed 4 (27%) horses in the VAE oral group with complete ES regression, 3 (21%) in the VAE SC injection group, and 2 (13%) in the placebo group. The clinical response revealed complete or partial regression in 6 horses of the oral VAE group (40%), 4 of the SC injection group (29%), and 4 of the placebo group (25%). Direct comparison of oral VAE and placebo showed an odds ratio, stratified for prognosis of 2.16 (95%-CI: 0.45-10.42) and a P-value of 0.336., Conclusion and Clinical Importance: Oral administration of VAE is well tolerated. No statistically significant difference in the effectiveness of systemic VAE versus placebo against ES was found., (© 2024 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals LLC on behalf of American College of Veterinary Internal Medicine.)

Bovine papillomavirus (BPV) types 1 and 2 are causally associated with equine sarcoid, the most common mesenchymal neoplasm of horses, but the viral load (VL) differs between lesions. Sensitive and accurate BPV detection and quantification is essential for clinicians to confirm clinical suspicion, as well as in research settings for stratifying these skin lesions. Due to the limitations of histopathology in sarcoid diagnosis, PCR screening of superficial swabs constitutes the principal sampling method for BPV detection. This study aimed to investigate the ability of superficial swabs and fine-needle aspirates (FNA) to accurately detect the VL in equine sarcoids, considering the main clinical types: occult, nodular, verrucous and fibroblastic. Superficial swabs and FNAs from a series of sarcoid-affected horses were tested in parallel for BPV DNA quantification. Quantitative real-time PCR screening of postoperative tissue biopsies served as reference standard for the accuracy assessment of the viral titters. Our results indicate that VL is not a predictor of the clinical type. Student's t-test results gave evidence of a significant difference between both sample methods (P < 0.001) with FNA giving the best approximation of the actual VL (P < 0.01). In contrast to superficial swabs, the reference standard correlated moderately with FNA in general (P < 0.05; r = 0.39) and strongly with FNA results within the occult sarcoid group (P < 0.05; r = 0.59). In conclusion, the correlation of FNA with the reference standard was strong enough to suggest this is the preferred method for quantifying VL in sarcoids., Competing Interests: Declaration of Competing Interest None., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Sarcoids are the most common equine skin tumours Although they do not metastasize, they can be locally aggressive and cause significant clinical symptoms in affected horses. Despite being common, very little is known about the host immune response and the biological mechanisms underlying persistence and recurrence of equine sarcoids. The latter reflects the need for further research in this field. This in-vitro study used sarcoid explants from horses with naturally occurring sarcoids (n = 12) to evaluate the induction of a humoral immune response directed against equine sarcoid-derived bovine papilloma-virus (BPV)- 1 infected fibroblasts using a flow cytometric crossmatch assay. The presence of antibodies against exogenous bovine serum albumin (BSA) and fibroblast-like mesenchymal stromal cells (MSCs) was also evaluated by ELISA and flow cytometry, respectively. The viral load in the sarcoid explants, the corresponding cultured sarcoid fibroblasts, and matched peripheral blood mononuclear cells (PBMCs) from affected horses were determined by quantitative BPV-1/- 2 PCR analysis. Antibodies against autologous sarcoid cells were present in six out of twelve sarcoid-affected horses. Serum from all horses showed cross reactivity with allogeneic sarcoid cells, while only a part reacted with BSA or MSCs. Screening of host PBMCs demonstrated the absence of BPV E1 nucleic acids. Statistical analysis revealed a significantly higher mean viral load in the parental sarcoid tissue compared to the low passage fibroblasts (P < 0.001). These results support the hypothesis that sarcoid-affected horses may develop antibodies recognizing tumour-specific antigens. In contrast to sarcoid explants, equine PBMCs do not seem to contain complete BPV genomes. These results provide a basis for future investigations on the clinical relevance of these antibodies., Competing Interests: Declaration of Interest Jan H. Spaas and Eva Depuydt were employed by Boehringer Ingelheim Veterinary Medicine Belgium at the time of the study. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Sarcoids are the most common cutaneous neoplasm of the horse, arising as a result of a neoplastic proliferation of fibroblasts associated with infection with bovine papillomavirus, most notably types 1 and 2. Although they do not metastasise, they are locally invasive and aggressive, and can lead to important welfare concerns, interfere with tack and therefore impede athleticism, and undoubtedly lead to a reduction in the value of affected horses. This review discusses the evidence behind the most commonly used treatments for equine sarcoids. The most commonly used treatments are discussed. No one treatment is universally successful, and there are many treatments with varying level of scientific evaluation and reported success rates., (Copyright © 2022. Published by Elsevier Ltd.)

Background: Sarcoid tumors are common in horses and may negatively impact the performance and value of the horse. No known treatment is reliably successful., Hypotheses/objectives: To determine tolerability, overall response rate, time to response, and progression-free survival of horses with biopsy-confirmed or suspected sarcoids treated with ALVAC-fIL2., Animals: Client-owned horses with measurable, presumed- or biopsy-confirmed sarcoid tumors., Methods: Prospective pilot study. One milliliter of ALVAC-fIL2 was injected into 4 to 5 areas of the sarcoid(s) in each horse (week 0); this treatment was repeated in weeks 1, 3, and 7. Sarcoids were measured at each visit, and response to treatment was determined according to the Response Evaluation Criteria in Solid Tumors for dogs (v1.0). After the final treatment, horses were reassessed and sarcoids remeasured every 3 months until tumor progression or for a minimum of 1 year if progression was not documented., Results: Fourteen horses were included. Tumor size decreased in 86% of the horses, and the median time to first response was 89 days (range, 34-406 days). Median time to best response was 211 days (range, 56-406 days), but 3 of the sarcoids still were decreasing in size at the time of final evaluation. The median progression-free interval was not reached. Adverse events were minimal and included transient focal inflammation in 2 horses., Conclusions and Clinical Importance: Intratumoral injection of ALVAC-fIL2 has promise as a well-tolerated and effective, tissue-sparing treatment for horses with sarcoid tumors., (© 2022 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals LLC. on behalf of the American College of Veterinary Internal Medicine.)

