Progressive cutaneous viral pigmented plaques in three Hungarian Vizslas and the response of lesions to topical tigilanol tiglate gel

Abstract

Cutaneous pigmented viral plaques is a disorder of epidermal growth caused by canine papillomavirus type 4 (CPV‐4). There is currently no standard of care for managing this condition and it has not been reported in the Hungarian Vizsla. This case series documents the clinical features of canine pigmented viral plaques in Hungarian Vizsla dogs and the treatment of a severe case using a novel topical agent tigilanol tiglate (EBC‐46). A 4‐year‐old spayed Hungarian Vizsla in Australia was presented for multiple cutaneous pigmented plaques extending from the ventral cervical region. Lesions were neither painful nor pruritic. The number and size of these sessile plaques increased over time, with the largest lesions eventually taking on an exophytic (wart‐like) appearance. These lesions did not affect the dog's wellbeing. Two much less severe cases in a 5‐year‐old Vizsla from the UK and a 7‐year‐old Vizsla from New Zealand were also diagnosed. Histology was consistent with papillomavirus‐induced pigmented plaques and CPV‐4 DNA sequences were amplified from paraffin‐embedded formalin‐fixed tissue using the polymerase chain reaction from the most severely affected patient. Topical imiquimod was ineffective although used for only a short time. Two topical applications of novel anti‐neoplastic diterpene ester tigilanol tiglate as a gel, 9 days apart, greatly reduced the size and number of lesions in a limited portion of skin treated, over the lateral hock. While CPV‐4 has been previously reported to cause pigmented plaques, most commonly on pug dogs, but sporadically on other breeds, this is the first report of this virus causing plaques in Hungarian Vizslas. The cases illustrate some of the difficulties in diagnosing papillomavirus‐induced disease in dogs, especially in its early stages. Topical tigilanol tiglate is a potentially useful topical therapy for this viral‐induced disorder of cell growth and represents a treatment deserving of further investigation.

An appraisal of natural products active against parasitic nematodes of animals

“…This latter company, although listed as the inventor of the newest anthelmintic family granted patent protection (the tigliane phorbol esters) (Fig. 10), seems focused on developing this series for the potentially more lucrative anti-cancer indication [123, 124]. These compounds would be an example of an “old” structure (originally described from traditional medicinal plants from Africa; [125]) that was rediscovered later in a different source (Australian species of Hylandia and Fontainea ) and can still generate actionable IP.…”

Extensive progressive pigmented viral plaques in a Chihuahua dog

“…The early disease onset and severity of lesions suggests a genetic immunodeficiency. Pugs and vizslas appear to be predisposed to viral plaques, 4,5 although, to the best of the authors' knowledge, this is the first report in a Chihuahua. The dog appeared otherwise healthy, suggesting that any immune-deficiency was limited to the immune response against PVs.…”

“…However, whether or not PV vaccines are useful as treatments for PV‐induced lesions is currently unclear and a recent large‐scale study in which vaccines against human PV types were used to treat human gential warts did not show efficacy 10 . Cryotherapy and topical treatment with tigilanol tiglate gel are additional treatments suggested for canine pigmented viral plaques, and were not attempted in the present case 5 . Currently there is no treatment known to be definitively effective for all cases of EV in people 6 and this also may be true for canine pigmented viral plaques.…”

“…10 Cryotherapy and topical treatment with tigilanol tiglate gel are additional treatments suggested for canine pigmented viral plaques, and were not attempted in the present case. 5 Currently there is no treatment known to be definitively effective for all cases of EV in people 6 and this also may be true for canine pigmented viral plaques.…”

Clinical, histopathological, and molecular characterization of canine pigmented viral plaques

“…All other attempts to use drugs such as retinoids, interferon, and firocoxib, in addition to other drugs, were unsuccessful or with inconsistent results. 9,20,23,29 To date, it appears that no medical therapy is able to cure multiple to generalized viral plaques; laser therapy is the only one that can benefit dogs without the side effects of a more aggressive conventional surgery. 10 Although considered rare, spontaneous regression was observed in 3 cases.…”