Treatment of equine sarcoids: A systematic review

Molecular Characterization of Bovine Deltapapillomavirus in Equine Sarcoids in Egypt

Bovine papillomaviruses (BPVs) commonly cause sarcoids in equines worldwide. Equine sarcoids (ESs) reduce the working ability of draft animals and produce untoward cosmetic changes in racing and dancing equine. In this study, nine horses and 16 donkeys with sarcoids were presented to Zagazig University Veterinary Clinic, Zagazig, Egypt. Of these, eight horses and six donkeys were found to be infected with BPV. On sequencing, all 14 viruses were found to be BPV1, which were distributed in two clades without specific differentiation among papillomaviruses (PVs) of donkeys, horses, and cattle. Comparison of 135 aa (319-454) of the sequenced L1 gene with reference strains revealed three conservative mutations (D346N, Q398E, and F441Y) and two nonconservative mutations (T348N and K351T). Illumina sequencing revealed that PVs of donkeys and horses were identical and had 98.5% identity with the closest reference sequence (KX907623) of BPV1. In addition, there was high identity among all genes except E5 and L2. The substitution ranged between 0.5% (nt) and 0.89% (aa) in E4 and 5.18% (nt) and 6.81% (aa) in E5. These results indicate that BPV1 is the main cause of ESs in Egypt without marked phylogenetic variation among PVs of cattle, horses, and donkeys.

What Is the Evidence Behind Sarcoid Treatments?

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.

A randomized placebo-controlled double-blinded study comparing oral and subcutaneous administration of mistletoe extract for the treatment of equine sarcoid disease

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.