Background: Interleukin (IL)-2 stimulates antitumour immunity and is successfully used for the treatment of different neoplasias., Hypothesis/objectives: Canarypox virus locally expressing feline IL-2 is safe and can be used to treat equine sarcoids., Animals: Twenty horses of different breeds with a median age of eight years (interquartile range 6.0-13.3 years) and a total number of 59 sarcoids were included in the study., Methods: In this prospective clinical trial, sarcoids were injected twice seven days apart, with a recombinant canarypox virus expressing feline IL-2. Complete blood counts (CBC) and fibrinogen levels were measured before treatment and on days 1, 2, 7 and 8., Results: Complete regression was achieved in eight horses (40%) and partial regression in two horses (10%). No change in sarcoid size was observed in two horses (10%) and the disease progressed in five horses (25%). Sarcoids of three horses (15%) showed initial response followed by tumour growth. There were no significant changes in CBC and fibrinogen levels after either injection. One horse developed a mild fever the day after each injection, which subsided without treatment the following day., Conclusions: Treatment of equine sarcoids with recombinant canarypox virus expressing feline IL-2 seems to be a safe therapy option. Although the expression of IL-2 after vector injection and its biological activity in horses were not proven in this study, the treatment resulted in regression and partial regression in 50% of the cases. Further studies are necessary to verify these findings and to establish a treatment protocol., (© 2021 The Authors. Veterinary Dermatology published by John Wiley & Sons Ltd on behalf of the ESVD and ACVD.)

Feline sarcoids (or cutaneous fibropapillomas) are rare dermal neoplasms. There are currently no reported statistics concerning their clinical behaviour. Our objective with this retrospective, multi-institutional study was to describe the clinical presentation and biological behaviour of sarcoids in cats and to determine the oncologic outcome following surgical resection. Medical records from a laboratory database and six contributing institutions were searched to identify cats with histologically confirmed sarcoids. Forty-two cats were included in the study. The majority of sarcoids occurred on the face, particularly rostral locations such as the lips and nasal planum. Complete and incomplete histologic excision was achieved in 18 and 21 cats, respectively. The overall local recurrence rate was 40.5%. Complete histologic excision was associated with a significantly lower local recurrence rate (11.1%) and longer disease-free interval (not reached) compared with cats with incompletely excised sarcoids (66.7% and 250 days, respectively). The 1- and 2-year local recurrence rates were 0% and 7%, respectively, for cats with complete histologic excision, and 67% at both time intervals for cats with incomplete histologic excision. Five of the cats (83.3%) treated with curative-intent surgical revision following local tumour recurrence had no further local recurrence. All cats that died secondary to tumour-related causes had initial incomplete histologic excision and were euthanized because of local recurrence. Wide surgical resection of feline sarcoids is recommended to achieve complete histologic excision, local tumour control and a potential cure. For cats with incomplete histologic excision or local tumour recurrence, repeat surgical resection is recommended., (© 2020 John Wiley & Sons Ltd.)

A reformulation of Mycobacterium cell wall fraction immunotherapeutic can be used to successfully treat sarcoids in horses. Sarcoids are reported to be the most common equine skin tumors with tumor type and location influencing the choice of treatment. Wide surgical excision is curative for many tumors, but may not always be feasible. Previous studies have reported sarcoid regression after injection with mycobacterial cell wall immunotherapeutics. A new formulation of the Mycobacterium phlei cell wall fraction immunostimulant (Immunocidin Equine) was used to treat cutaneous tumors in horses. Equids with skin tumors diagnosed as sarcoids were enrolled in the study. Sarcoids were injected at the initial visit with Immunocidin Equine and subsequently at approximately 2-week intervals. Of 17 cases, nine cases were completely resolved at the end of the study period evaluation or at the time of final follow-up (52.9%). Three cases were reported as improved (smaller), but not resolved (17.6%). Three cases were discontinued from the study as the respective masses were growing larger or not resolving (17.6%). One case (5.8%) with two masses had resolution of one mass, whereas the other tumor had a small regrowth 5 months after the last treatment. One case (5.8%) was lost to follow-up. All cases had mild to moderate swelling of the injection site, and some cases had discharge after the second, third, or fourth injections. No serious systemic side effects or complications were encountered during the study., (Copyright © 2020 The Author(s). Published by Elsevier Inc. All rights reserved.)

Background: Sarcoidosis is a granulomatous disease histologically characterized by naked granulomas in various mammals. Canine sarcoidosis is a rare disease which can cause nonpruritic papule, plaques and nodules on the trunk, neck, face and ear; it is usually treated with corticosteroids. To date, there are no published reports on alternatives to corticosteroids treatment., Objectives: To report a case of canine cutaneous sarcoidosis successfully treated with oral ciclosporin., Animal: An 11-year-old beagle dog was presented with multiple pleomorphic plaques on the lateral thighs and dorsal trunk., Methods and Materials: Skin punch biopsy specimen were collected and analysed via routine histological examination and immunohistochemistry. After 14 weeks of oral ciclosporin treatment, repeat skin biopsy specimens were collected., Results: Histopathological examination revealed noncaseating epithelioid cell granuloma formation in the dermis. Dermal epithelioid cells were positive for CD18 and Iba1, but not for CD3, CD20 and E-cadherin based on immunohistochemistry findings. Acid-fast bacteria, fungi and Leishmania spp. were not detected by special stains, culture or polymerase chain reaction. An initial two week treatment with immunosuppressive doses of oral prednisolone and doxycycline was not effective. Skin lesions were almost in remission after 14 weeks of oral ciclosporin treatment without adverse events. Histologically, the dermal granulomatous lesions regressed and were replaced by fibrous tissues after ciclosporin treatment., Conclusions and Clinical Relevance: This case report describes the clinical and histopathological presentation including immunohistochemistry and treatment outcome of a case of canine sarcoidosis Ciclosporin may be an effective alternative to corticosteroids for treating canine sarcoidosis., (© 2019 ESVD and ACVD.)

This article discusses the main treatments for sarcoid and the specific difficulties of these. It explains to some extent why the frustrations of a condition for which there is no single treatment option have led to the burgeoning of an industry of irrational treatments. The factors that need to be considered before selecting an option for treatment are wider than is the case in most other disease entities as a result of the complexity of the condition, its variable phenotypes, and the individual perceptions and experiences of both veterinarians and owners., (Copyright © 2019 Elsevier Inc. All rights reserved.)

The aim of this study was to investigate microRNA (miRNA) differential expression in the two most common equine skin tumours, equine sarcoid (ES) and squamous cell carcinoma (SCC), and its potential influence on the tumour microenvironment at post-transcriptional level. We investigated miRNA fingerprints in four subgroups: mild (ESM) and aggressive (ESA) ES and ocular SCC (oSCC) and genital SCC (gSCC). Three tumours and three control samples were included in each of the four subgroups. Following next generation sequencing, miRNA differential expression analysis using DESeq2 was carried out. Pathways associated with the human mature homologues of identified dysregulated miRNAs were predicted using DIANA- miRPath v3.0. When comparing tumour vs control tissue, 57 miRNAs in ESM, six in ESA, 47 in oSCC and zero in gSCC were found to be differentially expressed and may thus serve as potential diagnostic tissue biomarkers. Whereas, ES lesions in general were associated with downregulation of the miR-200 family, which may trigger epithelial-mesenchymal transition, ESM lesions were associated with upregulation of the proposed tumour-suppressive miRNA cluster on equine chromosome 24. In contrast, the oSCC tumours showed downregulation of this cluster as well as downregulation of the miR-34 family, which may favour oSCC tumour cell metabolism. To further validate the proposed diagnostic miRNA fingerprints and their suggested biological effects, further miRNA studies need to be carried out in larger study cohorts., (© 2019 John Wiley & Sons Ltd.)

Background: Equine sarcoids are the most common neoplasms in horses. Bovine papilloma- virus type 1 (BPV-1) is the main viral type identified in equine sarcoids in Europe., Objective: The aim of the present study was to genetically evaluate BPV types based on DNA analyses of the CDS of the L1 gene. The presence of BPV DNA was confirmed by Degenerate Oligonucleotide-Primed Polymerase Chain Reaction (DOP PCR) with FAP59/FAP64 consensus primers., Results: The DNA was detected in 21/40 (52.5%) of clinically diagnosed sarcoids. More than half of 14 isolates (66.7%) shared 100% homology with BPV-1 Deltapapillomavirus 4 isolate 09 asi UK (Acc. No. MF384289) and 99% nucleotide identity with BPV-1 isolate EqSarc1 (Acc. No. JX678969). A comparison with BPV-1 isolate EqSarc1 revealed one silent mutation in C5827T which did not change the aminoacid codon. The remaining 6 isolates (28.6%) shared 100% nucleotide identity with the BPV-1 (Acc. No. X02346) "wild type" isolate, and 1 isolate (4.8%) demonstrated 99% nucleotide identity with BPV-2 (Acc. No. M20219)., Conclusions: Variants of BPV-1 isolate EqSarc1 (Acc. No. JX678969) constitute the most prevalent type of BPV-1 in Polish horses., (Copyright© by the Polish Academy of Sciences.)

Equine clinicians and researchers often make the diagnosis of equine sarcoids (ES) on clinical assessment alone, without histopathological confirmation. However, the accuracy of the clinical diagnosis of ES has not been critically assessed. To assess sensitivity, specificity, positive and negative predictive values of the clinical diagnosis of ES, 40 clinical cases with histologically confirmed equine skin lesions (26 ES and 14 non-ES) were compiled in a representative online examination. For each case and lesion, at least one photograph and all relevant information were presented in a standardised format. This included the horse's signalment, lesion localisation, lesion progression, presence of other skin lesions, earlier treatments and response to treatment. No information relevant for the assessment of the lesion was intentionally withheld. Fourteen ES experts, 39 board-certified equine specialists, 103 equine practitioners and 25 novices categorised the cases into ES or non-ES and graded their level of diagnostic confidence on a scale from 1 to 6 for each case. The overall success rate was 82.0% while sensitivity and specificity were 83.3% and 79.6%, respectively. The positive and negative predictive values were 88.4% and 72.0%, respectively, in the tested population with a 66% prevalence of ES. However, less experienced veterinarians were frequently wrong in their clinical judgement despite a high level of diagnostic confidence. Therefore, the authors propose to develop a diagnostic tool to help clinicians optimise their selection of lesions requiring a biopsy. Ultimately, this will help reduce costs and morbidity generated by unnecessary diagnostic and therapeutic efforts., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Research has shown that the accuracy of the clinical diagnosis of equine sarcoids (ES) can be improved. Particularly, less experienced veterinarians are often mistaken in their clinical judgement despite a high level of diagnostic confidence. The aim of this study was to develop and assess the performance of a diagnostic protocol (DP) to improve diagnostic accuracy and identify diagnostically challenging cases. The design of the DP was based on typical clinical features of ES and its algorithm was optimised through repeated tests on clinical cases prior to validating its performance in a representative online examination. A total of 22 equine practitioners and 31 veterinary students used the DP to diagnose 40 standardised ES and non-ES cases in an online examination. Scores of these 53 respondents were compared to scores of 128 respondents of comparable levels of expertise, and 14 experts, all assessing the same cases without using the DP. Overall, respondents using the DP were significantly more likely (odds ratio (OR) 1.25; 95% confidence interval (95% CI) 1.09-1.43) to diagnose a case correctly compared to respondents not using the DP and felt significantly more confident of their diagnosis (OR 1.53; 95% CI 1.39-1.67). Thus, the DP proved to be a reliable tool to increase clinical diagnostic accuracy and diagnostic confidence. The DP algorithms may be further improved with experiences gained from its application in equine practice and clinicians will be able to optimise their diagnostic accuracy and selection of lesions requiring a biopsy., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

The association between bovine papillomavirus (BPV) and equine sarcoids is well established, but it is unclear how the virus spreads. Although evidence in support of viral spread through direct animal contact exists, this does not explain sarcoid development in isolated equids. BPV DNA has been detected in flies, which could indicate that these insects serve as a vector. This study aimed to investigate whether BPV-negative stable flies (Stomoxys calcitrans) become positive for BPV DNA after exposure to equine sarcoid or bovine papilloma tissue under experimental conditions and, if so, for how long. A total of 420 stable flies were caught alive and exposed to BPV positive equine sarcoid or bovine papilloma tissue. During the following week, dead flies were collected daily and BPV loads were determined by quantitative PCR. There was a significant rise in BPV load after tissue exposure both in sarcoid and papilloma exposed flies, but the viral load was higher and remained high for a longer time after exposure to papilloma tissue compared to sarcoid tissue. Within days, viral loads decreased again and became indifferent from loads before exposure. The results of these experiments indicate that BPV transmission by S. calcitrans seems possible and is more likely to occur after contact with bovine papillomas than with equine sarcoids. Transmission seems only possible shortly after tissue exposure. Further research could include experimental induction of sarcoids with BPV positive stable flies, or a repeat of the experiment with micro-dissection prior to PCR., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

We have previously shown that immunization of horses with bovine papillomavirus type 1 (BPV1) L1 virus-like particles (VLPs) is safe and highly immunogenic and that BPV1 and bovine papillomavirus type 2 (BPV2) are closely related serotypes. Here we evaluated the protective potential of a BPV1 L1 VLP vaccine against experimental BPV1 and BPV2 challenge and studied the safety and immunogenicity of a bivalent equine papillomavirus type 2 (EcPV2)/BPV1 L1 VLP vaccine. Fourteen healthy horses were immunized with BPV1 L1 VLPs (100 µg per injection) plus adjuvant on days 0 and 28, while seven remained unvaccinated. On day 42, all 21 horses were challenged intradermally at 10 sites of the neck with 107 BPV1 virions per injection. In analogy, 14 horses immunized twice with EcPV2 plus BPV1 L1 VLPs (50 µg each) and seven control animals were challenged with 107 BPV2 virions per injection. Immunization with BPV1 L1 VLPs alone induced a robust antibody response (day 42 median titre: 12 800), and BPV1-inoculated skin remained unchanged in 13/14 vaccinated horses. Immunization with the bivalent vaccine was safe, resulted in lower median day 42 antibody titres of 400 for BPV1 and 1600 for EcPV2 and conferred significant yet incomplete cross-protection from BPV2-induced tumour formation, with 11/14 horses developing small, short-lived papules. Control horses developed pseudo-sarcoids at all inoculation sites. The monovalent BPV1 L1 VLP vaccine proved highly effective in protecting horses from BPV1-induced pseudo-sarcoid formation. Incomplete protection from BPV2-induced tumour development conferred by the bivalent vaccine is due to the poorer immune response by immune interference or lower cross-neutralization titres to heterologous BPV2 virions.

OBJECTIVE To evaluate outcomes following treatment of sarcoids in equids and to identify risk factors for treatment failure in these patients. DESIGN Retrospective case series. ANIMALS 230 equids with 614 sarcoids. PROCEDURES Records were searched to identify equids treated for ≥ 1 sarcoid between 2008 and 2013. A standardized protocol was used to determine treatment choice (electrosurgery, electrosurgery with intralesional placement of cisplatin-containing beads, topical administration of imiquimod or acyclovir, cryosurgery, bacillus Calmette-Guerin vaccine injection, or intralesional injection of platinum-containing drugs). Data regarding animal, tumor, treatment, and outcome variables were collected. Complete tumor regression without recurrence for ≥ 6 months was considered a successful outcome. Success rates were calculated; binary logistic regression analysis was used to identify risk factors for treatment failure and to compare effects of the 2 topical treatments. A χ(2) test was used to compare effects of the number of Bacillus Calmette-Guerin vaccine or cisplatin-containing drug injections on outcome. RESULTS The overall success rate was 460 of 614 (74.9%). Electrosurgical excision resulted in the highest treatment success rate (277/319 [86.8%]); odds of treatment failure were significantly greater for intralesional injection of platinum-containing drugs, cryosurgery, and topical acyclovir treatment. Odds of treatment failure were also significantly greater for sarcoids on equids with multiple tumors than for solitary lesions, and significantly lower for sarcoids on equids that received concurrent immunostimulating treatment for another sarcoid than for those on patients that did not receive such treatment. CONCLUSIONS AND CLINICAL RELEVANCE Selection bias for treatments was inherent to the study design; however, results may assist clinicians in selecting treatments and in determining prognosis for equids with sarcoids treated according to the described methods.

Recent studies suggest that regulatory T cells (Tregs) are associated with disease severity and progression in papilloma virus induced neoplasia. Bovine papilloma virus (BPV) is recognised as the most important aetiological factor in equine sarcoid (ES) disease. The aim of this study was to compare expression levels of Treg markers and associated cytokines in tissue samples of ES-affected equids with skin samples of healthy control horses. Eleven ES-affected, and 12 healthy horses were included in the study. Expression levels of forkhead box protein 3 (FOXP3), interleukin 10 (IL10), interleukin 4 (IL4) and interferon gamma (IFNG) mRNA in lesional and tumour-distant samples from ES-affected horses, as well as in dermal samples of healthy control horses were measured using quantitative reverse transcription polymerase chain reaction (PCR). Expression levels were compared between lesional and tumour-distant as well as between tumour-distant and control samples. Furthermore, BPV-1 E5 DNA in samples of ES-affected horses was quantified using quantitative PCR, and possible associations of viral load, disease severity and gene expression levels were evaluated. Expression levels of FOXP3, IL10 and IFNG mRNA and BPV-1 E5 copy numbers were significantly increased in lesional compared to tumour-distant samples. There was no difference in FOXP3 and cytokine expression in tumour-distant samples from ES- compared with control horses. In tumour-distant samples viral load was positively correlated with IL10 expression and severity score. The increased expression of Treg markers in tumour-associated tissues of ES-affected equids indicates a local, Treg-induced immune suppression., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Sarcoids are the most prevalent equine skin tumours and remain a therapeutic challenge due to their differing clinical morphology, local aggressive behaviour, and high recurrence following surgical treatment. In vitro, sarcoid derived fibroblasts are invasive and express matrix metalloproteinase (MMP) -1, -2 and -9. It was hypothesised that the MMPs produced by neoplastic cells play a role in both their local invasiveness and interaction with the overlying epidermis (picket fence formation). The objective of this morphological study was to investigate the local behaviour and in situ MMP expression pattern in sarcoids of different clinical types. A total of 43 surgically excised sarcoids were examined by histology, immunohistology for the expression of MMP-1, -2 and -9, and transmission electron microscopy. Regardless of the clinical type, sarcoids showed local invasion of the dermis and damage to the basement membrane in areas of interaction with the epidermis. This was associated with MMP-1 expression in both neoplastic cells and epidermis. The results suggest a link between MMP-1 expression and the local aggressiveness of sarcoids regardless of the clinical type., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

The mode of inheritance for susceptibility to equine sarcoid disease (ES) remains unknown. The objectives of this study were to analyse a large sample of the Franches-Montagnes (FM) horse population and investigate the heritability and mode of inheritance for susceptibility to ES. Horses were clinically examined for the presence of sarcoid tumours. A standardized examination protocol and client questionnaire were used and a pedigree- and subsequent segregation-analysis for the ES trait performed. To investigate the mode of inheritance, five models were evaluated and compared in a hierarchical way. The analyses reveal that variation in susceptibility to ES is best explained by a model incorporating polygenic variation. The possible effect of a major gene, such as specific equine leukocyte antigen alleles, is unlikely, but cannot be ruled-out entirely. The heritability of the phenotype on the observation scale for the trait 'affected with ES' was estimated to be 8%. A corrected value for the heritability on a liability scale was estimated at 21% and it is therefore possible to estimate breeding values for ES. The arguments against the practical implementation of an estimated breeding value in a multifactorial condition like ES are discussed., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Sarcoids are the most common skin tumors seen in horses worldwide. The pathogenesis of sarcoids is multifactorial, including an association with bovine papillomavirus types 1 and 2 and a genetic susceptibility to tumor development. Clinical manifestations vary and include occult, verrucous, nodular, fibroblastic, mixed, and malignant (malevolent) types. The tumor is nonmetastasizing but can become very aggressive locally. Multiple tumors are common. All clinical types can be present in the same horse. No treatment protocol is universally effective. The tumor has a high risk of recurrence. Recurrent and large tumors are associated with poorer prognoses., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Equine sarcoidosis seems to be an emerging problem. As more horses are referred for dermatologic disease, equine sarcoidosis should be considered in any case of exfoliative and/or nodular skin disease with or without systemic involvement, including generalized granulomatous disease affecting most internal organs. Multiple breeds are affected with mares being predisposed. Affected horses are typically 3 years or older. The prognosis for generalized granulomatous disease is generally poor, whereas the prognosis for the localized cutaneous form is favorable but may require lifelong treatment., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Equine sarcoids are locally aggressive fibroblastic neoplasms considered to be the most common skin tumors of horses worldwide. Bovine papillomavirus types 1 and 2 have typically been associated with sarcoids in equids. Investigations aiming to identify papillomavirus strains, aside from bovine papillomaviruses 1 and 2, which might be associated with sarcoid lesions, have been lacking. The aim of this article is to report the identification of a third bovine papillomavirus type, bovine papillomavirus 13, associated with equine sarcoids. Six sarcoid lesions were collected from diverse anatomical sites on two horses from southern Brazil. To detect a broad spectrum of papillomavirus strains, eight degenerate primer pairs designed to detect conserved regions on the L1 and E1 genes were tested on the DNA samples. Direct sequencing was then performed on the obtained amplicons, and sequence identities were compared with sequences from all bovine papillomavirus types. The FAP59/FAP64, MY09/MY11, and AR-E1F2/AR-E1R4 sequences generated from the sarcoids were shown to present 99 to 100% identity with bovine papillomavirus 13, a new bovine papillomavirus type previously described in cattle. The results from this study suggest that there is a need to identify bovine papillomavirus type 13 and other papillomavirus strains that might be associated with sarcoids in diverse geographical areas; such investigations might establish the frequency of occurrence of this viral type in these common tumors of equids.

Background: Equine sarcoidosis may present as a generalized or localized exfoliative dermatitis and/or as a granulomatous inflammation of multiple organs., Objectives: To report the clinical signs, diagnosis, treatment and outcome for 22 horses with histologically confirmed sarcoidosis., Animals: Twenty-two horses of different breeds, between 3 and 17 years of age., Methods: Diagnosis was based on clinical signs and histopathological findings., Results: The following three forms of equine sarcoidosis were identified: generalized (13.6%), partially generalized (18.2%) and localized (68.2%). High-dose systemic corticosteroids were used as the initial treatment in all three forms, followed by lower doses for a variable number of weeks. No local treatment was prescribed. Case outcome was variable; one of three cases of generalized sarcoidosis was euthanized immediately and the remaining two were euthanized after 2-3 months of unsuccessful treatment; all four cases of partially generalized sarcoidosis deteriorated despite treatment and were euthanized after 3.5-12 months; two cases with localized disease showed no response or insufficient response to treatment and were euthanized; four cases recovered fully with or without treatment, and one showed partial recovery without treatment; and eight cases improved whilst receiving prednisolone but required continuous low doses to maintain remission., Conclusions and Clinical Importance: Recognition of the different forms of sarcoidosis based on history, clinical appearance and histopathology assisted in making an informed choice between treatment and euthanasia and prevented unnecessary local treatment. Equine sarcoidosis should be included in the differential diagnosis of a localized exfoliative dermatitis of unknown origin., (© 2013 The Authors. Veterinary Dermatology © 2013 ESVD and ACVD.)

The diversity of papillomavirus (PV) found in bovine cutaneous warts from Brazilian cattle was evaluated using the PCR technique with the utilization of consensus primers MY09/11 and by PCR using Bovine Papillomavirus (BPV) type-specific primers followed by sequencing. Eleven cutaneous warts from 6 cattle herds were selected. Six warts were positive for the presence of PV. The presence of BPV types 1, 2, 3, 6 and feline sarcoid-associated PV (FeSarPV) in cutaneous wart lesions, as well as the presence of co-infections, was found. To the best of our knowledge, this is the first time that FeSarPV is described co-infecting a cutaneous wart in Brazil. The present study confirms the previous finding of FeSarPV infecting cattle. These results show the necessity of more studies to investigate the diversity of PV in cattle, its diversity and the possibility of co-infection in cattle and other animals., (© 2012 Blackwell Verlag GmbH.)

The case report describes the surgical and photodynamic treatment (PDT) of an equine sarcoid in a 6-year-old gelding. A mass on the ventral prepuce, several tumours on the lateral aspect of the prepuce and one sarcoid on the front aspect of the chest were treated. For PDT, Temoporfin (Fospeg® Biolitec AG, Jena) at a concentration of 0.15mg/ml was injected locally. The subsequent irradiation was performed using a red-light laser (652nm) with an energy density of 10J/cm². The mass on the ventral aspect of the prepuce and some of the lateral tumours displayed total remission. The remaining tumours decreased in size or stopped growing.

Sarcoidosis is a rare equine skin disease characterized primarily by an exfoliative and granulomatous dermatitis but also presenting granulomatous inflammation of multiple systems. The current report presents the clinical and histopathological findings of sarcoidosis in a 16-year-old American Quarter Horse gelding with nested polymerase chain reaction Mycobacterium spp. DNA detection within hepatic and skin samples. Mycobacterium spp. may play a role in the pathogenesis of equine sarcoidosis as has been proposed for human sarcoidosis.

Equine sarcoids are the most common tumor of horses. Bovine papillomavirus (BPV) has been suggested as the cause of sarcoids. Studies have shown that BPV is present in swabs or biopsies from nonsarcoid-bearing equine skin. Skin biopsies from a variety of different conditions and normal skin from horses with no reported history of sarcoids were examined by polymerase chain reaction (PCR) for the presence of BPV, which was found in all different types of skin conditions as well as normal skin. Forty-one out of 86 skin biopsies from horses without sarcoids were found to contain BPV DNA. Laser microdissection, followed by DNA amplification through both PCR and isothermal loop-mediated amplification, was performed on these 41 biopsies and on 70 additional BPV-positive sarcoid biopsies to localize the virus. Location of BPV DNA was different between sarcoid and nonsarcoid groups. Nonsarcoid skin biopsies were more likely to have BPV within intact or inflamed epidermis than sarcoids (P = 0.016 and P = 0.007, respectively). Areas of inflammation within the dermis and epidermis were more likely to contain BPV than in noninflamed areas (P = 0.008 and P = 0.009, respectively). Bovine papillomavirus was also found in the epidermis of all types of sarcoids examined, more frequently in occult sarcoids than in fibroblastic and nodular types (P = 0.03 and P = 0.01, respectively). Results suggest that BPV is commonly found in normal and inflamed equine skin, and it is likely an important predisposing factor in the development of sarcoids.

Equine sarcoid has been diagnosed in endangered Cape mountain zebra (Equus zebra zebra) in at least two game reserves in South Africa, with prevalence as high as 53% in Bontebok National Park. Seven Cape mountain zebras with sarcoids were treated with either surgical excision, 5-fluorouracil, allogenous vaccine, or a combination of 5-fluorouracil and allogenous vaccine. One of the two sarcoids on one of the 5-fluorouracil-treated zebras was left untreated. The microscopic features of the tumors evaluated showed either all or most of the typical epidermal and dermal histologic features of equine sarcoid. The zebras were examined 2 yr posttreatment to determine outcome. All sarcoids had resolved except on the zebra on which one of the sarcoids was left untreated. The efficacy of the three treatment methods in Cape mountain zebra is encouraging.

Based on the anecdotally reported eradication of a sarcoid using aciclovir cream, the curative potential of this ointment was investigated in 22 sarcoid-affected horses referred to the Equine Clinic Tillysburg, Austria, between 2006 and 2009. Sarcoid disease was diagnosed by clinical examination and bovine papillomavirus types 1 and 2 from intact skin and tumour tissue. As nine horses had more than one lesion, a total of 47 sarcoids were treated by daily topical application of aciclovir 5 per cent cream for a period of two to six months; in four horses, surgical tumour ablation was performed before treatment. Disease parameters, including the tumour type, number, location and size, were recorded before and after aciclovir therapy. All 47 (100 per cent) of the sarcoids responded to treatment, with complete tumour regression observed for 32 (68 per cent) lesions and no recurrences reported thus far. Incomplete resolution was observed for 15 (32 per cent) lesions, probably due to their thickness. Aciclovir is proposed to be routinely used for the treatment of mild-type sarcoids and as an adjuvant therapeutic agent in combination with surgery.

Reasons for Performing Study: Sarcoids are nonmetastasising, yet locally aggressive skin tumours that constitute the most frequent neoplasm in equids. Infection by bovine papillomaviruses types 1 and 2 (BPV-1, BPV-2) has been recognised as major causative factor in sarcoid pathogenesis, but a possible correlation of intralesional virus load with disease severity has not been established thus far., Hypothesis: Given the pathogenic role of BPV-1 and BPV-2 in sarcoid disease, we suggest that intralesional viral DNA concentration may reflect the degree of affection., Methods: Severity of disease was addressed by recording the tumour growth kinetics, lesion number and tumour type for 37 sarcoid-bearing horses and one donkey. Viral load was estimated via quantitative real-time PCR (qPCR) of the E2, E5, L1 and L2 genes from the BPV-1/-2 genome for one randomly selected lesion per horse and correlated with disease severity., Results: Quantitative PCR against E2 identified viral DNA concentrations ranging from 0-556 copies/tumour cell. Of 16 horses affected by quiescent, slowly growing single tumours or multiple mild-type lesions, 15 showed a viral load up to 1.4 copies per cell. In stark contrast, all equids (22/22) bearing rapidly growing and/or multiple aggressive sarcoids had a viral load between 3 and 569 copies per cell. Consistent results were obtained with qPCR against E5, L1 and L2., Conclusions: While tumours of the same clinical type carried variable virus load, confirming that viral titre does not determine clinical appearance, we identified a highly significant correlation between intralesional viral load and disease severity., Potential Relevance: The rapid determination of BPV viral load will give a reliable marker for disease severity and may also be considered when establishing a therapeutic strategy.

BPV-1 is now recognized as a main etiological agent of equine sarcoids. The etiopathogenesis of the equine sarcoids is equivocal and is not yet fully understood. The aim of the present study was to analyse a partial sequence of the L1 gene of BPV associated with equine sarcoids in Polish horses. After clinical diagnosis, 40 skin lesions obtained from 29 horses were collected. The amplicons of a fragment of BPV L1 DNA were detected using PCR with MY09/MY11 primers in 31 specimens. All of them were recognized as BPV-1. Phylogenetic analysis has allowed the amplicons of partial L1 gene to be divided into 3 phylogenetic groups (A, B, C) and one separate isolate (20c). Sequence variants from phylogenetic groups B, C and isolate 20c represented new genetic variants of BPV-1 L1. Sequence variants from groups B and C were submitted to GenBank NCBI.

Feline sarcoids are uncommon dermal neoplasms that are associated with papillomavirus (PV) infection. A single PV type, designated feline sarcoid-associated PV (FeSarPV), was detected in 9 feline sarcoids from North America. As FeSarPV has only been detected within feline sarcoids, the epidemiology of the infection remains unknown. The present study used polymerase chain reaction (PCR) to investigate whether this PV is also present within sarcoids from New Zealand cats. Additionally, as PVs are often host-specific, it was hypothesized that FeSarPV may often asymptomatically infect cats but rarely cause disease. To test this hypothesis, specific PCR primers were designed to investigate the presence of FeSarPV DNA within 120 samples from the skin and mouth of cats without sarcoids. Feline sarcoids from both New Zealand and North America contained FeSarPV DNA sequences. However, FeSarPV DNA was not detected within any non-sarcoid feline sample. To the authors' knowledge, this is the first time that FeSarPV has been reported in a country outside North America. As FeSarPV does not asymptomatically infect cats, feline sarcoids are likely due to cross-species infection. Although the reservoir host of FeSarPV is unknown, the host is present and has contact with cats, in both New Zealand and North America.

Background: Equine sarcoidosis is a rare, multisystemic, noncaseating, granulomatous and lymphoplasmacytic disease of unknown etiology. A recent report described a horse with granulomatous skin disease displaying histologic, electron microscopic, and polymerase chain reaction (PCR) findings consistent with equine herpesvirus 2 (EHV-2)., Objective: To investigate the presence of EHV-2 and equine herpesvirus 1 (EHV-1) in 8 horses with sarcoidosis., Animals: Eight horses with sarcoidosis, reported previously., Methods: Retrospective study. PCR assays of the tissues were performed to detect DNA associated with EHV-1 and EHV-2. For both herpesviruses the target was their respective glycoprotein B gene. Positive controls consisted of DNA from viral cultures of culturettes from naturally occurring respiratory infections of EHV-1 and EHV-2., Results: The PCR analyses for both equine herpesviruses' DNA were negative in all 8 horses., Conclusion: The failure to detect DNA from EHV-1 and EHV-2 in paraffin-embedded skin of these 8 horses does not discount EHV-1 or EHV-2 as causing some cases of ES, but lends support to the presumably multifactorial etiologic nature of the disease.

For an effective tissue controlled electropermeabilization as requested for electrochemotherapy and electrogenotherapy, it is very important to have informations about the electric field distribution provided by a defined set of electrodes. Computer simulations using the finite element models approach predicted the associated field distributions and currents. Phantoms made of gels with well-defined electrical conductance were used to measure the current responses of a new electrode geometry (wires), A good agreement between the measured and predicted currents was observed supporting the validity of the prediction for the field distribution. Field distribution was observed to be very localized and highly homogeneous with the new concept of contact wire electrodes. They allowed to focus the field effect along the surface of the tissue to induce a controlled release of drugs or plasmids. Non invasive (contact) electrodes can be moved rapidly on the body and avoid puncturing the skin and the tissue. They can be used for large surface effects, to treat the skin and subcutaneous tumors. The use of contact electrodes after drug or DNA intradermal injection were validated by clinical treatment of large surface skin tumors and by in vivo imaging of permeabilization or of gene expression.

Equine sarcoidosis is a rare disorder usually characterized by exfoliative dermatitis, moderate to severe wasting, and sarcoidal granulomatous inflammation of multiple organ systems. It has an unknown aetiopathogenesis. The condition is not related to equine sarcoid. This case report describes generalized cutaneous and systemic sarcoidosis in an 11-year-old Trakehner mare (case A) and in a 7-year-old Dutch Warmblood gelding (case B). Case A was presented with cutaneous sarcoidosis on the head and body and was diagnosed on the basis of histological examination of skin. Case B presented with multiple subcutaneous nodules (2-15 cm in diameter) and the diagnosis was established at postmortem examination. Both horses showed distinctive histology of the skin with extensive lymphohistiocytic infiltration and Langhans-type multinucleated giant cells. Haematology and biochemistry revealed a normal total white blood cell count with a right shift in both horses. Case B was anaemic and had a slightly elevated total protein concentration with hyperglobulinaemia. Both horses were unresponsive to corticosteroids and were euthanized.

Bovine papillomavirus type 1 or 2 (BPV-1, BPV-2) are accepted causal factors in equine sarcoid pathogenesis. Whereas viral genomes are consistently found and expressed within lesions, intact virions have never been detected, thus permissiveness of sarcoids for BPV-1 replication remains unclear. To reassess this issue, an immunocapture PCR (IC/PCR) was established using L1-specific antibodies to capture L1-DNA complexes followed by amplification of the viral genome. Following validation of the assay, 13 sarcoid-bearing horses were evaluated by IC/PCR. Samples were derived from 21 tumours, 4 perilesional/intact skin biopsies, and 1 serum. Tissue extracts from sarcoid-free equines served as controls. IC/PCR scored positive in 14/24 (58.3%) specimens obtained from sarcoid-patients, but negative for controls. Quantitative IC/PCR demonstrated <125 immunoprecipitable viral genomes/50 microl extract for the majority of specimens. Moreover, full-length BPV-1 genomes were detected in a complex with L1 proteins. These complexes may correspond to virion precursors or intact virions.

Bovine papillomaviruses of types 1 and 2 (BPV-1 and -2) chiefly contribute to equine sarcoid pathogenesis. However, the mode of virus transmission and the presence of latent infections are largely unknown. This study established a PCR protocol allowing detection of

Equine sarcoids are fibroblastic skin tumours affecting equids worldwide. While the pathogenesis is not entirely understood, infection with bovine papillomavirus (BPV) type 1 (and less commonly type 2) has been implicated as a major factor in the disease process. Sarcoids very seldom regress and in fact often recrudesce following therapy. Nothing is known about the immune response of the equine host to BPV. Given that the viral genes are expressed in sarcoids, it is reasonable to assume that vaccination of animals against the expressed viral proteins would lead to the induction of an immune response against the antigens and possible tumour rejection. To this end we vaccinated sarcoid-bearing donkeys in a placebo-controlled trial using chimeric virus-like particles (CVLPs) comprising BPV-1 L1 and E7 proteins. The results show a tendency towards enhanced tumour regression and reduced progression in the vaccinated group compared to control animals. Although promising, further studies are required with larger animal groups to definitely conclude that vaccination with CVLPs is a potential therapy for the induction of sarcoid regression.

Equine sarcoids are fibrosarcoma-like skin tumours with a prevalence of approximately 1-2 %. Strong evidence exists for a causative role of bovine papillomavirus (BPV) type 1 or type 2 in the development of sarcoids. No effective treatment of equine sarcoid is available and after surgical excision relapse of the tumours is very frequent. We developed chimeric virus-like particles (CVLPs) of BPV 1 L1-E7 for the immunotherapy of equine sarcoid. In a phase I clinical trial 12 horses suffering from equine sarcoid with an average number of more than 22 tumours per animal were vaccinated in a dose-escalation setting. The animals were followed-up for 63 days, eight of the twelve horses were followed-up for more than a year and side-effects, humoral immune responses and tumour appearance were recorded. BPV DNA was detected in tumours of 11 cases. CVLPs were well tolerated in all dose groups, a robust anti-L1 antibody response was induced in all but one of the horses. Anti-E7 antibodies were detected in five of the 12 animals at low titres. Two animals showed a clear improvement of the clinical status after treatment, i.e. the number of the tumours per horse was reduced. In another horse regression of five sarcoids was observed; three of them relapsed during the study. Two animals showed tumour regression as well as growth of new sarcoids. In two horses the clinical status remained unchanged, in another two horses growth of existing tumours or growth of additional tumours was observed. The remaining three animals showed simultaneously regression and growth of existing tumours. Neither the humoral immune responses nor the observed effects on the tumours was correlated with the dose group.

There are no reports in the literature describing any tumours, and specifically sarcoids, in zebras. The equine sarcoid, a locally aggressive, fibroblastic skin tumour, is the most common dermatological neoplasm reported in horses. The Cape mountain zebra (CMZ) has been described as one of the most vulnerable mammals in South Africa with current populations existing in isolated units. All South African CMZ are descendants from no more than 30 individual animals originating from 3 populations, namely the Mountain Zebra National Park, and Kammanassie and Gamka Mountain Nature Reserves near Cradock. The possibility therefore exists that the existing populations arose from a very small gene pool and that they are considerably inbred. A reduction in major histocompatibility complex diversity due to genetic bottlenecks and subsequent inbreeding probably contributed to uniform population sensitivity and the subsequent development of sarcoid in two CMZ populations, namely in the Bontebok National Park and Gariep Nature Reserve. The entire population of CMZ in the Bontebok National Park was observed and sampled during 2002 to document the prevalence and body distribution of sarcoids. During the same year, a comparative study was carried out on an outbred population of Burchell's zebra in the Kruger National Park. The prevalence in CMZ in the Bontebok National Park was 53 %, while the Burchell's zebra in Kruger National Park had a prevalence of 1.9 %. The most common sites for sarcoid in CMZ were the ventral abdomen and limbs. Prevalence of sarcoids in horses recorded in the literature varies between 0.5 % and 2 %. The Gariep Nature Reserve recently reported a prevalence of almost 25 % in CMZ in the reserve.

An outbreak of equine sarcoid occurred in a population of Cape mountain zebra (Equus zebra zebra) at the Gariep Nature Reserve located in the southern Free State Province of South Africa in 1996. The course of the outbreak during 1996 to 2003 is described. During this period the average population size was 69 animals. Initially (1996) all affected animals were removed from the population. New cases continued to manifest and the incidence varied between 4.6% and 17.6%. Prevalence reached 24.7% in 2002. No sexual predilection was noticed in the 39 recorded cases. Of the affected individuals, 64% had a single lesion and no animal had more than 4 lesions. In males, the majority of lesions occurred in the inguinal area (55.17%), whereas in females they mostly occurred on the head and neck (41.38%). Lesions can increase 260% in size annually and may impede movement.

Treatment of the equine sarcoid has posed a significant challenge to clinicians for years and many different methods have been tried with varying success, including ionising radiation. The aim of this study was to review the efficacy of iridium-192 interstitial brachytherapy for the treatment of eight periocular sarcoids and 15 non-ocular sarcoids on 18 horses. All the periocular sarcoids and 13 of the 15 non-ocular sarcoids were treated successfully.